diff --git a/.bazelversion b/.bazelversion
index c7cb131..5e32542 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-5.3.1
+6.1.2
diff --git a/Documentation/config-gerrit.txt b/Documentation/config-gerrit.txt
index 55abe47..c853226 100644
--- a/Documentation/config-gerrit.txt
+++ b/Documentation/config-gerrit.txt
@@ -2107,6 +2107,16 @@
 +
 Default is 1 hour.
 
+[[core.usePerRequestRefCache]]core.usePerRequestRefCache::
++
+Use a per request (currently per request thread) ref cache. The ref
+cache uses JGit's SnapshottingRefDirectory to ensure that packed
+refs are checked and potentially read at least once per request
+(lazily) if needed. This helps reduce the overhead of checking if
+the packed-refs file is outdated.
++
+Default is true.
+
 [[dashboard]]
 === Section dashboard
 
diff --git a/Documentation/dev-bazel.txt b/Documentation/dev-bazel.txt
index d1a5bcf..514a4c9 100644
--- a/Documentation/dev-bazel.txt
+++ b/Documentation/dev-bazel.txt
@@ -352,7 +352,7 @@
 ----
 
 Now attach with a debugger to the port `5005`. For example use "Remote Java Application" launch
-configuration in Eclipe and specify the port `5005`.
+configuration in Eclipse and specify the port `5005`.
 
 [[logging]]
 === Controlling logging level
@@ -551,7 +551,7 @@
 ----
 
 Update the `polygerrit-ui/app/node_modules_licenses/licenses.ts` file. You should add licenses
-for the package itself and for all transitive depndencies. If you forgot to add a license, the
+for the package itself and for all transitive dependencies. If you forgot to add a license, the
 `Documentation:check_licenses` test will fail.
 
 After the update, commit all changes to the repository (including `yarn.lock`).
diff --git a/Documentation/dev-crafting-changes.txt b/Documentation/dev-crafting-changes.txt
index ac0780d..6150c20 100644
--- a/Documentation/dev-crafting-changes.txt
+++ b/Documentation/dev-crafting-changes.txt
@@ -28,7 +28,7 @@
   might take a while until you could benefit from it. In that case,
   implement the feature on master and, if you really need it on an
   earlier `stable-*` branch, cherry-pick the change and build
-  Gerrit on your own environent.
+  Gerrit in your own environment.
 * Bug-fixes should generally at least cover the oldest affected and
   still supported version. If you're affected and run an even older
   version, you're welcome to upload to that older version, even if
diff --git a/Documentation/dev-design.txt b/Documentation/dev-design.txt
index 5636dfd..176b53f 100644
--- a/Documentation/dev-design.txt
+++ b/Documentation/dev-design.txt
@@ -98,7 +98,7 @@
 User authentication is handled by identity realms. Gerrit supports the
 following types of authentication:
 
-* OpenId (see link:http://openid.net/developers/specs/[OpenID Specifications,role=external,window=_blank])
+* OpenID (see link:http://openid.net/developers/specs/[OpenID Specifications,role=external,window=_blank])
 * OAuth2
 * LDAP
 * Google accounts (on googlesource.com)
@@ -373,7 +373,7 @@
 and one for SSH).
 
 The git wire protocol does a client/server negotiation to avoid
-sending too much data. This negotation occupies a CPU, so the number
+sending too much data. This negotiation occupies a CPU, so the number
 of concurrent push/fetch operations should be capped by the number of
 CPUs.
 
diff --git a/Documentation/dev-eclipse.txt b/Documentation/dev-eclipse.txt
index 79febe4..7353092 100644
--- a/Documentation/dev-eclipse.txt
+++ b/Documentation/dev-eclipse.txt
@@ -61,9 +61,10 @@
 startup --output_user_root=/Users/johndoe/.cache/bazel
 ----
 
-==== Increase the treshold for the cleanup of temporary files
-The default treshold for the cleanup can be overriden by creating a configuration file under
-`/etc/periodic.conf` and setting a larger value for the `daily_clean_tmps_days`.
+==== Increase the threshold for the cleanup of temporary files
+The default threshold for the cleanup can be overridden by creating a configuration
+file under `/etc/periodic.conf` and setting a larger value for the
+`daily_clean_tmps_days`.
 
 An example `/etc/periodic.conf` file:
 
diff --git a/Documentation/dev-intellij.txt b/Documentation/dev-intellij.txt
index 149b14a..49fdc8f 100644
--- a/Documentation/dev-intellij.txt
+++ b/Documentation/dev-intellij.txt
@@ -31,13 +31,13 @@
 === Installation of IntelliJ IDEA
 
 Please refer to the
-link:https://www.jetbrains.com/help/idea/installation-guide.html[installation guide provided by Jetbrains,role=external,window=_blank]
+link:https://www.jetbrains.com/help/idea/installation-guide.html[installation guide provided by JetBrains,role=external,window=_blank]
 to install it on your platform. Make sure to install a version compatible with
 the Bazel plugin as mentioned above.
 
 == Installation of the Bazel plugin
 
-The plugin is usually installed using the Jetbrains plugin repository as shown
+The plugin is usually installed using the JetBrains plugin repository as shown
 in the steps below, but it's also possible to
 link:https://github.com/bazelbuild/intellij[build it from source].
 
diff --git a/Documentation/dev-plugins.txt b/Documentation/dev-plugins.txt
index 7918920..7961d81 100644
--- a/Documentation/dev-plugins.txt
+++ b/Documentation/dev-plugins.txt
@@ -963,7 +963,7 @@
 When calling command options not provided by your plugin, there is always
 a risk that the options may not exist, perhaps because the options being
 called are to be provided by another plugin, and said plugin is not
-currently installed. To protect againt this situation, it is possible to
+currently installed. To protect against this situation, it is possible to
 define an option as being dependent on other options using the
 @RequiresOptions() annotation. If the required options are not all not
 currently present, then the dependent option will not be available or
@@ -999,7 +999,7 @@
 @RequiresOptions("--format")
 @Option(
   name = "--special",
-  usage = "ouptut results using json",
+  usage = "output results using json",
   handler = JsonOutputOptionHandler.class
 )
 boolean json;
@@ -2725,7 +2725,7 @@
 Plugins are expected to support rules inheritance themselves, providing ways
 to configure it and handling the logic behind it.
 Please note that no inheritance is sometimes better than badly handled
-inheritance: mis-communication and strange behaviors caused by inheritance
+inheritance: miscommunication and strange behaviors caused by inheritance
 may and will confuse the users. Each plugins is responsible for handling the
 project hierarchy and taking wise actions. Gerrit does not enforce it.
 
diff --git a/Documentation/dev-readme.txt b/Documentation/dev-readme.txt
index 6ff064c..70f41af 100644
--- a/Documentation/dev-readme.txt
+++ b/Documentation/dev-readme.txt
@@ -178,7 +178,7 @@
 NOTE: To learn why using `java -jar` isn't sufficient, see
 <<special_bazel_java_version,this explanation>>.
 
-NOTE: When launching the daemong this way, the settings from the `[container]` section from the
+NOTE: When launching the daemon this way, the settings from the `[container]` section from the
 `$GERRIT_SITE/etc/gerrit.config` are not honored.
 
 To debug the Gerrit server of this test site:
diff --git a/Documentation/pgm-init.txt b/Documentation/pgm-init.txt
index 3c9e3fc..4b346fe 100644
--- a/Documentation/pgm-init.txt
+++ b/Documentation/pgm-init.txt
@@ -38,11 +38,6 @@
 	install, reasonable configuration defaults are chosen based
 	on the whims of the Gerrit developers. On upgrades, the existing
 	settings in `gerrit.config` are respected.
-+
-If during a schema migration unused objects (e.g. tables, columns)
-are detected, they are *not* automatically dropped; a list of SQL
-statements to drop these objects is provided. To drop the unused
-objects these SQL statements must be executed manually.
 
 --delete-caches::
 	Force deletion of all persistent cache files. Note that
diff --git a/Documentation/rest-api-changes.txt b/Documentation/rest-api-changes.txt
index bf51252..cc5a4b8 100644
--- a/Documentation/rest-api-changes.txt
+++ b/Documentation/rest-api-changes.txt
@@ -6921,7 +6921,8 @@
 |`id`                 ||
 The ID of the change in the format "'<project>\~<branch>~<Change-Id>'",
 where 'project', 'branch' and 'Change-Id' are URL encoded. For 'branch' the
-`refs/heads/` prefix is omitted.
+`refs/heads/` prefix is omitted. The callers must not rely on the format
+ of the `id` field.
 |`project`            ||The name of the project.
 |`branch`             ||
 The name of the target branch. +
diff --git a/Documentation/rest-api-config.txt b/Documentation/rest-api-config.txt
index 4c12f9f..1faffb2 100644
--- a/Documentation/rest-api-config.txt
+++ b/Documentation/rest-api-config.txt
@@ -1577,6 +1577,8 @@
 bit is indexed.
 |`enable_robot_comments`|not set if `false`|
 link:config-gerrit.html#change.enableRobotComments[Are robot comments enabled?].
+|`conflicts_predicate_enabled`|not set if `false`|
+link:config-gerrit.html#change.conflictsPredicateEnabled[Are conflicts enabled?].
 |=============================
 
 [[change-index-config-info]]
diff --git a/WORKSPACE b/WORKSPACE
index 047da6a..29266cd 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -40,6 +40,53 @@
     ],
 )
 
+# TODO: Remove this when java_tools v12.1 included in regular Bazel release
+# See https://github.com/bazelbuild/bazel/issues/17695
+http_archive(
+    name = "remote_java_tools",
+    sha256 = "0db35ec44745fd15b77d9df954e70a4fcf74554dd5bfe3f6e6cb6bbdc1f1c649",
+    urls = [
+        "https://mirror.bazel.build/bazel_java_tools/releases/java/v12.1/java_tools-v12.1.zip",
+        "https://github.com/bazelbuild/java_tools/releases/download/java_v12.1/java_tools-v12.1.zip",
+    ],
+)
+
+http_archive(
+    name = "remote_java_tools_linux",
+    sha256 = "093ecac3b42fcbc3621d08edc3ae3c8b0bc2bf56a0d9a85ddcdb1e0bcf10cbc7",
+    urls = [
+        "https://mirror.bazel.build/bazel_java_tools/releases/java/v12.1/java_tools_linux-v12.1.zip",
+        "https://github.com/bazelbuild/java_tools/releases/download/java_v12.1/java_tools_linux-v12.1.zip",
+    ],
+)
+
+http_archive(
+    name = "remote_java_tools_windows",
+    sha256 = "1df7cc7fac54f437f43c24c019462e13058f394fdba5a64f566b92e8af18d0cf",
+    urls = [
+        "https://mirror.bazel.build/bazel_java_tools/releases/java/v12.1/java_tools_windows-v12.1.zip",
+        "https://github.com/bazelbuild/java_tools/releases/download/java_v12.1/java_tools_windows-v12.1.zip",
+    ],
+)
+
+http_archive(
+    name = "remote_java_tools_darwin_x86_64",
+    sha256 = "16ca145203a62a1fcd6ae50513c0935d938591cb309b9b1172e257c57873f60d",
+    urls = [
+        "https://mirror.bazel.build/bazel_java_tools/releases/java/v12.1/java_tools_darwin_x86_64-v12.1.zip",
+        "https://github.com/bazelbuild/java_tools/releases/download/java_v12.1/java_tools_darwin_x86_64-v12.1.zip",
+    ],
+)
+
+http_archive(
+    name = "remote_java_tools_darwin_arm64",
+    sha256 = "1d8e575e558782c2ceec0940e424f0e2df56b0df3d7fae68333eaceef2c4e41c",
+    urls = [
+        "https://mirror.bazel.build/bazel_java_tools/releases/java/v12.1/java_tools_darwin_arm64-v12.1.zip",
+        "https://github.com/bazelbuild/java_tools/releases/download/java_v12.1/java_tools_darwin_arm64-v12.1.zip",
+    ],
+)
+
 http_archive(
     name = "rbe_jdk11",
     sha256 = "dbcfd6f26589ef506b91fe03a12dc559ca9c84699e4cf6381150522287f0e6f6",
diff --git a/java/com/google/gerrit/entities/BooleanProjectConfig.java b/java/com/google/gerrit/entities/BooleanProjectConfig.java
index 605c40c..09f63d4 100644
--- a/java/com/google/gerrit/entities/BooleanProjectConfig.java
+++ b/java/com/google/gerrit/entities/BooleanProjectConfig.java
@@ -14,6 +14,8 @@
 
 package com.google.gerrit.entities;
 
+import com.google.gerrit.common.Nullable;
+
 /**
  * Contains all inheritable boolean project configs and maps internal representations to API
  * objects.
@@ -58,6 +60,7 @@
     return section;
   }
 
+  @Nullable
   public String getSubSection() {
     return null;
   }
diff --git a/java/com/google/gerrit/extensions/common/ChangeConfigInfo.java b/java/com/google/gerrit/extensions/common/ChangeConfigInfo.java
index 2295922..80bf130 100644
--- a/java/com/google/gerrit/extensions/common/ChangeConfigInfo.java
+++ b/java/com/google/gerrit/extensions/common/ChangeConfigInfo.java
@@ -22,4 +22,5 @@
   public Boolean submitWholeTopic;
   public String mergeabilityComputationBehavior;
   public Boolean enableRobotComments;
+  public Boolean conflictsPredicateEnabled;
 }
diff --git a/java/com/google/gerrit/extensions/events/CommentAddedListener.java b/java/com/google/gerrit/extensions/events/CommentAddedListener.java
index 071dac1..7e0b623 100644
--- a/java/com/google/gerrit/extensions/events/CommentAddedListener.java
+++ b/java/com/google/gerrit/extensions/events/CommentAddedListener.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.extensions.events;
 
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.extensions.annotations.ExtensionPoint;
 import com.google.gerrit.extensions.common.ApprovalInfo;
 import java.util.Map;
@@ -22,6 +23,7 @@
 @ExtensionPoint
 public interface CommentAddedListener {
   interface Event extends RevisionEvent {
+    @Nullable
     String getComment();
 
     Map<String, ApprovalInfo> getApprovals();
diff --git a/java/com/google/gerrit/index/project/IndexedProjectQuery.java b/java/com/google/gerrit/index/project/IndexedProjectQuery.java
index 5fc74ca..52d08d6 100644
--- a/java/com/google/gerrit/index/project/IndexedProjectQuery.java
+++ b/java/com/google/gerrit/index/project/IndexedProjectQuery.java
@@ -14,11 +14,14 @@
 
 package com.google.gerrit.index.project;
 
+import static com.google.common.base.Preconditions.checkState;
+
 import com.google.gerrit.entities.Project;
 import com.google.gerrit.index.Index;
 import com.google.gerrit.index.QueryOptions;
 import com.google.gerrit.index.query.DataSource;
 import com.google.gerrit.index.query.IndexedQuery;
+import com.google.gerrit.index.query.Matchable;
 import com.google.gerrit.index.query.Predicate;
 import com.google.gerrit.index.query.QueryParseException;
 
@@ -27,11 +30,27 @@
  * com.google.gerrit.index.IndexRewriter}. See {@link IndexedQuery}.
  */
 public class IndexedProjectQuery extends IndexedQuery<Project.NameKey, ProjectData>
-    implements DataSource<ProjectData> {
+    implements DataSource<ProjectData>, Matchable<ProjectData> {
 
   public IndexedProjectQuery(
       Index<Project.NameKey, ProjectData> index, Predicate<ProjectData> pred, QueryOptions opts)
       throws QueryParseException {
     super(index, pred, opts.convertForBackend());
   }
+
+  @Override
+  public boolean match(ProjectData object) {
+    Predicate<ProjectData> pred = getChild(0);
+    checkState(
+        pred.isMatchable(),
+        "match invoked, but child predicate %s doesn't implement %s",
+        pred,
+        Matchable.class.getName());
+    return pred.asMatchable().match(object);
+  }
+
+  @Override
+  public int getCost() {
+    return 1;
+  }
 }
diff --git a/java/com/google/gerrit/index/project/ProjectSchemaDefinitions.java b/java/com/google/gerrit/index/project/ProjectSchemaDefinitions.java
index 3ac594e..dac1012 100644
--- a/java/com/google/gerrit/index/project/ProjectSchemaDefinitions.java
+++ b/java/com/google/gerrit/index/project/ProjectSchemaDefinitions.java
@@ -62,7 +62,10 @@
   @Deprecated static final Schema<ProjectData> V4 = schema(V3);
 
   // Upgrade Lucene to 7.x requires reindexing.
-  static final Schema<ProjectData> V5 = schema(V4);
+  @Deprecated static final Schema<ProjectData> V5 = schema(V4);
+
+  // Upgrade Lucene to 8.x requires reindexing.
+  static final Schema<ProjectData> V6 = schema(V5);
 
   /**
    * Name of the project index to be used when contacting index backends or loading configurations.
diff --git a/java/com/google/gerrit/index/query/AndSource.java b/java/com/google/gerrit/index/query/AndSource.java
index f5f30bd..3adf881 100644
--- a/java/com/google/gerrit/index/query/AndSource.java
+++ b/java/com/google/gerrit/index/query/AndSource.java
@@ -16,7 +16,6 @@
 
 import static com.google.common.base.Preconditions.checkArgument;
 
-import com.google.common.collect.ImmutableList;
 import com.google.gerrit.index.IndexConfig;
 import java.util.Collection;
 import java.util.List;
@@ -24,36 +23,17 @@
 public class AndSource<T> extends AndPredicate<T> implements DataSource<T> {
   protected final DataSource<T> source;
 
-  private final IsVisibleToPredicate<T> isVisibleToPredicate;
   private final int start;
   private final int cardinality;
   private final IndexConfig indexConfig;
 
   public AndSource(Collection<? extends Predicate<T>> that, IndexConfig indexConfig) {
-    this(that, null, 0, indexConfig);
+    this(that, 0, indexConfig);
   }
 
-  public AndSource(
-      Predicate<T> that, IsVisibleToPredicate<T> isVisibleToPredicate, IndexConfig indexConfig) {
-    this(that, isVisibleToPredicate, 0, indexConfig);
-  }
-
-  public AndSource(
-      Predicate<T> that,
-      IsVisibleToPredicate<T> isVisibleToPredicate,
-      int start,
-      IndexConfig indexConfig) {
-    this(ImmutableList.of(that), isVisibleToPredicate, start, indexConfig);
-  }
-
-  public AndSource(
-      Collection<? extends Predicate<T>> that,
-      IsVisibleToPredicate<T> isVisibleToPredicate,
-      int start,
-      IndexConfig indexConfig) {
+  public AndSource(Collection<? extends Predicate<T>> that, int start, IndexConfig indexConfig) {
     super(that);
     checkArgument(start >= 0, "negative start: %s", start);
-    this.isVisibleToPredicate = isVisibleToPredicate;
     this.start = start;
     this.indexConfig = indexConfig;
 
@@ -93,16 +73,7 @@
   }
 
   @Override
-  public boolean isMatchable() {
-    return isVisibleToPredicate != null || super.isMatchable();
-  }
-
-  @Override
   public boolean match(T object) {
-    if (isVisibleToPredicate != null && !isVisibleToPredicate.match(object)) {
-      return false;
-    }
-
     if (super.isMatchable() && !super.match(object)) {
       return false;
     }
diff --git a/java/com/google/gerrit/index/query/PaginatingSource.java b/java/com/google/gerrit/index/query/PaginatingSource.java
index 337332f..8431ccc6 100644
--- a/java/com/google/gerrit/index/query/PaginatingSource.java
+++ b/java/com/google/gerrit/index/query/PaginatingSource.java
@@ -87,6 +87,9 @@
                   r.add(data);
                 }
                 pageResultSize++;
+                if (r.size() > limit) {
+                  break;
+                }
               }
               nextStart += pageResultSize;
               searchAfter = next.searchAfter();
diff --git a/java/com/google/gerrit/lucene/AbstractLuceneIndex.java b/java/com/google/gerrit/lucene/AbstractLuceneIndex.java
index f9dc31a..78ee128 100644
--- a/java/com/google/gerrit/lucene/AbstractLuceneIndex.java
+++ b/java/com/google/gerrit/lucene/AbstractLuceneIndex.java
@@ -544,8 +544,7 @@
         int realLimit = opts.start() + opts.pageSize();
         TopFieldDocs docs =
             opts.searchAfter() != null
-                ? searcher.searchAfter(
-                    (ScoreDoc) opts.searchAfter(), query, realLimit, sort, false, false)
+                ? searcher.searchAfter((ScoreDoc) opts.searchAfter(), query, realLimit, sort, false)
                 : searcher.search(query, realLimit, sort);
         ImmutableList.Builder<T> b = ImmutableList.builderWithExpectedSize(docs.scoreDocs.length);
         for (int i = opts.start(); i < docs.scoreDocs.length; i++) {
diff --git a/java/com/google/gerrit/lucene/LuceneChangeIndex.java b/java/com/google/gerrit/lucene/LuceneChangeIndex.java
index 6365260..728606d 100644
--- a/java/com/google/gerrit/lucene/LuceneChangeIndex.java
+++ b/java/com/google/gerrit/lucene/LuceneChangeIndex.java
@@ -415,12 +415,7 @@
             if (maxRemainingHits > 0) {
               TopFieldDocs subIndexHits =
                   searchers[i].searchAfter(
-                      searchAfter,
-                      query,
-                      maxRemainingHits,
-                      sort,
-                      /* doDocScores= */ false,
-                      /* doMaxScore= */ false);
+                      searchAfter, query, maxRemainingHits, sort, /* doDocScores= */ false);
               searchAfterHitsCount += subIndexHits.scoreDocs.length;
               hits.add(subIndexHits);
               searchAfterBySubIndex.put(
diff --git a/java/com/google/gerrit/metrics/dropwizard/BUILD b/java/com/google/gerrit/metrics/dropwizard/BUILD
index 4b3859f..dbb8f5e 100644
--- a/java/com/google/gerrit/metrics/dropwizard/BUILD
+++ b/java/com/google/gerrit/metrics/dropwizard/BUILD
@@ -12,6 +12,7 @@
         "//lib:args4j",
         "//lib:guava",
         "//lib/dropwizard:dropwizard-core",
+        "//lib/flogger:api",
         "//lib/guice",
     ],
 )
diff --git a/java/com/google/gerrit/metrics/dropwizard/BucketedCallback.java b/java/com/google/gerrit/metrics/dropwizard/BucketedCallback.java
index b3860f7..da9ec70 100644
--- a/java/com/google/gerrit/metrics/dropwizard/BucketedCallback.java
+++ b/java/com/google/gerrit/metrics/dropwizard/BucketedCallback.java
@@ -110,7 +110,7 @@
     }
   }
 
-  private String submetric(Object key) {
+  String submetric(Object key) {
     return DropWizardMetricMaker.name(ordering, name, name(key));
   }
 
diff --git a/java/com/google/gerrit/metrics/dropwizard/CallbackMetricImpl1.java b/java/com/google/gerrit/metrics/dropwizard/CallbackMetricImpl1.java
index d718035..bd3caf9 100644
--- a/java/com/google/gerrit/metrics/dropwizard/CallbackMetricImpl1.java
+++ b/java/com/google/gerrit/metrics/dropwizard/CallbackMetricImpl1.java
@@ -15,13 +15,17 @@
 package com.google.gerrit.metrics.dropwizard;
 
 import com.codahale.metrics.MetricRegistry;
+import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.metrics.CallbackMetric1;
 import com.google.gerrit.metrics.Description;
 import com.google.gerrit.metrics.Field;
+import java.util.concurrent.TimeUnit;
 import java.util.function.Function;
 
 /** Optimized version of {@link BucketedCallback} for single dimension. */
 class CallbackMetricImpl1<F1, V> extends BucketedCallback<V> {
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
   CallbackMetricImpl1(
       DropWizardMetricMaker metrics,
       MetricRegistry registry,
@@ -44,9 +48,14 @@
 
     @Override
     public void set(F1 field1, V value) {
-      BucketedCallback<V>.ValueGauge cell = getOrCreate(field1);
-      cell.value = value;
-      cell.set = true;
+      try {
+        BucketedCallback<V>.ValueGauge cell = getOrCreate(field1);
+        cell.value = value;
+        cell.set = true;
+      } catch (IllegalArgumentException e) {
+        logger.atWarning().withCause(e).atMostEvery(1, TimeUnit.HOURS).log(
+            "Unable to register duplicate metric: %s", submetric(field1));
+      }
     }
 
     @Override
diff --git a/java/com/google/gerrit/pgm/util/RuntimeShutdown.java b/java/com/google/gerrit/pgm/util/RuntimeShutdown.java
index c5e8567..37cf20e 100644
--- a/java/com/google/gerrit/pgm/util/RuntimeShutdown.java
+++ b/java/com/google/gerrit/pgm/util/RuntimeShutdown.java
@@ -95,6 +95,7 @@
       }
     }
 
+    @SuppressWarnings("DoNotCall")
     void manualShutdown() {
       Runtime.getRuntime().removeShutdownHook(this);
       run();
diff --git a/java/com/google/gerrit/server/account/AccountCacheImpl.java b/java/com/google/gerrit/server/account/AccountCacheImpl.java
index 66a36f6..9fec1fa 100644
--- a/java/com/google/gerrit/server/account/AccountCacheImpl.java
+++ b/java/com/google/gerrit/server/account/AccountCacheImpl.java
@@ -122,13 +122,6 @@
   public Map<Account.Id, AccountState> get(Set<Account.Id> accountIds) {
     try {
       try (Repository allUsers = repoManager.openRepository(allUsersName)) {
-        // Get the default preferences for this Gerrit host
-        Ref ref = allUsers.exactRef(RefNames.REFS_USERS_DEFAULT);
-        CachedPreferences defaultPreferences =
-            ref != null
-                ? defaultPreferenceCache.get(ref.getObjectId())
-                : DefaultPreferencesCache.EMPTY;
-
         Set<CachedAccountDetails.Key> keys =
             Sets.newLinkedHashSetWithExpectedSize(accountIds.size());
         for (Account.Id id : accountIds) {
@@ -138,6 +131,7 @@
           }
           keys.add(CachedAccountDetails.Key.create(id, userRef.getObjectId()));
         }
+        CachedPreferences defaultPreferences = defaultPreferenceCache.get();
         ImmutableMap.Builder<Account.Id, AccountState> result = ImmutableMap.builder();
         for (Map.Entry<CachedAccountDetails.Key, CachedAccountDetails> account :
             accountDetailsCache.getAll(keys).entrySet()) {
diff --git a/java/com/google/gerrit/server/cache/PerThreadRefDbCache.java b/java/com/google/gerrit/server/cache/PerThreadRefDbCache.java
new file mode 100644
index 0000000..82c2856b
--- /dev/null
+++ b/java/com/google/gerrit/server/cache/PerThreadRefDbCache.java
@@ -0,0 +1,44 @@
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.cache;
+
+import java.io.File;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Function;
+import org.eclipse.jgit.internal.storage.file.RefDirectory;
+import org.eclipse.jgit.lib.RefDatabase;
+
+/** A per request thread cache of RefDatabases by directory (Project). */
+public class PerThreadRefDbCache {
+  protected static final PerThreadCache.Key<PerThreadRefDbCache> REFDB_CACHE_KEY =
+      PerThreadCache.Key.create(PerThreadRefDbCache.class);
+
+  public static RefDatabase getRefDatabase(File path, RefDatabase refDb) {
+    if (PerThreadCache.get() != null) {
+      return PerThreadCache.get()
+          .get(REFDB_CACHE_KEY, PerThreadRefDbCache::new)
+          .computeIfAbsent(path, p -> ((RefDirectory) refDb).createSnapshottingRefDirectory());
+    }
+    return refDb;
+  }
+
+  protected final Map<File, RefDatabase> refDbByRefsDir = new HashMap<>();
+
+  public RefDatabase computeIfAbsent(
+      File path, Function<? super File, ? extends RefDatabase> mappingFunction) {
+    return refDbByRefsDir.computeIfAbsent(path, mappingFunction);
+  }
+}
diff --git a/java/com/google/gerrit/server/change/AddToAttentionSetOp.java b/java/com/google/gerrit/server/change/AddToAttentionSetOp.java
index ec90bec..f0a70bb 100644
--- a/java/com/google/gerrit/server/change/AddToAttentionSetOp.java
+++ b/java/com/google/gerrit/server/change/AddToAttentionSetOp.java
@@ -14,13 +14,13 @@
 
 package com.google.gerrit.server.change;
 
+import static com.google.gerrit.server.mail.send.AttentionSetChangeEmailDecorator.AttentionSetChange.USER_ADDED;
 import static java.util.Objects.requireNonNull;
 
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.entities.AttentionSetUpdate;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.extensions.restapi.RestApiException;
-import com.google.gerrit.server.mail.send.AddToAttentionSetSender;
 import com.google.gerrit.server.notedb.ChangeUpdate;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.update.BatchUpdateOp;
@@ -37,7 +37,6 @@
   }
 
   private final ChangeData.Factory changeDataFactory;
-  private final AddToAttentionSetSender.Factory addToAttentionSetSender;
   private final AttentionSetEmail.Factory attentionSetEmailFactory;
 
   private final Account.Id attentionUserId;
@@ -56,15 +55,12 @@
   @Inject
   AddToAttentionSetOp(
       ChangeData.Factory changeDataFactory,
-      AddToAttentionSetSender.Factory addToAttentionSetSender,
       AttentionSetEmail.Factory attentionSetEmailFactory,
       @Assisted Account.Id attentionUserId,
       @Assisted String reason,
       @Assisted boolean notify) {
     this.changeDataFactory = changeDataFactory;
-    this.addToAttentionSetSender = addToAttentionSetSender;
     this.attentionSetEmailFactory = attentionSetEmailFactory;
-
     this.attentionUserId = requireNonNull(attentionUserId, "user");
     this.reason = requireNonNull(reason, "reason");
     this.notify = notify;
@@ -97,13 +93,6 @@
     if (!notify) {
       return;
     }
-    attentionSetEmailFactory
-        .create(
-            addToAttentionSetSender.create(ctx.getProject(), change.getId()),
-            ctx,
-            change,
-            reason,
-            attentionUserId)
-        .sendAsync();
+    attentionSetEmailFactory.create(USER_ADDED, ctx, change, reason, attentionUserId).sendAsync();
   }
 }
diff --git a/java/com/google/gerrit/server/change/DeleteReviewerByEmailOp.java b/java/com/google/gerrit/server/change/DeleteReviewerByEmailOp.java
index f3fd68e..2030ef2 100644
--- a/java/com/google/gerrit/server/change/DeleteReviewerByEmailOp.java
+++ b/java/com/google/gerrit/server/change/DeleteReviewerByEmailOp.java
@@ -19,8 +19,11 @@
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.server.ChangeMessagesUtil;
-import com.google.gerrit.server.mail.send.DeleteReviewerSender;
+import com.google.gerrit.server.mail.EmailModule.DeleteReviewerChangeEmailFactories;
+import com.google.gerrit.server.mail.send.ChangeEmailNew;
+import com.google.gerrit.server.mail.send.DeleteReviewerChangeEmailDecorator;
 import com.google.gerrit.server.mail.send.MessageIdGenerator;
+import com.google.gerrit.server.mail.send.OutgoingEmailNew;
 import com.google.gerrit.server.notedb.ChangeUpdate;
 import com.google.gerrit.server.update.ChangeContext;
 import com.google.gerrit.server.update.PostUpdateContext;
@@ -35,7 +38,7 @@
     DeleteReviewerByEmailOp create(Address reviewer);
   }
 
-  private final DeleteReviewerSender.Factory deleteReviewerSenderFactory;
+  private final DeleteReviewerChangeEmailFactories deleteReviewerChangeEmailFactories;
   private final MessageIdGenerator messageIdGenerator;
   private final ChangeMessagesUtil changeMessagesUtil;
 
@@ -45,11 +48,11 @@
 
   @Inject
   DeleteReviewerByEmailOp(
-      DeleteReviewerSender.Factory deleteReviewerSenderFactory,
+      DeleteReviewerChangeEmailFactories deleteReviewerChangeEmailFactories,
       MessageIdGenerator messageIdGenerator,
       ChangeMessagesUtil changeMessagesUtil,
       @Assisted Address reviewer) {
-    this.deleteReviewerSenderFactory = deleteReviewerSenderFactory;
+    this.deleteReviewerChangeEmailFactories = deleteReviewerChangeEmailFactories;
     this.messageIdGenerator = messageIdGenerator;
     this.changeMessagesUtil = changeMessagesUtil;
     this.reviewer = reviewer;
@@ -76,15 +79,20 @@
     if (sendEmail) {
       try {
         NotifyResolver.Result notify = ctx.getNotify(change.getId());
-        DeleteReviewerSender emailSender =
-            deleteReviewerSenderFactory.create(ctx.getProject(), change.getId());
-        emailSender.setFrom(ctx.getAccountId());
-        emailSender.addReviewersByEmail(Collections.singleton(reviewer));
-        emailSender.setChangeMessage(mailMessage, ctx.getWhen());
-        emailSender.setNotify(notify);
-        emailSender.setMessageId(
+        DeleteReviewerChangeEmailDecorator deleteReviewerEmail =
+            deleteReviewerChangeEmailFactories.createDeleteReviewerChangeEmail();
+        deleteReviewerEmail.addReviewersByEmail(Collections.singleton(reviewer));
+        ChangeEmailNew changeEmail =
+            deleteReviewerChangeEmailFactories.createChangeEmail(
+                ctx.getProject(), change.getId(), deleteReviewerEmail);
+        changeEmail.setChangeMessage(mailMessage, ctx.getWhen());
+        OutgoingEmailNew outgoingEmail =
+            deleteReviewerChangeEmailFactories.createEmail(changeEmail);
+        outgoingEmail.setFrom(ctx.getAccountId());
+        outgoingEmail.setNotify(notify);
+        outgoingEmail.setMessageId(
             messageIdGenerator.fromChangeUpdate(ctx.getRepoView(), change.currentPatchSetId()));
-        emailSender.send();
+        outgoingEmail.send();
       } catch (Exception err) {
         logger.atSevere().withCause(err).log("Cannot email update for change %s", change.getId());
       }
diff --git a/java/com/google/gerrit/server/change/DeleteReviewerOp.java b/java/com/google/gerrit/server/change/DeleteReviewerOp.java
index fc07592..a1c4f71 100644
--- a/java/com/google/gerrit/server/change/DeleteReviewerOp.java
+++ b/java/com/google/gerrit/server/change/DeleteReviewerOp.java
@@ -36,8 +36,11 @@
 import com.google.gerrit.server.account.AccountState;
 import com.google.gerrit.server.approval.ApprovalsUtil;
 import com.google.gerrit.server.extensions.events.ReviewerDeleted;
-import com.google.gerrit.server.mail.send.DeleteReviewerSender;
+import com.google.gerrit.server.mail.EmailModule.DeleteReviewerChangeEmailFactories;
+import com.google.gerrit.server.mail.send.ChangeEmailNew;
+import com.google.gerrit.server.mail.send.DeleteReviewerChangeEmailDecorator;
 import com.google.gerrit.server.mail.send.MessageIdGenerator;
+import com.google.gerrit.server.mail.send.OutgoingEmailNew;
 import com.google.gerrit.server.notedb.ChangeUpdate;
 import com.google.gerrit.server.notedb.ReviewerStateInternal;
 import com.google.gerrit.server.permissions.PermissionBackendException;
@@ -68,7 +71,7 @@
   private final ChangeMessagesUtil cmUtil;
   private final ReviewerDeleted reviewerDeleted;
   private final Provider<IdentifiedUser> user;
-  private final DeleteReviewerSender.Factory deleteReviewerSenderFactory;
+  private final DeleteReviewerChangeEmailFactories deleteReviewerChangeEmailFactories;
   private final RemoveReviewerControl removeReviewerControl;
   private final ProjectCache projectCache;
   private final MessageIdGenerator messageIdGenerator;
@@ -89,7 +92,7 @@
       ChangeMessagesUtil cmUtil,
       ReviewerDeleted reviewerDeleted,
       Provider<IdentifiedUser> user,
-      DeleteReviewerSender.Factory deleteReviewerSenderFactory,
+      DeleteReviewerChangeEmailFactories deleteReviewerChangeEmailFactories,
       RemoveReviewerControl removeReviewerControl,
       ProjectCache projectCache,
       MessageIdGenerator messageIdGenerator,
@@ -101,7 +104,7 @@
     this.cmUtil = cmUtil;
     this.reviewerDeleted = reviewerDeleted;
     this.user = user;
-    this.deleteReviewerSenderFactory = deleteReviewerSenderFactory;
+    this.deleteReviewerChangeEmailFactories = deleteReviewerChangeEmailFactories;
     this.removeReviewerControl = removeReviewerControl;
     this.projectCache = projectCache;
     this.messageIdGenerator = messageIdGenerator;
@@ -250,14 +253,18 @@
       // The user knows they removed themselves, don't bother emailing them.
       return;
     }
-    DeleteReviewerSender emailSender =
-        deleteReviewerSenderFactory.create(projectName, change.getId());
-    emailSender.setFrom(userId);
-    emailSender.addReviewers(Collections.singleton(reviewer.id()));
-    emailSender.setChangeMessage(mailMessage, timestamp.toInstant());
-    emailSender.setNotify(notify);
-    emailSender.setMessageId(
+    DeleteReviewerChangeEmailDecorator deleteReviewerEmail =
+        deleteReviewerChangeEmailFactories.createDeleteReviewerChangeEmail();
+    deleteReviewerEmail.addReviewers(Collections.singleton(reviewer.id()));
+    ChangeEmailNew changeEmail =
+        deleteReviewerChangeEmailFactories.createChangeEmail(
+            projectName, change.getId(), deleteReviewerEmail);
+    changeEmail.setChangeMessage(mailMessage, timestamp.toInstant());
+    OutgoingEmailNew outgoingEmail = deleteReviewerChangeEmailFactories.createEmail(changeEmail);
+    outgoingEmail.setFrom(userId);
+    outgoingEmail.setNotify(notify);
+    outgoingEmail.setMessageId(
         messageIdGenerator.fromChangeUpdate(repoView, change.currentPatchSetId()));
-    emailSender.send();
+    outgoingEmail.send();
   }
 }
diff --git a/java/com/google/gerrit/server/change/EmailNewPatchSet.java b/java/com/google/gerrit/server/change/EmailNewPatchSet.java
index f67ce4a..fedaad2 100644
--- a/java/com/google/gerrit/server/change/EmailNewPatchSet.java
+++ b/java/com/google/gerrit/server/change/EmailNewPatchSet.java
@@ -28,9 +28,12 @@
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.config.SendEmailExecutor;
+import com.google.gerrit.server.mail.EmailModule.ReplacePatchSetChangeEmailFactories;
+import com.google.gerrit.server.mail.send.ChangeEmailNew;
 import com.google.gerrit.server.mail.send.MessageIdGenerator;
 import com.google.gerrit.server.mail.send.MessageIdGenerator.MessageId;
-import com.google.gerrit.server.mail.send.ReplacePatchSetSender;
+import com.google.gerrit.server.mail.send.OutgoingEmailNew;
+import com.google.gerrit.server.mail.send.ReplacePatchSetChangeEmailDecorator;
 import com.google.gerrit.server.patch.PatchSetInfoFactory;
 import com.google.gerrit.server.update.PostUpdateContext;
 import com.google.gerrit.server.util.RequestContext;
@@ -71,7 +74,7 @@
   EmailNewPatchSet(
       @SendEmailExecutor ExecutorService sendEmailExecutor,
       ThreadLocalRequestContext threadLocalRequestContext,
-      ReplacePatchSetSender.Factory replacePatchSetFactory,
+      ReplacePatchSetChangeEmailFactories replacePatchSetChangeEmailFactories,
       PatchSetInfoFactory patchSetInfoFactory,
       MessageIdGenerator messageIdGenerator,
       @Assisted PostUpdateContext postUpdateContext,
@@ -107,7 +110,7 @@
     this.asyncSender =
         new AsyncSender(
             postUpdateContext.getIdentifiedUser(),
-            replacePatchSetFactory,
+            replacePatchSetChangeEmailFactories,
             patchSetInfoFactory,
             messageId,
             postUpdateContext.getNotify(changeId),
@@ -153,7 +156,7 @@
    */
   private static class AsyncSender implements Runnable, RequestContext {
     private final IdentifiedUser user;
-    private final ReplacePatchSetSender.Factory replacePatchSetFactory;
+    private final ReplacePatchSetChangeEmailFactories replacePatchSetChangeEmailFactories;
     private final PatchSetInfoFactory patchSetInfoFactory;
     private final MessageId messageId;
     private final NotifyResolver.Result notify;
@@ -172,7 +175,7 @@
 
     AsyncSender(
         IdentifiedUser user,
-        ReplacePatchSetSender.Factory replacePatchSetFactory,
+        ReplacePatchSetChangeEmailFactories replacePatchSetChangeEmailFactories,
         PatchSetInfoFactory patchSetInfoFactory,
         MessageId messageId,
         NotifyResolver.Result notify,
@@ -188,7 +191,7 @@
         ObjectId preUpdateMetaId,
         Map<SubmitRequirement, SubmitRequirementResult> postUpdateSubmitRequirementResults) {
       this.user = user;
-      this.replacePatchSetFactory = replacePatchSetFactory;
+      this.replacePatchSetChangeEmailFactories = replacePatchSetChangeEmailFactories;
       this.patchSetInfoFactory = patchSetInfoFactory;
       this.messageId = messageId;
       this.notify = notify;
@@ -208,22 +211,27 @@
     @Override
     public void run() {
       try {
-        ReplacePatchSetSender emailSender =
-            replacePatchSetFactory.create(
+        ReplacePatchSetChangeEmailDecorator replacePatchSetEmail =
+            replacePatchSetChangeEmailFactories.createReplacePatchSetChangeEmail(
                 projectName,
                 changeId,
                 changeKind,
                 preUpdateMetaId,
                 postUpdateSubmitRequirementResults);
-        emailSender.setFrom(user.getAccountId());
-        emailSender.setPatchSet(patchSet, patchSetInfoFactory.get(projectName, patchSet));
-        emailSender.setChangeMessage(message, timestamp);
-        emailSender.setNotify(notify);
-        emailSender.addReviewers(reviewers);
-        emailSender.addExtraCC(extraCcs);
-        emailSender.addOutdatedApproval(outdatedApprovals);
-        emailSender.setMessageId(messageId);
-        emailSender.send();
+        replacePatchSetEmail.addReviewers(reviewers);
+        replacePatchSetEmail.addExtraCC(extraCcs);
+        replacePatchSetEmail.addOutdatedApproval(outdatedApprovals);
+        ChangeEmailNew changeEmail =
+            replacePatchSetChangeEmailFactories.createChangeEmail(
+                projectName, changeId, replacePatchSetEmail);
+        changeEmail.setPatchSet(patchSet, patchSetInfoFactory.get(projectName, patchSet));
+        changeEmail.setChangeMessage(message, timestamp);
+        OutgoingEmailNew outgoingEmail =
+            replacePatchSetChangeEmailFactories.createEmail(changeEmail);
+        outgoingEmail.setFrom(user.getAccountId());
+        outgoingEmail.setNotify(notify);
+        outgoingEmail.setMessageId(messageId);
+        outgoingEmail.send();
       } catch (Exception e) {
         logger.atSevere().withCause(e).log("Cannot send email for new patch set %s", patchSet.id());
       }
diff --git a/java/com/google/gerrit/server/change/EmailReviewComments.java b/java/com/google/gerrit/server/change/EmailReviewComments.java
index a9886c7..a1201ed 100644
--- a/java/com/google/gerrit/server/change/EmailReviewComments.java
+++ b/java/com/google/gerrit/server/change/EmailReviewComments.java
@@ -28,9 +28,12 @@
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.config.SendEmailExecutor;
-import com.google.gerrit.server.mail.send.CommentSender;
+import com.google.gerrit.server.mail.EmailModule.CommentChangeEmailFactories;
+import com.google.gerrit.server.mail.send.ChangeEmailNew;
+import com.google.gerrit.server.mail.send.CommentChangeEmailDecorator;
 import com.google.gerrit.server.mail.send.MessageIdGenerator;
 import com.google.gerrit.server.mail.send.MessageIdGenerator.MessageId;
+import com.google.gerrit.server.mail.send.OutgoingEmailNew;
 import com.google.gerrit.server.patch.PatchSetInfoFactory;
 import com.google.gerrit.server.update.PostUpdateContext;
 import com.google.gerrit.server.util.LabelVote;
@@ -84,7 +87,7 @@
   EmailReviewComments(
       @SendEmailExecutor ExecutorService executor,
       PatchSetInfoFactory patchSetInfoFactory,
-      CommentSender.Factory commentSenderFactory,
+      CommentChangeEmailFactories commentChangeEmailFactories,
       ThreadLocalRequestContext requestContext,
       MessageIdGenerator messageIdGenerator,
       @Assisted PostUpdateContext postUpdateContext,
@@ -118,7 +121,7 @@
     this.asyncSender =
         new AsyncSender(
             requestContext,
-            commentSenderFactory,
+            commentChangeEmailFactories,
             patchSetInfoFactory,
             postUpdateContext.getUser().asIdentifiedUser(),
             messageId,
@@ -149,7 +152,7 @@
   // TODO: The passed in Comment class is not thread-safe, replace it with an AutoValue type.
   private static class AsyncSender implements Runnable, RequestContext {
     private final ThreadLocalRequestContext requestContext;
-    private final CommentSender.Factory commentSenderFactory;
+    private final CommentChangeEmailFactories commentChangeEmailFactories;
     private final PatchSetInfoFactory patchSetInfoFactory;
     private final IdentifiedUser user;
     private final MessageId messageId;
@@ -168,7 +171,7 @@
 
     AsyncSender(
         ThreadLocalRequestContext requestContext,
-        CommentSender.Factory commentSenderFactory,
+        CommentChangeEmailFactories commentChangeEmailFactories,
         PatchSetInfoFactory patchSetInfoFactory,
         IdentifiedUser user,
         MessageId messageId,
@@ -184,7 +187,7 @@
         ImmutableList<LabelVote> labels,
         Map<SubmitRequirement, SubmitRequirementResult> postUpdateSubmitRequirementResults) {
       this.requestContext = requestContext;
-      this.commentSenderFactory = commentSenderFactory;
+      this.commentChangeEmailFactories = commentChangeEmailFactories;
       this.patchSetInfoFactory = patchSetInfoFactory;
       this.user = user;
       this.messageId = messageId;
@@ -205,18 +208,22 @@
     public void run() {
       RequestContext old = requestContext.setContext(this);
       try {
-        CommentSender emailSender =
-            commentSenderFactory.create(
+        CommentChangeEmailDecorator commentChangeEmail =
+            commentChangeEmailFactories.createCommentChangeEmail(
                 projectName, changeId, preUpdateMetaId, postUpdateSubmitRequirementResults);
-        emailSender.setFrom(user.getAccountId());
-        emailSender.setPatchSet(patchSet, patchSetInfoFactory.get(projectName, patchSet));
-        emailSender.setChangeMessage(message, timestamp);
-        emailSender.setComments(comments);
-        emailSender.setPatchSetComment(patchSetComment);
-        emailSender.setLabels(labels);
-        emailSender.setNotify(notify);
-        emailSender.setMessageId(messageId);
-        emailSender.send();
+        commentChangeEmail.setComments(comments);
+        commentChangeEmail.setPatchSetComment(patchSetComment);
+        commentChangeEmail.setLabels(labels);
+        ChangeEmailNew changeEmail =
+            commentChangeEmailFactories.createChangeEmail(
+                projectName, changeId, commentChangeEmail);
+        changeEmail.setPatchSet(patchSet, patchSetInfoFactory.get(projectName, patchSet));
+        changeEmail.setChangeMessage(message, timestamp);
+        OutgoingEmailNew outgoingEmail = commentChangeEmailFactories.createEmail(changeEmail);
+        outgoingEmail.setFrom(user.getAccountId());
+        outgoingEmail.setNotify(notify);
+        outgoingEmail.setMessageId(messageId);
+        outgoingEmail.send();
       } catch (Exception e) {
         logger.atSevere().withCause(e).log("Cannot email comments for %s", patchSet.id());
       } finally {
diff --git a/java/com/google/gerrit/server/change/RemoveFromAttentionSetOp.java b/java/com/google/gerrit/server/change/RemoveFromAttentionSetOp.java
index 1d92521..5930f7a 100644
--- a/java/com/google/gerrit/server/change/RemoveFromAttentionSetOp.java
+++ b/java/com/google/gerrit/server/change/RemoveFromAttentionSetOp.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.change;
 
+import static com.google.gerrit.server.mail.send.AttentionSetChangeEmailDecorator.AttentionSetChange.USER_REMOVED;
 import static java.util.Objects.requireNonNull;
 
 import com.google.gerrit.entities.Account;
@@ -21,7 +22,6 @@
 import com.google.gerrit.entities.AttentionSetUpdate.Operation;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.extensions.restapi.RestApiException;
-import com.google.gerrit.server.mail.send.RemoveFromAttentionSetSender;
 import com.google.gerrit.server.notedb.ChangeUpdate;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.update.BatchUpdateOp;
@@ -39,7 +39,6 @@
   }
 
   private final ChangeData.Factory changeDataFactory;
-  private final RemoveFromAttentionSetSender.Factory removeFromAttentionSetSender;
   private final AttentionSetEmail.Factory attentionSetEmailFactory;
 
   private final Account.Id attentionUserId;
@@ -58,13 +57,11 @@
   @Inject
   RemoveFromAttentionSetOp(
       ChangeData.Factory changeDataFactory,
-      RemoveFromAttentionSetSender.Factory removeFromAttentionSetSenderFactory,
       AttentionSetEmail.Factory attentionSetEmailFactory,
       @Assisted Account.Id attentionUserId,
       @Assisted String reason,
       @Assisted boolean notify) {
     this.changeDataFactory = changeDataFactory;
-    this.removeFromAttentionSetSender = removeFromAttentionSetSenderFactory;
     this.attentionSetEmailFactory = attentionSetEmailFactory;
     this.attentionUserId = requireNonNull(attentionUserId, "user");
     this.reason = requireNonNull(reason, "reason");
@@ -97,13 +94,6 @@
     if (!notify) {
       return;
     }
-    attentionSetEmailFactory
-        .create(
-            removeFromAttentionSetSender.create(ctx.getProject(), change.getId()),
-            ctx,
-            change,
-            reason,
-            attentionUserId)
-        .sendAsync();
+    attentionSetEmailFactory.create(USER_REMOVED, ctx, change, reason, attentionUserId).sendAsync();
   }
 }
diff --git a/java/com/google/gerrit/server/config/GerritServerConfig.java b/java/com/google/gerrit/server/config/GerritServerConfig.java
index ead0d63..484c1e9 100644
--- a/java/com/google/gerrit/server/config/GerritServerConfig.java
+++ b/java/com/google/gerrit/server/config/GerritServerConfig.java
@@ -16,8 +16,8 @@
 
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
 
-import com.google.inject.BindingAnnotation;
 import java.lang.annotation.Retention;
+import javax.inject.Qualifier;
 
 /**
  * Marker on {@link org.eclipse.jgit.lib.Config} holding {@code gerrit.config} .
@@ -26,5 +26,5 @@
  * Gerrit Code Review server.
  */
 @Retention(RUNTIME)
-@BindingAnnotation
+@Qualifier
 public @interface GerritServerConfig {}
diff --git a/java/com/google/gerrit/server/documentation/QueryDocumentationExecutor.java b/java/com/google/gerrit/server/documentation/QueryDocumentationExecutor.java
index cd49ea6..093b87c 100644
--- a/java/com/google/gerrit/server/documentation/QueryDocumentationExecutor.java
+++ b/java/com/google/gerrit/server/documentation/QueryDocumentationExecutor.java
@@ -34,6 +34,7 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.search.TopDocs;
+import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.store.ByteBuffersDirectory;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.IndexOutput;
@@ -84,10 +85,10 @@
       // We don't have much documentation, so we just use MAX_VALUE here and skip paging.
       TopDocs results = searcher.search(query, Integer.MAX_VALUE);
       ScoreDoc[] hits = results.scoreDocs;
-      long totalHits = results.totalHits;
+      TotalHits totalHits = results.totalHits;
 
       List<DocResult> out = new ArrayList<>();
-      for (int i = 0; i < totalHits; i++) {
+      for (int i = 0; i < totalHits.value; i++) {
         DocResult result = new DocResult();
         Document doc = searcher.doc(hits[i].doc);
         result.url = doc.get(Constants.URL_FIELD);
diff --git a/java/com/google/gerrit/server/events/CommentAddedEvent.java b/java/com/google/gerrit/server/events/CommentAddedEvent.java
index dbbebe8..d59ab08d2 100644
--- a/java/com/google/gerrit/server/events/CommentAddedEvent.java
+++ b/java/com/google/gerrit/server/events/CommentAddedEvent.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.server.events;
 
 import com.google.common.base.Supplier;
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.server.data.AccountAttribute;
 import com.google.gerrit.server.data.ApprovalAttribute;
@@ -23,7 +24,7 @@
   static final String TYPE = "comment-added";
   public Supplier<AccountAttribute> author;
   public Supplier<ApprovalAttribute[]> approvals;
-  public String comment;
+  @Nullable public String comment;
 
   public CommentAddedEvent(Change change) {
     super(TYPE, change);
diff --git a/java/com/google/gerrit/server/extensions/events/CommentAdded.java b/java/com/google/gerrit/server/extensions/events/CommentAdded.java
index 79544f2..c6661bd 100644
--- a/java/com/google/gerrit/server/extensions/events/CommentAdded.java
+++ b/java/com/google/gerrit/server/extensions/events/CommentAdded.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.server.extensions.events;
 
 import com.google.common.flogger.FluentLogger;
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.exceptions.StorageException;
 import com.google.gerrit.extensions.api.changes.NotifyHandling;
@@ -54,7 +55,7 @@
       ChangeData changeData,
       PatchSet ps,
       AccountState author,
-      String comment,
+      @Nullable String comment,
       Map<String, Short> approvals,
       Map<String, Short> oldApprovals,
       Instant when) {
@@ -86,7 +87,7 @@
   /** Event to be fired when a comment or vote has been added to a change. */
   private static class Event extends AbstractRevisionEvent implements CommentAddedListener.Event {
 
-    private final String comment;
+    @Nullable private final String comment;
     private final Map<String, ApprovalInfo> approvals;
     private final Map<String, ApprovalInfo> oldApprovals;
 
@@ -94,7 +95,7 @@
         ChangeInfo change,
         RevisionInfo revision,
         AccountInfo author,
-        String comment,
+        @Nullable String comment,
         Map<String, ApprovalInfo> approvals,
         Map<String, ApprovalInfo> oldApprovals,
         Instant when) {
@@ -105,6 +106,7 @@
     }
 
     @Override
+    @Nullable
     public String getComment() {
       return comment;
     }
diff --git a/java/com/google/gerrit/server/git/CommitUtil.java b/java/com/google/gerrit/server/git/CommitUtil.java
index ffb6c66..6913b1e 100644
--- a/java/com/google/gerrit/server/git/CommitUtil.java
+++ b/java/com/google/gerrit/server/git/CommitUtil.java
@@ -43,8 +43,10 @@
 import com.google.gerrit.server.change.NotifyResolver;
 import com.google.gerrit.server.change.ValidationOptionsUtil;
 import com.google.gerrit.server.extensions.events.ChangeReverted;
+import com.google.gerrit.server.mail.EmailModule.RevertedChangeEmailFactories;
+import com.google.gerrit.server.mail.send.ChangeEmailNew;
 import com.google.gerrit.server.mail.send.MessageIdGenerator;
-import com.google.gerrit.server.mail.send.RevertedSender;
+import com.google.gerrit.server.mail.send.OutgoingEmailNew;
 import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.notedb.ReviewerStateInternal;
 import com.google.gerrit.server.notedb.Sequences;
@@ -93,7 +95,7 @@
   private final ApprovalsUtil approvalsUtil;
   private final ChangeInserter.Factory changeInserterFactory;
   private final NotifyResolver notifyResolver;
-  private final RevertedSender.Factory revertedSenderFactory;
+  private final RevertedChangeEmailFactories revertedChangeEmailFactories;
   private final ChangeMessagesUtil cmUtil;
   private final ChangeNotes.Factory changeNotesFactory;
   private final ChangeReverted changeReverted;
@@ -108,7 +110,7 @@
       ApprovalsUtil approvalsUtil,
       ChangeInserter.Factory changeInserterFactory,
       NotifyResolver notifyResolver,
-      RevertedSender.Factory revertedSenderFactory,
+      RevertedChangeEmailFactories revertedChangeEmailFactories,
       ChangeMessagesUtil cmUtil,
       ChangeNotes.Factory changeNotesFactory,
       ChangeReverted changeReverted,
@@ -120,7 +122,7 @@
     this.approvalsUtil = approvalsUtil;
     this.changeInserterFactory = changeInserterFactory;
     this.notifyResolver = notifyResolver;
-    this.revertedSenderFactory = revertedSenderFactory;
+    this.revertedChangeEmailFactories = revertedChangeEmailFactories;
     this.cmUtil = cmUtil;
     this.changeNotesFactory = changeNotesFactory;
     this.changeReverted = changeReverted;
@@ -381,14 +383,16 @@
           ctx.getChangeData(changeNotesFactory.createChecked(ctx.getProject(), revertingChangeId));
       changeReverted.fire(revertedChange, revertingChange, ctx.getWhen());
       try {
-        RevertedSender emailSender =
-            revertedSenderFactory.create(ctx.getProject(), revertedChange.getId());
-        emailSender.setFrom(ctx.getAccountId());
-        emailSender.setNotify(ctx.getNotify(revertedChangeId));
-        emailSender.setMessageId(
+        ChangeEmailNew changeEmail =
+            revertedChangeEmailFactories.createChangeEmail(
+                ctx.getProject(), revertedChange.getId());
+        OutgoingEmailNew outgoingEmail = revertedChangeEmailFactories.createEmail(changeEmail);
+        outgoingEmail.setFrom(ctx.getAccountId());
+        outgoingEmail.setNotify(ctx.getNotify(revertedChangeId));
+        outgoingEmail.setMessageId(
             messageIdGenerator.fromChangeUpdate(
                 ctx.getRepoView(), revertedChange.currentPatchSet().id()));
-        emailSender.send();
+        outgoingEmail.send();
       } catch (Exception err) {
         logger.atSevere().withCause(err).log(
             "Cannot send email for revert change %s", revertedChangeId);
diff --git a/java/com/google/gerrit/server/git/DynamicRefDbRepository.java b/java/com/google/gerrit/server/git/DynamicRefDbRepository.java
new file mode 100644
index 0000000..2e81ad4
--- /dev/null
+++ b/java/com/google/gerrit/server/git/DynamicRefDbRepository.java
@@ -0,0 +1,83 @@
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.git;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.function.BiFunction;
+import org.eclipse.jgit.errors.RepositoryNotFoundException;
+import org.eclipse.jgit.internal.storage.file.FileRepository;
+import org.eclipse.jgit.lib.RefDatabase;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.lib.RepositoryCache;
+import org.eclipse.jgit.util.FS;
+
+/** A FileRepository with a dynamic RefDatabase supplied via a BiFunction. */
+public class DynamicRefDbRepository extends FileRepository {
+  public static class FileKey extends RepositoryCache.FileKey {
+    private BiFunction<File, RefDatabase, RefDatabase> refDatabaseSupplier;
+
+    public static FileKey lenient(
+        File directory, FS fs, BiFunction<File, RefDatabase, RefDatabase> refDatabaseSupplier) {
+      final File gitdir = resolve(directory, fs);
+      return new FileKey(gitdir != null ? gitdir : directory, fs, refDatabaseSupplier);
+    }
+
+    private final FS fs;
+
+    /**
+     * @param directory exact location of the repository.
+     * @param fs the file system abstraction which will be necessary to perform certain file system
+     *     operations.
+     */
+    public FileKey(
+        File directory, FS fs, BiFunction<File, RefDatabase, RefDatabase> refDatabaseSupplier) {
+      super(canonical(directory), fs);
+      this.fs = fs;
+      this.refDatabaseSupplier = refDatabaseSupplier;
+    }
+
+    @Override
+    public Repository open(boolean mustExist) throws IOException {
+      if (mustExist && !isGitRepository(getFile(), fs))
+        throw new RepositoryNotFoundException(getFile());
+      return new DynamicRefDbRepository(getFile(), refDatabaseSupplier);
+    }
+
+    private static File canonical(File path) {
+      try {
+        return path.getCanonicalFile();
+      } catch (IOException e) {
+        return path.getAbsoluteFile();
+      }
+    }
+  }
+
+  private final File path;
+  private final BiFunction<File, RefDatabase, RefDatabase> refDatabaseSupplier;
+
+  public DynamicRefDbRepository(
+      File path, BiFunction<File, RefDatabase, RefDatabase> refDatabaseSupplier)
+      throws IOException {
+    super(path);
+    this.path = path;
+    this.refDatabaseSupplier = refDatabaseSupplier;
+  }
+
+  @Override
+  public RefDatabase getRefDatabase() {
+    return refDatabaseSupplier.apply(path, super.getRefDatabase());
+  }
+}
diff --git a/java/com/google/gerrit/server/git/LocalDiskRepositoryManager.java b/java/com/google/gerrit/server/git/LocalDiskRepositoryManager.java
index 57d37fa..5eb913d 100644
--- a/java/com/google/gerrit/server/git/LocalDiskRepositoryManager.java
+++ b/java/com/google/gerrit/server/git/LocalDiskRepositoryManager.java
@@ -20,6 +20,7 @@
 import com.google.gerrit.entities.RefNames;
 import com.google.gerrit.extensions.events.LifecycleListener;
 import com.google.gerrit.lifecycle.LifecycleModule;
+import com.google.gerrit.server.cache.PerThreadRefDbCache;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.config.SitePaths;
 import com.google.inject.Inject;
@@ -112,6 +113,7 @@
 
   private final Path basePath;
   private final Map<Project.NameKey, FileKey> fileKeyByProject = new ConcurrentHashMap<>();
+  private final boolean usePerRequestRefCache;
 
   @Inject
   LocalDiskRepositoryManager(SitePaths site, @GerritServerConfig Config cfg) {
@@ -119,6 +121,7 @@
     if (basePath == null) {
       throw new IllegalStateException("gerrit.basePath must be configured");
     }
+    usePerRequestRefCache = cfg.getBoolean("core", null, "usePerRequestRefCache", true);
   }
 
   /**
@@ -168,7 +171,13 @@
     if (isUnreasonableName(name)) {
       throw new RepositoryNotFoundException("Invalid name: " + name);
     }
-    FileKey location = FileKey.lenient(getBasePath(name).resolve(name.get()).toFile(), FS.DETECTED);
+    FileKey location =
+        usePerRequestRefCache
+            ? DynamicRefDbRepository.FileKey.lenient(
+                getBasePath(name).resolve(name.get()).toFile(),
+                FS.DETECTED,
+                (path, refDb) -> PerThreadRefDbCache.getRefDatabase(path, refDb))
+            : FileKey.lenient(getBasePath(name).resolve(name.get()).toFile(), FS.DETECTED);
     try {
       Repository repo = RepositoryCache.open(location);
       fileKeyByProject.put(name, location);
diff --git a/java/com/google/gerrit/server/git/MergedByPushOp.java b/java/com/google/gerrit/server/git/MergedByPushOp.java
index 426f8db..cb46df1 100644
--- a/java/com/google/gerrit/server/git/MergedByPushOp.java
+++ b/java/com/google/gerrit/server/git/MergedByPushOp.java
@@ -26,8 +26,10 @@
 import com.google.gerrit.server.PatchSetUtil;
 import com.google.gerrit.server.config.SendEmailExecutor;
 import com.google.gerrit.server.extensions.events.ChangeMerged;
-import com.google.gerrit.server.mail.send.MergedSender;
+import com.google.gerrit.server.mail.EmailModule.MergedChangeEmailFactories;
+import com.google.gerrit.server.mail.send.ChangeEmailNew;
 import com.google.gerrit.server.mail.send.MessageIdGenerator;
+import com.google.gerrit.server.mail.send.OutgoingEmailNew;
 import com.google.gerrit.server.notedb.ChangeUpdate;
 import com.google.gerrit.server.patch.PatchSetInfoFactory;
 import com.google.gerrit.server.update.BatchUpdateOp;
@@ -67,7 +69,7 @@
   private final RequestScopePropagator requestScopePropagator;
   private final PatchSetInfoFactory patchSetInfoFactory;
   private final ChangeMessagesUtil cmUtil;
-  private final MergedSender.Factory mergedSenderFactory;
+  private final MergedChangeEmailFactories mergedChangeEmailFactories;
   private final PatchSetUtil psUtil;
   private final ExecutorService sendEmailExecutor;
   private final ChangeMerged changeMerged;
@@ -88,7 +90,7 @@
   MergedByPushOp(
       PatchSetInfoFactory patchSetInfoFactory,
       ChangeMessagesUtil cmUtil,
-      MergedSender.Factory mergedSenderFactory,
+      MergedChangeEmailFactories mergedChangeEmailFactories,
       PatchSetUtil psUtil,
       @SendEmailExecutor ExecutorService sendEmailExecutor,
       ChangeMerged changeMerged,
@@ -100,7 +102,7 @@
       @Assisted("mergeResultRevId") String mergeResultRevId) {
     this.patchSetInfoFactory = patchSetInfoFactory;
     this.cmUtil = cmUtil;
-    this.mergedSenderFactory = mergedSenderFactory;
+    this.mergedChangeEmailFactories = mergedChangeEmailFactories;
     this.psUtil = psUtil;
     this.sendEmailExecutor = sendEmailExecutor;
     this.changeMerged = changeMerged;
@@ -188,16 +190,18 @@
                     try {
                       // The stickyApprovalDiff is always empty here since this is not supported
                       // for direct pushes.
-                      MergedSender emailSender =
-                          mergedSenderFactory.create(
+                      ChangeEmailNew changeEmail =
+                          mergedChangeEmailFactories.createChangeEmail(
                               ctx.getProject(),
                               psId.changeId(),
                               /* stickyApprovalDiff= */ Optional.empty());
-                      emailSender.setFrom(ctx.getAccountId());
-                      emailSender.setPatchSet(patchSet, info);
-                      emailSender.setMessageId(
+                      changeEmail.setPatchSet(patchSet, info);
+                      OutgoingEmailNew outgoingEmail =
+                          mergedChangeEmailFactories.createEmail(changeEmail);
+                      outgoingEmail.setFrom(ctx.getAccountId());
+                      outgoingEmail.setMessageId(
                           messageIdGenerator.fromChangeUpdate(ctx.getRepoView(), patchSet.id()));
-                      emailSender.send();
+                      outgoingEmail.send();
                     } catch (Exception e) {
                       logger.atSevere().withCause(e).log(
                           "Cannot send email for submitted patch set %s", psId);
diff --git a/java/com/google/gerrit/server/git/receive/ReceiveCommits.java b/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
index 0e9f7ca..3b08d92 100644
--- a/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
+++ b/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
@@ -260,9 +260,9 @@
  *
  * <p>Conceptually, most use of Gerrit is a push of some commits to refs/for/BRANCH. However, the
  * receive-pack protocol that this is based on allows multiple ref updates to be processed at once.
- * So we have to be prepared to also handle normal pushes (refs/heads/BRANCH), and legacy pushes
- * (refs/changes/CHANGE). It is hard to split this class up further, because normal pushes can also
- * result in updates to reviews, through the autoclose mechanism.
+ * So we have to be prepared to also handle normal pushes (refs/heads/BRANCH). It is hard to split
+ * this class up further, because normal pushes can also result in updates to reviews, through the
+ * autoclose mechanism.
  */
 class ReceiveCommits {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
@@ -1038,111 +1038,29 @@
           return;
         }
         try {
-          retryHelper
-              .changeUpdate(
-                  "insertChangesAndPatchSets",
-                  updateFactory -> {
-                    try (BatchUpdate bu =
-                            batchUpdateFactory.create(
-                                project.getNameKey(), user.materializedCopy(), TimeUtil.now());
-                        ObjectInserter ins = repo.newObjectInserter();
-                        ObjectReader reader = ins.newReader();
-                        RevWalk rw = new RevWalk(reader)) {
-                      bu.setRepository(repo, rw, ins);
-                      bu.setRefLogMessage("push");
-                      if (magicBranch != null) {
-                        bu.setNotify(magicBranch.getNotifyForNewChange());
-                      }
-
-                      logger.atFine().log("Adding %d replace requests", newChanges.size());
-                      for (ReplaceRequest replace : replaceByChange.values()) {
-                        replace.addOps(bu, replaceProgress);
-                        if (magicBranch != null) {
-                          bu.setNotifyHandling(
-                              replace.ontoChange, magicBranch.getNotifyHandling(replace.notes));
-                          if (magicBranch.shouldPublishComments()) {
-                            bu.addOp(
-                                replace.notes.getChangeId(),
-                                publishCommentsOp.create(replace.psId, project.getNameKey()));
-                            Optional<ChangeNotes> changeNotes =
-                                getChangeNotes(replace.notes.getChangeId());
-                            if (!changeNotes.isPresent()) {
-                              // If not present, no need to update attention set here since this is
-                              // a new change.
-                              continue;
-                            }
-                            List<HumanComment> drafts =
-                                commentsUtil.draftByChangeAuthor(
-                                    changeNotes.get(), user.getAccountId());
-                            if (drafts.isEmpty()) {
-                              // If no comments, attention set shouldn't update since the user
-                              // didn't reply.
-                              continue;
-                            }
-                            replyAttentionSetUpdates.processAutomaticAttentionSetRulesOnReply(
-                                bu,
-                                changeNotes.get(),
-                                isReadyForReview(changeNotes.get()),
-                                user,
-                                drafts);
-                          }
-                        }
-                      }
-
-                      logger.atFine().log("Adding %d create requests", newChanges.size());
-                      for (CreateRequest create : newChanges) {
-                        create.addOps(bu);
-                      }
-
-                      logger.atFine().log("Adding %d group update requests", newChanges.size());
-                      updateGroups.forEach(r -> r.addOps(bu));
-
-                      logger.atFine().log("Executing batch");
-                      try {
-                        bu.execute();
-                      } catch (UpdateException e) {
-                        throw asRestApiException(e);
-                      }
-
-                      replaceByChange.values().stream()
-                          .forEach(
-                              req ->
-                                  result.addChange(
-                                      ReceiveCommitsResult.ChangeStatus.REPLACED, req.ontoChange));
-                      newChanges.stream()
-                          .forEach(
-                              req ->
-                                  result.addChange(
-                                      ReceiveCommitsResult.ChangeStatus.CREATED, req.changeId));
-
-                      if (magicBranchCmd != null) {
-                        magicBranchCmd.setResult(OK);
-                      }
-                      for (ReplaceRequest replace : replaceByChange.values()) {
-                        String rejectMessage = replace.getRejectMessage();
-                        if (rejectMessage == null) {
-                          if (replace.inputCommand.getResult() == NOT_ATTEMPTED) {
-                            // Not necessarily the magic branch, so need to set OK on the original
-                            // value.
-                            replace.inputCommand.setResult(OK);
-                          }
-                        } else {
-                          logger.atFine().log("Rejecting due to message from ReplaceOp");
-                          reject(replace.inputCommand, rejectMessage);
-                        }
-                      }
-                    }
-                    return null;
-                  })
-              .defaultTimeoutMultiplier(5)
-              .call();
+          if (!newChanges.isEmpty()) {
+            // TODO: Retry lock failures on new change insertions. The retry will
+            //  likely have to move to a higher layer to be able to achieve that
+            //  due to state that needs to be reset with each retry attempt.
+            insertChangesAndPatchSets(magicBranchCmd, newChanges, replaceProgress);
+          } else {
+            retryHelper
+                .changeUpdate(
+                    "insertPatchSets",
+                    updateFactory -> {
+                      insertChangesAndPatchSets(magicBranchCmd, newChanges, replaceProgress);
+                      return null;
+                    })
+                .defaultTimeoutMultiplier(5)
+                .call();
+          }
         } catch (ResourceConflictException e) {
           addError(e.getMessage());
           reject(magicBranchCmd, "conflict");
         } catch (BadRequestException | UnprocessableEntityException | AuthException e) {
           logger.atFine().withCause(e).log("Rejecting due to client error");
           reject(magicBranchCmd, e.getMessage());
-        } catch (RestApiException | UpdateException e) {
+        } catch (RestApiException | IOException | UpdateException e) {
           throw new StorageException("Can't insert change/patch set for " + project.getName(), e);
         }
 
@@ -1166,6 +1084,90 @@
     }
   }
 
+  private void insertChangesAndPatchSets(
+      ReceiveCommand magicBranchCmd, List<CreateRequest> newChanges, Task replaceProgress)
+      throws RestApiException, IOException {
+    try (BatchUpdate bu =
+            batchUpdateFactory.create(
+                project.getNameKey(), user.materializedCopy(), TimeUtil.now());
+        ObjectInserter ins = repo.newObjectInserter();
+        ObjectReader reader = ins.newReader();
+        RevWalk rw = new RevWalk(reader)) {
+      bu.setRepository(repo, rw, ins);
+      bu.setRefLogMessage("push");
+      if (magicBranch != null) {
+        bu.setNotify(magicBranch.getNotifyForNewChange());
+      }
+
+      logger.atFine().log("Adding %d replace requests", newChanges.size());
+      for (ReplaceRequest replace : replaceByChange.values()) {
+        replace.addOps(bu, replaceProgress);
+        if (magicBranch != null) {
+          bu.setNotifyHandling(replace.ontoChange, magicBranch.getNotifyHandling(replace.notes));
+          if (magicBranch.shouldPublishComments()) {
+            bu.addOp(
+                replace.notes.getChangeId(),
+                publishCommentsOp.create(replace.psId, project.getNameKey()));
+            Optional<ChangeNotes> changeNotes = getChangeNotes(replace.notes.getChangeId());
+            if (!changeNotes.isPresent()) {
+              // If not present, no need to update attention set here since this is
+              // a new change.
+              continue;
+            }
+            List<HumanComment> drafts =
+                commentsUtil.draftByChangeAuthor(changeNotes.get(), user.getAccountId());
+            if (drafts.isEmpty()) {
+              // If no comments, attention set shouldn't update since the user
+              // didn't reply.
+              continue;
+            }
+            replyAttentionSetUpdates.processAutomaticAttentionSetRulesOnReply(
+                bu, changeNotes.get(), isReadyForReview(changeNotes.get()), user, drafts);
+          }
+        }
+      }
+
+      logger.atFine().log("Adding %d create requests", newChanges.size());
+      for (CreateRequest create : newChanges) {
+        create.addOps(bu);
+      }
+
+      logger.atFine().log("Adding %d group update requests", newChanges.size());
+      updateGroups.forEach(r -> r.addOps(bu));
+
+      logger.atFine().log("Executing batch");
+      try {
+        bu.execute();
+      } catch (UpdateException e) {
+        throw asRestApiException(e);
+      }
+
+      replaceByChange.values().stream()
+          .forEach(
+              req -> result.addChange(ReceiveCommitsResult.ChangeStatus.REPLACED, req.ontoChange));
+      newChanges.stream()
+          .forEach(
+              req -> result.addChange(ReceiveCommitsResult.ChangeStatus.CREATED, req.changeId));
+
+      if (magicBranchCmd != null) {
+        magicBranchCmd.setResult(OK);
+      }
+      for (ReplaceRequest replace : replaceByChange.values()) {
+        String rejectMessage = replace.getRejectMessage();
+        if (rejectMessage == null) {
+          if (replace.inputCommand.getResult() == NOT_ATTEMPTED) {
+            // Not necessarily the magic branch, so need to set OK on the original
+            // value.
+            replace.inputCommand.setResult(OK);
+          }
+        } else {
+          logger.atFine().log("Rejecting due to message from ReplaceOp");
+          reject(replace.inputCommand, rejectMessage);
+        }
+      }
+    }
+  }
+
   private boolean isReadyForReview(ChangeNotes changeNotes) {
     return (!changeNotes.getChange().isWorkInProgress() && !magicBranch.workInProgress)
         || magicBranch.ready;
diff --git a/java/com/google/gerrit/server/group/testing/TestGroupBackend.java b/java/com/google/gerrit/server/group/testing/TestGroupBackend.java
index c31d1b9..1f3dbcb 100644
--- a/java/com/google/gerrit/server/group/testing/TestGroupBackend.java
+++ b/java/com/google/gerrit/server/group/testing/TestGroupBackend.java
@@ -73,11 +73,13 @@
           }
 
           @Override
+          @Nullable
           public String getEmailAddress() {
             return null;
           }
 
           @Override
+          @Nullable
           public String getUrl() {
             return null;
           }
diff --git a/java/com/google/gerrit/server/index/account/AccountSchemaDefinitions.java b/java/com/google/gerrit/server/index/account/AccountSchemaDefinitions.java
index 8e7d964..fd264a1 100644
--- a/java/com/google/gerrit/server/index/account/AccountSchemaDefinitions.java
+++ b/java/com/google/gerrit/server/index/account/AccountSchemaDefinitions.java
@@ -85,7 +85,10 @@
           .build();
 
   // Upgrade Lucene to 7.x requires reindexing.
-  static final Schema<AccountState> V12 = schema(V11);
+  @Deprecated static final Schema<AccountState> V12 = schema(V11);
+
+  // Upgrade Lucene to 8.x requires reindexing.
+  static final Schema<AccountState> V13 = schema(V12);
 
   /**
    * Name of the account index to be used when contacting index backends or loading configurations.
diff --git a/java/com/google/gerrit/server/index/change/ChangeIndexer.java b/java/com/google/gerrit/server/index/change/ChangeIndexer.java
index dc3907d..f046c7c 100644
--- a/java/com/google/gerrit/server/index/change/ChangeIndexer.java
+++ b/java/com/google/gerrit/server/index/change/ChangeIndexer.java
@@ -361,6 +361,7 @@
 
     protected abstract T callImpl() throws Exception;
 
+    @SuppressWarnings("unused")
     protected abstract void remove();
 
     @Override
diff --git a/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java b/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java
index e74ce8f..93521f3 100644
--- a/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java
+++ b/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java
@@ -239,7 +239,7 @@
           .build();
 
   /** Remove assignee field. */
-  @SuppressWarnings("deprecation")
+  @Deprecated
   static final Schema<ChangeData> V82 =
       new Schema.Builder<ChangeData>()
           .add(V81)
@@ -247,6 +247,10 @@
           .remove(ChangeField.ASSIGNEE_FIELD)
           .build();
 
+  /** Upgrade Lucene to 8.x requires reindexing. */
+  @SuppressWarnings("deprecation")
+  static final Schema<ChangeData> V83 = schema(V82);
+
   /**
    * Name of the change index to be used when contacting index backends or loading configurations.
    */
diff --git a/java/com/google/gerrit/server/index/change/ReindexAfterRefUpdate.java b/java/com/google/gerrit/server/index/change/ReindexAfterRefUpdate.java
index 861a5fa..b52b2d1 100644
--- a/java/com/google/gerrit/server/index/change/ReindexAfterRefUpdate.java
+++ b/java/com/google/gerrit/server/index/change/ReindexAfterRefUpdate.java
@@ -150,6 +150,7 @@
 
     protected abstract V impl(RequestContext ctx) throws Exception;
 
+    @SuppressWarnings("unused")
     protected abstract void remove();
   }
 
diff --git a/java/com/google/gerrit/server/index/group/GroupSchemaDefinitions.java b/java/com/google/gerrit/server/index/group/GroupSchemaDefinitions.java
index f0f3510..1b87d27 100644
--- a/java/com/google/gerrit/server/index/group/GroupSchemaDefinitions.java
+++ b/java/com/google/gerrit/server/index/group/GroupSchemaDefinitions.java
@@ -69,7 +69,10 @@
   @Deprecated static final Schema<InternalGroup> V8 = schema(V7);
 
   // Upgrade Lucene to 7.x requires reindexing.
-  static final Schema<InternalGroup> V9 = schema(V8);
+  @Deprecated static final Schema<InternalGroup> V9 = schema(V8);
+
+  // Upgrade Lucene to 8.x requires reindexing.
+  static final Schema<InternalGroup> V10 = schema(V9);
 
   /** Singleton instance of the schema definitions. This is one per JVM. */
   public static final GroupSchemaDefinitions INSTANCE = new GroupSchemaDefinitions();
diff --git a/java/com/google/gerrit/server/index/group/IndexedGroupQuery.java b/java/com/google/gerrit/server/index/group/IndexedGroupQuery.java
index 7013e27..1d8cc1e 100644
--- a/java/com/google/gerrit/server/index/group/IndexedGroupQuery.java
+++ b/java/com/google/gerrit/server/index/group/IndexedGroupQuery.java
@@ -14,6 +14,8 @@
 
 package com.google.gerrit.server.index.group;
 
+import static com.google.common.base.Preconditions.checkState;
+
 import com.google.gerrit.entities.AccountGroup;
 import com.google.gerrit.entities.InternalGroup;
 import com.google.gerrit.index.Index;
@@ -21,6 +23,7 @@
 import com.google.gerrit.index.QueryOptions;
 import com.google.gerrit.index.query.DataSource;
 import com.google.gerrit.index.query.IndexedQuery;
+import com.google.gerrit.index.query.Matchable;
 import com.google.gerrit.index.query.Predicate;
 import com.google.gerrit.index.query.QueryParseException;
 import java.util.HashSet;
@@ -31,7 +34,7 @@
  * com.google.gerrit.index.IndexRewriter}. See {@link IndexedQuery}.
  */
 public class IndexedGroupQuery extends IndexedQuery<AccountGroup.UUID, InternalGroup>
-    implements DataSource<InternalGroup> {
+    implements DataSource<InternalGroup>, Matchable<InternalGroup> {
 
   public static QueryOptions createOptions(
       IndexConfig config, int start, int pageSize, int limit, Set<String> fields) {
@@ -50,4 +53,20 @@
       throws QueryParseException {
     super(index, pred, opts.convertForBackend());
   }
+
+  @Override
+  public boolean match(InternalGroup object) {
+    Predicate<InternalGroup> pred = getChild(0);
+    checkState(
+        pred.isMatchable(),
+        "match invoked, but child predicate %s doesn't implement %s",
+        pred,
+        Matchable.class.getName());
+    return pred.asMatchable().match(object);
+  }
+
+  @Override
+  public int getCost() {
+    return 1;
+  }
 }
diff --git a/java/com/google/gerrit/server/mail/EmailModule.java b/java/com/google/gerrit/server/mail/EmailModule.java
index baa88ed..355dd5f 100644
--- a/java/com/google/gerrit/server/mail/EmailModule.java
+++ b/java/com/google/gerrit/server/mail/EmailModule.java
@@ -16,48 +16,47 @@
 
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.Project;
+import com.google.gerrit.entities.SubmitRequirement;
+import com.google.gerrit.entities.SubmitRequirementResult;
+import com.google.gerrit.extensions.client.ChangeKind;
 import com.google.gerrit.extensions.config.FactoryModule;
 import com.google.gerrit.server.mail.send.AbandonedChangeEmailDecorator;
 import com.google.gerrit.server.mail.send.AddKeySender;
-import com.google.gerrit.server.mail.send.AddToAttentionSetSender;
+import com.google.gerrit.server.mail.send.AttentionSetChangeEmailDecorator;
+import com.google.gerrit.server.mail.send.AttentionSetChangeEmailDecorator.AttentionSetChange;
 import com.google.gerrit.server.mail.send.ChangeEmailNew;
 import com.google.gerrit.server.mail.send.ChangeEmailNewFactory;
-import com.google.gerrit.server.mail.send.CommentSender;
+import com.google.gerrit.server.mail.send.CommentChangeEmailDecorator;
+import com.google.gerrit.server.mail.send.CommentChangeEmailDecoratorFactory;
 import com.google.gerrit.server.mail.send.CreateChangeSender;
 import com.google.gerrit.server.mail.send.DeleteKeySender;
-import com.google.gerrit.server.mail.send.DeleteReviewerSender;
-import com.google.gerrit.server.mail.send.DeleteVoteSender;
+import com.google.gerrit.server.mail.send.DeleteReviewerChangeEmailDecorator;
+import com.google.gerrit.server.mail.send.DeleteVoteChangeEmailDecorator;
 import com.google.gerrit.server.mail.send.EmailArguments;
 import com.google.gerrit.server.mail.send.HttpPasswordUpdateSender;
-import com.google.gerrit.server.mail.send.MergedSender;
+import com.google.gerrit.server.mail.send.MergedChangeEmailDecoratorFactory;
 import com.google.gerrit.server.mail.send.ModifyReviewerSender;
 import com.google.gerrit.server.mail.send.OutgoingEmailNew;
 import com.google.gerrit.server.mail.send.OutgoingEmailNewFactory;
 import com.google.gerrit.server.mail.send.RegisterNewEmailSender;
-import com.google.gerrit.server.mail.send.RemoveFromAttentionSetSender;
-import com.google.gerrit.server.mail.send.ReplacePatchSetSender;
-import com.google.gerrit.server.mail.send.RestoredSender;
-import com.google.gerrit.server.mail.send.RevertedSender;
+import com.google.gerrit.server.mail.send.ReplacePatchSetChangeEmailDecorator;
+import com.google.gerrit.server.mail.send.ReplacePatchSetChangeEmailDecoratorFactory;
+import com.google.gerrit.server.mail.send.RestoredChangeEmailDecorator;
+import com.google.gerrit.server.mail.send.RevertedChangeEmailDecorator;
 import com.google.inject.Inject;
+import java.util.Map;
+import java.util.Optional;
+import org.eclipse.jgit.lib.ObjectId;
 
 public class EmailModule extends FactoryModule {
   @Override
   protected void configure() {
     factory(AddKeySender.Factory.class);
     factory(ModifyReviewerSender.Factory.class);
-    factory(CommentSender.Factory.class);
     factory(CreateChangeSender.Factory.class);
     factory(DeleteKeySender.Factory.class);
-    factory(DeleteReviewerSender.Factory.class);
-    factory(DeleteVoteSender.Factory.class);
     factory(HttpPasswordUpdateSender.Factory.class);
-    factory(MergedSender.Factory.class);
     factory(RegisterNewEmailSender.Factory.class);
-    factory(ReplacePatchSetSender.Factory.class);
-    factory(RestoredSender.Factory.class);
-    factory(RevertedSender.Factory.class);
-    factory(AddToAttentionSetSender.Factory.class);
-    factory(RemoveFromAttentionSetSender.Factory.class);
   }
 
   public static class AbandonedChangeEmailFactories {
@@ -67,7 +66,7 @@
     private final AbandonedChangeEmailDecorator abandonedChangeEmailDecorator;
 
     @Inject
-    public AbandonedChangeEmailFactories(
+    AbandonedChangeEmailFactories(
         EmailArguments args,
         ChangeEmailNewFactory changeEmailFactory,
         OutgoingEmailNewFactory outgoingEmailFactory,
@@ -87,4 +86,269 @@
       return outgoingEmailFactory.create("abandon", changeEmail);
     }
   }
+
+  public static class AttentionSetChangeEmailFactories {
+    private final EmailArguments args;
+    private final ChangeEmailNewFactory changeEmailFactory;
+    private final OutgoingEmailNewFactory outgoingEmailFactory;
+
+    @Inject
+    AttentionSetChangeEmailFactories(
+        EmailArguments args,
+        ChangeEmailNewFactory changeEmailFactory,
+        OutgoingEmailNewFactory outgoingEmailFactory) {
+      this.args = args;
+      this.changeEmailFactory = changeEmailFactory;
+      this.outgoingEmailFactory = outgoingEmailFactory;
+    }
+
+    public AttentionSetChangeEmailDecorator createAttentionSetChangeEmail() {
+      return new AttentionSetChangeEmailDecorator();
+    }
+
+    public ChangeEmailNew createChangeEmail(
+        Project.NameKey project,
+        Change.Id changeId,
+        AttentionSetChangeEmailDecorator attentionSetChangeEmailDecorator) {
+      return changeEmailFactory.create(
+          args.newChangeData(project, changeId), attentionSetChangeEmailDecorator);
+    }
+
+    public OutgoingEmailNew createEmail(
+        AttentionSetChange attentionSetChange, ChangeEmailNew changeEmail) {
+      if (attentionSetChange.equals(AttentionSetChange.USER_ADDED)) {
+        return outgoingEmailFactory.create("addToAttentionSet", changeEmail);
+      } else {
+        return outgoingEmailFactory.create("removeFromAttentionSet", changeEmail);
+      }
+    }
+  }
+
+  public static class CommentChangeEmailFactories {
+    private final EmailArguments args;
+    private final CommentChangeEmailDecoratorFactory commentChangeEmailFactory;
+    private final ChangeEmailNewFactory changeEmailFactory;
+    private final OutgoingEmailNewFactory outgoingEmailFactory;
+
+    @Inject
+    CommentChangeEmailFactories(
+        EmailArguments args,
+        CommentChangeEmailDecoratorFactory commentChangeEmailFactory,
+        ChangeEmailNewFactory changeEmailFactory,
+        OutgoingEmailNewFactory outgoingEmailFactory) {
+      this.args = args;
+      this.commentChangeEmailFactory = commentChangeEmailFactory;
+      this.changeEmailFactory = changeEmailFactory;
+      this.outgoingEmailFactory = outgoingEmailFactory;
+    }
+
+    public CommentChangeEmailDecorator createCommentChangeEmail(
+        Project.NameKey project,
+        Change.Id changeId,
+        ObjectId preUpdateMetaId,
+        Map<SubmitRequirement, SubmitRequirementResult> postUpdateSubmitRequirementResults) {
+      return commentChangeEmailFactory.create(
+          project, changeId, preUpdateMetaId, postUpdateSubmitRequirementResults);
+    }
+
+    public ChangeEmailNew createChangeEmail(
+        Project.NameKey project,
+        Change.Id changeId,
+        CommentChangeEmailDecorator commentChangeEmailDecorator) {
+      return changeEmailFactory.create(
+          args.newChangeData(project, changeId), commentChangeEmailDecorator);
+    }
+
+    public OutgoingEmailNew createEmail(ChangeEmailNew changeEmail) {
+      return outgoingEmailFactory.create("comment", changeEmail);
+    }
+  }
+
+  public static class DeleteReviewerChangeEmailFactories {
+    private final EmailArguments args;
+    private final ChangeEmailNewFactory changeEmailFactory;
+    private final OutgoingEmailNewFactory outgoingEmailFactory;
+
+    @Inject
+    DeleteReviewerChangeEmailFactories(
+        EmailArguments args,
+        ChangeEmailNewFactory changeEmailFactory,
+        OutgoingEmailNewFactory outgoingEmailFactory) {
+      this.args = args;
+      this.changeEmailFactory = changeEmailFactory;
+      this.outgoingEmailFactory = outgoingEmailFactory;
+    }
+
+    public DeleteReviewerChangeEmailDecorator createDeleteReviewerChangeEmail() {
+      return new DeleteReviewerChangeEmailDecorator();
+    }
+
+    public ChangeEmailNew createChangeEmail(
+        Project.NameKey project,
+        Change.Id changeId,
+        DeleteReviewerChangeEmailDecorator deleteReviewerChangeEmailDecorator) {
+      return changeEmailFactory.create(
+          args.newChangeData(project, changeId), deleteReviewerChangeEmailDecorator);
+    }
+
+    public OutgoingEmailNew createEmail(ChangeEmailNew changeEmail) {
+      return outgoingEmailFactory.create("deleteReviewer", changeEmail);
+    }
+  }
+
+  public static class DeleteVoteChangeEmailFactories {
+    private final EmailArguments args;
+    private final ChangeEmailNewFactory changeEmailFactory;
+    private final OutgoingEmailNewFactory outgoingEmailFactory;
+    private final DeleteVoteChangeEmailDecorator deleteVoteChangeEmailDecorator;
+
+    @Inject
+    DeleteVoteChangeEmailFactories(
+        EmailArguments args,
+        ChangeEmailNewFactory changeEmailFactory,
+        OutgoingEmailNewFactory outgoingEmailFactory,
+        DeleteVoteChangeEmailDecorator deleteVoteChangeEmailDecorator) {
+      this.args = args;
+      this.changeEmailFactory = changeEmailFactory;
+      this.outgoingEmailFactory = outgoingEmailFactory;
+      this.deleteVoteChangeEmailDecorator = deleteVoteChangeEmailDecorator;
+    }
+
+    public ChangeEmailNew createChangeEmail(Project.NameKey project, Change.Id changeId) {
+      return changeEmailFactory.create(
+          args.newChangeData(project, changeId), deleteVoteChangeEmailDecorator);
+    }
+
+    public OutgoingEmailNew createEmail(ChangeEmailNew changeEmail) {
+      return outgoingEmailFactory.create("deleteVote", changeEmail);
+    }
+  }
+
+  public static class MergedChangeEmailFactories {
+    private final EmailArguments args;
+    private final MergedChangeEmailDecoratorFactory mergedChangeEmailDecoratorFactory;
+    private final ChangeEmailNewFactory changeEmailFactory;
+    private final OutgoingEmailNewFactory outgoingEmailFactory;
+
+    @Inject
+    MergedChangeEmailFactories(
+        EmailArguments args,
+        MergedChangeEmailDecoratorFactory mergedChangeEmailDecoratorFactory,
+        ChangeEmailNewFactory changeEmailFactory,
+        OutgoingEmailNewFactory outgoingEmailFactory) {
+      this.args = args;
+      this.mergedChangeEmailDecoratorFactory = mergedChangeEmailDecoratorFactory;
+      this.changeEmailFactory = changeEmailFactory;
+      this.outgoingEmailFactory = outgoingEmailFactory;
+    }
+
+    public ChangeEmailNew createChangeEmail(
+        Project.NameKey project, Change.Id changeId, Optional<String> stickyApprovalDiff) {
+      return changeEmailFactory.create(
+          args.newChangeData(project, changeId),
+          mergedChangeEmailDecoratorFactory.create(stickyApprovalDiff));
+    }
+
+    public OutgoingEmailNew createEmail(ChangeEmailNew changeEmail) {
+      return outgoingEmailFactory.create("merged", changeEmail);
+    }
+  }
+
+  public static class ReplacePatchSetChangeEmailFactories {
+    private final EmailArguments args;
+    private final ReplacePatchSetChangeEmailDecoratorFactory
+        replacePatchSetChangeEmailDecoratorFactory;
+    private final ChangeEmailNewFactory changeEmailFactory;
+    private final OutgoingEmailNewFactory outgoingEmailFactory;
+
+    @Inject
+    ReplacePatchSetChangeEmailFactories(
+        EmailArguments args,
+        ReplacePatchSetChangeEmailDecoratorFactory replacePatchSetChangeEmailDecoratorFactory,
+        ChangeEmailNewFactory changeEmailFactory,
+        OutgoingEmailNewFactory outgoingEmailFactory) {
+      this.args = args;
+      this.replacePatchSetChangeEmailDecoratorFactory = replacePatchSetChangeEmailDecoratorFactory;
+      this.changeEmailFactory = changeEmailFactory;
+      this.outgoingEmailFactory = outgoingEmailFactory;
+    }
+
+    public ReplacePatchSetChangeEmailDecorator createReplacePatchSetChangeEmail(
+        Project.NameKey project,
+        Change.Id changeId,
+        ChangeKind changeKind,
+        ObjectId preUpdateMetaId,
+        Map<SubmitRequirement, SubmitRequirementResult> postUpdateSubmitRequirementResults) {
+      return replacePatchSetChangeEmailDecoratorFactory.create(
+          project, changeId, changeKind, preUpdateMetaId, postUpdateSubmitRequirementResults);
+    }
+
+    public ChangeEmailNew createChangeEmail(
+        Project.NameKey project,
+        Change.Id changeId,
+        ReplacePatchSetChangeEmailDecorator replacePatchSetChangeEmailDecoratorFactory) {
+      return changeEmailFactory.create(
+          args.newChangeData(project, changeId), replacePatchSetChangeEmailDecoratorFactory);
+    }
+
+    public OutgoingEmailNew createEmail(ChangeEmailNew changeEmail) {
+      return outgoingEmailFactory.create("newpatchset", changeEmail);
+    }
+  }
+
+  public static class RestoredChangeEmailFactories {
+    private final EmailArguments args;
+    private final ChangeEmailNewFactory changeEmailFactory;
+    private final OutgoingEmailNewFactory outgoingEmailFactory;
+    private final RestoredChangeEmailDecorator restoredChangeEmailDecorator;
+
+    @Inject
+    RestoredChangeEmailFactories(
+        EmailArguments args,
+        ChangeEmailNewFactory changeEmailFactory,
+        OutgoingEmailNewFactory outgoingEmailFactory,
+        RestoredChangeEmailDecorator restoredChangeEmailDecorator) {
+      this.args = args;
+      this.changeEmailFactory = changeEmailFactory;
+      this.outgoingEmailFactory = outgoingEmailFactory;
+      this.restoredChangeEmailDecorator = restoredChangeEmailDecorator;
+    }
+
+    public ChangeEmailNew createChangeEmail(Project.NameKey project, Change.Id changeId) {
+      return changeEmailFactory.create(
+          args.newChangeData(project, changeId), restoredChangeEmailDecorator);
+    }
+
+    public OutgoingEmailNew createEmail(ChangeEmailNew changeEmail) {
+      return outgoingEmailFactory.create("restore", changeEmail);
+    }
+  }
+
+  public static class RevertedChangeEmailFactories {
+    private final EmailArguments args;
+    private final ChangeEmailNewFactory changeEmailFactory;
+    private final OutgoingEmailNewFactory outgoingEmailFactory;
+    private final RevertedChangeEmailDecorator revertedChangeEmailDecorator;
+
+    @Inject
+    RevertedChangeEmailFactories(
+        EmailArguments args,
+        ChangeEmailNewFactory changeEmailFactory,
+        OutgoingEmailNewFactory outgoingEmailFactory,
+        RevertedChangeEmailDecorator revertedChangeEmailDecorator) {
+      this.args = args;
+      this.changeEmailFactory = changeEmailFactory;
+      this.outgoingEmailFactory = outgoingEmailFactory;
+      this.revertedChangeEmailDecorator = revertedChangeEmailDecorator;
+    }
+
+    public ChangeEmailNew createChangeEmail(Project.NameKey project, Change.Id changeId) {
+      return changeEmailFactory.create(
+          args.newChangeData(project, changeId), revertedChangeEmailDecorator);
+    }
+
+    public OutgoingEmailNew createEmail(ChangeEmailNew changeEmail) {
+      return outgoingEmailFactory.create("revert", changeEmail);
+    }
+  }
 }
diff --git a/java/com/google/gerrit/server/mail/send/AbandonedChangeEmailDecorator.java b/java/com/google/gerrit/server/mail/send/AbandonedChangeEmailDecorator.java
index f40d3d6..2d25eba 100644
--- a/java/com/google/gerrit/server/mail/send/AbandonedChangeEmailDecorator.java
+++ b/java/com/google/gerrit/server/mail/send/AbandonedChangeEmailDecorator.java
@@ -15,7 +15,6 @@
 package com.google.gerrit.server.mail.send;
 
 import com.google.gerrit.entities.NotifyConfig.NotifyType;
-import com.google.gerrit.exceptions.EmailException;
 import com.google.gerrit.extensions.api.changes.RecipientType;
 
 /** Send notice about a change being abandoned by its owner. */
@@ -24,14 +23,14 @@
   private OutgoingEmailNew email;
 
   @Override
-  public void init(OutgoingEmailNew email, ChangeEmailNew changeEmail) throws EmailException {
+  public void init(OutgoingEmailNew email, ChangeEmailNew changeEmail) {
     this.email = email;
     this.changeEmail = changeEmail;
     changeEmail.markAsReply();
   }
 
   @Override
-  public void populateEmailContent() throws EmailException {
+  public void populateEmailContent() {
     changeEmail.addAuthors(RecipientType.TO);
     changeEmail.ccAllApprovals();
     changeEmail.bccStarredBy();
diff --git a/java/com/google/gerrit/server/mail/send/AddToAttentionSetSender.java b/java/com/google/gerrit/server/mail/send/AddToAttentionSetSender.java
deleted file mode 100644
index f9ef199..0000000
--- a/java/com/google/gerrit/server/mail/send/AddToAttentionSetSender.java
+++ /dev/null
@@ -1,43 +0,0 @@
-// Copyright (C) 2020 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-package com.google.gerrit.server.mail.send;
-
-import com.google.gerrit.entities.Change;
-import com.google.gerrit.entities.Project;
-import com.google.gerrit.exceptions.EmailException;
-import com.google.inject.Inject;
-import com.google.inject.assistedinject.Assisted;
-
-/** Let users know of a new user in the attention set. */
-public class AddToAttentionSetSender extends AttentionSetSender {
-
-  public interface Factory extends ReplyToChangeSender.Factory<AddToAttentionSetSender> {
-    @Override
-    AddToAttentionSetSender create(Project.NameKey project, Change.Id changeId);
-  }
-
-  @Inject
-  public AddToAttentionSetSender(
-      EmailArguments args, @Assisted Project.NameKey project, @Assisted Change.Id changeId) {
-    super(args, "addToAttentionSet", project, changeId);
-  }
-
-  @Override
-  protected void formatChange() throws EmailException {
-    appendText(textTemplate("AddToAttentionSet"));
-    if (useHtml()) {
-      appendHtml(soyHtmlTemplate("AddToAttentionSetHtml"));
-    }
-  }
-}
diff --git a/java/com/google/gerrit/server/mail/send/AttentionSetChangeEmailDecorator.java b/java/com/google/gerrit/server/mail/send/AttentionSetChangeEmailDecorator.java
new file mode 100644
index 0000000..38ec52f
--- /dev/null
+++ b/java/com/google/gerrit/server/mail/send/AttentionSetChangeEmailDecorator.java
@@ -0,0 +1,79 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.mail.send;
+
+import com.google.gerrit.entities.Account;
+import com.google.gerrit.extensions.api.changes.RecipientType;
+import com.google.gerrit.server.mail.send.ChangeEmailNew.ChangeEmailDecorator;
+
+/** Base class for Attention Set email senders */
+public final class AttentionSetChangeEmailDecorator implements ChangeEmailDecorator {
+  public enum AttentionSetChange {
+    USER_ADDED,
+    USER_REMOVED
+  }
+
+  private OutgoingEmailNew email;
+  private ChangeEmailNew changeEmail;
+
+  private Account.Id attentionSetUser;
+  private String reason;
+  private AttentionSetChange attentionSetChange;
+
+  public void setAttentionSetUser(Account.Id attentionSetUser) {
+    this.attentionSetUser = attentionSetUser;
+  }
+
+  public void setReason(String reason) {
+    this.reason = reason;
+  }
+
+  public void setAttentionSetChange(AttentionSetChange attentionSetChange) {
+    this.attentionSetChange = attentionSetChange;
+  }
+
+  @Override
+  public void init(OutgoingEmailNew email, ChangeEmailNew changeEmail) {
+    this.email = email;
+    this.changeEmail = changeEmail;
+    changeEmail.markAsReply();
+  }
+
+  @Override
+  public void populateEmailContent() {
+    email.addSoyParam("attentionSetUser", email.getNameFor(attentionSetUser));
+    email.addSoyParam("reason", reason);
+
+    changeEmail.addAuthors(RecipientType.TO);
+    changeEmail.ccAllApprovals();
+    changeEmail.bccStarredBy();
+    changeEmail.ccExistingReviewers();
+
+    switch (attentionSetChange) {
+      case USER_ADDED:
+        email.appendText(email.textTemplate("AddToAttentionSet"));
+        if (email.useHtml()) {
+          email.appendHtml(email.soyHtmlTemplate("AddToAttentionSetHtml"));
+        }
+        break;
+      case USER_REMOVED:
+        email.appendText(email.textTemplate("RemoveFromAttentionSet"));
+        if (email.useHtml()) {
+          email.appendHtml(email.soyHtmlTemplate("RemoveFromAttentionSetHtml"));
+        }
+        break;
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/mail/send/AttentionSetSender.java b/java/com/google/gerrit/server/mail/send/AttentionSetSender.java
deleted file mode 100644
index 35a47c9..0000000
--- a/java/com/google/gerrit/server/mail/send/AttentionSetSender.java
+++ /dev/null
@@ -1,50 +0,0 @@
-// Copyright (C) 2020 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.mail.send;
-
-import com.google.gerrit.entities.Account;
-import com.google.gerrit.entities.Change;
-import com.google.gerrit.entities.Project;
-import com.google.gerrit.exceptions.EmailException;
-
-/** Base class for Attention Set email senders */
-public abstract class AttentionSetSender extends ReplyToChangeSender {
-  private Account.Id attentionSetUser;
-  private String reason;
-
-  public AttentionSetSender(
-      EmailArguments args, String messageClass, Project.NameKey project, Change.Id changeId) {
-    super(args, messageClass, ChangeEmail.newChangeData(args, project, changeId));
-  }
-
-  public void setAttentionSetUser(Account.Id attentionSetUser) {
-    this.attentionSetUser = attentionSetUser;
-  }
-
-  public void setReason(String reason) {
-    this.reason = reason;
-  }
-
-  @Override
-  protected void populateEmailContent() throws EmailException {
-    super.populateEmailContent();
-    addSoyParam("attentionSetUser", getNameFor(attentionSetUser));
-    addSoyParam("reason", reason);
-
-    ccAllApprovals();
-    bccStarredBy();
-    ccExistingReviewers();
-  }
-}
diff --git a/java/com/google/gerrit/server/mail/send/ChangeEmailNew.java b/java/com/google/gerrit/server/mail/send/ChangeEmailNew.java
index 1fa2bc9..28dd3b1 100644
--- a/java/com/google/gerrit/server/mail/send/ChangeEmailNew.java
+++ b/java/com/google/gerrit/server/mail/send/ChangeEmailNew.java
@@ -86,7 +86,7 @@
 public final class ChangeEmailNew implements OutgoingEmailNew.EmailDecorator {
 
   /** Implementations of params interface populate details specific to the notification type. */
-  interface ChangeEmailDecorator {
+  public interface ChangeEmailDecorator {
     /**
      * Stores the reference to the {@link OutgoingEmailNew} and {@link ChangeEmailNew} for the
      * subsequent calls.
@@ -546,7 +546,6 @@
         return false;
       }
     }
-
     return args.permissionBackend.absentUser(to).change(changeData).test(ChangePermission.READ);
   }
 
diff --git a/java/com/google/gerrit/server/mail/send/CommentSender.java b/java/com/google/gerrit/server/mail/send/CommentChangeEmailDecorator.java
similarity index 82%
rename from java/com/google/gerrit/server/mail/send/CommentSender.java
rename to java/com/google/gerrit/server/mail/send/CommentChangeEmailDecorator.java
index a8bf02b..932e120 100644
--- a/java/com/google/gerrit/server/mail/send/CommentSender.java
+++ b/java/com/google/gerrit/server/mail/send/CommentChangeEmailDecorator.java
@@ -18,6 +18,8 @@
 import static com.google.gerrit.entities.Patch.PATCHSET_LEVEL;
 import static java.util.stream.Collectors.toList;
 
+import com.google.auto.factory.AutoFactory;
+import com.google.auto.factory.Provided;
 import com.google.common.base.Strings;
 import com.google.common.base.Supplier;
 import com.google.common.base.Suppliers;
@@ -35,20 +37,19 @@
 import com.google.gerrit.entities.RobotComment;
 import com.google.gerrit.entities.SubmitRequirement;
 import com.google.gerrit.entities.SubmitRequirementResult;
-import com.google.gerrit.exceptions.EmailException;
 import com.google.gerrit.exceptions.NoSuchEntityException;
 import com.google.gerrit.exceptions.StorageException;
 import com.google.gerrit.extensions.api.changes.NotifyHandling;
+import com.google.gerrit.extensions.api.changes.RecipientType;
 import com.google.gerrit.mail.MailHeader;
 import com.google.gerrit.mail.MailProcessingUtil;
 import com.google.gerrit.server.CommentsUtil;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.mail.receive.Protocol;
+import com.google.gerrit.server.mail.send.ChangeEmailNew.ChangeEmailDecorator;
 import com.google.gerrit.server.patch.PatchFile;
 import com.google.gerrit.server.patch.filediff.FileDiffOutput;
 import com.google.gerrit.server.util.LabelVote;
-import com.google.inject.Inject;
-import com.google.inject.assistedinject.Assisted;
 import java.io.IOException;
 import java.time.ZoneId;
 import java.time.ZonedDateTime;
@@ -66,19 +67,11 @@
 import org.eclipse.jgit.lib.Repository;
 
 /** Send comments, after the author of them hit used Publish Comments in the UI. */
-public class CommentSender extends ReplyToChangeSender {
+@AutoFactory
+public class CommentChangeEmailDecorator implements ChangeEmailDecorator {
 
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
-  public interface Factory {
-
-    CommentSender create(
-        Project.NameKey project,
-        Change.Id changeId,
-        ObjectId preUpdateMetaId,
-        Map<SubmitRequirement, SubmitRequirementResult> postUpdateSubmitRequirementResults);
-  }
-
   private class FileCommentGroup {
 
     public String filename;
@@ -89,19 +82,22 @@
     /** Returns a web link to a comment for a change. */
     @Nullable
     public String getCommentLink(String uuid) {
-      return args.urlFormatter.get().getInlineCommentView(getChange(), uuid).orElse(null);
+      return args.urlFormatter
+          .get()
+          .getInlineCommentView(changeEmail.getChange(), uuid)
+          .orElse(null);
     }
 
     /** Returns a web link to the comment tab view of a change. */
     @Nullable
     public String getCommentsTabLink() {
-      return args.urlFormatter.get().getCommentsTabView(getChange()).orElse(null);
+      return args.urlFormatter.get().getCommentsTabView(changeEmail.getChange()).orElse(null);
     }
 
     /** Returns a web link to the findings tab view of a change. */
     @Nullable
     public String getFindingsTabLink() {
-      return args.urlFormatter.get().getFindingsTabView(getChange()).orElse(null);
+      return args.urlFormatter.get().getFindingsTabView(changeEmail.getChange()).orElse(null);
     }
 
     /**
@@ -120,6 +116,9 @@
     }
   }
 
+  private EmailArguments args;
+  private OutgoingEmailNew email;
+  private ChangeEmailNew changeEmail;
   private List<? extends Comment> inlineComments = Collections.emptyList();
   @Nullable private String patchSetComment;
   private ImmutableList<LabelVote> labels = ImmutableList.of();
@@ -130,17 +129,15 @@
       preUpdateSubmitRequirementResultsSupplier;
   private final Map<SubmitRequirement, SubmitRequirementResult> postUpdateSubmitRequirementResults;
 
-  @Inject
-  public CommentSender(
-      EmailArguments args,
-      CommentsUtil commentsUtil,
-      @GerritServerConfig Config cfg,
-      @Assisted Project.NameKey project,
-      @Assisted Change.Id changeId,
-      @Assisted ObjectId preUpdateMetaId,
-      @Assisted
-          Map<SubmitRequirement, SubmitRequirementResult> postUpdateSubmitRequirementResults) {
-    super(args, "comment", newChangeData(args, project, changeId));
+  public CommentChangeEmailDecorator(
+      @Provided EmailArguments args,
+      @Provided CommentsUtil commentsUtil,
+      @Provided @GerritServerConfig Config cfg,
+      Project.NameKey project,
+      Change.Id changeId,
+      ObjectId preUpdateMetaId,
+      Map<SubmitRequirement, SubmitRequirementResult> postUpdateSubmitRequirementResults) {
+    this.args = args;
     this.commentsUtil = commentsUtil;
     this.incomingEmailEnabled =
         cfg.getEnum("receiveemail", null, "protocol", Protocol.NONE).ordinal()
@@ -151,7 +148,7 @@
             () ->
                 // Triggers an (expensive) evaluation of the submit requirements. This is OK since
                 // all callers sent this email asynchronously, see EmailReviewComments.
-                newChangeData(args, project, changeId, preUpdateMetaId)
+                args.newChangeData(project, changeId, preUpdateMetaId)
                     .submitRequirementsIncludingLegacy());
     this.postUpdateSubmitRequirementResults = postUpdateSubmitRequirementResults;
   }
@@ -169,45 +166,31 @@
   }
 
   @Override
-  protected void init() throws EmailException {
-    super.init();
-
+  public void init(OutgoingEmailNew email, ChangeEmailNew changeEmail) {
+    this.email = email;
+    this.changeEmail = changeEmail;
     // Add header that enables identifying comments on parsed email.
     // Grouping is currently done by timestamp.
-    setHeader(MailHeader.COMMENT_DATE.fieldName(), getTimestamp());
+    email.setHeader(MailHeader.COMMENT_DATE.fieldName(), changeEmail.getTimestamp());
 
     if (incomingEmailEnabled) {
       if (replyToAddress == null) {
         // Remove Reply-To and use outbound SMTP (default) instead.
-        removeHeader(FieldName.REPLY_TO);
+        email.removeHeader(FieldName.REPLY_TO);
       } else {
-        setHeader(FieldName.REPLY_TO, replyToAddress);
+        email.setHeader(FieldName.REPLY_TO, replyToAddress);
       }
     }
-  }
-
-  @Override
-  public void formatChange() throws EmailException {
-    appendText(textTemplate("Comment"));
-    if (useHtml()) {
-      appendHtml(soyHtmlTemplate("CommentHtml"));
-    }
-  }
-
-  @Override
-  public void formatFooter() throws EmailException {
-    appendText(textTemplate("CommentFooter"));
-    if (useHtml()) {
-      appendHtml(soyHtmlTemplate("CommentFooterHtml"));
-    }
+    changeEmail.markAsReply();
   }
 
   /**
    * Returns a list of FileCommentGroup objects representing the inline comments grouped by the
    * file.
    */
-  private List<CommentSender.FileCommentGroup> getGroupedInlineComments(Repository repo) {
-    List<CommentSender.FileCommentGroup> groups = new ArrayList<>();
+  private List<CommentChangeEmailDecorator.FileCommentGroup> getGroupedInlineComments(
+      Repository repo) {
+    List<CommentChangeEmailDecorator.FileCommentGroup> groups = new ArrayList<>();
 
     // Loop over the comments and collect them into groups based on the file
     // location of the comment.
@@ -221,7 +204,7 @@
         currentGroup.filename = c.key.filename;
         currentGroup.patchSetId = c.key.patchSetId;
         // Get the modified files:
-        Map<String, FileDiffOutput> modifiedFiles = listModifiedFiles(c.key.patchSetId);
+        Map<String, FileDiffOutput> modifiedFiles = changeEmail.listModifiedFiles(c.key.patchSetId);
 
         groups.add(currentGroup);
         if (modifiedFiles != null && !modifiedFiles.isEmpty()) {
@@ -232,7 +215,7 @@
                 "Cannot load %s from %s in %s",
                 c.key.filename,
                 modifiedFiles.values().iterator().next().newCommitId().name(),
-                getProjectState().getName());
+                changeEmail.getProjectState().getName());
             currentGroup.fileData = null;
           }
         }
@@ -317,7 +300,7 @@
     }
     Comment.Key key = new Comment.Key(child.parentUuid, child.key.filename, child.key.patchSetId);
     try {
-      return commentsUtil.getPublishedHumanComment(getChangeData().notes(), key);
+      return commentsUtil.getPublishedHumanComment(changeEmail.getChangeData().notes(), key);
     } catch (StorageException e) {
       logger.atWarning().log("Could not find the parent of this comment: %s", child);
       return Optional.empty();
@@ -352,7 +335,7 @@
    * or the first line, or following the last period within the first 100 characters, whichever is
    * shorter. If the message is shortened, an ellipsis is appended.
    */
-  protected static String getShortenedCommentMessage(String message) {
+  static String getShortenedCommentMessage(String message) {
     int threshold = 100;
     String fullMessage = message.trim();
     String msg = fullMessage;
@@ -381,7 +364,7 @@
     return msg;
   }
 
-  protected static String getShortenedCommentMessage(Comment comment) {
+  static String getShortenedCommentMessage(Comment comment) {
     return getShortenedCommentMessage(comment.message);
   }
 
@@ -392,7 +375,7 @@
   private List<Map<String, Object>> getCommentGroupsTemplateData(Repository repo) {
     List<Map<String, Object>> commentGroups = new ArrayList<>();
 
-    for (CommentSender.FileCommentGroup group : getGroupedInlineComments(repo)) {
+    for (CommentChangeEmailDecorator.FileCommentGroup group : getGroupedInlineComments(repo)) {
       Map<String, Object> groupData = new HashMap<>();
       groupData.put("title", group.getTitle());
       groupData.put("patchSetId", group.patchSetId);
@@ -503,55 +486,66 @@
   @Nullable
   private Repository getRepository() {
     try {
-      return args.server.openRepository(getProjectState().getNameKey());
+      return args.server.openRepository(changeEmail.getProjectState().getNameKey());
     } catch (IOException e) {
       return null;
     }
   }
 
   @Override
-  protected void populateEmailContent() throws EmailException {
-    super.populateEmailContent();
+  public void populateEmailContent() {
+    changeEmail.addAuthors(RecipientType.TO);
+
     boolean hasComments;
     try (Repository repo = getRepository()) {
       List<Map<String, Object>> files = getCommentGroupsTemplateData(repo);
-      addSoyParam("commentFiles", files);
+      email.addSoyParam("commentFiles", files);
       hasComments = !files.isEmpty();
     }
 
-    addSoyParam(
+    email.addSoyParam(
         "patchSetCommentBlocks", commentBlocksToSoyData(CommentFormatter.parse(patchSetComment)));
-    addSoyParam("labels", getLabelVoteSoyData(labels));
-    addSoyParam("commentCount", inlineComments.size());
-    addSoyParam("commentTimestamp", getCommentTimestamp());
-    addSoyParam(
-        "coverLetterBlocks", commentBlocksToSoyData(CommentFormatter.parse(getCoverLetter())));
+    email.addSoyParam("labels", getLabelVoteSoyData(labels));
+    email.addSoyParam("commentCount", inlineComments.size());
+    email.addSoyParam("commentTimestamp", getCommentTimestamp());
+    email.addSoyParam(
+        "coverLetterBlocks",
+        commentBlocksToSoyData(CommentFormatter.parse(changeEmail.getCoverLetter())));
 
     if (isChangeNoLongerSubmittable()) {
-      addSoyParam("unsatisfiedSubmitRequirements", formatUnsatisfiedSubmitRequirements());
-      addSoyParam(
+      email.addSoyParam("unsatisfiedSubmitRequirements", formatUnsatisfiedSubmitRequirements());
+      email.addSoyParam(
           "oldSubmitRequirements",
           formatSubmitRequirments(preUpdateSubmitRequirementResultsSupplier.get()));
-      addSoyParam(
+      email.addSoyParam(
           "newSubmitRequirements", formatSubmitRequirments(postUpdateSubmitRequirementResults));
     }
 
-    addFooter(MailHeader.COMMENT_DATE.withDelimiter() + getCommentTimestamp());
-    addFooter(MailHeader.HAS_COMMENTS.withDelimiter() + (hasComments ? "Yes" : "No"));
-    addFooter(MailHeader.HAS_LABELS.withDelimiter() + (labels.isEmpty() ? "No" : "Yes"));
+    email.addFooter(MailHeader.COMMENT_DATE.withDelimiter() + getCommentTimestamp());
+    email.addFooter(MailHeader.HAS_COMMENTS.withDelimiter() + (hasComments ? "Yes" : "No"));
+    email.addFooter(MailHeader.HAS_LABELS.withDelimiter() + (labels.isEmpty() ? "No" : "Yes"));
 
     for (Account.Id account : getReplyAccounts()) {
-      addFooter(MailHeader.COMMENT_IN_REPLY_TO.withDelimiter() + getNameEmailFor(account));
+      email.addFooter(
+          MailHeader.COMMENT_IN_REPLY_TO.withDelimiter() + email.getNameEmailFor(account));
     }
 
-    if (getNotify().handling().equals(NotifyHandling.OWNER_REVIEWERS)
-        || getNotify().handling().equals(NotifyHandling.ALL)) {
-      ccAllApprovals();
+    if (email.getNotify().handling().equals(NotifyHandling.OWNER_REVIEWERS)
+        || email.getNotify().handling().equals(NotifyHandling.ALL)) {
+      changeEmail.ccAllApprovals();
     }
-    if (getNotify().handling().equals(NotifyHandling.ALL)) {
-      bccStarredBy();
-      includeWatchers(
-          NotifyType.ALL_COMMENTS, !getChange().isWorkInProgress() && !getChange().isPrivate());
+    if (email.getNotify().handling().equals(NotifyHandling.ALL)) {
+      changeEmail.bccStarredBy();
+      changeEmail.includeWatchers(
+          NotifyType.ALL_COMMENTS,
+          !changeEmail.getChange().isWorkInProgress() && !changeEmail.getChange().isPrivate());
+    }
+
+    email.appendText(email.textTemplate("Comment"));
+    email.appendText(email.textTemplate("CommentFooter"));
+    if (email.useHtml()) {
+      email.appendHtml(email.soyHtmlTemplate("CommentHtml"));
+      email.appendHtml(email.soyHtmlTemplate("CommentFooterHtml"));
     }
   }
 
@@ -567,7 +561,7 @@
             .allMatch(SubmitRequirementResult::fulfilled);
     logger.atFine().log(
         "the submitability of change %s before the update is %s",
-        getChange().getId(), isSubmittablePreUpdate);
+        changeEmail.getChange().getId(), isSubmittablePreUpdate);
     if (!isSubmittablePreUpdate) {
       return false;
     }
@@ -577,7 +571,7 @@
             .allMatch(SubmitRequirementResult::fulfilled);
     logger.atFine().log(
         "the submitability of change %s after the update is %s",
-        getChange().getId(), isSubmittablePostUpdate);
+        changeEmail.getChange().getId(), isSubmittablePostUpdate);
     return !isSubmittablePostUpdate;
   }
 
@@ -645,6 +639,6 @@
   private String getCommentTimestamp() {
     // Grouping is currently done by timestamp.
     return MailProcessingUtil.rfcDateformatter.format(
-        ZonedDateTime.ofInstant(getTimestamp(), ZoneId.of("UTC")));
+        ZonedDateTime.ofInstant(changeEmail.getTimestamp(), ZoneId.of("UTC")));
   }
 }
diff --git a/java/com/google/gerrit/server/mail/send/DeleteReviewerChangeEmailDecorator.java b/java/com/google/gerrit/server/mail/send/DeleteReviewerChangeEmailDecorator.java
new file mode 100644
index 0000000..aa6aad2
--- /dev/null
+++ b/java/com/google/gerrit/server/mail/send/DeleteReviewerChangeEmailDecorator.java
@@ -0,0 +1,84 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.mail.send;
+
+import com.google.gerrit.common.Nullable;
+import com.google.gerrit.entities.Account;
+import com.google.gerrit.entities.Address;
+import com.google.gerrit.entities.NotifyConfig.NotifyType;
+import com.google.gerrit.extensions.api.changes.RecipientType;
+import com.google.gerrit.server.mail.send.ChangeEmailNew.ChangeEmailDecorator;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/** Let users know that a reviewer and possibly her review have been removed. */
+public class DeleteReviewerChangeEmailDecorator implements ChangeEmailDecorator {
+  private OutgoingEmailNew email;
+  private ChangeEmailNew changeEmail;
+
+  private final Set<Account.Id> reviewers = new HashSet<>();
+  private final Set<Address> reviewersByEmail = new HashSet<>();
+
+  public void addReviewers(Collection<Account.Id> cc) {
+    reviewers.addAll(cc);
+  }
+
+  public void addReviewersByEmail(Collection<Address> cc) {
+    reviewersByEmail.addAll(cc);
+  }
+
+  @Nullable
+  private List<String> getReviewerNames() {
+    if (reviewers.isEmpty() && reviewersByEmail.isEmpty()) {
+      return null;
+    }
+    List<String> names = new ArrayList<>();
+    for (Account.Id id : reviewers) {
+      names.add(email.getNameFor(id));
+    }
+    for (Address a : reviewersByEmail) {
+      names.add(a.toString());
+    }
+    return names;
+  }
+
+  @Override
+  public void init(OutgoingEmailNew email, ChangeEmailNew changeEmail) {
+    this.email = email;
+    this.changeEmail = changeEmail;
+    changeEmail.markAsReply();
+  }
+
+  @Override
+  public void populateEmailContent() {
+    email.addSoyEmailDataParam("reviewerNames", getReviewerNames());
+
+    changeEmail.addAuthors(RecipientType.TO);
+    changeEmail.ccAllApprovals();
+    changeEmail.bccStarredBy();
+    changeEmail.ccExistingReviewers();
+    changeEmail.includeWatchers(NotifyType.ALL_COMMENTS);
+    reviewers.stream().forEach(r -> email.addByAccountId(RecipientType.TO, r));
+    reviewersByEmail.stream().forEach(address -> email.addByEmail(RecipientType.TO, address));
+
+    email.appendText(email.textTemplate("DeleteReviewer"));
+    if (email.useHtml()) {
+      email.appendHtml(email.soyHtmlTemplate("DeleteReviewerHtml"));
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/mail/send/DeleteReviewerSender.java b/java/com/google/gerrit/server/mail/send/DeleteReviewerSender.java
deleted file mode 100644
index 8ebc15d..0000000
--- a/java/com/google/gerrit/server/mail/send/DeleteReviewerSender.java
+++ /dev/null
@@ -1,92 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.mail.send;
-
-import com.google.gerrit.common.Nullable;
-import com.google.gerrit.entities.Account;
-import com.google.gerrit.entities.Address;
-import com.google.gerrit.entities.Change;
-import com.google.gerrit.entities.NotifyConfig.NotifyType;
-import com.google.gerrit.entities.Project;
-import com.google.gerrit.exceptions.EmailException;
-import com.google.gerrit.extensions.api.changes.RecipientType;
-import com.google.inject.Inject;
-import com.google.inject.assistedinject.Assisted;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
-
-/** Let users know that a reviewer and possibly her review have been removed. */
-public class DeleteReviewerSender extends ReplyToChangeSender {
-  private final Set<Account.Id> reviewers = new HashSet<>();
-  private final Set<Address> reviewersByEmail = new HashSet<>();
-
-  public interface Factory extends ReplyToChangeSender.Factory<DeleteReviewerSender> {
-    @Override
-    DeleteReviewerSender create(Project.NameKey project, Change.Id changeId);
-  }
-
-  @Inject
-  public DeleteReviewerSender(
-      EmailArguments args, @Assisted Project.NameKey project, @Assisted Change.Id changeId) {
-    super(args, "deleteReviewer", newChangeData(args, project, changeId));
-  }
-
-  public void addReviewers(Collection<Account.Id> cc) {
-    reviewers.addAll(cc);
-  }
-
-  public void addReviewersByEmail(Collection<Address> cc) {
-    reviewersByEmail.addAll(cc);
-  }
-
-  @Override
-  protected void formatChange() throws EmailException {
-    appendText(textTemplate("DeleteReviewer"));
-    if (useHtml()) {
-      appendHtml(soyHtmlTemplate("DeleteReviewerHtml"));
-    }
-  }
-
-  @Nullable
-  public List<String> getReviewerNames() {
-    if (reviewers.isEmpty() && reviewersByEmail.isEmpty()) {
-      return null;
-    }
-    List<String> names = new ArrayList<>();
-    for (Account.Id id : reviewers) {
-      names.add(getNameFor(id));
-    }
-    for (Address a : reviewersByEmail) {
-      names.add(a.toString());
-    }
-    return names;
-  }
-
-  @Override
-  protected void populateEmailContent() throws EmailException {
-    super.populateEmailContent();
-    addSoyEmailDataParam("reviewerNames", getReviewerNames());
-
-    ccAllApprovals();
-    bccStarredBy();
-    ccExistingReviewers();
-    includeWatchers(NotifyType.ALL_COMMENTS);
-    reviewers.stream().forEach(r -> addByAccountId(RecipientType.TO, r));
-    reviewersByEmail.stream().forEach(address -> addByEmail(RecipientType.TO, address));
-  }
-}
diff --git a/java/com/google/gerrit/server/mail/send/DeleteVoteChangeEmailDecorator.java b/java/com/google/gerrit/server/mail/send/DeleteVoteChangeEmailDecorator.java
new file mode 100644
index 0000000..2bf67e5
--- /dev/null
+++ b/java/com/google/gerrit/server/mail/send/DeleteVoteChangeEmailDecorator.java
@@ -0,0 +1,45 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.mail.send;
+
+import com.google.gerrit.entities.NotifyConfig.NotifyType;
+import com.google.gerrit.extensions.api.changes.RecipientType;
+import com.google.gerrit.server.mail.send.ChangeEmailNew.ChangeEmailDecorator;
+
+/** Send notice about a vote that was removed from a change. */
+public class DeleteVoteChangeEmailDecorator implements ChangeEmailDecorator {
+  private OutgoingEmailNew email;
+  private ChangeEmailNew changeEmail;
+
+  @Override
+  public void init(OutgoingEmailNew email, ChangeEmailNew changeEmail) {
+    this.email = email;
+    this.changeEmail = changeEmail;
+    changeEmail.markAsReply();
+  }
+
+  @Override
+  public void populateEmailContent() {
+    changeEmail.addAuthors(RecipientType.TO);
+    changeEmail.ccAllApprovals();
+    changeEmail.bccStarredBy();
+    changeEmail.includeWatchers(NotifyType.ALL_COMMENTS);
+
+    email.appendText(email.textTemplate("DeleteVote"));
+    if (email.useHtml()) {
+      email.appendHtml(email.soyHtmlTemplate("DeleteVoteHtml"));
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/mail/send/DeleteVoteSender.java b/java/com/google/gerrit/server/mail/send/DeleteVoteSender.java
deleted file mode 100644
index cc37325c..0000000
--- a/java/com/google/gerrit/server/mail/send/DeleteVoteSender.java
+++ /dev/null
@@ -1,53 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.mail.send;
-
-import com.google.gerrit.entities.Change;
-import com.google.gerrit.entities.NotifyConfig.NotifyType;
-import com.google.gerrit.entities.Project;
-import com.google.gerrit.exceptions.EmailException;
-import com.google.inject.Inject;
-import com.google.inject.assistedinject.Assisted;
-
-/** Send notice about a vote that was removed from a change. */
-public class DeleteVoteSender extends ReplyToChangeSender {
-  public interface Factory extends ReplyToChangeSender.Factory<DeleteVoteSender> {
-    @Override
-    DeleteVoteSender create(Project.NameKey project, Change.Id changeId);
-  }
-
-  @Inject
-  protected DeleteVoteSender(
-      EmailArguments args, @Assisted Project.NameKey project, @Assisted Change.Id changeId) {
-    super(args, "deleteVote", newChangeData(args, project, changeId));
-  }
-
-  @Override
-  protected void populateEmailContent() throws EmailException {
-    super.populateEmailContent();
-
-    ccAllApprovals();
-    bccStarredBy();
-    includeWatchers(NotifyType.ALL_COMMENTS);
-  }
-
-  @Override
-  protected void formatChange() throws EmailException {
-    appendText(textTemplate("DeleteVote"));
-    if (useHtml()) {
-      appendHtml(soyHtmlTemplate("DeleteVoteHtml"));
-    }
-  }
-}
diff --git a/java/com/google/gerrit/server/mail/send/MergedSender.java b/java/com/google/gerrit/server/mail/send/MergedChangeEmailDecorator.java
similarity index 66%
rename from java/com/google/gerrit/server/mail/send/MergedSender.java
rename to java/com/google/gerrit/server/mail/send/MergedChangeEmailDecorator.java
index f8aa00d..dc80ba9 100644
--- a/java/com/google/gerrit/server/mail/send/MergedSender.java
+++ b/java/com/google/gerrit/server/mail/send/MergedChangeEmailDecorator.java
@@ -14,70 +14,57 @@
 
 package com.google.gerrit.server.mail.send;
 
+import com.google.auto.factory.AutoFactory;
+import com.google.auto.factory.Provided;
 import com.google.common.collect.HashBasedTable;
 import com.google.common.collect.Table;
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.entities.Account;
-import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.LabelType;
 import com.google.gerrit.entities.LabelTypes;
 import com.google.gerrit.entities.LabelValue;
 import com.google.gerrit.entities.NotifyConfig.NotifyType;
 import com.google.gerrit.entities.PatchSetApproval;
-import com.google.gerrit.entities.Project;
-import com.google.gerrit.exceptions.EmailException;
 import com.google.gerrit.exceptions.StorageException;
 import com.google.gerrit.extensions.api.changes.NotifyHandling;
+import com.google.gerrit.extensions.api.changes.RecipientType;
 import com.google.gerrit.server.change.NotifyResolver;
-import com.google.inject.Inject;
-import com.google.inject.assistedinject.Assisted;
+import com.google.gerrit.server.mail.send.ChangeEmailNew.ChangeEmailDecorator;
 import java.util.Optional;
 
 /** Send notice about a change successfully merged. */
-public class MergedSender extends ReplyToChangeSender {
+@AutoFactory
+public class MergedChangeEmailDecorator implements ChangeEmailDecorator {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
-  public interface Factory {
-    MergedSender create(
-        Project.NameKey project, Change.Id changeId, Optional<String> stickyApprovalDiff);
-  }
-
-  private final LabelTypes labelTypes;
+  private OutgoingEmailNew email;
+  private ChangeEmailNew changeEmail;
+  private LabelTypes labelTypes;
+  private final EmailArguments args;
   private final Optional<String> stickyApprovalDiff;
 
-  @Inject
-  public MergedSender(
-      EmailArguments args,
-      @Assisted Project.NameKey project,
-      @Assisted Change.Id changeId,
-      @Assisted Optional<String> stickyApprovalDiff) {
-    super(args, "merged", newChangeData(args, project, changeId));
-    labelTypes = getChangeData().getLabelTypes();
+  MergedChangeEmailDecorator(@Provided EmailArguments args, Optional<String> stickyApprovalDiff) {
+    this.args = args;
     this.stickyApprovalDiff = stickyApprovalDiff;
-    // We want to send the submit email even if the "send only when in attention set" is enabled.
-    setEmailOnlyAttentionSetIfEnabled(false);
   }
 
   @Override
-  protected void init() throws EmailException {
-    super.init();
+  public void init(OutgoingEmailNew email, ChangeEmailNew changeEmail) {
+    this.email = email;
+    this.changeEmail = changeEmail;
+    changeEmail.markAsReply();
+    labelTypes = changeEmail.getChangeData().getLabelTypes();
 
-    NotifyResolver.Result notify = getNotify();
+    // We want to send the submit email even if the "send only when in attention set" is enabled.
+    changeEmail.setEmailOnlyAttentionSetIfEnabled(false);
+
+    NotifyResolver.Result notify = email.getNotify();
     if (!stickyApprovalDiff.isEmpty() && !notify.handling().equals(NotifyHandling.ALL)) {
       logger.atFine().log(
           "Requested to notify %s, but for change submission with sticky approval diff,"
               + " Notify=ALL is enforced.",
           notify.handling().name());
-      setNotify(NotifyResolver.Result.create(NotifyHandling.ALL, notify.accounts()));
-    }
-  }
-
-  @Override
-  protected void formatChange() throws EmailException {
-    appendText(textTemplate("Merged"));
-
-    if (useHtml()) {
-      appendHtml(soyHtmlTemplate("MergedHtml"));
+      email.setNotify(NotifyResolver.Result.create(NotifyHandling.ALL, notify.accounts()));
     }
   }
 
@@ -86,7 +73,8 @@
       Table<Account.Id, String, PatchSetApproval> pos = HashBasedTable.create();
       Table<Account.Id, String, PatchSetApproval> neg = HashBasedTable.create();
       for (PatchSetApproval ca :
-          args.approvalsUtil.byPatchSet(getChangeData().notes(), getPatchSet().id())) {
+          args.approvalsUtil.byPatchSet(
+              changeEmail.getChangeData().notes(), changeEmail.getPatchSet().id())) {
         Optional<LabelType> lt = labelTypes.byLabel(ca.labelId());
         if (!lt.isPresent()) {
           continue;
@@ -113,7 +101,7 @@
     txt.append(type).append(":\n");
     for (Account.Id id : approvals.rowKeySet()) {
       txt.append("  ");
-      txt.append(getNameFor(id));
+      txt.append(email.getNameFor(id));
       txt.append(": ");
       boolean first = true;
       for (LabelType lt : labelTypes.getLabelTypes()) {
@@ -144,17 +132,24 @@
   }
 
   @Override
-  protected void populateEmailContent() throws EmailException {
-    super.populateEmailContent();
-    addSoyEmailDataParam("approvals", getApprovals());
+  public void populateEmailContent() {
+    email.addSoyEmailDataParam("approvals", getApprovals());
     if (stickyApprovalDiff.isPresent()) {
-      addSoyEmailDataParam("stickyApprovalDiff", stickyApprovalDiff.get());
-      addSoyEmailDataParam("stickyApprovalDiffHtml", getDiffTemplateData(stickyApprovalDiff.get()));
+      email.addSoyEmailDataParam("stickyApprovalDiff", stickyApprovalDiff.get());
+      email.addSoyEmailDataParam(
+          "stickyApprovalDiffHtml", ChangeEmailNew.getDiffTemplateData(stickyApprovalDiff.get()));
     }
 
-    ccAllApprovals();
-    bccStarredBy();
-    includeWatchers(NotifyType.ALL_COMMENTS);
-    includeWatchers(NotifyType.SUBMITTED_CHANGES);
+    changeEmail.addAuthors(RecipientType.TO);
+    changeEmail.ccAllApprovals();
+    changeEmail.bccStarredBy();
+    changeEmail.includeWatchers(NotifyType.ALL_COMMENTS);
+    changeEmail.includeWatchers(NotifyType.SUBMITTED_CHANGES);
+
+    email.appendText(email.textTemplate("Merged"));
+
+    if (email.useHtml()) {
+      email.appendHtml(email.soyHtmlTemplate("MergedHtml"));
+    }
   }
 }
diff --git a/java/com/google/gerrit/server/mail/send/OutgoingEmailNew.java b/java/com/google/gerrit/server/mail/send/OutgoingEmailNew.java
index 95b35be..ae558b7 100644
--- a/java/com/google/gerrit/server/mail/send/OutgoingEmailNew.java
+++ b/java/com/google/gerrit/server/mail/send/OutgoingEmailNew.java
@@ -64,7 +64,7 @@
 public final class OutgoingEmailNew {
 
   /** Provides content, recipients and any customizations of the email. */
-  interface EmailDecorator {
+  public interface EmailDecorator {
     /**
      * Stores the reference to the email for the subsequent calls.
      *
diff --git a/java/com/google/gerrit/server/mail/send/RemoveFromAttentionSetSender.java b/java/com/google/gerrit/server/mail/send/RemoveFromAttentionSetSender.java
deleted file mode 100644
index 5242bfb..0000000
--- a/java/com/google/gerrit/server/mail/send/RemoveFromAttentionSetSender.java
+++ /dev/null
@@ -1,43 +0,0 @@
-// Copyright (C) 2020 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-package com.google.gerrit.server.mail.send;
-
-import com.google.gerrit.entities.Change;
-import com.google.gerrit.entities.Project;
-import com.google.gerrit.exceptions.EmailException;
-import com.google.inject.Inject;
-import com.google.inject.assistedinject.Assisted;
-
-/** Let users know of a user removed from the attention set. */
-public class RemoveFromAttentionSetSender extends AttentionSetSender {
-
-  public interface Factory extends ReplyToChangeSender.Factory<RemoveFromAttentionSetSender> {
-    @Override
-    RemoveFromAttentionSetSender create(Project.NameKey project, Change.Id changeId);
-  }
-
-  @Inject
-  public RemoveFromAttentionSetSender(
-      EmailArguments args, @Assisted Project.NameKey project, @Assisted Change.Id changeId) {
-    super(args, "removeFromAttentionSet", project, changeId);
-  }
-
-  @Override
-  protected void formatChange() throws EmailException {
-    appendText(textTemplate("RemoveFromAttentionSet"));
-    if (useHtml()) {
-      appendHtml(soyHtmlTemplate("RemoveFromAttentionSetHtml"));
-    }
-  }
-}
diff --git a/java/com/google/gerrit/server/mail/send/ReplacePatchSetSender.java b/java/com/google/gerrit/server/mail/send/ReplacePatchSetChangeEmailDecorator.java
similarity index 72%
rename from java/com/google/gerrit/server/mail/send/ReplacePatchSetSender.java
rename to java/com/google/gerrit/server/mail/send/ReplacePatchSetChangeEmailDecorator.java
index 85d2757..a9bd32e 100644
--- a/java/com/google/gerrit/server/mail/send/ReplacePatchSetSender.java
+++ b/java/com/google/gerrit/server/mail/send/ReplacePatchSetChangeEmailDecorator.java
@@ -16,6 +16,8 @@
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
 
+import com.google.auto.factory.AutoFactory;
+import com.google.auto.factory.Provided;
 import com.google.common.base.Supplier;
 import com.google.common.base.Suppliers;
 import com.google.common.collect.ImmutableList;
@@ -28,13 +30,11 @@
 import com.google.gerrit.entities.Project;
 import com.google.gerrit.entities.SubmitRequirement;
 import com.google.gerrit.entities.SubmitRequirementResult;
-import com.google.gerrit.exceptions.EmailException;
 import com.google.gerrit.extensions.api.changes.NotifyHandling;
 import com.google.gerrit.extensions.api.changes.RecipientType;
 import com.google.gerrit.extensions.client.ChangeKind;
+import com.google.gerrit.server.mail.send.ChangeEmailNew.ChangeEmailDecorator;
 import com.google.gerrit.server.util.LabelVote;
-import com.google.inject.Inject;
-import com.google.inject.assistedinject.Assisted;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
@@ -44,18 +44,13 @@
 import org.eclipse.jgit.lib.ObjectId;
 
 /** Send notice of new patch sets for reviewers. */
-public class ReplacePatchSetSender extends ReplyToChangeSender {
+@AutoFactory
+public class ReplacePatchSetChangeEmailDecorator implements ChangeEmailDecorator {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
-  public interface Factory {
-    ReplacePatchSetSender create(
-        Project.NameKey project,
-        Change.Id changeId,
-        ChangeKind changeKind,
-        ObjectId preUpdateMetaId,
-        Map<SubmitRequirement, SubmitRequirementResult> postUpdateSubmitRequirementResults);
-  }
-
+  private final EmailArguments args;
+  private OutgoingEmailNew email;
+  private ChangeEmailNew changeEmail;
   private final Set<Account.Id> reviewers = new HashSet<>();
   private final Set<Account.Id> extraCC = new HashSet<>();
   private final ChangeKind changeKind;
@@ -64,16 +59,14 @@
       preUpdateSubmitRequirementResultsSupplier;
   private final Map<SubmitRequirement, SubmitRequirementResult> postUpdateSubmitRequirementResults;
 
-  @Inject
-  public ReplacePatchSetSender(
-      EmailArguments args,
-      @Assisted Project.NameKey project,
-      @Assisted Change.Id changeId,
-      @Assisted ChangeKind changeKind,
-      @Assisted ObjectId preUpdateMetaId,
-      @Assisted
-          Map<SubmitRequirement, SubmitRequirementResult> postUpdateSubmitRequirementResults) {
-    super(args, "newpatchset", newChangeData(args, project, changeId));
+  ReplacePatchSetChangeEmailDecorator(
+      @Provided EmailArguments args,
+      Project.NameKey project,
+      Change.Id changeId,
+      ChangeKind changeKind,
+      ObjectId preUpdateMetaId,
+      Map<SubmitRequirement, SubmitRequirementResult> postUpdateSubmitRequirementResults) {
+    this.args = args;
     this.changeKind = changeKind;
 
     this.preUpdateSubmitRequirementResultsSupplier =
@@ -81,22 +74,21 @@
             () ->
                 // Triggers an (expensive) evaluation of the submit requirements. This is OK since
                 // all callers sent this email asynchronously, see EmailNewPatchSet.
-                newChangeData(args, project, changeId, preUpdateMetaId)
+                args.newChangeData(project, changeId, preUpdateMetaId)
                     .submitRequirementsIncludingLegacy());
 
     this.postUpdateSubmitRequirementResults = postUpdateSubmitRequirementResults;
   }
 
   @Override
-  protected boolean shouldSendMessage() {
+  public boolean shouldSendMessage() {
     if (!isChangeNoLongerSubmittable() && changeKind.isTrivialRebase()) {
       logger.atFine().log(
           "skip email because new patch set is a trivial rebase that didn't make the change"
               + " non-submittable");
       return false;
     }
-
-    return super.shouldSendMessage();
+    return true;
   }
 
   public void addReviewers(Collection<Account.Id> cc) {
@@ -114,10 +106,12 @@
   }
 
   @Override
-  protected void init() throws EmailException {
-    super.init();
+  public void init(OutgoingEmailNew email, ChangeEmailNew changeEmail) {
+    this.email = email;
+    this.changeEmail = changeEmail;
+    changeEmail.markAsReply();
 
-    Account.Id fromId = getFrom();
+    Account.Id fromId = email.getFrom();
     if (fromId != null) {
       // Don't call yourself a reviewer of your own patch set.
       //
@@ -125,22 +119,14 @@
     }
   }
 
-  @Override
-  protected void formatChange() throws EmailException {
-    appendText(textTemplate("ReplacePatchSet"));
-    if (useHtml()) {
-      appendHtml(soyHtmlTemplate("ReplacePatchSetHtml"));
-    }
-  }
-
   @Nullable
-  public ImmutableList<String> getReviewerNames() {
+  private ImmutableList<String> getReviewerNames() {
     List<String> names = new ArrayList<>();
     for (Account.Id id : reviewers) {
-      if (id.equals(getFrom())) {
+      if (id.equals(email.getFrom())) {
         continue;
       }
-      names.add(getNameFor(id));
+      names.add(email.getNameFor(id));
     }
     if (names.isEmpty()) {
       return null;
@@ -155,37 +141,43 @@
                 String.format(
                     "%s by %s",
                     LabelVote.create(outdatedApproval.label(), outdatedApproval.value()).format(),
-                    getNameFor(outdatedApproval.accountId())))
+                    email.getNameFor(outdatedApproval.accountId())))
         .sorted()
         .collect(toImmutableList());
   }
 
   @Override
-  protected void populateEmailContent() throws EmailException {
-    super.populateEmailContent();
-    addSoyEmailDataParam("reviewerNames", getReviewerNames());
-    addSoyEmailDataParam("outdatedApprovals", formatOutdatedApprovals());
+  public void populateEmailContent() {
+    changeEmail.addAuthors(RecipientType.TO);
+
+    email.addSoyEmailDataParam("reviewerNames", getReviewerNames());
+    email.addSoyEmailDataParam("outdatedApprovals", formatOutdatedApprovals());
 
     if (isChangeNoLongerSubmittable()) {
-      addSoyParam("unsatisfiedSubmitRequirements", formatUnsatisfiedSubmitRequirements());
-      addSoyParam(
+      email.addSoyParam("unsatisfiedSubmitRequirements", formatUnsatisfiedSubmitRequirements());
+      email.addSoyParam(
           "oldSubmitRequirements",
           formatSubmitRequirments(preUpdateSubmitRequirementResultsSupplier.get()));
-      addSoyParam(
+      email.addSoyParam(
           "newSubmitRequirements", formatSubmitRequirments(postUpdateSubmitRequirementResults));
     }
 
     if (args.settings.sendNewPatchsetEmails) {
-      if (getNotify().handling().equals(NotifyHandling.ALL)
-          || getNotify().handling().equals(NotifyHandling.OWNER_REVIEWERS)) {
-        reviewers.stream().forEach(r -> addByAccountId(RecipientType.TO, r));
-        extraCC.stream().forEach(cc -> addByAccountId(RecipientType.CC, cc));
+      if (email.getNotify().handling().equals(NotifyHandling.ALL)
+          || email.getNotify().handling().equals(NotifyHandling.OWNER_REVIEWERS)) {
+        reviewers.stream().forEach(r -> email.addByAccountId(RecipientType.TO, r));
+        extraCC.stream().forEach(cc -> email.addByAccountId(RecipientType.CC, cc));
       }
-      addAuthors(RecipientType.CC);
     }
-    bccStarredBy();
-    includeWatchers(
-        NotifyType.NEW_PATCHSETS, !getChange().isWorkInProgress() && !getChange().isPrivate());
+    changeEmail.bccStarredBy();
+    changeEmail.includeWatchers(
+        NotifyType.NEW_PATCHSETS,
+        !changeEmail.getChange().isWorkInProgress() && !changeEmail.getChange().isPrivate());
+
+    email.appendText(email.textTemplate("ReplacePatchSet"));
+    if (email.useHtml()) {
+      email.appendHtml(email.soyHtmlTemplate("ReplacePatchSetHtml"));
+    }
   }
 
   /**
@@ -200,7 +192,7 @@
             .allMatch(SubmitRequirementResult::fulfilled);
     logger.atFine().log(
         "the submitability of change %s before the update is %s",
-        getChange().getId(), isSubmittablePreUpdate);
+        changeEmail.getChange().getId(), isSubmittablePreUpdate);
     if (!isSubmittablePreUpdate) {
       return false;
     }
@@ -210,7 +202,7 @@
             .allMatch(SubmitRequirementResult::fulfilled);
     logger.atFine().log(
         "the submitability of change %s after the update is %s",
-        getChange().getId(), isSubmittablePostUpdate);
+        changeEmail.getChange().getId(), isSubmittablePostUpdate);
     return !isSubmittablePostUpdate;
   }
 
diff --git a/java/com/google/gerrit/server/mail/send/RestoredChangeEmailDecorator.java b/java/com/google/gerrit/server/mail/send/RestoredChangeEmailDecorator.java
new file mode 100644
index 0000000..d8c2696
--- /dev/null
+++ b/java/com/google/gerrit/server/mail/send/RestoredChangeEmailDecorator.java
@@ -0,0 +1,46 @@
+// Copyright (C) 2011 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.mail.send;
+
+import com.google.gerrit.entities.NotifyConfig.NotifyType;
+import com.google.gerrit.extensions.api.changes.RecipientType;
+import com.google.gerrit.server.mail.send.ChangeEmailNew.ChangeEmailDecorator;
+
+/** Send notice about a change being restored by its owner. */
+public class RestoredChangeEmailDecorator implements ChangeEmailDecorator {
+  private OutgoingEmailNew email;
+  private ChangeEmailNew changeEmail;
+
+  @Override
+  public void init(OutgoingEmailNew email, ChangeEmailNew changeEmail) {
+    this.email = email;
+    this.changeEmail = changeEmail;
+    changeEmail.markAsReply();
+  }
+
+  @Override
+  public void populateEmailContent() {
+    changeEmail.addAuthors(RecipientType.TO);
+
+    changeEmail.ccAllApprovals();
+    changeEmail.bccStarredBy();
+    changeEmail.includeWatchers(NotifyType.ALL_COMMENTS);
+
+    email.appendText(email.textTemplate("Restored"));
+    if (email.useHtml()) {
+      email.appendHtml(email.soyHtmlTemplate("RestoredHtml"));
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/mail/send/RestoredSender.java b/java/com/google/gerrit/server/mail/send/RestoredSender.java
deleted file mode 100644
index 672b758..0000000
--- a/java/com/google/gerrit/server/mail/send/RestoredSender.java
+++ /dev/null
@@ -1,53 +0,0 @@
-// Copyright (C) 2011 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.mail.send;
-
-import com.google.gerrit.entities.Change;
-import com.google.gerrit.entities.NotifyConfig.NotifyType;
-import com.google.gerrit.entities.Project;
-import com.google.gerrit.exceptions.EmailException;
-import com.google.inject.Inject;
-import com.google.inject.assistedinject.Assisted;
-
-/** Send notice about a change being restored by its owner. */
-public class RestoredSender extends ReplyToChangeSender {
-  public interface Factory extends ReplyToChangeSender.Factory<RestoredSender> {
-    @Override
-    RestoredSender create(Project.NameKey project, Change.Id changeId);
-  }
-
-  @Inject
-  public RestoredSender(
-      EmailArguments args, @Assisted Project.NameKey project, @Assisted Change.Id changeId) {
-    super(args, "restore", ChangeEmail.newChangeData(args, project, changeId));
-  }
-
-  @Override
-  protected void populateEmailContent() throws EmailException {
-    super.populateEmailContent();
-
-    ccAllApprovals();
-    bccStarredBy();
-    includeWatchers(NotifyType.ALL_COMMENTS);
-  }
-
-  @Override
-  protected void formatChange() throws EmailException {
-    appendText(textTemplate("Restored"));
-    if (useHtml()) {
-      appendHtml(soyHtmlTemplate("RestoredHtml"));
-    }
-  }
-}
diff --git a/java/com/google/gerrit/server/mail/send/RevertedChangeEmailDecorator.java b/java/com/google/gerrit/server/mail/send/RevertedChangeEmailDecorator.java
new file mode 100644
index 0000000..2a802f3
--- /dev/null
+++ b/java/com/google/gerrit/server/mail/send/RevertedChangeEmailDecorator.java
@@ -0,0 +1,46 @@
+// Copyright (C) 2011 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.mail.send;
+
+import com.google.gerrit.entities.NotifyConfig.NotifyType;
+import com.google.gerrit.extensions.api.changes.RecipientType;
+import com.google.gerrit.server.mail.send.ChangeEmailNew.ChangeEmailDecorator;
+
+/** Send notice about a change being reverted. */
+public class RevertedChangeEmailDecorator implements ChangeEmailDecorator {
+  private OutgoingEmailNew email;
+  private ChangeEmailNew changeEmail;
+
+  @Override
+  public void init(OutgoingEmailNew email, ChangeEmailNew changeEmail) {
+    this.email = email;
+    this.changeEmail = changeEmail;
+    changeEmail.markAsReply();
+  }
+
+  @Override
+  public void populateEmailContent() {
+    changeEmail.addAuthors(RecipientType.TO);
+
+    changeEmail.ccAllApprovals();
+    changeEmail.bccStarredBy();
+    changeEmail.includeWatchers(NotifyType.ALL_COMMENTS);
+
+    email.appendText(email.textTemplate("Reverted"));
+    if (email.useHtml()) {
+      email.appendHtml(email.soyHtmlTemplate("RevertedHtml"));
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/mail/send/RevertedSender.java b/java/com/google/gerrit/server/mail/send/RevertedSender.java
deleted file mode 100644
index 6ab44a7..0000000
--- a/java/com/google/gerrit/server/mail/send/RevertedSender.java
+++ /dev/null
@@ -1,52 +0,0 @@
-// Copyright (C) 2011 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.mail.send;
-
-import com.google.gerrit.entities.Change;
-import com.google.gerrit.entities.NotifyConfig.NotifyType;
-import com.google.gerrit.entities.Project;
-import com.google.gerrit.exceptions.EmailException;
-import com.google.inject.Inject;
-import com.google.inject.assistedinject.Assisted;
-
-/** Send notice about a change being reverted. */
-public class RevertedSender extends ReplyToChangeSender {
-  public interface Factory {
-    RevertedSender create(Project.NameKey project, Change.Id changeId);
-  }
-
-  @Inject
-  public RevertedSender(
-      EmailArguments args, @Assisted Project.NameKey project, @Assisted Change.Id changeId) {
-    super(args, "revert", ChangeEmail.newChangeData(args, project, changeId));
-  }
-
-  @Override
-  protected void populateEmailContent() throws EmailException {
-    super.populateEmailContent();
-
-    ccAllApprovals();
-    bccStarredBy();
-    includeWatchers(NotifyType.ALL_COMMENTS);
-  }
-
-  @Override
-  protected void formatChange() throws EmailException {
-    appendText(textTemplate("Reverted"));
-    if (useHtml()) {
-      appendHtml(soyHtmlTemplate("RevertedHtml"));
-    }
-  }
-}
diff --git a/java/com/google/gerrit/server/query/account/AccountQueryProcessor.java b/java/com/google/gerrit/server/query/account/AccountQueryProcessor.java
index 9893d1a..eef913e 100644
--- a/java/com/google/gerrit/server/query/account/AccountQueryProcessor.java
+++ b/java/com/google/gerrit/server/query/account/AccountQueryProcessor.java
@@ -17,6 +17,7 @@
 import static com.google.common.base.Preconditions.checkState;
 import static com.google.gerrit.server.query.account.AccountQueryBuilder.FIELD_LIMIT;
 
+import com.google.common.collect.ImmutableList;
 import com.google.gerrit.index.IndexConfig;
 import com.google.gerrit.index.query.AndSource;
 import com.google.gerrit.index.query.IndexPredicate;
@@ -78,7 +79,9 @@
   @Override
   protected Predicate<AccountState> enforceVisibility(Predicate<AccountState> pred) {
     return new AndSource<>(
-        pred, new AccountIsVisibleToPredicate(accountControlFactory.get()), start, indexConfig);
+        ImmutableList.of(pred, new AccountIsVisibleToPredicate(accountControlFactory.get())),
+        start,
+        indexConfig);
   }
 
   @Override
diff --git a/java/com/google/gerrit/server/query/change/AndChangeSource.java b/java/com/google/gerrit/server/query/change/AndChangeSource.java
index 98cada3..e4f768e 100644
--- a/java/com/google/gerrit/server/query/change/AndChangeSource.java
+++ b/java/com/google/gerrit/server/query/change/AndChangeSource.java
@@ -16,7 +16,6 @@
 
 import com.google.gerrit.index.IndexConfig;
 import com.google.gerrit.index.query.AndSource;
-import com.google.gerrit.index.query.IsVisibleToPredicate;
 import com.google.gerrit.index.query.Predicate;
 import java.util.Collection;
 import java.util.List;
@@ -28,11 +27,8 @@
   }
 
   public AndChangeSource(
-      Predicate<ChangeData> that,
-      IsVisibleToPredicate<ChangeData> isVisibleToPredicate,
-      int start,
-      IndexConfig indexConfig) {
-    super(that, isVisibleToPredicate, start, indexConfig);
+      Collection<Predicate<ChangeData>> that, int start, IndexConfig indexConfig) {
+    super(that, start, indexConfig);
   }
 
   @Override
diff --git a/java/com/google/gerrit/server/query/change/ChangeQueryProcessor.java b/java/com/google/gerrit/server/query/change/ChangeQueryProcessor.java
index 0f0535a..b7dc127 100644
--- a/java/com/google/gerrit/server/query/change/ChangeQueryProcessor.java
+++ b/java/com/google/gerrit/server/query/change/ChangeQueryProcessor.java
@@ -17,6 +17,7 @@
 import static com.google.common.base.Preconditions.checkState;
 import static com.google.gerrit.server.query.change.ChangeQueryBuilder.FIELD_LIMIT;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableListMultimap;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.extensions.common.PluginDefinedInfo;
@@ -143,7 +144,9 @@
   @Override
   protected Predicate<ChangeData> enforceVisibility(Predicate<ChangeData> pred) {
     return new AndChangeSource(
-        pred, changeIsVisibleToPredicateFactory.forUser(userProvider.get()), start, indexConfig);
+        ImmutableList.of(pred, changeIsVisibleToPredicateFactory.forUser(userProvider.get())),
+        start,
+        indexConfig);
   }
 
   @Override
diff --git a/java/com/google/gerrit/server/query/group/GroupQueryProcessor.java b/java/com/google/gerrit/server/query/group/GroupQueryProcessor.java
index c6683fa..344a978 100644
--- a/java/com/google/gerrit/server/query/group/GroupQueryProcessor.java
+++ b/java/com/google/gerrit/server/query/group/GroupQueryProcessor.java
@@ -17,6 +17,7 @@
 import static com.google.common.base.Preconditions.checkState;
 import static com.google.gerrit.server.query.group.GroupQueryBuilder.FIELD_LIMIT;
 
+import com.google.common.collect.ImmutableList;
 import com.google.gerrit.entities.InternalGroup;
 import com.google.gerrit.index.IndexConfig;
 import com.google.gerrit.index.query.AndSource;
@@ -80,8 +81,8 @@
   @Override
   protected Predicate<InternalGroup> enforceVisibility(Predicate<InternalGroup> pred) {
     return new AndSource<>(
-        pred,
-        new GroupIsVisibleToPredicate(groupControlFactory, userProvider.get()),
+        ImmutableList.of(
+            pred, new GroupIsVisibleToPredicate(groupControlFactory, userProvider.get())),
         start,
         indexConfig);
   }
diff --git a/java/com/google/gerrit/server/query/project/ProjectQueryProcessor.java b/java/com/google/gerrit/server/query/project/ProjectQueryProcessor.java
index 6dafa92..3877c25 100644
--- a/java/com/google/gerrit/server/query/project/ProjectQueryProcessor.java
+++ b/java/com/google/gerrit/server/query/project/ProjectQueryProcessor.java
@@ -17,6 +17,7 @@
 import static com.google.common.base.Preconditions.checkState;
 import static com.google.gerrit.server.query.project.ProjectQueryBuilder.FIELD_LIMIT;
 
+import com.google.common.collect.ImmutableList;
 import com.google.gerrit.index.IndexConfig;
 import com.google.gerrit.index.project.ProjectData;
 import com.google.gerrit.index.project.ProjectIndexCollection;
@@ -82,8 +83,8 @@
   @Override
   protected Predicate<ProjectData> enforceVisibility(Predicate<ProjectData> pred) {
     return new AndSource<>(
-        pred,
-        new ProjectIsVisibleToPredicate(permissionBackend, userProvider.get()),
+        ImmutableList.of(
+            pred, new ProjectIsVisibleToPredicate(permissionBackend, userProvider.get())),
         start,
         indexConfig);
   }
diff --git a/java/com/google/gerrit/server/restapi/change/DeleteVoteOp.java b/java/com/google/gerrit/server/restapi/change/DeleteVoteOp.java
index 3ac4d22..ef1b6f6 100644
--- a/java/com/google/gerrit/server/restapi/change/DeleteVoteOp.java
+++ b/java/com/google/gerrit/server/restapi/change/DeleteVoteOp.java
@@ -35,9 +35,10 @@
 import com.google.gerrit.server.approval.ApprovalsUtil;
 import com.google.gerrit.server.change.NotifyResolver;
 import com.google.gerrit.server.extensions.events.VoteDeleted;
-import com.google.gerrit.server.mail.send.DeleteVoteSender;
+import com.google.gerrit.server.mail.EmailModule.DeleteVoteChangeEmailFactories;
+import com.google.gerrit.server.mail.send.ChangeEmailNew;
 import com.google.gerrit.server.mail.send.MessageIdGenerator;
-import com.google.gerrit.server.mail.send.ReplyToChangeSender;
+import com.google.gerrit.server.mail.send.OutgoingEmailNew;
 import com.google.gerrit.server.permissions.LabelRemovalPermission;
 import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.project.DeleteVoteControl;
@@ -76,7 +77,7 @@
   private final PatchSetUtil psUtil;
   private final ChangeMessagesUtil cmUtil;
   private final VoteDeleted voteDeleted;
-  private final DeleteVoteSender.Factory deleteVoteSenderFactory;
+  private final DeleteVoteChangeEmailFactories deleteVoteChangeEmailFactories;
 
   private final DeleteVoteControl deleteVoteControl;
   private final RemoveReviewerControl removeReviewerControl;
@@ -99,7 +100,7 @@
       PatchSetUtil psUtil,
       ChangeMessagesUtil cmUtil,
       VoteDeleted voteDeleted,
-      DeleteVoteSender.Factory deleteVoteSenderFactory,
+      DeleteVoteChangeEmailFactories deleteVoteChangeEmailFactories,
       DeleteVoteControl deleteVoteControl,
       MessageIdGenerator messageIdGenerator,
       RemoveReviewerControl removeReviewerControl,
@@ -113,7 +114,7 @@
     this.psUtil = psUtil;
     this.cmUtil = cmUtil;
     this.voteDeleted = voteDeleted;
-    this.deleteVoteSenderFactory = deleteVoteSenderFactory;
+    this.deleteVoteChangeEmailFactories = deleteVoteChangeEmailFactories;
     this.deleteVoteControl = deleteVoteControl;
     this.removeReviewerControl = removeReviewerControl;
     this.messageIdGenerator = messageIdGenerator;
@@ -187,17 +188,18 @@
 
     CurrentUser user = ctx.getUser();
     try {
+      ChangeEmailNew changeEmail =
+          deleteVoteChangeEmailFactories.createChangeEmail(ctx.getProject(), change.getId());
+      changeEmail.setChangeMessage(mailMessage, ctx.getWhen());
+      OutgoingEmailNew outgoingEmail = deleteVoteChangeEmailFactories.createEmail(changeEmail);
       NotifyResolver.Result notify = ctx.getNotify(change.getId());
-      ReplyToChangeSender emailSender =
-          deleteVoteSenderFactory.create(ctx.getProject(), change.getId());
       if (user.isIdentifiedUser()) {
-        emailSender.setFrom(user.getAccountId());
+        outgoingEmail.setFrom(user.getAccountId());
       }
-      emailSender.setChangeMessage(mailMessage, ctx.getWhen());
-      emailSender.setNotify(notify);
-      emailSender.setMessageId(
+      outgoingEmail.setNotify(notify);
+      outgoingEmail.setMessageId(
           messageIdGenerator.fromChangeUpdate(ctx.getRepoView(), change.currentPatchSetId()));
-      emailSender.send();
+      outgoingEmail.send();
     } catch (Exception e) {
       logger.atSevere().withCause(e).log("Cannot email update for change %s", change.getId());
     }
diff --git a/java/com/google/gerrit/server/restapi/change/Restore.java b/java/com/google/gerrit/server/restapi/change/Restore.java
index 6ac9c21..a47e88d 100644
--- a/java/com/google/gerrit/server/restapi/change/Restore.java
+++ b/java/com/google/gerrit/server/restapi/change/Restore.java
@@ -35,9 +35,10 @@
 import com.google.gerrit.server.change.ChangeJson;
 import com.google.gerrit.server.change.ChangeResource;
 import com.google.gerrit.server.extensions.events.ChangeRestored;
+import com.google.gerrit.server.mail.EmailModule.RestoredChangeEmailFactories;
+import com.google.gerrit.server.mail.send.ChangeEmailNew;
 import com.google.gerrit.server.mail.send.MessageIdGenerator;
-import com.google.gerrit.server.mail.send.ReplyToChangeSender;
-import com.google.gerrit.server.mail.send.RestoredSender;
+import com.google.gerrit.server.mail.send.OutgoingEmailNew;
 import com.google.gerrit.server.notedb.ChangeUpdate;
 import com.google.gerrit.server.permissions.ChangePermission;
 import com.google.gerrit.server.permissions.PermissionBackendException;
@@ -60,7 +61,7 @@
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
   private final BatchUpdate.Factory updateFactory;
-  private final RestoredSender.Factory restoredSenderFactory;
+  private final RestoredChangeEmailFactories restoredChangeEmailFactories;
   private final ChangeJson.Factory json;
   private final ChangeMessagesUtil cmUtil;
   private final PatchSetUtil psUtil;
@@ -71,7 +72,7 @@
   @Inject
   Restore(
       BatchUpdate.Factory updateFactory,
-      RestoredSender.Factory restoredSenderFactory,
+      RestoredChangeEmailFactories restoredChangeEmailFactories,
       ChangeJson.Factory json,
       ChangeMessagesUtil cmUtil,
       PatchSetUtil psUtil,
@@ -79,7 +80,7 @@
       ProjectCache projectCache,
       MessageIdGenerator messageIdGenerator) {
     this.updateFactory = updateFactory;
-    this.restoredSenderFactory = restoredSenderFactory;
+    this.restoredChangeEmailFactories = restoredChangeEmailFactories;
     this.json = json;
     this.cmUtil = cmUtil;
     this.psUtil = psUtil;
@@ -151,13 +152,14 @@
     @Override
     public void postUpdate(PostUpdateContext ctx) {
       try {
-        ReplyToChangeSender emailSender =
-            restoredSenderFactory.create(ctx.getProject(), change.getId());
-        emailSender.setFrom(ctx.getAccountId());
-        emailSender.setChangeMessage(mailMessage, ctx.getWhen());
-        emailSender.setMessageId(
+        ChangeEmailNew changeEmail =
+            restoredChangeEmailFactories.createChangeEmail(ctx.getProject(), change.getId());
+        changeEmail.setChangeMessage(mailMessage, ctx.getWhen());
+        OutgoingEmailNew outgoingEmail = restoredChangeEmailFactories.createEmail(changeEmail);
+        outgoingEmail.setFrom(ctx.getAccountId());
+        outgoingEmail.setMessageId(
             messageIdGenerator.fromChangeUpdate(ctx.getRepoView(), change.currentPatchSetId()));
-        emailSender.send();
+        outgoingEmail.send();
       } catch (Exception e) {
         logger.atSevere().withCause(e).log("Cannot email update for change %s", change.getId());
       }
diff --git a/java/com/google/gerrit/server/restapi/config/GetServerInfo.java b/java/com/google/gerrit/server/restapi/config/GetServerInfo.java
index e586216..0116804 100644
--- a/java/com/google/gerrit/server/restapi/config/GetServerInfo.java
+++ b/java/com/google/gerrit/server/restapi/config/GetServerInfo.java
@@ -223,6 +223,8 @@
     info.mergeabilityComputationBehavior =
         MergeabilityComputationBehavior.fromConfig(config).name();
     info.enableRobotComments = toBoolean(config.getBoolean("change", "enableRobotComments", true));
+    info.conflictsPredicateEnabled =
+        toBoolean(config.getBoolean("change", "conflictsPredicateEnabled", true));
     return info;
   }
 
diff --git a/java/com/google/gerrit/server/submit/EmailMerge.java b/java/com/google/gerrit/server/submit/EmailMerge.java
index 7aa3716..1cac440 100644
--- a/java/com/google/gerrit/server/submit/EmailMerge.java
+++ b/java/com/google/gerrit/server/submit/EmailMerge.java
@@ -23,8 +23,10 @@
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.change.NotifyResolver;
 import com.google.gerrit.server.config.SendEmailExecutor;
-import com.google.gerrit.server.mail.send.MergedSender;
+import com.google.gerrit.server.mail.EmailModule.MergedChangeEmailFactories;
+import com.google.gerrit.server.mail.send.ChangeEmailNew;
 import com.google.gerrit.server.mail.send.MessageIdGenerator;
+import com.google.gerrit.server.mail.send.OutgoingEmailNew;
 import com.google.gerrit.server.update.RepoView;
 import com.google.gerrit.server.util.RequestContext;
 import com.google.gerrit.server.util.ThreadLocalRequestContext;
@@ -49,7 +51,7 @@
   }
 
   private final ExecutorService sendEmailsExecutor;
-  private final MergedSender.Factory mergedSenderFactory;
+  private final MergedChangeEmailFactories mergedChangeEmailFactories;
   private final ThreadLocalRequestContext requestContext;
   private final MessageIdGenerator messageIdGenerator;
 
@@ -63,7 +65,7 @@
   @Inject
   EmailMerge(
       @SendEmailExecutor ExecutorService executor,
-      MergedSender.Factory mergedSenderFactory,
+      MergedChangeEmailFactories mergedChangeEmailFactories,
       ThreadLocalRequestContext requestContext,
       MessageIdGenerator messageIdGenerator,
       @Assisted Project.NameKey project,
@@ -73,7 +75,7 @@
       @Assisted RepoView repoView,
       @Assisted String stickyApprovalDiff) {
     this.sendEmailsExecutor = executor;
-    this.mergedSenderFactory = mergedSenderFactory;
+    this.mergedChangeEmailFactories = mergedChangeEmailFactories;
     this.requestContext = requestContext;
     this.messageIdGenerator = messageIdGenerator;
     this.project = project;
@@ -93,18 +95,19 @@
   public void run() {
     RequestContext old = requestContext.setContext(this);
     try {
-      MergedSender emailSender =
-          mergedSenderFactory.create(
+      ChangeEmailNew changeEmail =
+          mergedChangeEmailFactories.createChangeEmail(
               project,
               change.getId(),
               Optional.ofNullable(Strings.emptyToNull(stickyApprovalDiff)));
+      OutgoingEmailNew outgoingEmail = mergedChangeEmailFactories.createEmail(changeEmail);
       if (submitter != null) {
-        emailSender.setFrom(submitter.getAccountId());
+        outgoingEmail.setFrom(submitter.getAccountId());
       }
-      emailSender.setNotify(notify);
-      emailSender.setMessageId(
+      outgoingEmail.setNotify(notify);
+      outgoingEmail.setMessageId(
           messageIdGenerator.fromChangeUpdate(repoView, change.currentPatchSetId()));
-      emailSender.send();
+      outgoingEmail.send();
     } catch (Exception e) {
       logger.atSevere().withCause(e).log("Cannot email merged notification for %s", change.getId());
     } finally {
diff --git a/java/com/google/gerrit/server/submit/RebaseSorter.java b/java/com/google/gerrit/server/submit/RebaseSorter.java
index 4775768..e960284 100644
--- a/java/com/google/gerrit/server/submit/RebaseSorter.java
+++ b/java/com/google/gerrit/server/submit/RebaseSorter.java
@@ -40,7 +40,7 @@
   private final CurrentUser caller;
   private final CodeReviewRevWalk rw;
   private final RevFlag canMergeFlag;
-  private final RevCommit initialTip;
+  private final Set<RevCommit> uninterestingBranchTips;
   private final Set<RevCommit> alreadyAccepted;
   private final Provider<InternalChangeQuery> queryProvider;
   private final Set<CodeReviewCommit> incoming;
@@ -48,7 +48,7 @@
   public RebaseSorter(
       CurrentUser caller,
       CodeReviewRevWalk rw,
-      RevCommit initialTip,
+      Set<RevCommit> uninterestingBranchTips,
       Set<RevCommit> alreadyAccepted,
       RevFlag canMergeFlag,
       Provider<InternalChangeQuery> queryProvider,
@@ -56,7 +56,7 @@
     this.caller = caller;
     this.rw = rw;
     this.canMergeFlag = canMergeFlag;
-    this.initialTip = initialTip;
+    this.uninterestingBranchTips = uninterestingBranchTips;
     this.alreadyAccepted = alreadyAccepted;
     this.queryProvider = queryProvider;
     this.incoming = incoming;
@@ -70,15 +70,16 @@
 
       rw.resetRetain(canMergeFlag);
       rw.markStart(n);
-      if (initialTip != null) {
-        rw.markUninteresting(initialTip);
+      for (RevCommit uninterestingBranchTip : uninterestingBranchTips) {
+        rw.markUninteresting(uninterestingBranchTip);
       }
 
       CodeReviewCommit c;
       final List<CodeReviewCommit> contents = new ArrayList<>();
       while ((c = rw.next()) != null) {
         if (!c.has(canMergeFlag) || !incoming.contains(c)) {
-          if (isAlreadyMerged(c, n.change().getDest())) {
+          if (isMergedInBranchAsSubmittedChange(c, n.change().getDest())
+              || isAlreadyMergedInAnyBranch(c)) {
             rw.markUninteresting(c);
           } else {
             // We cannot merge n as it would bring something we
@@ -108,7 +109,7 @@
     return sorted;
   }
 
-  private boolean isAlreadyMerged(CodeReviewCommit commit, BranchNameKey dest) throws IOException {
+  private boolean isAlreadyMergedInAnyBranch(CodeReviewCommit commit) throws IOException {
     try (CodeReviewRevWalk mirw = CodeReviewCommit.newRevWalk(rw.getObjectReader())) {
       mirw.reset();
       mirw.markStart(commit);
@@ -120,22 +121,24 @@
           return true;
         }
       }
-
-      // check if the commit associated change is merged in the same branch
-      List<ChangeData> changes = queryProvider.get().byCommit(commit);
-      for (ChangeData change : changes) {
-        if (change.change().isMerged() && change.change().getDest().equals(dest)) {
-          logger.atFine().log(
-              "Dependency %s associated with merged change %s.", commit.getName(), change.getId());
-          return true;
-        }
-      }
       return false;
     } catch (StorageException e) {
       throw new IOException(e);
     }
   }
 
+  private boolean isMergedInBranchAsSubmittedChange(CodeReviewCommit commit, BranchNameKey dest) {
+    List<ChangeData> changes = queryProvider.get().byBranchCommit(dest, commit.getId().getName());
+    for (ChangeData change : changes) {
+      if (change.change().isMerged()) {
+        logger.atFine().log(
+            "Dependency %s associated with merged change %s.", commit.getName(), change.getId());
+        return true;
+      }
+    }
+    return false;
+  }
+
   private static <T> T removeOne(Collection<T> c) {
     final Iterator<T> i = c.iterator();
     final T r = i.next();
diff --git a/java/com/google/gerrit/server/submit/SubmitStrategy.java b/java/com/google/gerrit/server/submit/SubmitStrategy.java
index bdda3fc5..c7b322e 100644
--- a/java/com/google/gerrit/server/submit/SubmitStrategy.java
+++ b/java/com/google/gerrit/server/submit/SubmitStrategy.java
@@ -22,6 +22,7 @@
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Sets;
 import com.google.common.flogger.FluentLogger;
+import com.google.gerrit.entities.BooleanProjectConfig;
 import com.google.gerrit.entities.BranchNameKey;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.SubmissionId;
@@ -217,11 +218,18 @@
           projectCache.get(destBranch.project()).orElseThrow(illegalState(destBranch.project()));
       this.mergeSorter =
           new MergeSorter(caller, rw, alreadyAccepted, canMergeFlag, queryProvider, incoming);
+      Set<RevCommit> uninterestingBranchTips;
+      if (project.is(BooleanProjectConfig.CREATE_NEW_CHANGE_FOR_ALL_NOT_IN_TARGET)) {
+        RevCommit initialTip = mergeTip.getInitialTip();
+        uninterestingBranchTips = initialTip == null ? Set.of() : Set.of(initialTip);
+      } else {
+        uninterestingBranchTips = alreadyAccepted;
+      }
       this.rebaseSorter =
           new RebaseSorter(
               caller,
               rw,
-              mergeTip.getInitialTip(),
+              uninterestingBranchTips,
               alreadyAccepted,
               canMergeFlag,
               queryProvider,
diff --git a/java/com/google/gerrit/server/util/AttentionSetEmail.java b/java/com/google/gerrit/server/util/AttentionSetEmail.java
index 948b6e3..c00e810 100644
--- a/java/com/google/gerrit/server/util/AttentionSetEmail.java
+++ b/java/com/google/gerrit/server/util/AttentionSetEmail.java
@@ -17,14 +17,17 @@
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.entities.Change;
+import com.google.gerrit.entities.Project;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.change.NotifyResolver;
 import com.google.gerrit.server.config.SendEmailExecutor;
-import com.google.gerrit.server.mail.send.AddToAttentionSetSender;
-import com.google.gerrit.server.mail.send.AttentionSetSender;
+import com.google.gerrit.server.mail.EmailModule.AttentionSetChangeEmailFactories;
+import com.google.gerrit.server.mail.send.AttentionSetChangeEmailDecorator;
+import com.google.gerrit.server.mail.send.AttentionSetChangeEmailDecorator.AttentionSetChange;
+import com.google.gerrit.server.mail.send.ChangeEmailNew;
 import com.google.gerrit.server.mail.send.MessageIdGenerator;
 import com.google.gerrit.server.mail.send.MessageIdGenerator.MessageId;
-import com.google.gerrit.server.mail.send.RemoveFromAttentionSetSender;
+import com.google.gerrit.server.mail.send.OutgoingEmailNew;
 import com.google.gerrit.server.update.Context;
 import com.google.inject.Inject;
 import com.google.inject.assistedinject.Assisted;
@@ -42,15 +45,14 @@
     /**
      * factory for sending an email when adding users to the attention set or removing them from it.
      *
-     * @param sender sender in charge of sending the email, can be {@link AddToAttentionSetSender}
-     *     or {@link RemoveFromAttentionSetSender}.
+     * @param attentionSetChange whether the user is added or removed.
      * @param ctx context for sending the email.
      * @param change the change that the user was added/removed in.
      * @param reason reason for adding/removing the user.
      * @param attentionUserId the user added/removed.
      */
     AttentionSetEmail create(
-        AttentionSetSender sender,
+        AttentionSetChange attentionSetChange,
         Context ctx,
         Change change,
         String reason,
@@ -66,7 +68,8 @@
       ThreadLocalRequestContext requestContext,
       MessageIdGenerator messageIdGenerator,
       AccountTemplateUtil accountTemplateUtil,
-      @Assisted AttentionSetSender sender,
+      AttentionSetChangeEmailFactories attentionSetChangeEmailFactories,
+      @Assisted AttentionSetChange attentionSetChange,
       @Assisted Context ctx,
       @Assisted Change change,
       @Assisted String reason,
@@ -85,8 +88,10 @@
     this.asyncSender =
         new AsyncSender(
             requestContext,
+            attentionSetChangeEmailFactories,
             ctx.getUser(),
-            sender,
+            ctx.getProject(),
+            attentionSetChange,
             messageId,
             ctx.getNotify(change.getId()),
             attentionUserId,
@@ -107,8 +112,10 @@
    */
   private static class AsyncSender implements Runnable, RequestContext {
     private final ThreadLocalRequestContext requestContext;
+    private final AttentionSetChangeEmailFactories attentionSetChangeEmailFactories;
     private final CurrentUser user;
-    private final AttentionSetSender sender;
+    private final AttentionSetChange attentionSetChange;
+    private final Project.NameKey projectId;
     private final MessageIdGenerator.MessageId messageId;
     private final NotifyResolver.Result notify;
     private final Account.Id attentionUserId;
@@ -117,16 +124,20 @@
 
     AsyncSender(
         ThreadLocalRequestContext requestContext,
+        AttentionSetChangeEmailFactories attentionSetChangeEmailFactories,
         CurrentUser user,
-        AttentionSetSender sender,
+        Project.NameKey projectId,
+        AttentionSetChange attentionSetChange,
         MessageIdGenerator.MessageId messageId,
         NotifyResolver.Result notify,
         Account.Id attentionUserId,
         String reason,
         Change.Id changeId) {
       this.requestContext = requestContext;
+      this.attentionSetChangeEmailFactories = attentionSetChangeEmailFactories;
       this.user = user;
-      this.sender = sender;
+      this.projectId = projectId;
+      this.attentionSetChange = attentionSetChange;
       this.messageId = messageId;
       this.notify = notify;
       this.attentionUserId = attentionUserId;
@@ -138,18 +149,27 @@
     public void run() {
       RequestContext old = requestContext.setContext(this);
       try {
+        AttentionSetChangeEmailDecorator changeEmailParams =
+            attentionSetChangeEmailFactories.createAttentionSetChangeEmail();
+        changeEmailParams.setAttentionSetChange(attentionSetChange);
+        changeEmailParams.setAttentionSetUser(attentionUserId);
+        changeEmailParams.setReason(reason);
+        ChangeEmailNew changeEmail =
+            attentionSetChangeEmailFactories.createChangeEmail(
+                projectId, changeId, changeEmailParams);
+        OutgoingEmailNew outgoingEmail =
+            attentionSetChangeEmailFactories.createEmail(attentionSetChange, changeEmail);
+
         Optional<Account.Id> accountId =
             user.isIdentifiedUser()
                 ? Optional.of(user.asIdentifiedUser().getAccountId())
                 : Optional.empty();
         if (accountId.isPresent()) {
-          sender.setFrom(accountId.get());
+          outgoingEmail.setFrom(accountId.get());
         }
-        sender.setNotify(notify);
-        sender.setAttentionSetUser(attentionUserId);
-        sender.setReason(reason);
-        sender.setMessageId(messageId);
-        sender.send();
+        outgoingEmail.setNotify(notify);
+        outgoingEmail.setMessageId(messageId);
+        outgoingEmail.send();
       } catch (Exception e) {
         logger.atSevere().withCause(e).log("Cannot email update for change %s", changeId);
       } finally {
diff --git a/java/com/google/gerrit/sshd/BaseCommand.java b/java/com/google/gerrit/sshd/BaseCommand.java
index 547aff3..a77ada4 100644
--- a/java/com/google/gerrit/sshd/BaseCommand.java
+++ b/java/com/google/gerrit/sshd/BaseCommand.java
@@ -544,6 +544,7 @@
     }
 
     @Override
+    @Nullable
     public String getRemoteName() {
       return null;
     }
diff --git a/javatests/com/google/gerrit/acceptance/api/group/GroupsUpdateIT.java b/javatests/com/google/gerrit/acceptance/api/group/GroupsUpdateIT.java
index e57c82e..2796488 100644
--- a/javatests/com/google/gerrit/acceptance/api/group/GroupsUpdateIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/group/GroupsUpdateIT.java
@@ -102,6 +102,7 @@
     return groups.getAllGroupReferences().map(GroupReference::getName);
   }
 
+  @SuppressWarnings("MathAbsoluteNegative")
   private static InternalGroupCreation getGroupCreation(String groupName, String groupUuid) {
     return InternalGroupCreation.builder()
         .setGroupUUID(AccountGroup.uuid(groupUuid))
diff --git a/javatests/com/google/gerrit/acceptance/git/SubmoduleSubscriptionsWholeTopicMergeIT.java b/javatests/com/google/gerrit/acceptance/git/SubmoduleSubscriptionsWholeTopicMergeIT.java
index ef2ca95..0d751f1 100644
--- a/javatests/com/google/gerrit/acceptance/git/SubmoduleSubscriptionsWholeTopicMergeIT.java
+++ b/javatests/com/google/gerrit/acceptance/git/SubmoduleSubscriptionsWholeTopicMergeIT.java
@@ -461,17 +461,19 @@
     allowMatchingSubmoduleSubscription(subKey, "refs/heads/master", superKey, "refs/heads/master");
     allowMatchingSubmoduleSubscription(subKey, "refs/heads/dev", superKey, "refs/heads/master");
 
-    ObjectId devHead = pushChangeTo(subRepo, "dev");
+    ObjectId revMasterBranch = pushChangeTo(subRepo, "master");
+    ObjectId revDevBranch = pushChangeTo(subRepo, "dev");
     Config config = new Config();
     prepareSubmoduleConfigEntry(config, subKey, nameKey("sub-master"), "master");
     prepareSubmoduleConfigEntry(config, subKey, nameKey("sub-dev"), "dev");
     pushSubmoduleConfig(superRepo, "master", config);
 
+    subRepo.reset(revMasterBranch);
     ObjectId subMasterId =
         pushChangeTo(
             subRepo, "refs/for/master", "some message", "b.txt", "content b", "same-topic");
 
-    subRepo.reset(devHead);
+    subRepo.reset(revDevBranch);
     ObjectId subDevId =
         pushChangeTo(
             subRepo, "refs/for/dev", "some message in dev", "b.txt", "content b", "same-topic");
@@ -673,14 +675,16 @@
 
     TestRepository<?> repoA = cloneProject(keyA);
     TestRepository<?> repoB = cloneProject(keyB);
-    // bootstrap the dev branch
-    ObjectId a0 = pushChangeTo(repoA, "dev");
 
-    // bootstrap the dev branch
-    ObjectId b0 = pushChangeTo(repoB, "dev");
+    // Create master- and dev branches in both repositories
+    ObjectId revMasterBranchA = pushChangeTo(repoA, "master");
+    ObjectId revMasterBranchB = pushChangeTo(repoB, "master");
+    ObjectId revDevBranchA = pushChangeTo(repoA, "dev");
+    ObjectId revDevBranchB = pushChangeTo(repoB, "dev");
 
     // create a change for master branch in repo a
-    ObjectId aHead =
+    repoA.reset(revMasterBranchA);
+    ObjectId revMasterChangeA =
         pushChangeTo(
             repoA,
             "refs/for/master",
@@ -690,7 +694,8 @@
             "same-topic");
 
     // create a change for master branch in repo b
-    ObjectId bHead =
+    repoB.reset(revMasterBranchB);
+    ObjectId revMasterChangeB =
         pushChangeTo(
             repoB,
             "refs/for/master",
@@ -700,8 +705,8 @@
             "same-topic");
 
     // create a change for dev branch in repo a
-    repoA.reset(a0);
-    ObjectId aDevHead =
+    repoA.reset(revDevBranchA);
+    ObjectId revDevChangeA =
         pushChangeTo(
             repoA,
             "refs/for/dev",
@@ -711,8 +716,8 @@
             "same-topic");
 
     // create a change for dev branch in repo b
-    repoB.reset(b0);
-    ObjectId bDevHead =
+    repoB.reset(revDevBranchB);
+    ObjectId revDevChangeB =
         pushChangeTo(
             repoB,
             "refs/for/dev",
@@ -721,12 +726,12 @@
             "some message in b dev.txt",
             "same-topic");
 
-    approve(getChangeId(repoA, aHead).get());
-    approve(getChangeId(repoB, bHead).get());
-    approve(getChangeId(repoA, aDevHead).get());
-    approve(getChangeId(repoB, bDevHead).get());
+    approve(getChangeId(repoA, revMasterChangeA).get());
+    approve(getChangeId(repoB, revMasterChangeB).get());
+    approve(getChangeId(repoA, revDevChangeA).get());
+    approve(getChangeId(repoB, revDevChangeB).get());
 
-    gApi.changes().id(getChangeId(repoA, aDevHead).get()).current().submit();
+    gApi.changes().id(getChangeId(repoA, revDevChangeA).get()).current().submit();
     assertThat(projectOperations.project(keyA).getHead("refs/heads/master").getShortMessage())
         .contains("some message in a master.txt");
     assertThat(projectOperations.project(keyA).getHead("refs/heads/dev").getShortMessage())
@@ -746,8 +751,9 @@
     // bootstrap the dev branch
     pushChangeTo(repoA, "dev");
 
-    // bootstrap the dev branch
-    ObjectId b0 = pushChangeTo(repoB, "dev");
+    // Create master- and dev branches in repo b
+    ObjectId revMasterBranch = pushChangeTo(repoB, "master");
+    ObjectId revDevBranch = pushChangeTo(repoB, "dev");
 
     allowMatchingSubmoduleSubscription(keyB, "refs/heads/master", keyA, "refs/heads/master");
     allowMatchingSubmoduleSubscription(keyB, "refs/heads/dev", keyA, "refs/heads/dev");
@@ -756,7 +762,8 @@
     createSubmoduleSubscription(repoA, "dev", keyB, "dev");
 
     // create a change for master branch in repo b
-    ObjectId bHead =
+    repoB.reset(revMasterBranch);
+    ObjectId revMasterChange =
         pushChangeTo(
             repoB,
             "refs/for/master",
@@ -766,8 +773,8 @@
             "same-topic");
 
     // create a change for dev branch in repo b
-    repoB.reset(b0);
-    ObjectId bDevHead =
+    repoB.reset(revDevBranch);
+    ObjectId revDevChange =
         pushChangeTo(
             repoB,
             "refs/for/dev",
@@ -776,9 +783,9 @@
             "some message in b dev.txt",
             "same-topic");
 
-    approve(getChangeId(repoB, bHead).get());
-    approve(getChangeId(repoB, bDevHead).get());
-    gApi.changes().id(getChangeId(repoB, bHead).get()).current().submit();
+    approve(getChangeId(repoB, revMasterChange).get());
+    approve(getChangeId(repoB, revDevChange).get());
+    gApi.changes().id(getChangeId(repoB, revMasterChange).get()).current().submit();
 
     expectToHaveSubmoduleState(repoA, "master", keyB, repoB, "master");
     expectToHaveSubmoduleState(repoA, "dev", keyB, repoB, "dev");
diff --git a/javatests/com/google/gerrit/acceptance/server/permissions/ExternalUserPermissionIT.java b/javatests/com/google/gerrit/acceptance/server/permissions/ExternalUserPermissionIT.java
index 3508112..7a55ecb 100644
--- a/javatests/com/google/gerrit/acceptance/server/permissions/ExternalUserPermissionIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/permissions/ExternalUserPermissionIT.java
@@ -30,6 +30,7 @@
 import com.google.gerrit.acceptance.testsuite.change.ChangeOperations;
 import com.google.gerrit.acceptance.testsuite.group.GroupOperations;
 import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.entities.AccountGroup;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.GroupDescription;
@@ -123,6 +124,7 @@
                       }
 
                       @Override
+                      @Nullable
                       public String getUrl() {
                         return null;
                       }
diff --git a/javatests/com/google/gerrit/acceptance/server/rules/BUILD b/javatests/com/google/gerrit/acceptance/server/rules/BUILD
index 20f4ca6..911c85c 100644
--- a/javatests/com/google/gerrit/acceptance/server/rules/BUILD
+++ b/javatests/com/google/gerrit/acceptance/server/rules/BUILD
@@ -1,11 +1,7 @@
 load("//javatests/com/google/gerrit/acceptance:tests.bzl", "acceptance_tests")
 
 acceptance_tests(
-    srcs = glob(
-        ["*IT.java"],
-        exclude = ["prolog/*.java"],
-    ),
+    srcs = glob(["*IT.java"]),
     group = "server_rules",
     labels = ["server"],
-    deps = [],
 )
diff --git a/javatests/com/google/gerrit/acceptance/server/rules/prolog/BUILD b/javatests/com/google/gerrit/acceptance/server/rules/prolog/BUILD
index 3d28dea..03c24a2 100644
--- a/javatests/com/google/gerrit/acceptance/server/rules/prolog/BUILD
+++ b/javatests/com/google/gerrit/acceptance/server/rules/prolog/BUILD
@@ -1,10 +1,8 @@
 load("//javatests/com/google/gerrit/acceptance:tests.bzl", "acceptance_tests")
 
 acceptance_tests(
-    srcs = glob(
-        ["*IT.java"],
-    ),
-    group = "server_rules",
+    srcs = glob(["*IT.java"]),
+    group = "prolog_rules",
     labels = ["server"],
     deps = [
         "//java/com/google/gerrit/server/rules/prolog",
diff --git a/javatests/com/google/gerrit/common/data/BUILD b/javatests/com/google/gerrit/common/data/BUILD
index f2b7d63..154fd89 100644
--- a/javatests/com/google/gerrit/common/data/BUILD
+++ b/javatests/com/google/gerrit/common/data/BUILD
@@ -4,6 +4,7 @@
     name = "data_tests",
     srcs = glob(["*.java"]),
     deps = [
+        "//java/com/google/gerrit/common:annotations",
         "//java/com/google/gerrit/common:server",
         "//java/com/google/gerrit/entities",
         "//java/com/google/gerrit/testing:gerrit-test-util",
diff --git a/javatests/com/google/gerrit/common/data/GroupReferenceTest.java b/javatests/com/google/gerrit/common/data/GroupReferenceTest.java
index 477f9d2..ba4b586 100644
--- a/javatests/com/google/gerrit/common/data/GroupReferenceTest.java
+++ b/javatests/com/google/gerrit/common/data/GroupReferenceTest.java
@@ -17,6 +17,7 @@
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.gerrit.testing.GerritJUnit.assertThrows;
 
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.entities.AccountGroup;
 import com.google.gerrit.entities.AccountGroup.UUID;
 import com.google.gerrit.entities.GroupDescription;
@@ -33,6 +34,7 @@
             new GroupDescription.Basic() {
 
               @Override
+              @Nullable
               public String getUrl() {
                 return null;
               }
@@ -48,6 +50,7 @@
               }
 
               @Override
+              @Nullable
               public String getEmailAddress() {
                 return null;
               }
diff --git a/javatests/com/google/gerrit/index/query/QueryBuilderTest.java b/javatests/com/google/gerrit/index/query/QueryBuilderTest.java
index f653759..eb3358d 100644
--- a/javatests/com/google/gerrit/index/query/QueryBuilderTest.java
+++ b/javatests/com/google/gerrit/index/query/QueryBuilderTest.java
@@ -57,6 +57,7 @@
     }
 
     @Operator
+    @SuppressWarnings("unused")
     public Predicate<Object> a(String value) {
       return new TestPredicate("a", value);
     }
diff --git a/javatests/com/google/gerrit/pgm/http/jetty/ProjectQoSFilterTest.java b/javatests/com/google/gerrit/pgm/http/jetty/ProjectQoSFilterTest.java
index b969d68..7cc4b2e 100644
--- a/javatests/com/google/gerrit/pgm/http/jetty/ProjectQoSFilterTest.java
+++ b/javatests/com/google/gerrit/pgm/http/jetty/ProjectQoSFilterTest.java
@@ -49,6 +49,7 @@
   @Mock ServletContext context;
 
   @Test
+  @SuppressWarnings("DoNotCall")
   public void shouldCallTaskEndOnListenerCompleteFromDifferentThread() {
     ProjectQoSFilter.TaskThunk taskThunk = getTaskThunk();
     ScheduledThreadPoolExecutor scheduledThreadPoolExecutor = new ScheduledThreadPoolExecutor(1);
@@ -71,6 +72,7 @@
   }
 
   @Test
+  @SuppressWarnings("DoNotCall")
   public void shouldCallTaskEndOnListenerTimeoutFromDifferentThread() {
     ProjectQoSFilter.TaskThunk taskThunk = getTaskThunk();
     ScheduledThreadPoolExecutor scheduledThreadPoolExecutor = new ScheduledThreadPoolExecutor(1);
@@ -93,6 +95,7 @@
   }
 
   @Test
+  @SuppressWarnings("DoNotCall")
   public void shouldCallTaskEndOnListenerErrorFromDifferentThread() {
     ProjectQoSFilter.TaskThunk taskThunk = getTaskThunk();
     ScheduledThreadPoolExecutor scheduledThreadPoolExecutor = new ScheduledThreadPoolExecutor(1);
diff --git a/javatests/com/google/gerrit/server/account/externalids/ExternalIDCacheLoaderTest.java b/javatests/com/google/gerrit/server/account/externalids/ExternalIDCacheLoaderTest.java
index 8f2d613..0a874db 100644
--- a/javatests/com/google/gerrit/server/account/externalids/ExternalIDCacheLoaderTest.java
+++ b/javatests/com/google/gerrit/server/account/externalids/ExternalIDCacheLoaderTest.java
@@ -183,7 +183,7 @@
   public void handlesTreePrefixesInDifferentialReload() throws Exception {
     // Create more than 256 notes (NoteMap's current sharding limit) and check that we really have
     // created a situation where NoteNames are sharded.
-    ObjectId oldState = inserExternalIds(257);
+    ObjectId oldState = insertExternalIds(257);
     assertAllFilesHaveSlashesInPath();
     ObjectId head = insertExternalId(500, 500);
     externalIdCache.put(oldState, allFromGit(oldState));
@@ -196,7 +196,7 @@
   @Test
   public void handlesReshard() throws Exception {
     // Create 256 notes (NoteMap's current sharding limit) and check that we are not yet sharding
-    ObjectId oldState = inserExternalIds(256);
+    ObjectId oldState = insertExternalIds(256);
     assertNoFilesHaveSlashesInPath();
     // Create one more external ID and then have the Loader compute the new state
     ObjectId head = insertExternalId(500, 500);
@@ -223,7 +223,7 @@
     return AllExternalIds.create(externalIdReader.all(revision).stream());
   }
 
-  private ObjectId inserExternalIds(int numberOfIdsToInsert) throws Exception {
+  private ObjectId insertExternalIds(int numberOfIdsToInsert) throws Exception {
     ObjectId oldState = null;
     // Create more than 256 notes (NoteMap's current sharding limit) and check that we really have
     // created a situation where NoteNames are sharded.
diff --git a/javatests/com/google/gerrit/server/cache/mem/BUILD b/javatests/com/google/gerrit/server/cache/mem/BUILD
index e50d95f..baa6ff8 100644
--- a/javatests/com/google/gerrit/server/cache/mem/BUILD
+++ b/javatests/com/google/gerrit/server/cache/mem/BUILD
@@ -4,6 +4,7 @@
     name = "tests",
     srcs = glob(["*Test.java"]),
     deps = [
+        "//java/com/google/gerrit/common:annotations",
         "//java/com/google/gerrit/extensions:api",
         "//java/com/google/gerrit/metrics",
         "//java/com/google/gerrit/server",
diff --git a/javatests/com/google/gerrit/server/cache/mem/DefaultMemoryCacheFactoryTest.java b/javatests/com/google/gerrit/server/cache/mem/DefaultMemoryCacheFactoryTest.java
index 42b74e3..e7dbbfe 100644
--- a/javatests/com/google/gerrit/server/cache/mem/DefaultMemoryCacheFactoryTest.java
+++ b/javatests/com/google/gerrit/server/cache/mem/DefaultMemoryCacheFactoryTest.java
@@ -22,6 +22,7 @@
 import com.google.common.cache.RemovalNotification;
 import com.google.common.cache.Weigher;
 import com.google.common.collect.ImmutableMap;
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.metrics.DisabledMetricMaker;
 import com.google.gerrit.server.cache.CacheDef;
@@ -282,11 +283,13 @@
       }
 
       @Override
+      @Nullable
       public TypeLiteral<Integer> keyType() {
         return null;
       }
 
       @Override
+      @Nullable
       public TypeLiteral<Integer> valueType() {
         return null;
       }
@@ -297,26 +300,31 @@
       }
 
       @Override
+      @Nullable
       public Duration expireAfterWrite() {
         return null;
       }
 
       @Override
+      @Nullable
       public Duration expireFromMemoryAfterAccess() {
         return null;
       }
 
       @Override
+      @Nullable
       public Duration refreshAfterWrite() {
         return null;
       }
 
       @Override
+      @Nullable
       public Weigher<Integer, Integer> weigher() {
         return null;
       }
 
       @Override
+      @Nullable
       public CacheLoader<Integer, Integer> loader() {
         return null;
       }
diff --git a/javatests/com/google/gerrit/server/mail/send/CommentSenderTest.java b/javatests/com/google/gerrit/server/mail/send/CommentChangeEmailDecoratorTest.java
similarity index 68%
rename from javatests/com/google/gerrit/server/mail/send/CommentSenderTest.java
rename to javatests/com/google/gerrit/server/mail/send/CommentChangeEmailDecoratorTest.java
index d7a6282..ae45209 100644
--- a/javatests/com/google/gerrit/server/mail/send/CommentSenderTest.java
+++ b/javatests/com/google/gerrit/server/mail/send/CommentChangeEmailDecoratorTest.java
@@ -18,44 +18,41 @@
 
 import java.util.Collections;
 import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
 
-public class CommentSenderTest {
-  private static class TestSender extends CommentSender {
-    TestSender() {
-      super(null, null, null, null, null, null, null);
-    }
-  }
-
+@RunWith(JUnit4.class)
+public class CommentChangeEmailDecoratorTest {
   // A 100-character long string.
   private static String chars100 = String.join("", Collections.nCopies(25, "abcd"));
 
   @Test
   public void shortMessageNotShortened() {
     String message = "foo bar baz";
-    assertThat(TestSender.getShortenedCommentMessage(message)).isEqualTo(message);
+    assertThat(CommentChangeEmailDecorator.getShortenedCommentMessage(message)).isEqualTo(message);
 
     message = "foo bar baz.";
-    assertThat(TestSender.getShortenedCommentMessage(message)).isEqualTo(message);
+    assertThat(CommentChangeEmailDecorator.getShortenedCommentMessage(message)).isEqualTo(message);
   }
 
   @Test
   public void longMessageIsShortened() {
     String message = chars100 + "x";
     String expected = chars100 + " […]";
-    assertThat(TestSender.getShortenedCommentMessage(message)).isEqualTo(expected);
+    assertThat(CommentChangeEmailDecorator.getShortenedCommentMessage(message)).isEqualTo(expected);
   }
 
   @Test
   public void shortenedToFirstLine() {
     String message = "abc\n" + chars100;
     String expected = "abc […]";
-    assertThat(TestSender.getShortenedCommentMessage(message)).isEqualTo(expected);
+    assertThat(CommentChangeEmailDecorator.getShortenedCommentMessage(message)).isEqualTo(expected);
   }
 
   @Test
   public void shortenedToFirstSentence() {
     String message = "foo bar baz. " + chars100;
     String expected = "foo bar baz. […]";
-    assertThat(TestSender.getShortenedCommentMessage(message)).isEqualTo(expected);
+    assertThat(CommentChangeEmailDecorator.getShortenedCommentMessage(message)).isEqualTo(expected);
   }
 }
diff --git a/javatests/com/google/gerrit/server/rules/BUILD b/javatests/com/google/gerrit/server/rules/BUILD
index 5c57ede..3732bd4 100644
--- a/javatests/com/google/gerrit/server/rules/BUILD
+++ b/javatests/com/google/gerrit/server/rules/BUILD
@@ -1,22 +1,11 @@
 load("//tools/bzl:junit.bzl", "junit_tests")
 
 junit_tests(
-    name = "prolog_tests",
+    name = "rules_tests",
     srcs = glob(["*.java"]),
-    resource_strip_prefix = "prologtests",
-    resources = ["//prologtests:gerrit_common_test"],
-    runtime_deps = ["//prolog:gerrit-prolog-common"],
     deps = [
         "//java/com/google/gerrit/entities",
         "//java/com/google/gerrit/server",
-        "//java/com/google/gerrit/server/project/testing:project-test-util",
-        "//java/com/google/gerrit/server/util/time",
-        "//java/com/google/gerrit/testing:gerrit-test-util",
-        "//lib:guava",
-        "//lib:jgit",
-        "//lib/guice",
-        "//lib/mockito",
-        "//lib/prolog:runtime",
         "//lib/truth",
     ],
 )
diff --git a/javatests/com/google/gerrit/server/rules/prolog/BUILD b/javatests/com/google/gerrit/server/rules/prolog/BUILD
new file mode 100644
index 0000000..ce02a06
--- /dev/null
+++ b/javatests/com/google/gerrit/server/rules/prolog/BUILD
@@ -0,0 +1,23 @@
+load("//tools/bzl:junit.bzl", "junit_tests")
+
+junit_tests(
+    name = "prolog_tests",
+    srcs = glob(["*.java"]),
+    resource_strip_prefix = "prologtests",
+    resources = ["//prologtests:gerrit_common_test"],
+    runtime_deps = ["//prolog:gerrit-prolog-common"],
+    deps = [
+        "//java/com/google/gerrit/entities",
+        "//java/com/google/gerrit/server",
+        "//java/com/google/gerrit/server/project/testing:project-test-util",
+        "//java/com/google/gerrit/server/rules/prolog",
+        "//java/com/google/gerrit/server/util/time",
+        "//java/com/google/gerrit/testing:gerrit-test-util",
+        "//lib:guava",
+        "//lib:jgit",
+        "//lib/guice",
+        "//lib/mockito",
+        "//lib/prolog:runtime",
+        "//lib/truth",
+    ],
+)
diff --git a/plugins/codemirror-editor b/plugins/codemirror-editor
index 1a7835b..be8e04b 160000
--- a/plugins/codemirror-editor
+++ b/plugins/codemirror-editor
@@ -1 +1 @@
-Subproject commit 1a7835bdfa55d60c717bad20b943e34499da0016
+Subproject commit be8e04b1a6de091a63c9bc79b56508f2ad56a830
diff --git a/plugins/package.json b/plugins/package.json
index 612062b..504fc17 100644
--- a/plugins/package.json
+++ b/plugins/package.json
@@ -9,28 +9,29 @@
     "@open-wc/testing": "^3.1.6",
     "@web/dev-server-esbuild": "^0.3.2",
     "@web/test-runner": "^0.14.0",
-    "@codemirror/autocomplete": "^6.4.2",
-    "@codemirror/commands": "^6.2.1",
-    "@codemirror/legacy-modes": "^6.3.1",
+    "@codemirror/autocomplete": "^6.5.1",
+    "@codemirror/commands": "^6.2.3",
+    "@codemirror/legacy-modes": "^6.3.2",
     "@codemirror/lang-cpp": "^6.0.2",
-    "@codemirror/lang-css": "^6.0.2",
-    "@codemirror/lang-html": "^6.4.2",
+    "@codemirror/lang-css": "^6.2.0",
+    "@codemirror/lang-html": "^6.4.3",
     "@codemirror/lang-java": "^6.0.1",
-    "@codemirror/lang-javascript": "^6.1.4",
+    "@codemirror/lang-javascript": "^6.1.7",
     "@codemirror/lang-json": "^6.0.1",
-    "@codemirror/lang-markdown": "^6.1.0",
+    "@codemirror/lang-less": "^6.0.0",
+    "@codemirror/lang-markdown": "^6.1.1",
     "@codemirror/lang-php": "^6.0.1",
-    "@codemirror/lang-python": "^6.1.1",
+    "@codemirror/lang-python": "^6.1.2",
     "@codemirror/lang-rust": "^6.0.1",
-    "@codemirror/lang-sql": "^6.4.0",
+    "@codemirror/lang-sass": "^6.0.1",
+    "@codemirror/lang-sql": "^6.4.1",
     "@codemirror/lang-xml": "^6.0.2",
-    "@codemirror/language": "^6.2.0",
-    "@codemirror/language-data": "^6.1.0",
-    "@codemirror/lint": "^6.1.1",
-    "@codemirror/search": "^6.2.3",
+    "@codemirror/language": "^6.6.0",
+    "@codemirror/language-data": "^6.3.0",
+    "@codemirror/lint": "^6.2.1",
+    "@codemirror/search": "^6.4.0",
     "@codemirror/state": "^6.2.0",
-    "@codemirror/theme-one-dark": "^6.1.1",
-    "@codemirror/view": "^6.9.1",
+    "@codemirror/view": "^6.10.0",
     "lit": "^2.2.3",
     "rxjs": "^6.6.7",
     "sinon": "^13.0.0"
diff --git a/plugins/reviewnotes b/plugins/reviewnotes
index 158435d..9321303 160000
--- a/plugins/reviewnotes
+++ b/plugins/reviewnotes
@@ -1 +1 @@
-Subproject commit 158435d2aa9f8729e4e78835969e54701af9203b
+Subproject commit 9321303265fcab2ff7f764a444f8c23915747638
diff --git a/plugins/yarn.lock b/plugins/yarn.lock
index 3156f4c..3f53453 100644
--- a/plugins/yarn.lock
+++ b/plugins/yarn.lock
@@ -23,26 +23,37 @@
     chalk "^2.0.0"
     js-tokens "^4.0.0"
 
-"@codemirror/autocomplete@^6.0.0", "@codemirror/autocomplete@^6.3.2", "@codemirror/autocomplete@^6.4.2":
-  version "6.4.2"
-  resolved "https://registry.yarnpkg.com/@codemirror/autocomplete/-/autocomplete-6.4.2.tgz#938b25223bd21f97b2a6d85474643355f98b505b"
-  integrity sha512-8WE2xp+D0MpWEv5lZ6zPW1/tf4AGb358T5GWYiKEuCP8MvFfT3tH2mIF9Y2yr2e3KbHuSvsVhosiEyqCpiJhZQ==
+"@codemirror/autocomplete@^6.0.0", "@codemirror/autocomplete@^6.3.2", "@codemirror/autocomplete@^6.5.1":
+  version "6.5.1"
+  resolved "https://registry.yarnpkg.com/@codemirror/autocomplete/-/autocomplete-6.5.1.tgz#539cfff291dbffd3841cba078b222cea28ff7eda"
+  integrity sha512-/Sv9yJmqyILbZ26U4LBHnAtbikuVxWUp+rQ8BXuRGtxZfbfKOY/WPbsUtvSP2h0ZUZMlkxV/hqbKRFzowlA6xw==
   dependencies:
     "@codemirror/language" "^6.0.0"
     "@codemirror/state" "^6.0.0"
     "@codemirror/view" "^6.6.0"
     "@lezer/common" "^1.0.0"
 
-"@codemirror/commands@^6.2.1":
-  version "6.2.1"
-  resolved "https://registry.yarnpkg.com/@codemirror/commands/-/commands-6.2.1.tgz#ab5e979ad1458bbe395bf69ac601f461ac73cf08"
-  integrity sha512-FFiNKGuHA5O8uC6IJE5apI5rT9gyjlw4whqy4vlcX0wE/myxL6P1s0upwDhY4HtMWLOwzwsp0ap3bjdQhvfDOA==
+"@codemirror/commands@^6.2.3":
+  version "6.2.3"
+  resolved "https://registry.yarnpkg.com/@codemirror/commands/-/commands-6.2.3.tgz#ec476fd588f7a4333f54584d4783dd3862befe3b"
+  integrity sha512-9uf0g9m2wZyrIim1SavcxMdwsu8wc/y5uSw6JRUBYIGWrN+RY4vSru/BqB+MyNWqx4C2uRhQ/Kh7Pw8lAyT3qQ==
   dependencies:
     "@codemirror/language" "^6.0.0"
     "@codemirror/state" "^6.2.0"
     "@codemirror/view" "^6.0.0"
     "@lezer/common" "^1.0.0"
 
+"@codemirror/lang-angular@^0.1.0":
+  version "0.1.0"
+  resolved "https://registry.yarnpkg.com/@codemirror/lang-angular/-/lang-angular-0.1.0.tgz#1054747c8196357a2aee2b9c36f0f6de9a6ffef9"
+  integrity sha512-vTjoHjzJmLrrMFmf/tojwp+O0P+R9mgWtjjaKDNDoY58PzOPg7ldMEBqIzABBc+/2mYPD85SG7O5byfBxc83eA==
+  dependencies:
+    "@codemirror/lang-html" "^6.0.0"
+    "@codemirror/lang-javascript" "^6.1.2"
+    "@codemirror/language" "^6.0.0"
+    "@lezer/common" "^1.0.0"
+    "@lezer/highlight" "^1.0.0"
+
 "@codemirror/lang-cpp@^6.0.0", "@codemirror/lang-cpp@^6.0.2":
   version "6.0.2"
   resolved "https://registry.yarnpkg.com/@codemirror/lang-cpp/-/lang-cpp-6.0.2.tgz#076c98340c3beabde016d7d83e08eebe17254ef9"
@@ -51,20 +62,21 @@
     "@codemirror/language" "^6.0.0"
     "@lezer/cpp" "^1.0.0"
 
-"@codemirror/lang-css@^6.0.0", "@codemirror/lang-css@^6.0.2":
-  version "6.0.2"
-  resolved "https://registry.yarnpkg.com/@codemirror/lang-css/-/lang-css-6.0.2.tgz#b286d0226755a751f60599e1e2969d351aebbd4c"
-  integrity sha512-4V4zmUOl2Glx0GWw0HiO1oGD4zvMlIQ3zx5hXOE6ipCjhohig2bhWRAasrZylH9pRNTcl1VMa59Lsl8lZWlTzw==
+"@codemirror/lang-css@^6.0.0", "@codemirror/lang-css@^6.1.1", "@codemirror/lang-css@^6.2.0":
+  version "6.2.0"
+  resolved "https://registry.yarnpkg.com/@codemirror/lang-css/-/lang-css-6.2.0.tgz#f84f9da392099432445c75e32fdac63ae572315f"
+  integrity sha512-oyIdJM29AyRPM3+PPq1I2oIk8NpUfEN3kAM05XWDDs6o3gSneIKaVJifT2P+fqONLou2uIgXynFyMUDQvo/szA==
   dependencies:
     "@codemirror/autocomplete" "^6.0.0"
     "@codemirror/language" "^6.0.0"
     "@codemirror/state" "^6.0.0"
+    "@lezer/common" "^1.0.2"
     "@lezer/css" "^1.0.0"
 
-"@codemirror/lang-html@^6.0.0", "@codemirror/lang-html@^6.4.2":
-  version "6.4.2"
-  resolved "https://registry.yarnpkg.com/@codemirror/lang-html/-/lang-html-6.4.2.tgz#3c7117e45bae009bc7bc08eef8a79b5d05930d83"
-  integrity sha512-bqCBASkteKySwtIbiV/WCtGnn/khLRbbiV5TE+d9S9eQJD7BA4c5dTRm2b3bVmSpilff5EYxvB4PQaZzM/7cNw==
+"@codemirror/lang-html@^6.0.0", "@codemirror/lang-html@^6.4.3":
+  version "6.4.3"
+  resolved "https://registry.yarnpkg.com/@codemirror/lang-html/-/lang-html-6.4.3.tgz#dec78f76d9d0261cbe9f2a3a247a1b546327f700"
+  integrity sha512-VKzQXEC8nL69Jg2hvAFPBwOdZNvL8tMFOrdFwWpU+wc6a6KEkndJ/19R5xSaglNX6v2bttm8uIEFYxdQDcIZVQ==
   dependencies:
     "@codemirror/autocomplete" "^6.0.0"
     "@codemirror/lang-css" "^6.0.0"
@@ -84,10 +96,10 @@
     "@codemirror/language" "^6.0.0"
     "@lezer/java" "^1.0.0"
 
-"@codemirror/lang-javascript@^6.0.0", "@codemirror/lang-javascript@^6.1.4":
-  version "6.1.4"
-  resolved "https://registry.yarnpkg.com/@codemirror/lang-javascript/-/lang-javascript-6.1.4.tgz#8a41f4d213e1143b4eef6f65f8b77b349aaf894c"
-  integrity sha512-OxLf7OfOZBTMRMi6BO/F72MNGmgOd9B0vetOLvHsDACFXayBzW8fm8aWnDM0yuy68wTK03MBf4HbjSBNRG5q7A==
+"@codemirror/lang-javascript@^6.0.0", "@codemirror/lang-javascript@^6.1.2", "@codemirror/lang-javascript@^6.1.7":
+  version "6.1.7"
+  resolved "https://registry.yarnpkg.com/@codemirror/lang-javascript/-/lang-javascript-6.1.7.tgz#e39fb9757b1cf47de432e4244d18ca5284a73a58"
+  integrity sha512-KXKqxlZ4W6t5I7i2ScmITUD3f/F5Cllk3kj0De9P9mFeYVfhOVOWuDLgYiLpk357u7Xh4dhqjJAnsNPPoTLghQ==
   dependencies:
     "@codemirror/autocomplete" "^6.0.0"
     "@codemirror/language" "^6.6.0"
@@ -105,10 +117,20 @@
     "@codemirror/language" "^6.0.0"
     "@lezer/json" "^1.0.0"
 
-"@codemirror/lang-markdown@^6.0.0", "@codemirror/lang-markdown@^6.1.0":
-  version "6.1.0"
-  resolved "https://registry.yarnpkg.com/@codemirror/lang-markdown/-/lang-markdown-6.1.0.tgz#218a6ddcd6ea25039e143058fbc95cfd82f003b4"
-  integrity sha512-HQDJg1Js19fPKKsI3Rp1X0J6mxyrRy2NX6+Evh0+/jGm6IZHL5ygMGKBYNWKXodoDQFvgdofNRG33gWOwV59Ag==
+"@codemirror/lang-less@^6.0.0":
+  version "6.0.0"
+  resolved "https://registry.yarnpkg.com/@codemirror/lang-less/-/lang-less-6.0.0.tgz#47ac36242f45bcc211dbcbce11e10f3b249519c9"
+  integrity sha512-hQVj+AxcUW/LybRkwaOope8K8+U6bjWH91t0tW8MMok33Y65xo+Wx0t1BaXi3Iuo6CgJ4tW7Rz09cfNwloIdNA==
+  dependencies:
+    "@codemirror/lang-css" "^6.2.0"
+    "@codemirror/language" "^6.0.0"
+    "@lezer/highlight" "^1.0.0"
+    "@lezer/lr" "^1.0.0"
+
+"@codemirror/lang-markdown@^6.0.0", "@codemirror/lang-markdown@^6.1.1":
+  version "6.1.1"
+  resolved "https://registry.yarnpkg.com/@codemirror/lang-markdown/-/lang-markdown-6.1.1.tgz#ff3cdd339c277f6a02d08eb12f1090977873e771"
+  integrity sha512-n87Ms6Y5UYb1UkFu8sRzTLfq/yyF1y2AYiWvaVdbBQi5WDj1tFk5N+AKA+WC0Jcjc1VxvrCCM0iizjdYYi9sFQ==
   dependencies:
     "@codemirror/lang-html" "^6.0.0"
     "@codemirror/language" "^6.3.0"
@@ -128,7 +150,7 @@
     "@lezer/common" "^1.0.0"
     "@lezer/php" "^1.0.0"
 
-"@codemirror/lang-python@^6.0.0", "@codemirror/lang-python@^6.1.1":
+"@codemirror/lang-python@^6.0.0", "@codemirror/lang-python@^6.1.2":
   version "6.1.2"
   resolved "https://registry.yarnpkg.com/@codemirror/lang-python/-/lang-python-6.1.2.tgz#cabb57529679981f170491833dbf798576e7ab18"
   integrity sha512-nbQfifLBZstpt6Oo4XxA2LOzlSp4b/7Bc5cmodG1R+Cs5PLLCTUvsMNWDnziiCfTOG/SW1rVzXq/GbIr6WXlcw==
@@ -145,10 +167,21 @@
     "@codemirror/language" "^6.0.0"
     "@lezer/rust" "^1.0.0"
 
-"@codemirror/lang-sql@^6.0.0", "@codemirror/lang-sql@^6.4.0":
-  version "6.4.0"
-  resolved "https://registry.yarnpkg.com/@codemirror/lang-sql/-/lang-sql-6.4.0.tgz#f9303e511fb9511884f90043e354d5df3bd4b032"
-  integrity sha512-UWGK1+zc9+JtkiT+XxHByp4N6VLgLvC2x0tIudrJG26gyNtn0hWOVoB0A8kh/NABPWkKl3tLWDYf2qOBJS9Zdw==
+"@codemirror/lang-sass@^6.0.0", "@codemirror/lang-sass@^6.0.1":
+  version "6.0.1"
+  resolved "https://registry.yarnpkg.com/@codemirror/lang-sass/-/lang-sass-6.0.1.tgz#e390f427c8601175f155046e142371c3c4fb718c"
+  integrity sha512-USy9zqtdLYxSuqq0s4peMoQi+BDzyOyO7chUzli+X2xVCjmBhc3CsWQ4kkDU0NYtCHHFQRkcFO8770eaOwZqfw==
+  dependencies:
+    "@codemirror/lang-css" "^6.1.1"
+    "@codemirror/language" "^6.0.0"
+    "@codemirror/state" "^6.0.0"
+    "@lezer/common" "^1.0.2"
+    "@lezer/sass" "^1.0.0"
+
+"@codemirror/lang-sql@^6.0.0", "@codemirror/lang-sql@^6.4.1":
+  version "6.4.1"
+  resolved "https://registry.yarnpkg.com/@codemirror/lang-sql/-/lang-sql-6.4.1.tgz#e680fe8c12e5902a29fd952207bf454ae02b3bdc"
+  integrity sha512-PFB56L+A0WGY35uRya+Trt5g19V9k2V9X3c55xoFW4RgiATr/yLqWsbbnEsdxuMn5tLpuikp7Kmj9smRsqBXAg==
   dependencies:
     "@codemirror/autocomplete" "^6.0.0"
     "@codemirror/language" "^6.0.0"
@@ -156,6 +189,18 @@
     "@lezer/highlight" "^1.0.0"
     "@lezer/lr" "^1.0.0"
 
+"@codemirror/lang-vue@^0.1.1":
+  version "0.1.1"
+  resolved "https://registry.yarnpkg.com/@codemirror/lang-vue/-/lang-vue-0.1.1.tgz#79567fb3be3f411354cd135af59d67f956cdb042"
+  integrity sha512-GIfc/MemCFKUdNSYGTFZDN8XsD2z0DUY7DgrK34on0dzdZ/CawZbi+SADYfVzWoPPdxngHzLhqlR5pSOqyPCvA==
+  dependencies:
+    "@codemirror/lang-html" "^6.0.0"
+    "@codemirror/lang-javascript" "^6.1.2"
+    "@codemirror/language" "^6.0.0"
+    "@lezer/common" "^1.0.0"
+    "@lezer/highlight" "^1.0.0"
+    "@lezer/lr" "^1.3.1"
+
 "@codemirror/lang-wast@^6.0.0":
   version "6.0.1"
   resolved "https://registry.yarnpkg.com/@codemirror/lang-wast/-/lang-wast-6.0.1.tgz#c15bec84548a5e9b0a43fa69fb63631d087d6047"
@@ -176,11 +221,12 @@
     "@lezer/common" "^1.0.0"
     "@lezer/xml" "^1.0.0"
 
-"@codemirror/language-data@^6.1.0":
-  version "6.1.0"
-  resolved "https://registry.yarnpkg.com/@codemirror/language-data/-/language-data-6.1.0.tgz#479eff66289a6453493f7c8213d7b2ceb95c89f6"
-  integrity sha512-g9V23fuLRI9AEbpM6bDy1oquqgpFlIDHTihUhL21NPmxp+x67ZJbsKk+V71W7/Bj8SCqEO1PtqQA/tDGgt1nfw==
+"@codemirror/language-data@^6.3.0":
+  version "6.3.0"
+  resolved "https://registry.yarnpkg.com/@codemirror/language-data/-/language-data-6.3.0.tgz#058365fc2e857eb48810ed92134ee469d9a9bba6"
+  integrity sha512-D9tOZS38mK59jDs1Flqe8GgCdUAYI339SqBdwHJZwxgyXHsBc8RIhAlz2oXWGpvZeP/kVHy9LVfoBFgO02mx7w==
   dependencies:
+    "@codemirror/lang-angular" "^0.1.0"
     "@codemirror/lang-cpp" "^6.0.0"
     "@codemirror/lang-css" "^6.0.0"
     "@codemirror/lang-html" "^6.0.0"
@@ -191,13 +237,15 @@
     "@codemirror/lang-php" "^6.0.0"
     "@codemirror/lang-python" "^6.0.0"
     "@codemirror/lang-rust" "^6.0.0"
+    "@codemirror/lang-sass" "^6.0.0"
     "@codemirror/lang-sql" "^6.0.0"
+    "@codemirror/lang-vue" "^0.1.1"
     "@codemirror/lang-wast" "^6.0.0"
     "@codemirror/lang-xml" "^6.0.0"
     "@codemirror/language" "^6.0.0"
     "@codemirror/legacy-modes" "^6.1.0"
 
-"@codemirror/language@^6.0.0", "@codemirror/language@^6.2.0", "@codemirror/language@^6.3.0", "@codemirror/language@^6.4.0", "@codemirror/language@^6.6.0":
+"@codemirror/language@^6.0.0", "@codemirror/language@^6.3.0", "@codemirror/language@^6.4.0", "@codemirror/language@^6.6.0":
   version "6.6.0"
   resolved "https://registry.yarnpkg.com/@codemirror/language/-/language-6.6.0.tgz#2204407174a38a68053715c19e28ad61f491779f"
   integrity sha512-cwUd6lzt3MfNYOobdjf14ZkLbJcnv4WtndYaoBkbor/vF+rCNguMPK0IRtvZJG4dsWiaWPcK8x1VijhvSxnstg==
@@ -209,26 +257,26 @@
     "@lezer/lr" "^1.0.0"
     style-mod "^4.0.0"
 
-"@codemirror/legacy-modes@^6.1.0", "@codemirror/legacy-modes@^6.3.1":
-  version "6.3.1"
-  resolved "https://registry.yarnpkg.com/@codemirror/legacy-modes/-/legacy-modes-6.3.1.tgz#77ab3f3db1ce3e47aad7a5baac3a4b12844734a5"
-  integrity sha512-icXmCs4Mhst2F8mE0TNpmG6l7YTj1uxam3AbZaFaabINH5oWAdg2CfR/PVi+d/rqxJ+TuTnvkKK5GILHrNThtw==
+"@codemirror/legacy-modes@^6.1.0", "@codemirror/legacy-modes@^6.3.2":
+  version "6.3.2"
+  resolved "https://registry.yarnpkg.com/@codemirror/legacy-modes/-/legacy-modes-6.3.2.tgz#d5616b453f38866717437b51c16bde1ae3f011ec"
+  integrity sha512-ki5sqNKWzKi5AKvpVE6Cna4Q+SgxYuYVLAZFSsMjGBWx5qSVa+D+xipix65GS3f2syTfAD9pXKMX4i4p49eneQ==
   dependencies:
     "@codemirror/language" "^6.0.0"
 
-"@codemirror/lint@^6.0.0", "@codemirror/lint@^6.1.1":
-  version "6.2.0"
-  resolved "https://registry.yarnpkg.com/@codemirror/lint/-/lint-6.2.0.tgz#25cdab7425fcda1b38a9d63f230f833c8b6b369f"
-  integrity sha512-KVCECmR2fFeYBr1ZXDVue7x3q5PMI0PzcIbA+zKufnkniMBo1325t0h1jM85AKp8l3tj67LRxVpZfgDxEXlQkg==
+"@codemirror/lint@^6.0.0", "@codemirror/lint@^6.2.1":
+  version "6.2.1"
+  resolved "https://registry.yarnpkg.com/@codemirror/lint/-/lint-6.2.1.tgz#654581d8cc293c315ecfa5c9d61d78c52bbd9ccd"
+  integrity sha512-y1muai5U/uUPAGRyHMx9mHuHLypPcHWxzlZGknp/U5Mdb5Ol8Q5ZLp67UqyTbNFJJ3unVxZ8iX3g1fMN79S1JQ==
   dependencies:
     "@codemirror/state" "^6.0.0"
     "@codemirror/view" "^6.0.0"
     crelt "^1.0.5"
 
-"@codemirror/search@^6.2.3":
-  version "6.2.3"
-  resolved "https://registry.yarnpkg.com/@codemirror/search/-/search-6.2.3.tgz#fab933fef1b1de8ef40cda275c73d9ac7a1ff40f"
-  integrity sha512-V9n9233lopQhB1dyjsBK2Wc1i+8hcCqxl1wQ46c5HWWLePoe4FluV3TGHoZ04rBRlGjNyz9DTmpJErig8UE4jw==
+"@codemirror/search@^6.4.0":
+  version "6.4.0"
+  resolved "https://registry.yarnpkg.com/@codemirror/search/-/search-6.4.0.tgz#2b256a9e0eaa9317fb48e3cc81eb2735360a59b4"
+  integrity sha512-zMDgaBXah+nMLK2dHz9GdCnGbQu+oaGRXS1qviqNZkvOCv/whp5XZFyoikLp/23PM9RBcbuKUUISUmQHM1eRHw==
   dependencies:
     "@codemirror/state" "^6.0.0"
     "@codemirror/view" "^6.0.0"
@@ -239,20 +287,10 @@
   resolved "https://registry.yarnpkg.com/@codemirror/state/-/state-6.2.0.tgz#a0fb08403ced8c2a68d1d0acee926bd20be922f2"
   integrity sha512-69QXtcrsc3RYtOtd+GsvczJ319udtBf1PTrr2KbLWM/e2CXUPnh0Nz9AUo8WfhSQ7GeL8dPVNUmhQVgpmuaNGA==
 
-"@codemirror/theme-one-dark@^6.1.1":
-  version "6.1.1"
-  resolved "https://registry.yarnpkg.com/@codemirror/theme-one-dark/-/theme-one-dark-6.1.1.tgz#76600555cbb314c495216f018f75b0c28daff158"
-  integrity sha512-+CfzmScfJuD6uDF5bHJkAjWTQ2QAAHxODCPxUEgcImDYcJLT+4l5vLnBHmDVv46kCC5uUJGMrBJct2Z6JbvqyQ==
-  dependencies:
-    "@codemirror/language" "^6.0.0"
-    "@codemirror/state" "^6.0.0"
-    "@codemirror/view" "^6.0.0"
-    "@lezer/highlight" "^1.0.0"
-
-"@codemirror/view@^6.0.0", "@codemirror/view@^6.2.2", "@codemirror/view@^6.6.0", "@codemirror/view@^6.9.1":
-  version "6.9.1"
-  resolved "https://registry.yarnpkg.com/@codemirror/view/-/view-6.9.1.tgz#2ce4c528974b6172a5a4a738b7b0a0f04a4c1140"
-  integrity sha512-bzfSjJn9dAADVpabLKWKNmMG4ibyTV2e3eOGowjElNPTdTkSbi6ixPYHm2u0ADcETfKsi2/R84Rkmi91dH9yEg==
+"@codemirror/view@^6.0.0", "@codemirror/view@^6.10.0", "@codemirror/view@^6.2.2", "@codemirror/view@^6.6.0":
+  version "6.10.0"
+  resolved "https://registry.yarnpkg.com/@codemirror/view/-/view-6.10.0.tgz#40bb39f391955db8960337a9e80fd7564f8915e2"
+  integrity sha512-Oea3rvE4JQLMmLsy2b54yxXQJgJM9xKpUQIpF/LGgKUTH2lA06GAmEtKKWn5OUnbW3jrH1hHeUd8DJEgePMOeQ==
   dependencies:
     "@codemirror/state" "^6.1.4"
     style-mod "^4.0.0"
@@ -275,7 +313,7 @@
   resolved "https://registry.yarnpkg.com/@gerritcodereview/typescript-api/-/typescript-api-3.8.0.tgz#2e418b814d7451c40365b2dc4f88e9965ece0769"
   integrity sha512-wUkIWUx99Rj1vxRYQISxyzN0nplqu7t5sRDyJ8R3yNNkvALQAMC6Whj63qzCsZsymVFzC5up3y+ZVxaeh7b+xA==
 
-"@lezer/common@^1.0.0":
+"@lezer/common@^1.0.0", "@lezer/common@^1.0.2":
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/@lezer/common/-/common-1.0.2.tgz#8fb9b86bdaa2ece57e7d59e5ffbcb37d71815087"
   integrity sha512-SVgiGtMnMnW3ActR8SXgsDhw7a0w0ChHSYAyAUxxrOiJ1OqYWEKk/xJd84tTSPo1mo6DXLObAJALNnd0Hrv7Ng==
@@ -297,16 +335,16 @@
     "@lezer/lr" "^1.0.0"
 
 "@lezer/highlight@^1.0.0", "@lezer/highlight@^1.1.3":
-  version "1.1.3"
-  resolved "https://registry.yarnpkg.com/@lezer/highlight/-/highlight-1.1.3.tgz#bf5a36c2ee227f526d74997ac91f7777e29bd25d"
-  integrity sha512-3vLKLPThO4td43lYRBygmMY18JN3CPh9w+XS2j8WC30vR4yZeFG4z1iFe4jXE43NtGqe//zHW5q8ENLlHvz9gw==
+  version "1.1.4"
+  resolved "https://registry.yarnpkg.com/@lezer/highlight/-/highlight-1.1.4.tgz#98ed821e89f72981b7ba590474e6ee86c8185619"
+  integrity sha512-IECkFmw2l7sFcYXrV8iT9GeY4W0fU4CxX0WMwhmhMIVjoDdD1Hr6q3G2NqVtLg/yVe5n7i4menG3tJ2r4eCrPQ==
   dependencies:
     "@lezer/common" "^1.0.0"
 
 "@lezer/html@^1.3.0":
-  version "1.3.3"
-  resolved "https://registry.yarnpkg.com/@lezer/html/-/html-1.3.3.tgz#2eddae2ad000f9b184d9fc4686394d0fa0849993"
-  integrity sha512-04Fyvu66DjV2EjhDIG1kfDdktn5Pfw56SXPrzKNQH5B2m7BDfc6bDsz+ZJG8dLS3kIPEKbyyq1Sm2/kjeG0+AA==
+  version "1.3.4"
+  resolved "https://registry.yarnpkg.com/@lezer/html/-/html-1.3.4.tgz#7a5c5498dae6c93aee3de208bfb01aa3a0a932e3"
+  integrity sha512-HdJYMVZcT4YsMo7lW3ipL4NoyS2T67kMPuSVS5TgLGqmaCjEU/D6xv7zsa1ktvTK5lwk7zzF1e3eU6gBZIPm5g==
   dependencies:
     "@lezer/common" "^1.0.0"
     "@lezer/highlight" "^1.0.0"
@@ -321,9 +359,9 @@
     "@lezer/lr" "^1.0.0"
 
 "@lezer/javascript@^1.0.0":
-  version "1.4.1"
-  resolved "https://registry.yarnpkg.com/@lezer/javascript/-/javascript-1.4.1.tgz#97a15042c76b5979af6a069fac83cf6485628cbf"
-  integrity sha512-Hqx36DJeYhKtdpc7wBYPR0XF56ZzIp0IkMO/zNNj80xcaFOV4Oj/P7TQc/8k2TxNhzl7tV5tXS8ZOCPbT4L3nA==
+  version "1.4.3"
+  resolved "https://registry.yarnpkg.com/@lezer/javascript/-/javascript-1.4.3.tgz#f59e764a0578184c6fb86abb5279a9679777c3ba"
+  integrity sha512-k7Eo9z9B1supZ5cCD4ilQv/RZVN30eUQL+gGbr6ybrEY3avBAL5MDiYi2aa23Aj0A79ry4rJRvPAwE2TM8bd+A==
   dependencies:
     "@lezer/highlight" "^1.1.3"
     "@lezer/lr" "^1.3.0"
@@ -336,10 +374,10 @@
     "@lezer/highlight" "^1.0.0"
     "@lezer/lr" "^1.0.0"
 
-"@lezer/lr@^1.0.0", "@lezer/lr@^1.1.0", "@lezer/lr@^1.3.0":
-  version "1.3.3"
-  resolved "https://registry.yarnpkg.com/@lezer/lr/-/lr-1.3.3.tgz#0ac6c889f1235874f33c45a1b9785d7054f60708"
-  integrity sha512-JPQe3mwJlzEVqy67iQiiGozhcngbO8QBgpqZM6oL1Wj/dXckrEexpBLeFkq0edtW5IqnPRFxA24BHJni8Js69w==
+"@lezer/lr@^1.0.0", "@lezer/lr@^1.1.0", "@lezer/lr@^1.3.0", "@lezer/lr@^1.3.1":
+  version "1.3.4"
+  resolved "https://registry.yarnpkg.com/@lezer/lr/-/lr-1.3.4.tgz#8795bf2ba4f69b998e8fb4b5a7c57ea68753474c"
+  integrity sha512-7o+e4og/QoC/6btozDPJqnzBhUaD1fMfmvnEKQO1wRRiTse1WxaJ3OMEXZJnkgT6HCcTVOctSoXK9jGJw2oe9g==
   dependencies:
     "@lezer/common" "^1.0.0"
 
@@ -360,9 +398,9 @@
     "@lezer/lr" "^1.1.0"
 
 "@lezer/python@^1.0.0":
-  version "1.1.2"
-  resolved "https://registry.yarnpkg.com/@lezer/python/-/python-1.1.2.tgz#1db9faf182ca04815b2c7e0f1ce37104b2564ec5"
-  integrity sha512-ukm4VhDasFX7/9BUYHTyUNXH0xQ5B7/QBlZD8P51+dh6GtXRSCQqNxloez5d+MxVb2Sg+31S8E/33qoFREfkpA==
+  version "1.1.4"
+  resolved "https://registry.yarnpkg.com/@lezer/python/-/python-1.1.4.tgz#6ef58ff965286150fea9f2db776944a1d69cd9b9"
+  integrity sha512-x82XgYxqqX0Yiw7uIemQJ3z2QyQme5BYpectkPfNg99OQrakqfwqVolqEVIrsj4QO9rVDLFZZ49J0Vbne7UbAA==
   dependencies:
     "@lezer/highlight" "^1.0.0"
     "@lezer/lr" "^1.0.0"
@@ -375,6 +413,14 @@
     "@lezer/highlight" "^1.0.0"
     "@lezer/lr" "^1.0.0"
 
+"@lezer/sass@^1.0.0":
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/@lezer/sass/-/sass-1.0.1.tgz#c0ec3ece28b04e92437a75ac4a806367e5cb6fd4"
+  integrity sha512-S/aYAzABzMqWLfKKqV89pCWME4yjZYC6xzD02l44wbmb0sHxmN9/8aE4GULrKFzFaGazHdXcGEbPZ4zzB6yqwQ==
+  dependencies:
+    "@lezer/highlight" "^1.0.0"
+    "@lezer/lr" "^1.0.0"
+
 "@lezer/xml@^1.0.0":
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/@lezer/xml/-/xml-1.0.1.tgz#c4c738a407db610f0e9c59d0e9b16607cd029591"
@@ -2598,9 +2644,9 @@
     ansi-regex "^5.0.1"
 
 style-mod@^4.0.0:
-  version "4.0.0"
-  resolved "https://registry.yarnpkg.com/style-mod/-/style-mod-4.0.0.tgz#97e7c2d68b592975f2ca7a63d0dd6fcacfe35a01"
-  integrity sha512-OPhtyEjyyN9x3nhPsu76f52yUGXiZcgvsrFVtvTkyGRQJ0XK+GPc6ov1z+lRpbeabka+MYEQxOYRnt5nF30aMw==
+  version "4.0.3"
+  resolved "https://registry.yarnpkg.com/style-mod/-/style-mod-4.0.3.tgz#136c4abc905f82a866a18b39df4dc08ec762b1ad"
+  integrity sha512-78Jv8kYJdjbvRwwijtCevYADfsI0lGzYJe4mMFdceO8l75DFFDoqBhR1jVDicDRRaX4//g1u9wKeo+ztc2h1Rw==
 
 supports-color@^5.3.0:
   version "5.5.0"
diff --git a/polygerrit-ui/app/constants/reporting.ts b/polygerrit-ui/app/constants/reporting.ts
index ad59edd..18ee992 100644
--- a/polygerrit-ui/app/constants/reporting.ts
+++ b/polygerrit-ui/app/constants/reporting.ts
@@ -95,6 +95,12 @@
   LCP = 'LCP',
   // WebVitals - Interaction to Next Paint (INP): measures responsiveness
   INP = 'INP',
+  // Time to load preview for a user suggested edit or a fix from checks
+  PREVIEW_FIX_LOAD = 'PreviewFixLoad',
+  // Time to apply fix for a user suggested edit or a fix from checks
+  APPLY_FIX_LOAD = 'ApplyFixLoad',
+  // Time to copy target to clipboard
+  COPY_TO_CLIPBOARD = 'CopyToClipboard',
 }
 
 export enum Interaction {
@@ -127,4 +133,6 @@
   CHANGE_ACTION_FIRED = 'change-action-fired',
   BUTTON_CLICK = 'button-click',
   LINK_CLICK = 'link-click',
+  USER_ACTIVE = 'user-active',
+  USER_PASSIVE = 'user-passive',
 }
diff --git a/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list.ts b/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list.ts
index 893a997..b30619e 100644
--- a/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list.ts
+++ b/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list.ts
@@ -61,7 +61,7 @@
   override connectedCallback() {
     super.connectedCallback();
     this.getCreateGroupCapability();
-    fireTitleChange(this, 'Groups');
+    fireTitleChange('Groups');
   }
 
   static override get styles() {
diff --git a/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log.ts b/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log.ts
index e0c0d30..f4a7bf3 100644
--- a/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log.ts
+++ b/polygerrit-ui/app/elements/admin/gr-group-audit-log/gr-group-audit-log.ts
@@ -40,7 +40,7 @@
 
   override connectedCallback() {
     super.connectedCallback();
-    fireTitleChange(this, 'Audit Log');
+    fireTitleChange('Audit Log');
   }
 
   static override get styles() {
diff --git a/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members.ts b/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members.ts
index f8d9934..cffde7a 100644
--- a/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members.ts
+++ b/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members.ts
@@ -129,7 +129,7 @@
     super.connectedCallback();
     this.loadGroupDetails();
 
-    fireTitleChange(this, 'Members');
+    fireTitleChange('Members');
   }
 
   static override get styles() {
diff --git a/polygerrit-ui/app/elements/admin/gr-group/gr-group.ts b/polygerrit-ui/app/elements/admin/gr-group/gr-group.ts
index 1ec83efa8..223a700 100644
--- a/polygerrit-ui/app/elements/admin/gr-group/gr-group.ts
+++ b/polygerrit-ui/app/elements/admin/gr-group/gr-group.ts
@@ -342,7 +342,7 @@
     this.groupConfig = config;
     this.originalOptionsVisibleToAll = config?.options?.visible_to_all;
 
-    fireTitleChange(this, config.name);
+    fireTitleChange(config.name);
 
     await Promise.all(promises);
     this.loading = false;
diff --git a/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list.ts b/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list.ts
index a2de840..cb17de7 100644
--- a/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list.ts
+++ b/polygerrit-ui/app/elements/admin/gr-plugin-list/gr-plugin-list.ts
@@ -47,7 +47,7 @@
 
   override connectedCallback() {
     super.connectedCallback();
-    fireTitleChange(this, 'Plugins');
+    fireTitleChange('Plugins');
   }
 
   static override get styles() {
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands.ts b/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands.ts
index 11cfaab..553de0e 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands.ts
@@ -91,7 +91,7 @@
 
   override connectedCallback() {
     super.connectedCallback();
-    fireTitleChange(this, 'Repo Commands');
+    fireTitleChange('Repo Commands');
   }
 
   static override get styles() {
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list.ts b/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list.ts
index 4837f1a..5318500 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list.ts
@@ -59,7 +59,7 @@
   override async connectedCallback() {
     super.connectedCallback();
     await this.getCreateRepoCapability();
-    fireTitleChange(this, 'Repos');
+    fireTitleChange('Repos');
     this.maybeOpenCreateModal(this.params);
   }
 
diff --git a/polygerrit-ui/app/elements/admin/gr-repo/gr-repo.ts b/polygerrit-ui/app/elements/admin/gr-repo/gr-repo.ts
index 3599224..4bbd533 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo/gr-repo.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo/gr-repo.ts
@@ -134,7 +134,7 @@
   override connectedCallback() {
     super.connectedCallback();
 
-    fireTitleChange(this, `${this.repo}`);
+    fireTitleChange(`${this.repo}`);
   }
 
   static override get styles() {
diff --git a/polygerrit-ui/app/elements/change-list/gr-change-list-bulk-abandon-flow/gr-change-list-bulk-abandon-flow.ts b/polygerrit-ui/app/elements/change-list/gr-change-list-bulk-abandon-flow/gr-change-list-bulk-abandon-flow.ts
index df63780..2ca7f36 100644
--- a/polygerrit-ui/app/elements/change-list/gr-change-list-bulk-abandon-flow/gr-change-list-bulk-abandon-flow.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-change-list-bulk-abandon-flow/gr-change-list-bulk-abandon-flow.ts
@@ -147,7 +147,7 @@
   private handleClose() {
     this.actionModal.close();
     fireAlert(this, 'Reloading page..');
-    fireReload(this, true);
+    fireReload(this);
   }
 }
 
diff --git a/polygerrit-ui/app/elements/change-list/gr-change-list-bulk-vote-flow/gr-change-list-bulk-vote-flow.ts b/polygerrit-ui/app/elements/change-list/gr-change-list-bulk-vote-flow/gr-change-list-bulk-vote-flow.ts
index db82523..6d7045a 100644
--- a/polygerrit-ui/app/elements/change-list/gr-change-list-bulk-vote-flow/gr-change-list-bulk-vote-flow.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-change-list-bulk-vote-flow/gr-change-list-bulk-vote-flow.ts
@@ -308,7 +308,7 @@
     this.actionModal.close();
     if (getOverallStatus(this.progressByChange) === ProgressStatus.NOT_STARTED)
       return;
-    fireReload(this, true);
+    fireReload(this);
   }
 
   private async handleConfirm() {
diff --git a/polygerrit-ui/app/elements/change-list/gr-change-list-view/gr-change-list-view.ts b/polygerrit-ui/app/elements/change-list/gr-change-list-view/gr-change-list-view.ts
index 8afc283..07a27c6 100644
--- a/polygerrit-ui/app/elements/change-list/gr-change-list-view/gr-change-list-view.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-change-list-view/gr-change-list-view.ts
@@ -32,12 +32,6 @@
 
 @customElement('gr-change-list-view')
 export class GrChangeListView extends LitElement {
-  /**
-   * Fired when the title of the page should change.
-   *
-   * @event title-change
-   */
-
   @query('#prevArrow') protected prevArrow?: HTMLAnchorElement;
 
   @query('#nextArrow') protected nextArrow?: HTMLAnchorElement;
@@ -248,7 +242,7 @@
 
   override updated(changedProperties: PropertyValues) {
     if (changedProperties.has('query')) {
-      fireTitleChange(this, this.query);
+      fireTitleChange(this.query);
     }
   }
 
diff --git a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.ts b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.ts
index 70f1755..cb6d047 100644
--- a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.ts
@@ -68,12 +68,6 @@
 
 @customElement('gr-dashboard-view')
 export class GrDashboardView extends LitElement {
-  /**
-   * Fired when the title of the page should change.
-   *
-   * @event title-change
-   */
-
   @query('#confirmDeleteDialog') protected confirmDeleteDialog?: GrDialog;
 
   @query('#commandsDialog') protected commandsDialog?: GrCreateCommandsDialog;
@@ -404,7 +398,7 @@
     return dashboardPromise
       .then(res => {
         if (res && res.title) {
-          fireTitleChange(this, res.title);
+          fireTitleChange(res.title);
         }
         return this.fetchDashboardChanges(res, checkForNewUser);
       })
@@ -413,7 +407,7 @@
         this.reporting.dashboardDisplayed();
       })
       .catch(err => {
-        fireTitleChange(this, title || this.computeTitle(user));
+        fireTitleChange(title || this.computeTitle(user));
         this.reporting.error('Dashboard reload', err);
       })
       .finally(() => {
diff --git a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.ts b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.ts
index 0b96ce7..4eee3cb 100644
--- a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.ts
@@ -81,7 +81,6 @@
   fireAlert,
   fireError,
   fireNoBubbleNoCompose,
-  fireReload,
 } from '../../../utils/event-util';
 import {
   getApprovalInfo,
@@ -393,9 +392,6 @@
   @property({type: Boolean})
   disableEdit = false;
 
-  @property({type: Boolean})
-  _hasKnownChainState = false;
-
   // private but used in test
   @state() _hideQuickApproveAction = false;
 
@@ -411,9 +407,6 @@
   @property({type: String})
   commitNum?: CommitId;
 
-  @property({type: Boolean})
-  hasParent?: boolean;
-
   @state() latestPatchNum?: PatchSetNumber;
 
   @property({type: String})
@@ -678,14 +671,12 @@
         <gr-confirm-rebase-dialog
           id="confirmRebase"
           class="confirmDialog"
-          .changeNumber=${this.change?._number}
           @confirm-rebase=${this.handleRebaseConfirm}
           @cancel=${this.handleConfirmDialogCancel}
           .disableActions=${this.inProgressActionKeys.has(
             RevisionActions.REBASE
           )}
           .branch=${this.change?.branch}
-          .hasParent=${this.hasParent}
           .rebaseOnCurrent=${this.revisionRebaseAction
             ? !!this.revisionRebaseAction.enabled
             : null}
@@ -810,10 +801,6 @@
   }
 
   override willUpdate(changedProperties: PropertyValues) {
-    if (changedProperties.has('hasParent')) {
-      this.computeChainState();
-    }
-
     if (changedProperties.has('change')) {
       this.reload();
       this.actions = this.change?.actions ?? {};
@@ -1543,22 +1530,10 @@
     return key === '/' ? key : `/${key}`;
   }
 
-  /**
-   * _hasKnownChainState set to true true if hasParent is defined (can be
-   * either true or false). set to false otherwise.
-   *
-   * private but used in test
-   */
-  computeChainState() {
-    this._hasKnownChainState = true;
-  }
-
-  // private but used in test
-  calculateDisabled(action: UIActionInfo) {
-    if (action.__key === 'rebase') {
-      // Rebase button is only disabled when change has no parent(s).
-      return this._hasKnownChainState === false;
-    }
+  private calculateDisabled(action: UIActionInfo) {
+    // TODO(b/270972983): Remove this special casing once the backend is more
+    // aggressive about setting`enabled:true`.
+    if (action.__key === 'rebase') return false;
     return !action.enabled;
   }
 
@@ -1893,7 +1868,7 @@
           // Hide rebase dialog only if the action succeeds
           this.actionsModal?.close();
           this.hideAllDialogs();
-          fireReload(this, true);
+          this.getChangeModel().navigateToChangeResetReload();
           break;
         case ChangeActions.REVERT_SUBMISSION: {
           const revertSubmistionInfo = obj as unknown as RevertSubmissionInfo;
@@ -1909,7 +1884,7 @@
           break;
         }
         default:
-          fireReload(this, true);
+          this.getChangeModel().navigateToChangeResetReload();
           break;
       }
     });
@@ -1977,7 +1952,7 @@
               'Cannot set label: a newer patch has been ' +
               'uploaded to this change.',
             action: 'Reload',
-            callback: () => fireReload(this, true),
+            callback: () => this.getChangeModel().navigateToChangeResetReload(),
           });
 
           // Because this is not a network error, call the cleanup function
diff --git a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.ts b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.ts
index 277eddd..946191b 100644
--- a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.ts
@@ -40,7 +40,7 @@
   TopicName,
 } from '../../../types/common';
 import {ActionType} from '../../../api/change-actions';
-import {SinonFakeTimers} from 'sinon';
+import {SinonFakeTimers, SinonStubbedMember} from 'sinon';
 import {IronAutogrowTextareaElement} from '@polymer/iron-autogrow-textarea';
 import {GrButton} from '../../shared/gr-button/gr-button';
 import {GrDialog} from '../../shared/gr-dialog/gr-dialog';
@@ -56,10 +56,17 @@
 import {testResolver} from '../../../test/common-test-setup';
 import {storageServiceToken} from '../../../services/storage/gr-storage_impl';
 import {pluginLoaderToken} from '../../shared/gr-js-api-interface/gr-plugin-loader';
+import {
+  ChangeModel,
+  changeModelToken,
+} from '../../../models/change/change-model';
 
 // TODO(dhruvsri): remove use of _populateRevertMessage as it's private
 suite('gr-change-actions tests', () => {
   let element: GrChangeActions;
+  let navigateResetStub: SinonStubbedMember<
+    ChangeModel['navigateToChangeResetReload']
+  >;
 
   suite('basic tests', () => {
     setup(async () => {
@@ -139,6 +146,10 @@
         _account_id: 123 as AccountId,
       };
       stubRestApi('getRepoBranches').returns(Promise.resolve([]));
+      navigateResetStub = sinon.stub(
+        testResolver(changeModelToken),
+        'navigateToChangeResetReload'
+      );
 
       await element.updateComplete;
       await element.reload();
@@ -177,14 +188,13 @@
                 title="Rebase onto tip of branch or parent change"
               >
                 <gr-button
-                  aria-disabled="true"
+                  aria-disabled="false"
                   class="rebase"
                   data-action-key="rebase"
                   data-label="Rebase"
-                  disabled=""
                   link=""
                   role="button"
-                  tabindex="-1"
+                  tabindex="0"
                 >
                   <gr-icon icon="rebase"> </gr-icon>
                   Rebase
@@ -570,34 +580,6 @@
       assert.equal(fireActionStub.callCount, 0);
     });
 
-    test('chain state', async () => {
-      assert.equal(element._hasKnownChainState, false);
-      element.hasParent = true;
-      await element.updateComplete;
-      assert.equal(element._hasKnownChainState, true);
-    });
-
-    test('calculateDisabled', () => {
-      const action = {
-        __key: 'rebase',
-        enabled: true,
-        __type: ActionType.CHANGE,
-        label: 'l',
-      };
-      element._hasKnownChainState = false;
-      assert.equal(element.calculateDisabled(action), true);
-
-      action.__key = 'delete';
-      assert.equal(element.calculateDisabled(action), false);
-
-      action.__key = 'rebase';
-      element._hasKnownChainState = true;
-      assert.equal(element.calculateDisabled(action), false);
-
-      action.enabled = false;
-      assert.equal(element.calculateDisabled(action), false);
-    });
-
     test('rebase change', async () => {
       const fireActionStub = sinon.stub(element, 'fireAction');
       const fetchChangesStub = sinon
@@ -606,7 +588,6 @@
           'fetchRecentChanges'
         )
         .returns(Promise.resolve([]));
-      element._hasKnownChainState = true;
       await element.updateComplete;
       queryAndAssert<GrButton>(
         element,
@@ -642,13 +623,11 @@
     });
 
     test('rebase change fires reload event', async () => {
-      const eventStub = sinon.stub(element, 'dispatchEvent');
       await element.handleResponse(
         {__key: 'rebase', __type: ActionType.CHANGE, label: 'l'},
         new Response()
       );
-      assert.isTrue(eventStub.called);
-      assert.equal(eventStub.lastCall.args[0].type, 'reload');
+      assert.isTrue(navigateResetStub.called);
     });
 
     test("rebase dialog gets recent changes each time it's opened", async () => {
@@ -658,7 +637,6 @@
           'fetchRecentChanges'
         )
         .returns(Promise.resolve([]));
-      element._hasKnownChainState = true;
       await element.updateComplete;
       const rebaseButton = queryAndAssert<GrButton>(
         element,
@@ -683,7 +661,6 @@
     });
 
     test('two dialogs are not shown at the same time', async () => {
-      element._hasKnownChainState = true;
       await element.updateComplete;
       queryAndAssert<GrButton>(
         element,
diff --git a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts
index 54752b0..b7851a6 100644
--- a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts
@@ -126,6 +126,7 @@
 
   @property({type: Object}) revision?: RevisionInfo | EditRevisionInfo;
 
+  // TODO: Just use `revision.commit` instead.
   @property({type: Object}) commitInfo?: CommitInfoWithRequiredCommit;
 
   @property({type: Object}) serverConfig?: ServerInfo;
diff --git a/polygerrit-ui/app/elements/change/gr-change-summary/gr-change-summary.ts b/polygerrit-ui/app/elements/change/gr-change-summary/gr-change-summary.ts
index 2759830..531994c90 100644
--- a/polygerrit-ui/app/elements/change/gr-change-summary/gr-change-summary.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-summary/gr-change-summary.ts
@@ -151,7 +151,7 @@
     );
     subscribe(
       this,
-      () => this.getCommentsModel().threads$,
+      () => this.getCommentsModel().threadsSaved$,
       x => (this.commentThreads = x)
     );
     subscribe(
@@ -164,7 +164,7 @@
       () =>
         combineLatest([
           this.getUserModel().account$,
-          this.getCommentsModel().threads$,
+          this.getCommentsModel().threadsSaved$,
         ]),
       ([selfAccount, threads]) => {
         if (!selfAccount || !selfAccount.email) return;
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
index 474a31f..e1ae35c 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
@@ -34,27 +34,16 @@
 import {ChangeStarToggleStarDetail} from '../../shared/gr-change-star/gr-change-star';
 import {GrEditConstants} from '../../edit/gr-edit-constants';
 import {pluralize} from '../../../utils/string-util';
-import {whenVisible} from '../../../utils/dom-util';
+import {untilRendered, whenVisible} from '../../../utils/dom-util';
 import {navigationToken} from '../../core/gr-navigation/gr-navigation';
-import {RevisionInfo as RevisionInfoClass} from '../../shared/revision-info/revision-info';
-import {
-  ChangeStatus,
-  DefaultBase,
-  Tab,
-  DiffViewMode,
-} from '../../../constants/constants';
+import {ChangeStatus, Tab, DiffViewMode} from '../../../constants/constants';
 import {getAppContext} from '../../../services/app-context';
 import {
   computeAllPatchSets,
   computeLatestPatchNum,
-  findEdit,
-  findEditParentRevision,
   PatchSet,
 } from '../../../utils/patch-set-util';
 import {
-  changeIsAbandoned,
-  changeIsMerged,
-  changeIsOpen,
   changeStatuses,
   isInvolved,
   roleDetails,
@@ -63,38 +52,27 @@
 import {GrApplyFixDialog} from '../../diff/gr-apply-fix-dialog/gr-apply-fix-dialog';
 import {GrFileListHeader} from '../gr-file-list-header/gr-file-list-header';
 import {GrEditableContent} from '../../shared/gr-editable-content/gr-editable-content';
-import {GrRelatedChangesList} from '../gr-related-changes-list/gr-related-changes-list';
 import {GrChangeStar} from '../../shared/gr-change-star/gr-change-star';
 import {GrChangeActions} from '../gr-change-actions/gr-change-actions';
 import {
   AccountDetailInfo,
   ActionNameToActionInfoMap,
   BasePatchSetNum,
-  ChangeId,
   ChangeInfo,
   CommentThread,
-  CommitId,
-  CommitInfo,
   ConfigInfo,
   DetailedLabelInfo,
-  DraftInfo,
   EDIT,
   LabelNameToInfoMap,
   NumericChangeId,
   PARENT,
-  PatchRange,
   PatchSetNum,
-  PatchSetNumber,
-  PreferencesInfo,
   QuickLabelInfo,
-  RelatedChangeAndCommitInfo,
-  RelatedChangesInfo,
   RevisionInfo,
   RevisionPatchSetNum,
   ServerInfo,
   UrlEncodedCommentId,
   isRobot,
-  ChangeStates,
 } from '../../../types/common';
 import {FocusTarget, GrReplyDialog} from '../gr-reply-dialog/gr-reply-dialog';
 import {GrIncludedInDialog} from '../gr-included-in-dialog/gr-included-in-dialog';
@@ -128,16 +106,15 @@
   fireDialogChange,
   fire,
   fireReload,
-  fireTitleChange,
 } from '../../../utils/event-util';
 import {
   debounce,
   DelayedTask,
   throttleWrap,
   until,
+  waitUntil,
 } from '../../../utils/async-util';
-import {Interaction, Timing} from '../../../constants/reporting';
-import {getRevertCreatedChangeIds} from '../../../utils/message-util';
+import {Interaction} from '../../../constants/reporting';
 import {
   getAddedByReason,
   getRemovedByReason,
@@ -153,7 +130,7 @@
 import {resolve} from '../../../models/dependency';
 import {checksModelToken} from '../../../models/checks/checks-model';
 import {changeModelToken} from '../../../models/change/change-model';
-import {css, html, LitElement, nothing, PropertyValues} from 'lit';
+import {css, html, LitElement, nothing} from 'lit';
 import {a11yStyles} from '../../../styles/gr-a11y-styles';
 import {paperStyles} from '../../../styles/gr-paper-styles';
 import {sharedStyles} from '../../../styles/shared-styles';
@@ -163,7 +140,6 @@
 import {FilesExpandedState} from '../gr-file-list-constants';
 import {subscribe} from '../../lit/subscription-controller';
 import {configModelToken} from '../../../models/config/config-model';
-import {filesModelToken} from '../../../models/change/files-model';
 import {getBaseUrl, prependOrigin} from '../../../utils/url-util';
 import {CopyLink, GrCopyLinks} from '../gr-copy-links/gr-copy-links';
 import {
@@ -177,6 +153,7 @@
 import {userModelToken} from '../../../models/user/user-model';
 import {pluginLoaderToken} from '../../shared/gr-js-api-interface/gr-plugin-loader';
 import {modalStyles} from '../../../styles/gr-modal-styles';
+import {relatedChangesModelToken} from '../../../models/change/related-changes-model';
 
 const MIN_LINES_FOR_COMMIT_COLLAPSE = 18;
 
@@ -200,17 +177,9 @@
 // Making the tab names more unique in case a plugin adds one with same name
 const ROBOT_COMMENTS_LIMIT = 10;
 
-export type ChangeViewPatchRange = Partial<PatchRange>;
-
 @customElement('gr-change-view')
 export class GrChangeView extends LitElement {
   /**
-   * Fired when the title of the page should change.
-   *
-   * @event title-change
-   */
-
-  /**
    * Fired if an error occurs when fetching the change data.
    *
    * @event page-error
@@ -266,35 +235,18 @@
 
   @query('gr-copy-links') private copyLinksDropdown?: GrCopyLinks;
 
-  private _viewState?: ChangeViewState;
-
-  @property({type: Object})
-  get viewState() {
-    return this._viewState;
-  }
-
-  set viewState(viewState: ChangeViewState | undefined) {
-    if (this._viewState === viewState) return;
-    const oldViewState = this._viewState;
-    this._viewState = viewState;
-    this.viewStateChanged();
-    this.requestUpdate('viewState', oldViewState);
-  }
+  @state()
+  viewState?: ChangeViewState;
 
   @property({type: String})
   backPage?: string;
 
   @state()
-  private hasParent?: boolean;
-
-  // Private but used in tests.
-  @state()
   commentThreads?: CommentThread[];
 
   // Don't use, use serverConfig instead.
   private _serverConfig?: ServerInfo;
 
-  // Private but used in tests.
   @state()
   get serverConfig() {
     return this._serverConfig;
@@ -311,10 +263,6 @@
   @state()
   private account?: AccountDetailInfo;
 
-  // Private but used in tests.
-  @state()
-  prefs?: PreferencesInfo;
-
   canStartReview() {
     return !!(
       this.change &&
@@ -342,42 +290,19 @@
 
   // Private but used in tests.
   @state()
-  commitInfo?: CommitInfo;
-
-  // Private but used in tests.
-  @state()
   changeNum?: NumericChangeId;
 
-  // Private but used in tests.
-  @state()
-  diffDrafts?: {[path: string]: DraftInfo[]} = {};
-
   @state()
   private editingCommitMessage = false;
 
   @state()
-  private latestCommitMessage: string | null = '';
+  private latestCommitMessage = '';
 
-  // Use patchRange getter/setter.
-  private _patchRange?: ChangeViewPatchRange;
+  @state() basePatchNum: BasePatchSetNum = PARENT;
 
-  // Private but used in tests.
-  @state()
-  get patchRange() {
-    return this._patchRange;
-  }
+  @state() patchNum?: RevisionPatchSetNum;
 
-  set patchRange(patchRange: ChangeViewPatchRange | undefined) {
-    if (this._patchRange === patchRange) return;
-    const oldPatchRange = this._patchRange;
-    this._patchRange = patchRange;
-    this.patchNumChanged();
-    this.requestUpdate('patchRange', oldPatchRange);
-  }
-
-  // Private but used in tests.
-  @state()
-  selectedRevision?: RevisionInfo | EditRevisionInfo;
+  @state() revision?: RevisionInfo | EditRevisionInfo;
 
   /**
    * <gr-change-actions> populates this via two-way data binding.
@@ -405,30 +330,14 @@
 
   // Private but used in tests.
   @state()
-  initialLoadComplete = false;
-
-  // Private but used in tests.
-  @state()
   replyDisabled = true;
 
-  // Private but used in tests.
-  @state()
-  changeStatuses: ChangeStates[] = [];
-
   @state()
   private updateCheckTimerHandle?: number | null;
 
   // Private but used in tests.
-  getEditMode() {
-    if (!this.patchRange || !this.viewState) {
-      return false;
-    }
-
-    if (this.viewState.edit) {
-      return true;
-    }
-
-    return this.patchRange.patchNum === EDIT;
+  getEditMode(): boolean {
+    return !!this.viewState?.edit || this.patchNum === EDIT;
   }
 
   isSubmitEnabled(): boolean {
@@ -439,9 +348,7 @@
     );
   }
 
-  // Private but used in tests.
-  @state()
-  mergeable: boolean | null = null;
+  @state() mergeable?: boolean;
 
   /**
    * Plugins can provide (multiple) tabs. For each plugin tab we render an
@@ -490,7 +397,7 @@
   private showRobotCommentsButton = false;
 
   @state()
-  private draftCount = 0;
+  draftCount = 0;
 
   private throttledToggleChangeStar?: (e: KeyboardEvent) => void;
 
@@ -508,7 +415,7 @@
   private tabState?: TabState;
 
   @state()
-  private revertedChange?: ChangeInfo;
+  private revertingChange?: ChangeInfo;
 
   // Private but used in tests.
   @state()
@@ -535,10 +442,13 @@
 
   private readonly getConfigModel = resolve(this, configModelToken);
 
-  private readonly getFilesModel = resolve(this, filesModelToken);
-
   private readonly getViewModel = resolve(this, changeViewModelToken);
 
+  private readonly getRelatedChangesModel = resolve(
+    this,
+    relatedChangesModelToken
+  );
+
   private readonly getShortcutsService = resolve(this, shortcutsServiceToken);
 
   private scrollTask?: DelayedTask;
@@ -586,14 +496,7 @@
       this.handleCommitMessageCancel()
     );
     this.addEventListener('open-fix-preview', e => this.onOpenFixPreview(e));
-
     this.addEventListener('show-tab', e => this.setActiveTab(e));
-    this.addEventListener('reload', e => {
-      this.loadData(
-        /* isLocationChange= */ false,
-        /* clearPatchset= */ e.detail && e.detail.clearPatchset
-      );
-    });
   }
 
   private setupShortcuts() {
@@ -601,7 +504,7 @@
     this.shortcutsController.addAbstract(Shortcut.EMOJI_DROPDOWN, () => {}); // docOnly
     this.shortcutsController.addAbstract(Shortcut.MENTIONS_DROPDOWN, () => {}); // docOnly
     this.shortcutsController.addAbstract(Shortcut.REFRESH_CHANGE, () =>
-      fireReload(this, true)
+      this.getChangeModel().navigateToChangeResetReload()
     );
     this.shortcutsController.addAbstract(Shortcut.OPEN_REPLY_DIALOG, () =>
       this.handleOpenReplyDialog()
@@ -671,7 +574,21 @@
     subscribe(
       this,
       () => this.getViewModel().tab$,
-      t => (this.activeTab = t ?? Tab.FILES)
+      t => (this.activeTab = t)
+    );
+    subscribe(
+      this,
+      () => this.getViewModel().commentId$,
+      commentId => (this.scrollCommentId = commentId)
+    );
+    subscribe(
+      this,
+      () => this.getViewModel().openReplyDialog$,
+      openReplyDialog => {
+        // Here we are relying on `this.loggedIn` being set *before*
+        // `openReplyDialog`, but that is fine for this feature.
+        if (openReplyDialog && this.loggedIn) this.handleOpenReplyDialog();
+      }
     );
     subscribe(
       this,
@@ -692,6 +609,11 @@
       () => this.getViewModel().childView$,
       childView => {
         this.isViewCurrent = childView === ChangeChildView.OVERVIEW;
+        // When coming back from ChangeChildView.DIFF we want to restore the
+        // scroll position to what it was before leaving the OVERVIEW page.
+        if (this.isViewCurrent) {
+          document.documentElement.scrollTop = this.scrollPosition ?? 0;
+        }
       }
     );
     subscribe(
@@ -703,13 +625,6 @@
     );
     subscribe(
       this,
-      () => this.getCommentsModel().drafts$,
-      drafts => {
-        this.diffDrafts = {...drafts};
-      }
-    );
-    subscribe(
-      this,
       () => this.getUserModel().preferenceDiffViewMode$,
       diffViewMode => {
         this.diffViewMode = diffViewMode;
@@ -724,7 +639,7 @@
     );
     subscribe(
       this,
-      () => this.getCommentsModel().threads$,
+      () => this.getCommentsModel().threadsSaved$,
       threads => {
         this.commentThreads = threads;
       }
@@ -740,6 +655,49 @@
     );
     subscribe(
       this,
+      () => this.getChangeModel().changeNum$,
+      changeNum => {
+        // The change view is tied to a specific change number, so don't update
+        // changeNum to undefined and only set it once.
+        if (changeNum && !this.changeNum) this.changeNum = changeNum;
+      }
+    );
+    subscribe(
+      this,
+      () => this.getChangeModel().patchNum$,
+      patchNum => (this.patchNum = patchNum)
+    );
+    subscribe(
+      this,
+      () => this.getChangeModel().basePatchNum$,
+      basePatchNum => (this.basePatchNum = basePatchNum)
+    );
+    subscribe(
+      this,
+      () => this.getChangeModel().mergeable$,
+      mergeable => (this.mergeable = mergeable)
+    );
+    subscribe(
+      this,
+      () => this.getChangeModel().revision$,
+      revision => (this.revision = revision)
+    );
+    subscribe(
+      this,
+      () => this.getChangeModel().changeLoadingStatus$,
+      status => (this.loading = status !== LoadingStatus.LOADED)
+    );
+    subscribe(
+      this,
+      () => this.getChangeModel().latestRevision$,
+      revision => {
+        this.latestCommitMessage = this.prepareCommitMsgForLinkify(
+          revision?.commit?.message ?? ''
+        );
+      }
+    );
+    subscribe(
+      this,
       () => this.getUserModel().account$,
       account => {
         this.account = account;
@@ -767,6 +725,13 @@
         this.projectConfig = config;
       }
     );
+    subscribe(
+      this,
+      () => this.getRelatedChangesModel().revertingChange$,
+      revertingChange => {
+        this.revertingChange = revertingChange;
+      }
+    );
   }
 
   override connectedCallback() {
@@ -781,6 +746,8 @@
   }
 
   override firstUpdated() {
+    this.maybeScrollToMessage(window.location.hash);
+    this.maybeShowRevertDialog();
     // _onTabSizingChanged is called when iron-items-changed event is fired
     // from iron-selectable but that is called before the element is present
     // in view which whereas the method requires paper tabs already be visible
@@ -819,8 +786,7 @@
             new Error('Mismatch of headers and content.')
           );
         }
-      })
-      .then(() => this.initActiveTab());
+      });
 
     this.throttledToggleChangeStar = throttleWrap<KeyboardEvent>(_ =>
       this.handleToggleChangeStar()
@@ -842,16 +808,6 @@
     super.disconnectedCallback();
   }
 
-  protected override willUpdate(changedProperties: PropertyValues): void {
-    if (
-      changedProperties.has('change') ||
-      changedProperties.has('mergeable') ||
-      changedProperties.has('currentRevisionActions')
-    ) {
-      this.changeStatuses = this.computeChangeStatusChips();
-    }
-  }
-
   static override get styles() {
     return [
       a11yStyles,
@@ -1062,7 +1018,7 @@
           .relatedChanges {
             padding: 0;
           }
-          #relatedChanges {
+          .relatedChanges gr-related-changes-list {
             padding-top: var(--spacing-l);
           }
           #commitAndRelated {
@@ -1231,12 +1187,14 @@
   }
 
   private renderHeaderTitle() {
-    const resolveWeblinks = this.commitInfo?.resolve_conflicts_web_links ?? [];
+    const changeStatuses = this.computeChangeStatusChips();
+    const resolveWeblinks =
+      this.revision?.commit?.resolve_conflicts_web_links ?? [];
     return html` <div class="headerTitle">
       <div class="changeStatuses">
-        ${this.changeStatuses.map(
+        ${changeStatuses.map(
           status => html` <gr-change-status
-            .revertedChange=${this.revertedChange}
+            .revertedChange=${this.revertingChange}
             .status=${status}
             .resolveWeblinks=${resolveWeblinks}
           ></gr-change-status>`
@@ -1335,11 +1293,10 @@
         id="actions"
         .change=${this.change}
         .disableEdit=${false}
-        .hasParent=${this.hasParent}
         .account=${this.account}
         .changeNum=${this.changeNum}
         .changeStatus=${this.change?.status}
-        .commitNum=${this.commitInfo?.commit}
+        .commitNum=${this.revision?.commit?.commit}
         .commitMessage=${this.latestCommitMessage}
         .editMode=${this.getEditMode()}
         .privateByDefault=${this.projectConfig?.private_by_default}
@@ -1365,10 +1322,10 @@
         <gr-change-metadata
           id="metadata"
           .change=${this.change}
-          .revertedChange=${this.revertedChange}
+          .revertedChange=${this.revertingChange}
           .account=${this.account}
-          .revision=${this.selectedRevision}
-          .commitInfo=${this.commitInfo}
+          .revision=${this.revision}
+          .commitInfo=${this.revision?.commit}
           .serverConfig=${this.serverConfig}
           .parentIsCurrent=${this.isParentCurrent()}
           .repoConfig=${this.projectConfig}
@@ -1408,7 +1365,7 @@
                 remove-zero-width-space=""
               >
                 <gr-formatted-text
-                  .content=${this.latestCommitMessage ?? ''}
+                  .content=${this.latestCommitMessage}
                   .markdown=${false}
                 ></gr-formatted-text>
               </gr-editable-content>
@@ -1418,18 +1375,12 @@
             <gr-endpoint-decorator name="commit-container">
               <gr-endpoint-param name="change" .value=${this.change}>
               </gr-endpoint-param>
-              <gr-endpoint-param
-                name="revision"
-                .value=${this.selectedRevision}
-              >
+              <gr-endpoint-param name="revision" .value=${this.revision}>
               </gr-endpoint-param>
             </gr-endpoint-decorator>
           </div>
           <div class="relatedChanges">
-            <gr-related-changes-list
-              id="relatedChanges"
-              .mergeable=${this.mergeable}
-            ></gr-related-changes-list>
+            <gr-related-changes-list></gr-related-changes-list>
           </div>
           <div class="emptySpace"></div>
         </div>
@@ -1468,14 +1419,11 @@
         )}
         ${this.pluginTabsHeaderEndpoints.map(
           tabHeader => html`
-            <paper-tab data-name=${tabHeader}>
+            <paper-tab data-name=${tabHeader} @click=${this.onPaperTabClick}>
               <gr-endpoint-decorator name=${tabHeader}>
                 <gr-endpoint-param name="change" .value=${this.change}>
                 </gr-endpoint-param>
-                <gr-endpoint-param
-                  name="revision"
-                  .value=${this.selectedRevision}
-                >
+                <gr-endpoint-param name="revision" .value=${this.revision}>
                 </gr-endpoint-param>
               </gr-endpoint-decorator>
             </paper-tab>
@@ -1511,7 +1459,7 @@
           .account=${this.account}
           .change=${this.change}
           .changeNum=${this.changeNum}
-          .commitInfo=${this.commitInfo}
+          .commitInfo=${this.revision?.commit}
           .changeUrl=${this.computeChangeUrl()}
           .editMode=${this.getEditMode()}
           .loggedIn=${this.loggedIn}
@@ -1606,7 +1554,7 @@
       <gr-endpoint-decorator .name=${pluginTabContentEndpoint}>
         <gr-endpoint-param name="change" .value=${this.change}>
         </gr-endpoint-param>
-        <gr-endpoint-param name="revision" .value=${this.selectedRevision}></gr-endpoint-param>
+        <gr-endpoint-param name="revision" .value=${this.revision}></gr-endpoint-param>
         </gr-endpoint-param>
       </gr-endpoint-decorator>
     `;
@@ -1617,7 +1565,7 @@
       <gr-endpoint-decorator name="change-view-integration">
         <gr-endpoint-param name="change" .value=${this.change}>
         </gr-endpoint-param>
-        <gr-endpoint-param name="revision" .value=${this.selectedRevision}>
+        <gr-endpoint-param name="revision" .value=${this.revision}>
         </gr-endpoint-param>
       </gr-endpoint-decorator>
 
@@ -1631,7 +1579,7 @@
         <gr-messages-list
           .labels=${this.change?.labels}
           .messages=${this.change?.messages}
-          .reviewerUpdates=${this.change?.reviewer_updates}
+          .reviewerUpdates=${this.change?.reviewer_updates ?? []}
           @message-anchor-tap=${this.handleMessageAnchorTap}
         ></gr-messages-list>
       </section>
@@ -1641,11 +1589,12 @@
   override updated() {
     const tabs = [...queryAll<HTMLElement>(this.tabs!, 'paper-tab')];
     const tabIndex = tabs.findIndex(t => t.dataset['name'] === this.activeTab);
-    assert(tabIndex !== -1, `tab ${this.activeTab} not found`);
 
-    if (this.tabs!.selected !== tabIndex) {
+    if (tabIndex !== -1 && this.tabs!.selected !== tabIndex) {
       this.tabs!.selected = tabIndex;
     }
+    this.reportChangeDisplayed();
+    this.reportFullyLoaded();
   }
 
   private readonly handleScroll = () => {
@@ -1732,7 +1681,8 @@
   }
 
   private handleContentChanged(e: ValueChangedEvent) {
-    this.latestCommitMessage = e.detail.value;
+    // optimistic update
+    this.latestCommitMessage = e.detail.value ?? '';
   }
 
   // Private but used in tests.
@@ -1759,9 +1709,8 @@
           return;
         }
 
-        this.latestCommitMessage = this.prepareCommitMsgForLinkify(message);
         this.editingCommitMessage = false;
-        fireReload(this, true);
+        this.getChangeModel().navigateToChangeResetReload();
       })
       .catch(() => {
         assertIsDefined(this.commitMessageEditor);
@@ -1774,19 +1723,12 @@
   }
 
   private computeChangeStatusChips() {
-    if (!this.change) {
-      return [];
-    }
-
-    // Show no chips until mergeability is loaded.
-    if (this.mergeable === null) {
-      return [];
-    }
+    if (!this.change || this.mergeable === undefined) return [];
 
     const options = {
-      includeDerived: true,
-      mergeable: !!this.mergeable,
+      mergeable: this.mergeable,
       submitEnabled: !!this.isSubmitEnabled(),
+      revertingChangeStatus: this.revertingChange?.status,
     };
     return changeStatuses(this.change as ChangeInfo, options);
   }
@@ -1954,16 +1896,9 @@
 
   // Private but used in tests.
   handleReplySent() {
-    this.addEventListener(
-      'change-details-loaded',
-      () => {
-        this.reporting.timeEnd(Timing.SEND_REPLY);
-      },
-      {once: true}
-    );
     assertIsDefined(this.replyModal);
     this.replyModal.close();
-    fireReload(this);
+    this.getChangeModel().navigateToChangeResetReload();
   }
 
   private handleReplyCancel() {
@@ -2014,158 +1949,14 @@
   }
 
   // Private but used in tests.
-  hasPatchRangeChanged(viewState: ChangeViewState) {
-    if (!this.patchRange) return false;
-    if (this.patchRange.basePatchNum !== viewState.basePatchNum) return true;
-    return this.hasPatchNumChanged(viewState);
-  }
-
-  // Private but used in tests.
-  hasPatchNumChanged(viewState: ChangeViewState) {
-    if (!this.patchRange) return false;
-    if (viewState.patchNum !== undefined) {
-      return this.patchRange.patchNum !== viewState.patchNum;
-    } else {
-      // value.patchNum === undefined specifies the latest patchset
-      return (
-        this.patchRange.patchNum !== computeLatestPatchNum(this.allPatchSets)
-      );
-    }
-  }
-
-  // Private but used in tests.
-  viewStateChanged() {
-    if (!this.viewState) return;
-    if (this.isChangeObsolete()) return;
-
-    if (this.viewState.basePatchNum === undefined)
-      this.viewState.basePatchNum = PARENT;
-
-    const patchChanged = this.hasPatchRangeChanged(this.viewState);
-
-    this.patchRange = {
-      patchNum: this.viewState.patchNum,
-      basePatchNum: this.viewState.basePatchNum,
-    };
-    this.scrollCommentId = this.viewState.commentId;
-
-    const patchKnown =
-      !this.patchRange.patchNum ||
-      (this.allPatchSets ?? []).some(
-        ps => ps.num === this.patchRange!.patchNum
-      );
-    // _allPatchsets does not know value.patchNum so force a reload.
-    const forceReload = this.viewState.forceReload || !patchKnown;
-
-    // If changeNum is defined that means the change has already been
-    // rendered once before so a full reload is not required.
-    if (this.changeNum !== undefined && !forceReload) {
-      if (!this.patchRange.patchNum) {
-        this.patchRange = {
-          ...this.patchRange,
-          patchNum: computeLatestPatchNum(this.allPatchSets),
-        };
-      }
-      if (patchChanged) {
-        // We need to collapse all diffs when viewState changes so that a non
-        // existing diff is not requested. See Issue 125270 for more details.
-        this.fileList?.resetFileState();
-        this.fileList?.collapseAllDiffs();
-        this.reloadPatchNumDependentResources();
-      }
-
-      // If there is no change in patchset or changeNum, such as when user goes
-      // to the diff view and then comes back to change page then there is no
-      // need to reload anything and we render the change view component as is.
-      document.documentElement.scrollTop = this.scrollPosition ?? 0;
-      this.reporting.reportInteraction('change-view-re-rendered');
-      this.updateTitle(this.change);
-      // We still need to check if post load tasks need to be done such as when
-      // user wants to open the reply dialog when in the diff page, the change
-      // page should open the reply dialog
-      this.performPostLoadTasks();
-      return;
-    }
-
-    // We need to collapse all diffs when viewState changes so that a non
-    // existing diff is not requested. See Issue 125270 for more details.
-    this.updateComplete.then(() => {
-      assertIsDefined(this.fileList);
-      this.fileList?.collapseAllDiffs();
-      this.fileList?.resetFileState();
-    });
-
-    // If the change was loaded before, then we are firing a 'reload' event
-    // instead of calling `loadData()` directly for two reasons:
-    // 1. We want to avoid code such as `this.initialLoadComplete = false` that
-    //    is only relevant for the initial load of a change.
-    // 2. We have to somehow trigger the change-model reloading. Otherwise
-    //    this.change is not updated.
-    if (this.changeNum) {
-      if (!this._patchRange?.patchNum) {
-        this._patchRange = {
-          basePatchNum: PARENT,
-          patchNum: computeLatestPatchNum(this.allPatchSets),
-        };
-      }
-      fireReload(this);
-      return;
-    }
-
-    this.initialLoadComplete = false;
-    this.changeNum = this.viewState.changeNum;
-    this.loadData(true).then(() => {
-      this.performPostLoadTasks();
-    });
-
-    this.getPluginLoader()
-      .awaitPluginsLoaded()
-      .then(() => {
-        this.initActiveTab();
-      });
-  }
-
-  private initActiveTab() {
-    let tab = Tab.FILES;
-    if (this.viewState?.tab) {
-      tab = this.viewState?.tab as Tab;
-    } else if (this.viewState?.commentId) {
-      tab = Tab.COMMENT_THREADS;
-    }
-    this.setActiveTab(new CustomEvent('show-tab', {detail: {tab}}));
-  }
-
-  // Private but used in tests.
-  sendShowChangeEvent() {
-    assertIsDefined(this.patchRange, 'patchRange');
-    this.getPluginLoader().jsApiService.handleShowChange({
-      change: this.change,
-      patchNum: this.patchRange.patchNum,
-      info: {mergeable: this.mergeable},
-    });
-  }
-
-  private performPostLoadTasks() {
-    this.maybeShowReplyDialog();
-    this.maybeShowRevertDialog();
-
-    this.sendShowChangeEvent();
-
-    this.updateComplete.then(() => {
-      this.maybeScrollToMessage(window.location.hash);
-      this.initialLoadComplete = true;
-    });
-  }
-
-  // Private but used in tests.
   handleMessageAnchorTap(e: CustomEvent<{id: string}>) {
     assertIsDefined(this.change, 'change');
-    assertIsDefined(this.patchRange, 'patchRange');
+    assertIsDefined(this.patchNum, 'patchNum');
     const hash = PREFIX + e.detail.id;
     const url = createChangeUrl({
       change: this.change,
-      patchNum: this.patchRange.patchNum,
-      basePatchNum: this.patchRange.basePatchNum,
+      patchNum: this.patchNum,
+      basePatchNum: this.basePatchNum,
       edit: this.getEditMode(),
       messageHash: hash,
     });
@@ -2173,9 +1964,10 @@
   }
 
   // Private but used in tests.
-  maybeScrollToMessage(hash: string) {
-    if (hash.startsWith(PREFIX) && this.messagesList) {
-      this.messagesList.scrollToMessage(hash.substr(PREFIX.length));
+  async maybeScrollToMessage(hash: string) {
+    if (hash.startsWith(PREFIX)) {
+      await waitUntil(() => !!this.messagesList);
+      await this.messagesList!.scrollToMessage(hash.substr(PREFIX.length));
     }
   }
 
@@ -2198,39 +1990,18 @@
   }
 
   // Private but used in tests.
-  maybeShowRevertDialog() {
-    this.getPluginLoader()
-      .awaitPluginsLoaded()
-      .then(() => {
-        if (
-          !this.loggedIn ||
-          !this.change ||
-          this.change.status !== ChangeStatus.MERGED
-        ) {
-          // Do not display dialog if not logged-in or the change is not
-          // merged.
-          return;
-        }
-        if (this._getUrlParameter('revert')) {
-          assertIsDefined(this.actions);
-          this.actions.showRevertDialog();
-        }
-      });
-  }
+  async maybeShowRevertDialog() {
+    if (!this._getUrlParameter('revert')) return;
 
-  private maybeShowReplyDialog() {
-    if (!this.loggedIn) return;
-    if (this.viewState?.openReplyDialog) {
-      this.openReplyDialog(FocusTarget.ANY);
+    await this.getPluginLoader().awaitPluginsLoaded();
+    await waitUntil(() => !!this.actions);
+    await waitUntil(() => !!this.change);
+
+    if (this.change?.status === ChangeStatus.MERGED && this.loggedIn) {
+      this.actions!.showRevertDialog();
     }
   }
 
-  private updateTitle(change?: ChangeInfo | ParsedChangeInfo) {
-    if (!change) return;
-    const title = `${change.subject} (${change._number})`;
-    fireTitleChange(this, title);
-  }
-
   // Private but used in tests.
   changeChanged(oldChange: ParsedChangeInfo | undefined) {
     this.allPatchSets = computeAllPatchSets(this.change);
@@ -2244,57 +2015,11 @@
       this.currentRobotCommentsPatchSet =
         this.change.revisions[this.change.current_revision]._number;
     }
-    if (!this.change || !this.patchRange || !this.allPatchSets) {
-      return;
-    }
-
-    // We get the parent first so we keep the original value for basePatchNum
-    // and not the updated value.
-    const parent = this.getBasePatchNum();
-
-    this.patchRange = {
-      ...this.patchRange,
-      basePatchNum: parent,
-      patchNum:
-        this.patchRange.patchNum || computeLatestPatchNum(this.allPatchSets),
-    };
-    this.updateTitle(this.change);
   }
 
   /**
-   * Gets base patch number, if it is a parent try and decide from
-   * preference whether to default to `auto merge`, `Parent 1` or `PARENT`.
-   * Private but used in tests.
+   * This is the URL equivalent of changeModel.navigateToChangeResetReload().
    */
-  getBasePatchNum() {
-    if (
-      this.patchRange &&
-      this.patchRange.basePatchNum &&
-      this.patchRange.basePatchNum !== PARENT
-    ) {
-      return this.patchRange.basePatchNum;
-    }
-
-    const revisionInfo = this.getRevisionInfo();
-    if (!revisionInfo) return PARENT;
-
-    // TODO: It is a bit unclear why `1` is used here instead of
-    // `patchRange.patchNum`. Maybe that is a bug? Maybe if one patchset
-    // is a merge commit, then all patchsets are merge commits??
-    const isMerge = revisionInfo.isMergeCommit(1 as PatchSetNumber);
-    const preferFirst =
-      this.prefs &&
-      this.prefs.default_base_for_merges === DefaultBase.FIRST_PARENT;
-
-    // Verified via reportExecution that -1 is returned(1-5 times per day)
-    // changeChanged does set this.patchRange?.patchNum so it's still unclear
-    // how it is undefined.
-    if (isMerge && preferFirst && !this.patchRange?.patchNum) {
-      return -1 as BasePatchSetNum;
-    }
-    return PARENT;
-  }
-
   private computeChangeUrl(forceReload?: boolean) {
     if (!this.change) return undefined;
     return createChangeUrl({
@@ -2305,18 +2030,9 @@
 
   // Private but used in tests.
   computeReplyButtonLabel() {
-    if (this.diffDrafts === undefined) {
-      return 'Reply';
-    }
-
-    const draftCount = Object.keys(this.diffDrafts).reduce(
-      (count, file) => count + this.diffDrafts![file].length,
-      0
-    );
-
     let label = this.canStartReview() ? 'Start Review' : 'Reply';
-    if (draftCount > 0) {
-      label += ` (${draftCount})`;
+    if (this.draftCount > 0) {
+      label += ` (${this.draftCount})`;
     }
     return label;
   }
@@ -2379,13 +2095,13 @@
   // Private but used in tests.
   handleDiffAgainstBase() {
     assertIsDefined(this.change, 'change');
-    assertIsDefined(this.patchRange, 'patchRange');
-    if (this.patchRange.basePatchNum === PARENT) {
+    assertIsDefined(this.patchNum, 'patchNum');
+    if (this.basePatchNum === PARENT) {
       fireAlert(this, 'Base is already selected.');
       return;
     }
     this.getNavigation().setUrl(
-      createChangeUrl({change: this.change, patchNum: this.patchRange.patchNum})
+      createChangeUrl({change: this.change, patchNum: this.patchNum})
     );
   }
 
@@ -2393,16 +2109,16 @@
   handleDiffBaseAgainstLeft() {
     if (this.viewState?.childView !== ChangeChildView.OVERVIEW) return;
     assertIsDefined(this.change, 'change');
-    assertIsDefined(this.patchRange, 'patchRange');
+    assertIsDefined(this.patchNum, 'patchNum');
 
-    if (this.patchRange.basePatchNum === PARENT) {
+    if (this.basePatchNum === PARENT) {
       fireAlert(this, 'Left is already base.');
       return;
     }
     this.getNavigation().setUrl(
       createChangeUrl({
         change: this.change,
-        patchNum: this.patchRange.basePatchNum as RevisionPatchSetNum,
+        patchNum: this.basePatchNum as RevisionPatchSetNum,
       })
     );
   }
@@ -2410,9 +2126,9 @@
   // Private but used in tests.
   handleDiffAgainstLatest() {
     assertIsDefined(this.change, 'change');
-    assertIsDefined(this.patchRange, 'patchRange');
+    assertIsDefined(this.patchNum, 'patchNum');
     const latestPatchNum = computeLatestPatchNum(this.allPatchSets);
-    if (this.patchRange.patchNum === latestPatchNum) {
+    if (this.patchNum === latestPatchNum) {
       fireAlert(this, 'Latest is already selected.');
       return;
     }
@@ -2420,7 +2136,7 @@
       createChangeUrl({
         change: this.change,
         patchNum: latestPatchNum,
-        basePatchNum: this.patchRange.basePatchNum,
+        basePatchNum: this.basePatchNum,
       })
     );
   }
@@ -2428,9 +2144,9 @@
   // Private but used in tests.
   handleDiffRightAgainstLatest() {
     assertIsDefined(this.change, 'change');
-    assertIsDefined(this.patchRange, 'patchRange');
+    assertIsDefined(this.patchNum, 'patchNum');
     const latestPatchNum = computeLatestPatchNum(this.allPatchSets);
-    if (this.patchRange.patchNum === latestPatchNum) {
+    if (this.patchNum === latestPatchNum) {
       fireAlert(this, 'Right is already latest.');
       return;
     }
@@ -2438,7 +2154,7 @@
       createChangeUrl({
         change: this.change,
         patchNum: latestPatchNum,
-        basePatchNum: this.patchRange.patchNum as BasePatchSetNum,
+        basePatchNum: this.patchNum as BasePatchSetNum,
       })
     );
   }
@@ -2446,12 +2162,9 @@
   // Private but used in tests.
   handleDiffBaseAgainstLatest() {
     assertIsDefined(this.change, 'change');
-    assertIsDefined(this.patchRange, 'patchRange');
+    assertIsDefined(this.patchNum, 'patchNum');
     const latestPatchNum = computeLatestPatchNum(this.allPatchSets);
-    if (
-      this.patchRange.patchNum === latestPatchNum &&
-      this.patchRange.basePatchNum === PARENT
-    ) {
+    if (this.patchNum === latestPatchNum && this.basePatchNum === PARENT) {
       fireAlert(this, 'Already diffing base against latest.');
       return;
     }
@@ -2545,179 +2258,11 @@
     // TODO(wyatta) switch linkify sequence, see issue 5526.
     // This is a zero-with space. It is added to prevent the linkify library
     // from including R= or CC= as part of the email address.
+    // TODO: Is this comment referring to the ba-linkify library that we are
+    // not using anymore? If so, then remove this hack.
     return msg.replace(REVIEWERS_REGEX, '$1=\u200B');
   }
 
-  /**
-   * Utility function to make the necessary modifications to a change in the
-   * case an edit exists.
-   * Private but used in tests.
-   */
-  processEdit(change: ParsedChangeInfo) {
-    const revisions = Object.values(change.revisions || {});
-    const editRev = findEdit(revisions);
-    const editParentRev = findEditParentRevision(revisions);
-    if (
-      !editRev &&
-      this.patchRange?.patchNum === EDIT &&
-      changeIsOpen(change)
-    ) {
-      fireAlert(this, 'Change edit not found. Please create a change edit.');
-      fireReload(this, true);
-      return;
-    }
-
-    if (
-      !editRev &&
-      (changeIsMerged(change) || changeIsAbandoned(change)) &&
-      this.getEditMode()
-    ) {
-      fireAlert(
-        this,
-        'Change edits cannot be created if change is merged or abandoned. Redirecting to non edit mode.'
-      );
-      fireReload(this, true);
-      return;
-    }
-
-    if (!editRev) return;
-    assertIsDefined(this.patchRange, 'patchRange');
-    assertIsDefined(editRev.commit.commit, 'editRev.commit.commit');
-    assertIsDefined(editParentRev, 'editParentRev');
-
-    const latestPsNum = computeLatestPatchNum(computeAllPatchSets(change));
-    // If the change was loaded without a specific patchset, then this normally
-    // means that the *latest* patchset should be loaded. But if there is an
-    // active edit, then automatically switch to that edit as the current
-    // patchset.
-    // TODO: This goes together with `change.current_revision` being set, which
-    // is under change-model control. `patchRange.patchNum` should eventually
-    // also be model managed, so we can reconcile these two code snippets into
-    // one location.
-    if (!this.viewModelPatchNum && latestPsNum === editParentRev._number) {
-      this.patchRange = {...this.patchRange, patchNum: EDIT};
-      // The file list is not reactive (yet) with regards to patch range
-      // changes, so we have to actively trigger it.
-      this.reloadPatchNumDependentResources();
-    }
-  }
-
-  computeRevertSubmitted(change?: ChangeInfo | ParsedChangeInfo) {
-    if (!change?.messages) return;
-    Promise.all(
-      getRevertCreatedChangeIds(change.messages).map(changeId =>
-        this.restApiService.getChange(changeId)
-      )
-    ).then(changes => {
-      // if a change is deleted then getChanges returns null for that changeId
-      changes = changes.filter(
-        change => change && change.status !== ChangeStatus.ABANDONED
-      );
-      if (!changes.length) return;
-      const submittedRevert = changes.find(
-        change => change?.status === ChangeStatus.MERGED
-      );
-      if (!this.changeStatuses) return;
-      // Protect against `computeRevertSubmitted()` being called twice.
-      // TODO: Convert this to be rxjs based, so computeRevertSubmitted() is not
-      // actively called, but instead we can subscribe to something.
-      if (this.changeStatuses.includes(ChangeStates.REVERT_SUBMITTED)) return;
-      if (this.changeStatuses.includes(ChangeStates.REVERT_CREATED)) return;
-      if (submittedRevert) {
-        this.revertedChange = submittedRevert;
-        this.changeStatuses = this.changeStatuses.concat([
-          ChangeStates.REVERT_SUBMITTED,
-        ]);
-      } else {
-        if (changes[0]) this.revertedChange = changes[0];
-        this.changeStatuses = this.changeStatuses.concat([
-          ChangeStates.REVERT_CREATED,
-        ]);
-      }
-    });
-  }
-
-  private async untilModelLoaded() {
-    // NOTE: Wait until this page is connected before determining whether the
-    // model is loaded.  This can happen when viewState changes when setting up
-    // this view. It's unclear whether this issue is related to Polymer
-    // specifically.
-    if (!this.isConnected) {
-      await until(this.connected$, connected => connected);
-    }
-    await until(
-      this.getChangeModel().changeLoadingStatus$,
-      status => status === LoadingStatus.LOADED
-    );
-  }
-
-  /**
-   * Process edits
-   * Check if a revert of this change has been submitted
-   * Calculate selected revision
-   */
-  // private but used in tests
-  async performPostChangeLoadTasks() {
-    assertIsDefined(this.changeNum, 'changeNum');
-
-    const prefCompletes = this.restApiService.getPreferences();
-    await this.untilModelLoaded();
-
-    this.prefs = await prefCompletes;
-
-    if (!this.change) return false;
-
-    this.processEdit(this.change);
-    // Issue 4190: Coalesce missing topics to null.
-    // TODO(TS): code needs second thought,
-    // it might be that nulls were assigned to trigger some bindings
-    if (!this.change.topic) {
-      this.change.topic = null as unknown as undefined;
-    }
-    if (!this.change.reviewer_updates) {
-      this.change.reviewer_updates = null as unknown as undefined;
-    }
-    const latestRevisionSha = this.getLatestRevisionSHA(this.change);
-    if (!latestRevisionSha)
-      throw new Error('Could not find latest Revision Sha');
-    const currentRevision = this.change.revisions[latestRevisionSha];
-    if (currentRevision.commit && currentRevision.commit.message) {
-      this.latestCommitMessage = this.prepareCommitMsgForLinkify(
-        currentRevision.commit.message
-      );
-    } else {
-      this.latestCommitMessage = null;
-    }
-
-    this.computeRevertSubmitted(this.change);
-    if (
-      !this.patchRange ||
-      !this.patchRange.patchNum ||
-      this.patchRange.patchNum === currentRevision._number
-    ) {
-      // CommitInfo.commit is optional, and may need patching.
-      if (currentRevision.commit && !currentRevision.commit.commit) {
-        currentRevision.commit.commit = latestRevisionSha as CommitId;
-      }
-      this.commitInfo = currentRevision.commit;
-      this.selectedRevision = currentRevision;
-      // TODO: Fetch and process files.
-    } else {
-      if (!this.change?.revisions || !this.patchRange) return false;
-      this.selectedRevision = Object.values(this.change.revisions).find(
-        revision => {
-          // edit patchset is a special one
-          const thePatchNum = this.patchRange!.patchNum;
-          if (thePatchNum === EDIT) {
-            return revision._number === thePatchNum;
-          }
-          return revision._number === Number(`${thePatchNum}`);
-        }
-      );
-    }
-    return true;
-  }
-
   private isParentCurrent() {
     const revisionActions = this.currentRevisionActions;
     if (revisionActions && revisionActions.rebase) {
@@ -2727,226 +2272,35 @@
     }
   }
 
-  // Private but used in tests.
-  getLatestCommitMessage() {
-    assertIsDefined(this.changeNum, 'changeNum');
-    const lastpatchNum = computeLatestPatchNum(this.allPatchSets);
-    if (lastpatchNum === undefined)
-      throw new Error('missing lastPatchNum property');
-    return this.restApiService
-      .getChangeCommitInfo(this.changeNum, lastpatchNum)
-      .then(commitInfo => {
-        if (!commitInfo) return;
-        this.latestCommitMessage = this.prepareCommitMsgForLinkify(
-          commitInfo.message
-        );
-      });
+  private async reportChangeDisplayed() {
+    await waitUntil(() => !!this.metadata);
+    await untilRendered(this.metadata!);
+    await waitUntil(() => !!this.fileList);
+    await untilRendered(this.fileList!);
+    await waitUntil(() => !!this.messagesList);
+    await untilRendered(this.messagesList!);
+    // We are ending the timer after each change view update, because ending a
+    // timer that was not started is a no-op. :-)
+    if (this.change && this.isConnected && !this.isChangeObsolete()) {
+      this.reporting.changeDisplayed(roleDetails(this.change, this.account));
+    }
   }
 
-  // Private but used in tests.
-  getLatestRevisionSHA(change: ChangeInfo | ParsedChangeInfo) {
-    if (change.current_revision) return change.current_revision;
-    // current_revision may not be present in the case where the latest rev is
-    // a draft and the user doesn’t have permission to view that rev.
-    let latestRev = null;
-    let latestPatchNum = -1 as PatchSetNum;
-    for (const [rev, revInfo] of Object.entries(change.revisions ?? {})) {
-      if (revInfo._number > latestPatchNum) {
-        latestRev = rev;
-        latestPatchNum = revInfo._number;
-      }
+  private async reportFullyLoaded() {
+    await waitUntil(() => !!this.metadata);
+    await untilRendered(this.metadata!);
+    await waitUntil(() => !!this.fileList);
+    await untilRendered(this.fileList!);
+    await waitUntil(() => !!this.messagesList);
+    await untilRendered(this.messagesList!);
+    await waitUntil(() => this.mergeable !== undefined);
+    await until(this.getCommentsModel().comments$, c => c !== undefined);
+    await until(this.getCommentsModel().drafts$, c => c !== undefined);
+    // We are ending the timer after each change view update, because ending a
+    // timer that was not started is a no-op. :-)
+    if (this.change && this.isConnected && !this.isChangeObsolete()) {
+      this.reporting.changeFullyLoaded();
     }
-    return latestRev;
-  }
-
-  // visible for testing
-  loadAndSetCommitInfo() {
-    assertIsDefined(this.changeNum, 'changeNum');
-    assertIsDefined(this.patchRange?.patchNum, 'patchRange.patchNum');
-    return this.restApiService
-      .getChangeCommitInfo(this.changeNum, this.patchRange.patchNum)
-      .then(commitInfo => {
-        this.commitInfo = commitInfo;
-      });
-  }
-
-  /**
-   * Reload the change.
-   *
-   * @param isLocationChange Reloads the related changes
-   * when true and ends reporting events that started on location change.
-   * @param clearPatchset Reloads the change ignoring any patchset
-   * choice made.
-   * @return A promise that resolves when the core data has loaded.
-   * Some non-core data loading may still be in-flight when the core data
-   * promise resolves.
-   */
-  loadData(isLocationChange?: boolean, clearPatchset?: boolean) {
-    if (this.isChangeObsolete()) return Promise.resolve();
-    if (clearPatchset && this.change) {
-      this.getNavigation().setUrl(
-        createChangeUrl({change: this.change, forceReload: true})
-      );
-      return Promise.resolve();
-    }
-    this.loading = true;
-    this.reporting.time(Timing.CHANGE_RELOAD);
-    this.reporting.time(Timing.CHANGE_DATA);
-
-    // Array to house all promises related to data requests.
-    const allDataPromises: Promise<unknown>[] = [];
-
-    // Resolves when the change detail and the edit patch set (if available)
-    // are loaded.
-    const detailCompletes = this.untilModelLoaded();
-    allDataPromises.push(detailCompletes);
-
-    // Resolves when the loading flag is set to false, meaning that some
-    // change content may start appearing.
-    const loadingFlagSet = detailCompletes.then(() => {
-      this.loading = false;
-      this.performPostChangeLoadTasks();
-    });
-
-    let coreDataPromise;
-
-    // If the patch number is specified
-    if (this.patchRange && this.patchRange.patchNum) {
-      // Because a specific patchset is specified, reload the resources that
-      // are keyed by patch number or patch range.
-      const patchResourcesLoaded = this.reloadPatchNumDependentResources();
-      allDataPromises.push(patchResourcesLoaded);
-
-      // Promise resolves when the change detail and patch dependent resources
-      // have loaded.
-      coreDataPromise = Promise.all([patchResourcesLoaded, loadingFlagSet]);
-    } else {
-      const latestCommitMessageLoaded = loadingFlagSet.then(() => {
-        // If the latest commit message is known, there is nothing to do.
-        if (this.latestCommitMessage) {
-          return Promise.resolve();
-        }
-        return this.getLatestCommitMessage();
-      });
-      allDataPromises.push(latestCommitMessageLoaded);
-
-      coreDataPromise = loadingFlagSet;
-    }
-    const mergeabilityLoaded = coreDataPromise.then(() =>
-      this.getMergeability()
-    );
-    allDataPromises.push(mergeabilityLoaded);
-
-    coreDataPromise.then(() => {
-      fire(this, 'change-details-loaded', {});
-      this.reporting.timeEnd(Timing.CHANGE_RELOAD);
-      if (isLocationChange) {
-        this.reporting.changeDisplayed(roleDetails(this.change, this.account));
-      }
-    });
-
-    if (isLocationChange) {
-      this.editingCommitMessage = false;
-    }
-    const relatedChangesLoaded = coreDataPromise.then(() => {
-      let relatedChangesPromise:
-        | Promise<RelatedChangesInfo | undefined>
-        | undefined;
-      const patchNum = computeLatestPatchNum(this.allPatchSets);
-      if (this.change && patchNum) {
-        relatedChangesPromise = this.restApiService
-          .getRelatedChanges(this.change._number, patchNum)
-          .then(response => {
-            if (this.change && response) {
-              this.hasParent = this.calculateHasParent(
-                this.change.change_id,
-                response.changes
-              );
-            }
-            return response;
-          });
-      }
-      return this.getRelatedChangesList()?.reload(relatedChangesPromise);
-    });
-    allDataPromises.push(relatedChangesLoaded);
-    allDataPromises.push(this.filesLoaded());
-
-    Promise.all(allDataPromises).then(() => {
-      // Loading of commments data is no longer part of this reporting
-      this.reporting.timeEnd(Timing.CHANGE_DATA);
-      if (isLocationChange) {
-        this.reporting.changeFullyLoaded();
-      }
-    });
-
-    return coreDataPromise;
-  }
-
-  private async filesLoaded() {
-    if (!this.isConnected) await until(this.connected$, connected => connected);
-    await until(this.getFilesModel().files$, f => f.length > 0);
-  }
-
-  /**
-   * Determines whether or not the given change has a parent change. If there
-   * is a relation chain, and the change id is not the last item of the
-   * relation chain, there is a parent.
-   *
-   * Private but used in tests.
-   */
-  calculateHasParent(
-    currentChangeId: ChangeId,
-    relatedChanges: RelatedChangeAndCommitInfo[]
-  ) {
-    return (
-      relatedChanges.length > 0 &&
-      relatedChanges[relatedChanges.length - 1].change_id !== currentChangeId
-    );
-  }
-
-  /**
-   * Kicks off requests for resources that rely on the patch range
-   * (`this.patchRange`) being defined.
-   */
-  reloadPatchNumDependentResources() {
-    return this.loadAndSetCommitInfo();
-  }
-
-  // Private but used in tests
-  getMergeability(): Promise<void> {
-    if (!this.change) {
-      this.mergeable = null;
-      return Promise.resolve();
-    }
-    // If the change is closed, it is not mergeable. Note: already merged
-    // changes are obviously not mergeable, but the mergeability API will not
-    // answer for abandoned changes.
-    if (
-      this.change.status === ChangeStatus.MERGED ||
-      this.change.status === ChangeStatus.ABANDONED
-    ) {
-      this.mergeable = false;
-      return Promise.resolve();
-    }
-
-    if (!this.changeNum) {
-      return Promise.reject(new Error('missing required changeNum property'));
-    }
-
-    // If mergeable bit was already returned in detail REST endpoint, use it.
-    if (this.change.mergeable !== undefined) {
-      this.mergeable = this.change.mergeable;
-      return Promise.resolve();
-    }
-
-    this.mergeable = null;
-    return this.restApiService
-      .getMergeable(this.changeNum)
-      .then(mergableInfo => {
-        if (mergableInfo) {
-          this.mergeable = mergableInfo.mergeable;
-        }
-      });
   }
 
   /**
@@ -2962,13 +2316,11 @@
     );
   }
 
-  private computeCommitCollapsible() {
-    if (!this.latestCommitMessage) {
-      return false;
-    }
+  private computeCommitCollapsible(): boolean {
     return (
+      !!this.latestCommitMessage &&
       this.latestCommitMessage.split('\n').length >=
-      MIN_LINES_FOR_COMMIT_COLLAPSE
+        MIN_LINES_FOR_COMMIT_COLLAPSE
     );
   }
 
@@ -3029,7 +2381,7 @@
             dismissOnNavigation: true,
             showDismiss: true,
             action: 'Reload',
-            callback: () => fireReload(this, true),
+            callback: () => this.getChangeModel().navigateToChangeResetReload(),
           });
         });
     }, this.serverConfig.change.update_delay * 1000);
@@ -3068,7 +2420,7 @@
       );
     if (!controls) throw new Error('Missing edit controls');
     assertIsDefined(this.change, 'change');
-    assertIsDefined(this.patchRange, 'patchRange');
+    assertIsDefined(this.patchNum, 'patchNum');
 
     const path = e.detail.path;
     switch (e.detail.action) {
@@ -3076,12 +2428,12 @@
         controls.openDeleteDialog(path);
         break;
       case GrEditConstants.Actions.OPEN.id:
-        assertIsDefined(this.patchRange.patchNum, 'patchset number');
+        assertIsDefined(this.patchNum, 'patchset number');
         this.getNavigation().setUrl(
           createEditUrl({
             changeNum: this.change._number,
             repo: this.change.project,
-            patchNum: this.patchRange.patchNum,
+            patchNum: this.patchNum,
             editView: {path},
           })
         );
@@ -3095,21 +2447,6 @@
     }
   }
 
-  private patchNumChanged() {
-    if (!this.selectedRevision || !this.patchRange?.patchNum) {
-      return;
-    }
-    assertIsDefined(this.change, 'change');
-
-    if (this.patchRange.patchNum === this.selectedRevision._number) {
-      return;
-    }
-    if (!this.change.revisions) return;
-    this.selectedRevision = Object.values(this.change.revisions).find(
-      revision => revision._number === this.patchRange!.patchNum
-    );
-  }
-
   /**
    * If an edit exists already, load it. Otherwise, toggle edit mode via the
    * navigation API.
@@ -3139,11 +2476,11 @@
 
   private handleStopEditTap() {
     assertIsDefined(this.change, 'change');
-    assertIsDefined(this.patchRange, 'patchRange');
+    assertIsDefined(this.patchNum, 'patchNum');
     this.getNavigation().setUrl(
       createChangeUrl({
         change: this.change,
-        patchNum: this.patchRange.patchNum,
+        patchNum: this.patchNum,
         forceReload: true,
       })
     );
@@ -3173,17 +2510,6 @@
     fire(this, 'hide-alert', {});
   }
 
-  private getRevisionInfo(): RevisionInfoClass | undefined {
-    if (this.change === undefined) return undefined;
-    return new RevisionInfoClass(this.change);
-  }
-
-  getRelatedChangesList() {
-    return this.shadowRoot!.querySelector<GrRelatedChangesList>(
-      '#relatedChanges'
-    );
-  }
-
   createTitle(shortcutName: Shortcut, section: ShortcutSection) {
     return this.getShortcutsService().createTitle(shortcutName, section);
   }
@@ -3198,7 +2524,6 @@
 declare global {
   interface HTMLElementEventMap {
     'toggle-star': CustomEvent<ChangeStarToggleStarDetail>;
-    'change-details-loaded': CustomEvent<{}>;
   }
   interface HTMLElementTagNameMap {
     'gr-change-view': GrChangeView;
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts
index 8a4eb01..5331558 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts
@@ -10,9 +10,7 @@
 import {
   ChangeStatus,
   CommentSide,
-  DefaultBase,
   DiffViewMode,
-  MessageTag,
   createDefaultPreferences,
   Tab,
 } from '../../../constants/constants';
@@ -25,65 +23,43 @@
   queryAndAssert,
   stubFlags,
   stubRestApi,
-  waitEventLoop,
   waitUntil,
   waitUntilVisible,
 } from '../../../test/test-utils';
 import {
   createChangeViewState,
-  createApproval,
-  createChange,
   createChangeMessages,
-  createCommit,
-  createMergeable,
-  createPreferences,
   createRevision,
   createRevisions,
   createServerInfo,
   createUserConfig,
   TEST_NUMERIC_CHANGE_ID,
   TEST_PROJECT_NAME,
-  createEditRevision,
-  createAccountWithIdNameAndEmail,
   createChangeViewChange,
-  createRelatedChangeAndCommitInfo,
   createAccountDetailWithId,
   createParsedChange,
-  createDraft,
 } from '../../../test/test-data-generators';
 import {GrChangeView} from './gr-change-view';
 import {
   AccountId,
-  ApprovalInfo,
   BasePatchSetNum,
-  ChangeId,
-  ChangeInfo,
   CommitId,
   EDIT,
   NumericChangeId,
   PARENT,
-  RelatedChangeAndCommitInfo,
-  ReviewInputTag,
-  RevisionInfo,
   RevisionPatchSetNum,
   RobotId,
   RobotCommentInfo,
   Timestamp,
   UrlEncodedCommentId,
-  DetailedLabelInfo,
   RepoName,
-  QuickLabelInfo,
-  PatchSetNumber,
   CommentThread,
-  ChangeStates,
   SavingState,
 } from '../../../types/common';
 import {GrEditControls} from '../../edit/gr-edit-controls/gr-edit-controls';
-import {SinonFakeTimers, SinonStubbedMember} from 'sinon';
-import {RestApiService} from '../../../services/gr-rest-api/gr-rest-api';
+import {SinonFakeTimers} from 'sinon';
 import {GerritView} from '../../../services/router/router-model';
 import {ParsedChangeInfo} from '../../../types/types';
-import {GrRelatedChangesList} from '../gr-related-changes-list/gr-related-changes-list';
 import {
   ChangeModel,
   changeModelToken,
@@ -93,9 +69,7 @@
 import {GrChangeStar} from '../../shared/gr-change-star/gr-change-star';
 import {GrThreadList} from '../gr-thread-list/gr-thread-list';
 import {assertIsDefined} from '../../../utils/common-util';
-import {DEFAULT_NUM_FILES_SHOWN} from '../gr-file-list/gr-file-list';
 import {fixture, html, assert} from '@open-wc/testing';
-import {deepClone} from '../../../utils/deep-util';
 import {Modifier} from '../../../utils/dom-util';
 import {GrButton} from '../../shared/gr-button/gr-button';
 import {GrCopyLinks} from '../gr-copy-links/gr-copy-links';
@@ -104,6 +78,7 @@
 import {testResolver} from '../../../test/common-test-setup';
 import {UserModel, userModelToken} from '../../../models/user/user-model';
 import {pluginLoaderToken} from '../../shared/gr-js-api-interface/gr-plugin-loader';
+import {commentsModelToken} from '../../../models/comments/comments-model';
 
 suite('gr-change-view tests', () => {
   let element: GrChangeView;
@@ -458,8 +433,7 @@
                     </gr-endpoint-decorator>
                   </div>
                   <div class="relatedChanges">
-                    <gr-related-changes-list id="relatedChanges">
-                    </gr-related-changes-list>
+                    <gr-related-changes-list></gr-related-changes-list>
                   </div>
                   <div class="emptySpace"></div>
                 </div>
@@ -545,10 +519,7 @@
 
   test('handleMessageAnchorTap', async () => {
     element.changeNum = 1 as NumericChangeId;
-    element.patchRange = {
-      basePatchNum: PARENT,
-      patchNum: 1 as RevisionPatchSetNum,
-    };
+    element.patchNum = 1 as RevisionPatchSetNum;
     element.change = createChangeViewChange();
     await element.updateComplete;
     const replaceStateStub = sinon.stub(history, 'replaceState');
@@ -564,10 +535,8 @@
       ...createChangeViewChange(),
       revisions: createRevisions(10),
     };
-    element.patchRange = {
-      patchNum: 3 as RevisionPatchSetNum,
-      basePatchNum: 1 as BasePatchSetNum,
-    };
+    element.basePatchNum = 1 as BasePatchSetNum;
+    element.patchNum = 3 as RevisionPatchSetNum;
     element.handleDiffAgainstBase();
     assert.isTrue(setUrlStub.called);
     assert.equal(setUrlStub.lastCall.firstArg, '/c/test-project/+/42/3');
@@ -578,10 +547,8 @@
       ...createChangeViewChange(),
       revisions: createRevisions(10),
     };
-    element.patchRange = {
-      basePatchNum: 1 as BasePatchSetNum,
-      patchNum: 3 as RevisionPatchSetNum,
-    };
+    element.basePatchNum = 1 as BasePatchSetNum;
+    element.patchNum = 3 as RevisionPatchSetNum;
     element.handleDiffAgainstLatest();
     assert.isTrue(setUrlStub.called);
     assert.equal(setUrlStub.lastCall.firstArg, '/c/test-project/+/42/1..10');
@@ -592,10 +559,8 @@
       ...createChangeViewChange(),
       revisions: createRevisions(10),
     };
-    element.patchRange = {
-      patchNum: 3 as RevisionPatchSetNum,
-      basePatchNum: 1 as BasePatchSetNum,
-    };
+    element.basePatchNum = 1 as BasePatchSetNum;
+    element.patchNum = 3 as RevisionPatchSetNum;
     element.handleDiffBaseAgainstLeft();
     assert.isTrue(setUrlStub.called);
     assert.equal(setUrlStub.lastCall.firstArg, '/c/test-project/+/42/1');
@@ -606,10 +571,8 @@
       ...createChangeViewChange(),
       revisions: createRevisions(10),
     };
-    element.patchRange = {
-      basePatchNum: 1 as BasePatchSetNum,
-      patchNum: 3 as RevisionPatchSetNum,
-    };
+    element.basePatchNum = 1 as BasePatchSetNum;
+    element.patchNum = 3 as RevisionPatchSetNum;
     element.handleDiffRightAgainstLatest();
     assert.isTrue(setUrlStub.called);
     assert.equal(setUrlStub.lastCall.firstArg, '/c/test-project/+/42/3..10');
@@ -620,10 +583,8 @@
       ...createChangeViewChange(),
       revisions: createRevisions(10),
     };
-    element.patchRange = {
-      basePatchNum: 1 as BasePatchSetNum,
-      patchNum: 3 as RevisionPatchSetNum,
-    };
+    element.basePatchNum = 1 as BasePatchSetNum;
+    element.patchNum = 3 as RevisionPatchSetNum;
     element.handleDiffBaseAgainstLatest();
     assert.isTrue(setUrlStub.called);
     assert.equal(setUrlStub.lastCall.firstArg, '/c/test-project/+/42/10');
@@ -641,10 +602,8 @@
     const removeFromAttentionSetStub = stubRestApi(
       'removeFromAttentionSet'
     ).returns(Promise.resolve(new Response()));
-    element.patchRange = {
-      basePatchNum: 1 as BasePatchSetNum,
-      patchNum: 3 as RevisionPatchSetNum,
-    };
+    element.basePatchNum = 1 as BasePatchSetNum;
+    element.patchNum = 3 as RevisionPatchSetNum;
     await element.updateComplete;
     assert.isNotOk(element.change.attention_set);
     element.handleToggleAttentionSet();
@@ -699,19 +658,6 @@
       assert.equal(element.activeTab, 'change-view-tab-header-url');
     });
 
-    test('param change should switch primary tab correctly', async () => {
-      assert.equal(element.activeTab, Tab.FILES);
-      // view is required
-      element.changeNum = undefined;
-      element.viewState = {
-        ...createChangeViewState(),
-        ...element.viewState,
-        tab: Tab.COMMENT_THREADS,
-      };
-      await element.updateComplete;
-      assert.equal(element.activeTab, Tab.COMMENT_THREADS);
-    });
-
     test('invalid param change should not switch primary tab', async () => {
       assert.equal(element.activeTab, Tab.FILES);
       // view is required
@@ -816,8 +762,6 @@
       stubRestApi('getChangeDetail').returns(
         Promise.resolve(createParsedChange())
       );
-      sinon.stub(element, 'performPostChangeLoadTasks');
-      sinon.stub(element, 'getMergeability');
       const change = {
         ...createChangeViewChange(),
         revisions: createRevisions(1),
@@ -947,10 +891,8 @@
   suite('thread list and change log tabs', () => {
     setup(() => {
       element.changeNum = TEST_NUMERIC_CHANGE_ID;
-      element.patchRange = {
-        basePatchNum: PARENT,
-        patchNum: 1 as RevisionPatchSetNum,
-      };
+      element.basePatchNum = PARENT;
+      element.patchNum = 1 as RevisionPatchSetNum;
       element.change = {
         ...createChangeViewChange(),
         revisions: {
@@ -970,12 +912,6 @@
           },
         },
       };
-      const relatedChanges = element.shadowRoot!.querySelector(
-        '#relatedChanges'
-      ) as GrRelatedChangesList;
-      sinon.stub(relatedChanges, 'reload');
-      sinon.stub(element, 'loadData').returns(Promise.resolve());
-      sinon.spy(element, 'viewStateChanged');
       element.viewState = createChangeViewState();
     });
   });
@@ -1155,183 +1091,6 @@
     );
   });
 
-  test('changeStatuses', async () => {
-    element.loading = false;
-    element.change = {
-      ...createChangeViewChange(),
-      revisions: {
-        rev2: createRevision(2),
-        rev1: createRevision(1),
-        rev13: createRevision(13),
-        rev3: createRevision(3),
-      },
-      current_revision: 'rev3' as CommitId,
-      status: ChangeStatus.MERGED,
-      labels: {
-        test: {
-          all: [],
-          default_value: 0,
-          values: {},
-          approved: {},
-        },
-      },
-    };
-    element.mergeable = true;
-    await element.updateComplete;
-    const expectedStatuses = [ChangeStates.MERGED];
-    assert.deepEqual(element.changeStatuses, expectedStatuses);
-    const statusChips =
-      element.shadowRoot!.querySelectorAll('gr-change-status');
-    assert.equal(statusChips.length, 1);
-  });
-
-  suite('ChangeStatus revert', () => {
-    test('do not show any chip if no revert created', async () => {
-      const change = {
-        ...createParsedChange(),
-        messages: createChangeMessages(2),
-      };
-      const getChangeStub = stubRestApi('getChange');
-      getChangeStub.onFirstCall().returns(
-        Promise.resolve({
-          ...createChange(),
-        })
-      );
-      getChangeStub.onSecondCall().returns(
-        Promise.resolve({
-          ...createChange(),
-        })
-      );
-      element.change = change;
-      element.mergeable = true;
-      element.currentRevisionActions = {submit: {enabled: true}};
-      assert.isTrue(element.isSubmitEnabled());
-      await element.updateComplete;
-      element.computeRevertSubmitted(element.change);
-      await element.updateComplete;
-      assert.isFalse(
-        element.changeStatuses?.includes(ChangeStates.REVERT_SUBMITTED)
-      );
-      assert.isFalse(
-        element.changeStatuses?.includes(ChangeStates.REVERT_CREATED)
-      );
-    });
-
-    test('do not show any chip if all reverts are abandoned', async () => {
-      const change = {
-        ...createParsedChange(),
-        messages: createChangeMessages(2),
-      };
-      change.messages[0].message = 'Created a revert of this change as 12345';
-      change.messages[0].tag = MessageTag.TAG_REVERT as ReviewInputTag;
-
-      change.messages[1].message = 'Created a revert of this change as 23456';
-      change.messages[1].tag = MessageTag.TAG_REVERT as ReviewInputTag;
-
-      const getChangeStub = stubRestApi('getChange');
-      getChangeStub.onFirstCall().returns(
-        Promise.resolve({
-          ...createChange(),
-          status: ChangeStatus.ABANDONED,
-        })
-      );
-      getChangeStub.onSecondCall().returns(
-        Promise.resolve({
-          ...createChange(),
-          status: ChangeStatus.ABANDONED,
-        })
-      );
-      element.change = change;
-      element.mergeable = true;
-      element.currentRevisionActions = {submit: {enabled: true}};
-      assert.isTrue(element.isSubmitEnabled());
-      await element.updateComplete;
-      element.computeRevertSubmitted(element.change);
-      await element.updateComplete;
-      assert.isFalse(
-        element.changeStatuses?.includes(ChangeStates.REVERT_SUBMITTED)
-      );
-      assert.isFalse(
-        element.changeStatuses?.includes(ChangeStates.REVERT_CREATED)
-      );
-    });
-
-    test('show revert created if no revert is merged', async () => {
-      const change = {
-        ...createParsedChange(),
-        messages: createChangeMessages(2),
-      };
-      change.messages[0].message = 'Created a revert of this change as 12345';
-      change.messages[0].tag = MessageTag.TAG_REVERT as ReviewInputTag;
-
-      change.messages[1].message = 'Created a revert of this change as 23456';
-      change.messages[1].tag = MessageTag.TAG_REVERT as ReviewInputTag;
-
-      const getChangeStub = stubRestApi('getChange');
-      getChangeStub.onFirstCall().returns(
-        Promise.resolve({
-          ...createChange(),
-        })
-      );
-      getChangeStub.onSecondCall().returns(
-        Promise.resolve({
-          ...createChange(),
-        })
-      );
-      element.change = change;
-      element.mergeable = true;
-      element.currentRevisionActions = {submit: {enabled: true}};
-      assert.isTrue(element.isSubmitEnabled());
-      await element.updateComplete;
-      element.computeRevertSubmitted(element.change);
-      // Wait for promises to settle.
-      await waitEventLoop();
-      await element.updateComplete;
-      assert.isFalse(
-        element.changeStatuses?.includes(ChangeStates.REVERT_SUBMITTED)
-      );
-      assert.isTrue(
-        element.changeStatuses?.includes(ChangeStates.REVERT_CREATED)
-      );
-    });
-
-    test('show revert submitted if revert is merged', async () => {
-      const change = {
-        ...createParsedChange(),
-        messages: createChangeMessages(2),
-      };
-      change.messages[0].message = 'Created a revert of this change as 12345';
-      change.messages[0].tag = MessageTag.TAG_REVERT as ReviewInputTag;
-      const getChangeStub = stubRestApi('getChange');
-      getChangeStub.onFirstCall().returns(
-        Promise.resolve({
-          ...createChange(),
-          status: ChangeStatus.MERGED,
-        })
-      );
-      getChangeStub.onSecondCall().returns(
-        Promise.resolve({
-          ...createChange(),
-        })
-      );
-      element.change = change;
-      element.mergeable = true;
-      element.currentRevisionActions = {submit: {enabled: true}};
-      assert.isTrue(element.isSubmitEnabled());
-      await element.updateComplete;
-      element.computeRevertSubmitted(element.change);
-      // Wait for promises to settle.
-      await waitEventLoop();
-      await element.updateComplete;
-      assert.isFalse(
-        element.changeStatuses?.includes(ChangeStates.REVERT_CREATED)
-      );
-      assert.isTrue(
-        element.changeStatuses?.includes(ChangeStates.REVERT_SUBMITTED)
-      );
-    });
-  });
-
   test('diff preferences open when open-diff-prefs is fired', async () => {
     await element.updateComplete;
     assertIsDefined(element.fileList);
@@ -1369,66 +1128,6 @@
     assert.isTrue(element.isSubmitEnabled());
   });
 
-  test('reload is called when an approved label is removed', async () => {
-    const vote: ApprovalInfo = {
-      ...createApproval(),
-      _account_id: 1 as AccountId,
-      name: 'bojack',
-      value: 1,
-    };
-    element.changeNum = TEST_NUMERIC_CHANGE_ID;
-    element.patchRange = {
-      basePatchNum: PARENT,
-      patchNum: 1 as RevisionPatchSetNum,
-    };
-    const change = {
-      ...createParsedChange(),
-      owner: createAccountWithIdNameAndEmail(),
-      revisions: {
-        rev2: createRevision(2),
-        rev1: createRevision(1),
-        rev13: createRevision(13),
-        rev3: createRevision(3),
-      },
-      current_revision: 'rev3' as CommitId,
-      status: ChangeStatus.NEW,
-      labels: {
-        test: {
-          all: [vote],
-          default_value: 0,
-          values: {},
-          approved: {},
-        },
-      },
-    };
-    element.change = change;
-    await element.updateComplete;
-    const reloadStub = sinon.stub(element, 'loadData');
-    const newChange = {...element.change};
-    (newChange.labels!.test! as DetailedLabelInfo).all = [];
-    element.change = deepClone(newChange);
-    await element.updateComplete;
-    assert.isFalse(reloadStub.called);
-
-    assert.isDefined(element.change);
-    const testLabels: DetailedLabelInfo & QuickLabelInfo =
-      newChange.labels!.test;
-    assertIsDefined(testLabels);
-    testLabels.all!.push(vote);
-    testLabels.all!.push(vote);
-    testLabels.approved = vote;
-    element.change = deepClone(newChange);
-    await element.updateComplete;
-    assert.isFalse(reloadStub.called);
-
-    assert.isDefined(element.change);
-    (newChange.labels!.test! as DetailedLabelInfo).all = [];
-    element.change = deepClone(newChange);
-    await element.updateComplete;
-    assert.isTrue(reloadStub.called);
-    assert.isTrue(reloadStub.calledOnce);
-  });
-
   test('reply button has updated count when there are drafts', () => {
     const getLabel = (canReview: boolean) => {
       element.change!.actions!.ready = {enabled: canReview};
@@ -1436,150 +1135,19 @@
     };
     element.change = createParsedChange();
     element.change.actions = {};
-    element.diffDrafts = undefined;
-    assert.equal(getLabel(false), 'Reply');
-    assert.equal(getLabel(true), 'Reply');
-
-    element.diffDrafts = {};
+    element.draftCount = 0;
     assert.equal(getLabel(false), 'Reply');
     assert.equal(getLabel(true), 'Start Review');
 
-    element.diffDrafts = {
-      'file1.txt': [createDraft()],
-      'file2.txt': [createDraft(), createDraft()],
-    };
+    element.draftCount = 0;
+    assert.equal(getLabel(false), 'Reply');
+    assert.equal(getLabel(true), 'Start Review');
+
+    element.draftCount = 3;
     assert.equal(getLabel(false), 'Reply (3)');
     assert.equal(getLabel(true), 'Start Review (3)');
   });
 
-  test('change num change', async () => {
-    const change = {
-      ...createChangeViewChange(),
-      labels: {},
-    } as ParsedChangeInfo;
-    element.changeNum = undefined;
-    element.patchRange = {
-      basePatchNum: PARENT,
-      patchNum: 2 as RevisionPatchSetNum,
-    };
-    element.change = change;
-    assertIsDefined(element.fileList);
-    assert.equal(element.fileList.numFilesShown, DEFAULT_NUM_FILES_SHOWN);
-    element.fileList.numFilesShown = 150;
-    element.fileList.selectedIndex = 15;
-    await element.updateComplete;
-
-    element.changeNum = 2 as NumericChangeId;
-    element.viewState = {
-      ...createChangeViewState(),
-      changeNum: 2 as NumericChangeId,
-    };
-    await element.updateComplete;
-    assert.equal(element.fileList.numFilesShown, DEFAULT_NUM_FILES_SHOWN);
-    assert.equal(element.fileList.selectedIndex, 0);
-  });
-
-  test('don’t reload entire page when patchRange changes', async () => {
-    const reloadStub = sinon
-      .stub(element, 'loadData')
-      .callsFake(() => Promise.resolve());
-    const reloadPatchDependentStub = sinon
-      .stub(element, 'reloadPatchNumDependentResources')
-      .callsFake(() => Promise.resolve());
-    assertIsDefined(element.fileList);
-    await element.fileList.updateComplete;
-    const collapseStub = sinon.stub(element.fileList, 'collapseAllDiffs');
-    const value: ChangeViewState = {
-      ...createChangeViewState(),
-      view: GerritView.CHANGE,
-      patchNum: 1 as RevisionPatchSetNum,
-    };
-    element.changeNum = undefined;
-    element.viewState = value;
-    await element.updateComplete;
-    assert.isTrue(reloadStub.calledOnce);
-
-    element.initialLoadComplete = true;
-    element.fileList.selectedIndex = 15;
-    element.change = {
-      ...createChangeViewChange(),
-      revisions: {
-        rev1: createRevision(1),
-        rev2: createRevision(2),
-      },
-    };
-
-    value.basePatchNum = 1 as BasePatchSetNum;
-    value.patchNum = 2 as RevisionPatchSetNum;
-    element.viewState = {...value};
-    await element.updateComplete;
-    await waitEventLoop();
-    assert.equal(element.fileList.selectedIndex, 0);
-    assert.isFalse(reloadStub.calledTwice);
-    assert.isTrue(reloadPatchDependentStub.calledOnce);
-    assert.isTrue(collapseStub.calledTwice);
-  });
-
-  test('do not reload entire page when patchRange doesnt change', async () => {
-    assertIsDefined(element.fileList);
-    const reloadStub = sinon
-      .stub(element, 'loadData')
-      .callsFake(() => Promise.resolve());
-    const collapseStub = sinon.stub(element.fileList, 'collapseAllDiffs');
-    const value: ChangeViewState = createChangeViewState();
-    element.viewState = value;
-    // change already loaded
-    assert.isOk(element.changeNum);
-    await element.updateComplete;
-    assert.isFalse(reloadStub.calledOnce);
-    element.initialLoadComplete = true;
-    element.viewState = {...value};
-    await element.updateComplete;
-    assert.isFalse(reloadStub.calledTwice);
-    assert.isFalse(collapseStub.calledTwice);
-  });
-
-  test('forceReload updates the change', async () => {
-    assertIsDefined(element.fileList);
-    const getChangeStub = stubRestApi('getChangeDetail').returns(
-      Promise.resolve(createParsedChange())
-    );
-    const loadDataStub = sinon
-      .stub(element, 'loadData')
-      .callsFake(() => Promise.resolve());
-    const collapseStub = sinon.stub(element.fileList, 'collapseAllDiffs');
-    element.viewState = {...createChangeViewState(), forceReload: true};
-    await element.updateComplete;
-    assert.isTrue(getChangeStub.called);
-    assert.isTrue(loadDataStub.called);
-    assert.isTrue(collapseStub.called);
-    // patchNum is set by changeChanged, so this verifies that change was set.
-    assert.isOk(element.patchRange?.patchNum);
-  });
-
-  test('related changes are updated when loadData is called', async () => {
-    await element.updateComplete;
-    const relatedChanges = element.shadowRoot!.querySelector(
-      '#relatedChanges'
-    ) as GrRelatedChangesList;
-    const reloadStub = sinon.stub(relatedChanges, 'reload');
-    stubRestApi('getMergeable').returns(
-      Promise.resolve({...createMergeable(), mergeable: true})
-    );
-
-    element.viewState = createChangeViewState();
-    changeModel.setState({
-      loadingStatus: LoadingStatus.LOADED,
-      change: {
-        ...createChangeViewChange(),
-      },
-    });
-
-    await element.loadData(true);
-    assert.isFalse(setUrlStub.called);
-    assert.isTrue(reloadStub.called);
-  });
-
   test('computeCopyTextForTitle', () => {
     element.change = {
       ...createChangeViewChange(),
@@ -1597,26 +1165,6 @@
     );
   });
 
-  test('get latest revision', () => {
-    let change: ChangeInfo = {
-      ...createChange(),
-      revisions: {
-        rev1: createRevision(1),
-        rev3: createRevision(3),
-      },
-      current_revision: 'rev3' as CommitId,
-    };
-    assert.equal(element.getLatestRevisionSHA(change), 'rev3');
-    change = {
-      ...createChange(),
-      revisions: {
-        rev1: createRevision(1),
-      },
-      current_revision: undefined,
-    };
-    assert.equal(element.getLatestRevisionSHA(change), 'rev1');
-  });
-
   test('show commit message edit button', () => {
     const change = createParsedChange();
     const mergedChanged: ParsedChangeInfo = {
@@ -1639,6 +1187,7 @@
   });
 
   test('handleCommitMessageSave trims trailing whitespace', async () => {
+    element.changeNum = TEST_NUMERIC_CHANGE_ID;
     element.change = createChangeViewChange();
     // Response code is 500, because we want to avoid window reloading
     const putStub = stubRestApi('putChangeCommitMessage').returns(
@@ -1659,85 +1208,6 @@
     assert.equal(putStub.lastCall.args[1], '\n\n\n\n\n\n\n\n');
   });
 
-  test('topic is coalesced to null', async () => {
-    sinon.stub(element, 'changeChanged');
-    changeModel.setState({
-      loadingStatus: LoadingStatus.LOADED,
-      change: {
-        ...createChangeViewChange(),
-        labels: {},
-        current_revision: 'foo' as CommitId,
-        revisions: {foo: createRevision()},
-      },
-    });
-
-    await element.performPostChangeLoadTasks();
-    assert.isNull(element.change!.topic);
-  });
-
-  test('commit sha is populated from getChangeDetail', async () => {
-    changeModel.setState({
-      loadingStatus: LoadingStatus.LOADED,
-      change: {
-        ...createChangeViewChange(),
-        labels: {},
-        current_revision: 'foo' as CommitId,
-        revisions: {foo: createRevision()},
-      },
-    });
-
-    await element.performPostChangeLoadTasks();
-    assert.equal('foo', element.commitInfo!.commit);
-  });
-
-  test('getBasePatchNum', async () => {
-    element.change = {
-      ...createChangeViewChange(),
-      revisions: {
-        '98da160735fb81604b4c40e93c368f380539dd0e': createRevision(),
-      },
-    };
-    element.patchRange = {
-      basePatchNum: PARENT,
-    };
-    await element.updateComplete;
-    assert.equal(element.getBasePatchNum(), PARENT);
-
-    element.prefs = {
-      ...createPreferences(),
-      default_base_for_merges: DefaultBase.FIRST_PARENT,
-    };
-
-    element.change = {
-      ...createChangeViewChange(),
-      revisions: {
-        '98da160735fb81604b4c40e93c368f380539dd0e': {
-          ...createRevision(1),
-          commit: {
-            ...createCommit(),
-            parents: [
-              {
-                commit: '6e12bdf1176eb4ab24d8491ba3b6d0704409cde8' as CommitId,
-                subject: 'test',
-              },
-              {
-                commit: '22f7db4754b5d9816fc581f3d9a6c0ef8429c841' as CommitId,
-                subject: 'test3',
-              },
-            ],
-          },
-        },
-      },
-    };
-    await element.updateComplete;
-    assert.equal(element.getBasePatchNum(), -1 as BasePatchSetNum);
-
-    element.patchRange.basePatchNum = PARENT;
-    element.patchRange.patchNum = 1 as RevisionPatchSetNum;
-    await element.updateComplete;
-    assert.equal(element.getBasePatchNum(), PARENT);
-  });
-
   test('openReplyDialog called with `ANY` when coming from tap event', async () => {
     await element.updateComplete;
     assertIsDefined(element.replyBtn);
@@ -1791,10 +1261,8 @@
       .stub(testResolver(pluginLoaderToken), 'awaitPluginsLoaded')
       .callsFake(() => Promise.resolve());
 
-    element.patchRange = {
-      basePatchNum: PARENT,
-      patchNum: 2 as RevisionPatchSetNum,
-    };
+    element.basePatchNum = PARENT;
+    element.patchNum = 2 as RevisionPatchSetNum;
     element.change = {
       ...createChangeViewChange(),
       revisions: {
@@ -1858,14 +1326,18 @@
   });
 
   test('maybeScrollToMessage', async () => {
+    element.change = {
+      ...createChangeViewChange(),
+      messages: createChangeMessages(1),
+    };
     await element.updateComplete;
     const scrollStub = sinon.stub(element.messagesList!, 'scrollToMessage');
 
-    element.maybeScrollToMessage('');
+    await element.maybeScrollToMessage('');
     assert.isFalse(scrollStub.called);
-    element.maybeScrollToMessage('message');
+    await element.maybeScrollToMessage('message');
     assert.isFalse(scrollStub.called);
-    element.maybeScrollToMessage('#message-TEST');
+    await element.maybeScrollToMessage('#message-TEST');
     assert.isTrue(scrollStub.called);
     assert.equal(scrollStub.lastCall.args[0], 'TEST');
   });
@@ -1873,6 +1345,8 @@
   test('computeEditMode', async () => {
     const callCompute = async (viewState: ChangeViewState) => {
       element.viewState = viewState;
+      element.patchNum = viewState.patchNum;
+      element.basePatchNum = viewState.basePatchNum ?? PARENT;
       await element.updateComplete;
       return element.getEditMode();
     };
@@ -1900,46 +1374,8 @@
     );
   });
 
-  test('processEdit', () => {
-    element.patchRange = {};
-    const change: ParsedChangeInfo = {
-      ...createChangeViewChange(),
-      current_revision: 'foo' as CommitId,
-      revisions: {
-        foo: {...createRevision()},
-      },
-    };
-
-    // With no edit, nothing happens.
-    element.processEdit(change);
-    assert.equal(element.patchRange.patchNum, undefined);
-
-    change.revisions['bar'] = {
-      _number: EDIT,
-      basePatchNum: 1 as BasePatchSetNum,
-      commit: {
-        ...createCommit(),
-        commit: 'bar' as CommitId,
-      },
-      fetch: {},
-    };
-
-    // When edit is set, but not patchNum, then switch to edit ps.
-    element.processEdit(change);
-    assert.equal(element.patchRange.patchNum, EDIT);
-
-    // When edit is set, but patchNum as well, then keep patchNum.
-    element.patchRange.patchNum = 5 as RevisionPatchSetNum;
-    element.viewModelPatchNum = 5 as RevisionPatchSetNum;
-    element.processEdit(change);
-    assert.equal(element.patchRange.patchNum, 5 as RevisionPatchSetNum);
-  });
-
   test('file-action-tap handling', async () => {
-    element.patchRange = {
-      basePatchNum: PARENT,
-      patchNum: 1 as RevisionPatchSetNum,
-    };
+    element.patchNum = 1 as RevisionPatchSetNum;
     element.change = {
       ...createChangeViewChange(),
     };
@@ -2010,109 +1446,6 @@
     assert.isTrue(setUrlStub.called);
   });
 
-  test('selectedRevision updates when patchNum is changed', async () => {
-    const revision1: RevisionInfo = createRevision(1);
-    const revision2: RevisionInfo = createRevision(2);
-    changeModel.setState({
-      loadingStatus: LoadingStatus.LOADED,
-      change: {
-        ...createChangeViewChange(),
-        revisions: {
-          aaa: revision1,
-          bbb: revision2,
-        },
-        labels: {},
-        actions: {},
-        current_revision: 'bbb' as CommitId,
-      },
-    });
-    userModel.setPreferences(createPreferences());
-
-    element.patchRange = {patchNum: 2 as RevisionPatchSetNum};
-    await element.performPostChangeLoadTasks();
-    assert.strictEqual(element.selectedRevision, revision2);
-
-    element.patchRange = {patchNum: 1 as RevisionPatchSetNum};
-    await element.updateComplete;
-    assert.strictEqual(element.selectedRevision, revision1);
-  });
-
-  test('selectedRevision is assigned when patchNum is edit', async () => {
-    const revision1 = createRevision(1);
-    const revision2 = createRevision(2);
-    const revision3 = createEditRevision();
-    changeModel.setState({
-      loadingStatus: LoadingStatus.LOADED,
-      change: {
-        ...createChangeViewChange(),
-        revisions: {
-          aaa: revision1,
-          bbb: revision2,
-          ccc: revision3,
-        },
-        labels: {},
-        actions: {},
-        current_revision: 'ccc' as CommitId,
-      },
-    });
-    stubRestApi('getPreferences').returns(Promise.resolve(createPreferences()));
-
-    element.patchRange = {patchNum: EDIT};
-    await element.performPostChangeLoadTasks();
-    assert.strictEqual(element.selectedRevision, revision3);
-  });
-
-  test('sendShowChangeEvent', () => {
-    const change = {...createChangeViewChange(), labels: {}};
-    element.change = {...change};
-    element.patchRange = {patchNum: 4 as RevisionPatchSetNum};
-    element.mergeable = true;
-    const showStub = sinon.stub(
-      testResolver(pluginLoaderToken).jsApiService,
-      'handleShowChange'
-    );
-    element.sendShowChangeEvent();
-    assert.isTrue(showStub.calledOnce);
-    assert.deepEqual(showStub.lastCall.args[0], {
-      change,
-      patchNum: 4 as PatchSetNumber,
-      info: {mergeable: true},
-    });
-  });
-
-  test('patch range changed', () => {
-    element.patchRange = undefined;
-    element.change = createChangeViewChange();
-    element.change.revisions = createRevisions(4);
-    element.change.current_revision = '1' as CommitId;
-    element.change = {...element.change};
-
-    const viewState = createChangeViewState();
-
-    assert.isFalse(element.hasPatchRangeChanged(viewState));
-    assert.isFalse(element.hasPatchNumChanged(viewState));
-
-    viewState.basePatchNum = PARENT;
-    // undefined means navigate to latest patchset
-    viewState.patchNum = undefined;
-
-    element.patchRange = {
-      patchNum: 2 as RevisionPatchSetNum,
-      basePatchNum: PARENT,
-    };
-
-    assert.isTrue(element.hasPatchRangeChanged(viewState));
-    assert.isTrue(element.hasPatchNumChanged(viewState));
-
-    element.patchRange = {
-      patchNum: 4 as RevisionPatchSetNum,
-      basePatchNum: PARENT,
-    };
-
-    assert.isFalse(element.hasPatchRangeChanged(viewState));
-    assert.isFalse(element.hasPatchNumChanged(viewState));
-  });
-
   suite('handleEditTap', () => {
     let fireEdit: () => void;
 
@@ -2161,7 +1494,7 @@
       const newChange = {...element.change};
       newChange.revisions.rev2 = createRevision(2);
       element.change = newChange;
-      element.patchRange = {patchNum: 2 as RevisionPatchSetNum};
+      element.patchNum = 2 as RevisionPatchSetNum;
       await element.updateComplete;
 
       fireEdit();
@@ -2182,7 +1515,7 @@
     assertIsDefined(element.actions);
     sinon.stub(element.metadata, 'computeLabelNames');
 
-    element.patchRange = {patchNum: 1 as RevisionPatchSetNum};
+    element.patchNum = 1 as RevisionPatchSetNum;
     element.actions.dispatchEvent(
       new CustomEvent('stop-edit-tap', {bubbles: false})
     );
@@ -2197,7 +1530,7 @@
   suite('plugin endpoints', () => {
     test('endpoint params', async () => {
       element.change = {...createChangeViewChange(), labels: {}};
-      element.selectedRevision = createRevision();
+      element.revision = createRevision();
       const promise = mockPromise();
       window.Gerrit.install(
         promise.resolve,
@@ -2211,43 +1544,7 @@
         .getLastAttached();
       assert.strictEqual((hookEl as any).plugin, plugin);
       assert.strictEqual((hookEl as any).change, element.change);
-      assert.strictEqual((hookEl as any).revision, element.selectedRevision);
-    });
-  });
-
-  suite('getMergeability', () => {
-    let getMergeableStub: SinonStubbedMember<RestApiService['getMergeable']>;
-    setup(() => {
-      element.change = {...createChangeViewChange(), labels: {}};
-      getMergeableStub = stubRestApi('getMergeable').returns(
-        Promise.resolve({...createMergeable(), mergeable: true})
-      );
-    });
-
-    test('merged change', () => {
-      element.mergeable = null;
-      element.change!.status = ChangeStatus.MERGED;
-      return element.getMergeability().then(() => {
-        assert.isFalse(element.mergeable);
-        assert.isFalse(getMergeableStub.called);
-      });
-    });
-
-    test('abandoned change', () => {
-      element.mergeable = null;
-      element.change!.status = ChangeStatus.ABANDONED;
-      return element.getMergeability().then(() => {
-        assert.isFalse(element.mergeable);
-        assert.isFalse(getMergeableStub.called);
-      });
-    });
-
-    test('open change', () => {
-      element.mergeable = null;
-      return element.getMergeability().then(() => {
-        assert.isTrue(element.mergeable);
-        assert.isTrue(getMergeableStub.called);
-      });
+      assert.strictEqual((hookEl as any).revision, element.revision);
     });
   });
 
@@ -2269,18 +1566,8 @@
 
   suite('gr-reporting tests', () => {
     setup(() => {
-      element.patchRange = {
-        basePatchNum: PARENT,
-        patchNum: 1 as RevisionPatchSetNum,
-      };
-      sinon
-        .stub(element, 'performPostChangeLoadTasks')
-        .returns(Promise.resolve(false));
-      sinon.stub(element, 'getMergeability').returns(Promise.resolve());
-      sinon.stub(element, 'getLatestCommitMessage').returns(Promise.resolve());
-      sinon
-        .stub(element, 'reloadPatchNumDependentResources')
-        .returns(Promise.resolve());
+      element.basePatchNum = PARENT;
+      element.patchNum = 1 as RevisionPatchSetNum;
     });
 
     test("don't report changeDisplayed on reply", async () => {
@@ -2298,7 +1585,8 @@
       assert.isFalse(changeFullyLoadedStub.called);
     });
 
-    test('report changeDisplayed on viewStateChanged', async () => {
+    test('report changeDisplayed and changeFullyLoaded', async () => {
+      const commentsModel = testResolver(commentsModelToken);
       stubRestApi('getChangeOrEditFiles').resolves({
         'a-file.js': {},
       });
@@ -2326,32 +1614,23 @@
           revisions: {foo: createRevision()},
         },
       });
-      await element.updateComplete;
-      await waitEventLoop();
+
+      await waitUntil(() => changeDisplayStub.called);
       assert.isTrue(changeDisplayStub.called);
+      assert.isFalse(changeFullyLoadedStub.called);
+
+      element.mergeable = true;
+      commentsModel.setState({
+        comments: {},
+        drafts: {},
+        discardedDrafts: [],
+      });
+
+      await waitUntil(() => changeFullyLoadedStub.called);
       assert.isTrue(changeFullyLoadedStub.called);
     });
   });
 
-  test('calculateHasParent', () => {
-    const changeId = '123' as ChangeId;
-    const relatedChanges: RelatedChangeAndCommitInfo[] = [];
-
-    assert.equal(element.calculateHasParent(changeId, relatedChanges), false);
-
-    relatedChanges.push({
-      ...createRelatedChangeAndCommitInfo(),
-      change_id: '123' as ChangeId,
-    });
-    assert.equal(element.calculateHasParent(changeId, relatedChanges), false);
-
-    relatedChanges.push({
-      ...createRelatedChangeAndCommitInfo(),
-      change_id: '234' as ChangeId,
-    });
-    assert.equal(element.calculateHasParent(changeId, relatedChanges), true);
-  });
-
   test('renders sha in copy links', async () => {
     stubFlags('isEnabled').returns(true);
     const sha = '123' as CommitId;
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog.ts b/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog.ts
index 166d895..6ad416e 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog.ts
@@ -28,8 +28,9 @@
 import {fireNoBubbleNoCompose} from '../../../utils/event-util';
 import {resolve} from '../../../models/dependency';
 import {changeModelToken} from '../../../models/change/change-model';
-import {subscribe} from '../../lit/subscription-controller';
 import {userModelToken} from '../../../models/user/user-model';
+import {relatedChangesModelToken} from '../../../models/change/related-changes-model';
+import {subscribe} from '../../lit/subscription-controller';
 
 export interface RebaseChange {
   name: string;
@@ -63,12 +64,6 @@
   @property({type: String})
   branch?: BranchName;
 
-  @property({type: Number})
-  changeNumber?: NumericChangeId;
-
-  @property({type: Boolean})
-  hasParent?: boolean;
-
   @property({type: Boolean})
   rebaseOnCurrent?: boolean;
 
@@ -76,6 +71,12 @@
   disableActions = false;
 
   @state()
+  changeNum?: NumericChangeId;
+
+  @state()
+  hasParent?: boolean;
+
+  @state()
   text = '';
 
   @state()
@@ -91,16 +92,16 @@
   allowConflicts = false;
 
   @query('#rebaseOnParentInput')
-  private rebaseOnParentInput!: HTMLInputElement;
+  private rebaseOnParentInput?: HTMLInputElement;
 
   @query('#rebaseOnTipInput')
-  private rebaseOnTipInput!: HTMLInputElement;
+  private rebaseOnTipInput?: HTMLInputElement;
 
   @query('#rebaseOnOtherInput')
-  rebaseOnOtherInput!: HTMLInputElement;
+  rebaseOnOtherInput?: HTMLInputElement;
 
   @query('#rebaseAllowConflicts')
-  private rebaseAllowConflicts!: HTMLInputElement;
+  private rebaseAllowConflicts?: HTMLInputElement;
 
   @query('#rebaseChain')
   private rebaseChain?: HTMLInputElement;
@@ -120,6 +121,11 @@
 
   private readonly getUserModel = resolve(this, userModelToken);
 
+  private readonly getRelatedChangesModel = resolve(
+    this,
+    relatedChangesModelToken
+  );
+
   constructor() {
     super();
     this.query = input => this.getChangeSuggestions(input);
@@ -133,6 +139,16 @@
       () => this.getChangeModel().latestUploader$,
       x => (this.uploader = x)
     );
+    subscribe(
+      this,
+      () => this.getChangeModel().changeNum$,
+      x => (this.changeNum = x)
+    );
+    subscribe(
+      this,
+      () => this.getRelatedChangesModel().hasParent$,
+      x => (this.hasParent = x)
+    );
   }
 
   override willUpdate(changedProperties: PropertyValues): void {
@@ -199,6 +215,9 @@
               Rebase on parent change
             </label>
           </div>
+          <div class="message" ?hidden=${this.hasParent !== undefined}>
+            Still loading parent information ...
+          </div>
           <div
             id="parentUpToDateMsg"
             class="message"
@@ -361,8 +380,7 @@
   ): AutocompleteSuggestion[] {
     return changes
       .filter(
-        change =>
-          change.name.includes(input) && change.value !== this.changeNumber
+        change => change.name.includes(input) && change.value !== this.changeNum
       )
       .map(
         change =>
@@ -393,10 +411,10 @@
    * should be rebased on top of its current parent.
    */
   getSelectedBase() {
-    if (this.rebaseOnParentInput.checked) {
+    if (this.rebaseOnParentInput?.checked) {
       return null;
     }
-    if (this.rebaseOnTipInput.checked) {
+    if (this.rebaseOnTipInput?.checked) {
       return '';
     }
     if (!this.text) {
@@ -412,7 +430,7 @@
     e.stopPropagation();
     const detail: ConfirmRebaseEventDetail = {
       base: this.getSelectedBase(),
-      allowConflicts: this.rebaseAllowConflicts.checked,
+      allowConflicts: !!this.rebaseAllowConflicts?.checked,
       rebaseChain: !!this.rebaseChain?.checked,
       onBehalfOfUploader: this.rebaseOnBehalfOfUploader(),
     };
@@ -437,7 +455,7 @@
   }
 
   private handleEnterChangeNumberClick() {
-    this.rebaseOnOtherInput.checked = true;
+    if (this.rebaseOnOtherInput) this.rebaseOnOtherInput.checked = true;
   }
 
   /**
@@ -451,11 +469,11 @@
     }
 
     if (this.displayParentOption()) {
-      this.rebaseOnParentInput.checked = true;
+      if (this.rebaseOnParentInput) this.rebaseOnParentInput.checked = true;
     } else if (this.displayTipOption()) {
-      this.rebaseOnTipInput.checked = true;
+      if (this.rebaseOnTipInput) this.rebaseOnTipInput.checked = true;
     } else {
-      this.rebaseOnOtherInput.checked = true;
+      if (this.rebaseOnOtherInput) this.rebaseOnOtherInput.checked = true;
     }
   }
 }
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog_test.ts b/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog_test.ts
index 8d907c9..24f8a34 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog_test.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-rebase-dialog/gr-confirm-rebase-dialog_test.ts
@@ -44,6 +44,7 @@
 
   test('render', async () => {
     element.branch = 'test' as BranchName;
+    element.hasParent = false;
     await element.updateComplete;
     assert.shadowDom.equal(
       element,
@@ -60,6 +61,9 @@
               Rebase on parent change
             </label>
           </div>
+          <div class="message" hidden="">
+            Still loading parent information ...
+          </div>
           <div class="message" hidden="" id="parentUpToDateMsg">
             This change is up to date with its parent.
           </div>
@@ -239,7 +243,7 @@
     element.hasParent = false;
     await element.updateComplete;
 
-    assert.isTrue(element.rebaseOnOtherInput.checked);
+    assert.isTrue(element.rebaseOnOtherInput?.checked);
     assert.isTrue(
       queryAndAssert(element, '#rebaseOnParent').hasAttribute('hidden')
     );
@@ -360,7 +364,7 @@
       assert.equal(element.filterChanges('awesome', recentChanges).length, 3);
       assert.equal(element.filterChanges('third', recentChanges).length, 1);
 
-      element.changeNumber = 123 as NumericChangeId;
+      element.changeNum = 123 as NumericChangeId;
       await element.updateComplete;
 
       assert.equal(element.filterChanges('123', recentChanges).length, 0);
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.ts b/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.ts
index cdf618a..44e237b 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.ts
@@ -99,7 +99,7 @@
     );
     subscribe(
       this,
-      () => this.getCommentsModel().threads$,
+      () => this.getCommentsModel().threadsSaved$,
       x => (this.unresolvedThreads = x.filter(isUnresolved))
     );
   }
diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts
index c206d57..f9568f4 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts
@@ -86,7 +86,6 @@
 import {userModelToken} from '../../../models/user/user-model';
 import {pluginLoaderToken} from '../../shared/gr-js-api-interface/gr-plugin-loader';
 import {FileMode, fileModeToString} from '../../../utils/file-util';
-import {KnownExperimentId} from '../../../services/flags/flags';
 
 export const DEFAULT_NUM_FILES_SHOWN = 200;
 
@@ -309,8 +308,6 @@
 
   private readonly getBrowserModel = resolve(this, browserModelToken);
 
-  private readonly flagsService = getAppContext().flagsService;
-
   shortcutsController = new ShortcutController(this);
 
   private readonly getNavigation = resolve(this, navigationToken);
@@ -826,6 +823,13 @@
 
   override willUpdate(changedProperties: PropertyValues): void {
     if (
+      changedProperties.has('patchNum') ||
+      changedProperties.has('basePatchNum')
+    ) {
+      this.resetFileState();
+      this.collapseAllDiffs();
+    }
+    if (
       changedProperties.has('diffPrefs') ||
       changedProperties.has('diffViewMode')
     ) {
@@ -1279,16 +1283,7 @@
   private renderFileComments(file: NormalizedFileInfo) {
     return html` <div role="gridcell">
       <div class="comments desktop">
-        ${when(
-          this.flagsService.isEnabled(
-            KnownExperimentId.COMMENTS_CHIPS_IN_FILE_LIST
-          ),
-          () => html`<span>${this.renderCommentsChips(file)}</span>`,
-          () => html`<span class="drafts"
-              >${this.computeDraftsString(file)}</span
-            >
-            <span>${this.computeCommentsString(file)}</span>`
-        )}
+        <span>${this.renderCommentsChips(file)}</span>
         <span class="noCommentsScreenReaderText">
           <!-- Screen readers read the following content only if 2 other
           spans in the parent div is empty. The content is not visible on
diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.ts b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.ts
index 8fb5622..6033a25 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.ts
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.ts
@@ -192,7 +192,11 @@
           </span>
           <div role="gridcell">
             <div class="comments desktop">
-              <span class="drafts"> </span> <span> </span>
+              <span
+                ><gr-comments-summary
+                  emptywhennocomments=""
+                ></gr-comments-summary
+              ></span>
               <span class="noCommentsScreenReaderText"> No comments </span>
             </div>
             <div class="comments mobile">
diff --git a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.ts b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.ts
index 345feb2..d5da9c9 100644
--- a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.ts
+++ b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.ts
@@ -46,6 +46,7 @@
   shortcutsServiceToken,
 } from '../../../services/shortcuts/shortcuts-service';
 import {GrFormattedText} from '../../shared/gr-formatted-text/gr-formatted-text';
+import {waitUntil} from '../../../utils/async-util';
 
 /**
  * The content of the enum is also used in the UI for the button text.
@@ -348,7 +349,7 @@
     super();
     subscribe(
       this,
-      () => this.getCommentsModel().threads$,
+      () => this.getCommentsModel().threadsSaved$,
       x => {
         this.commentThreads = x;
       }
@@ -439,6 +440,9 @@
   }
 
   async scrollToMessage(messageID: string) {
+    await waitUntil(() => this.messages && this.messages.length > 0);
+    await this.updateComplete;
+
     const selector = `[data-message-id="${messageID}"]`;
     const el = this.shadowRoot!.querySelector(selector) as
       | GrMessage
diff --git a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list_test.ts b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list_test.ts
index 0217aa8..df04f68 100644
--- a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list_test.ts
+++ b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list_test.ts
@@ -195,9 +195,9 @@
       }
     });
 
-    test('expand/collapse from external keypress', () => {
+    test('expand/collapse from external keypress', async () => {
       // Start with one expanded message. -> not all collapsed
-      element.scrollToMessage(messages[1].id);
+      await element.scrollToMessage(messages[1].id);
       assert.isFalse(
         [...getMessages()].filter(m => m.message?.expanded).length === 0
       );
diff --git a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.ts b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.ts
index 05acb29..6bdabec 100644
--- a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.ts
+++ b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.ts
@@ -11,31 +11,26 @@
 import '../../shared/gr-icon/gr-icon';
 import {classMap} from 'lit/directives/class-map.js';
 import {LitElement, css, html, TemplateResult} from 'lit';
-import {customElement, property, state} from 'lit/decorators.js';
+import {customElement, state} from 'lit/decorators.js';
 import {sharedStyles} from '../../../styles/shared-styles';
 import {
   ChangeInfo,
   CommitId,
   PatchSetNumber,
   RelatedChangeAndCommitInfo,
-  RelatedChangesInfo,
   RevisionPatchSetNum,
   SubmittedTogetherInfo,
 } from '../../../types/common';
-import {getAppContext} from '../../../services/app-context';
 import {ParsedChangeInfo} from '../../../types/types';
 import {truncatePath} from '../../../utils/path-list-util';
 import {pluralize} from '../../../utils/string-util';
-import {
-  changeIsOpen,
-  getChangeNumber,
-  getRevisionKey,
-} from '../../../utils/change-util';
+import {getChangeNumber, getRevisionKey} from '../../../utils/change-util';
 import {DEFALT_NUM_CHANGES_WHEN_COLLAPSED} from './gr-related-collapse';
 import {createChangeUrl} from '../../../models/views/change';
 import {subscribe} from '../../lit/subscription-controller';
 import {resolve} from '../../../models/dependency';
 import {changeModelToken} from '../../../models/change/change-model';
+import {relatedChangesModelToken} from '../../../models/change/related-changes-model';
 
 export interface ChangeMarkersInList {
   showCurrentChangeArrow: boolean;
@@ -54,9 +49,6 @@
 
 @customElement('gr-related-changes-list')
 export class GrRelatedChangesList extends LitElement {
-  @property({type: Boolean})
-  mergeable?: boolean;
-
   @state()
   change?: ParsedChangeInfo;
 
@@ -81,10 +73,13 @@
   @state()
   sameTopicChanges: ChangeInfo[] = [];
 
-  private readonly restApiService = getAppContext().restApiService;
-
   private readonly getChangeModel = resolve(this, changeModelToken);
 
+  private readonly getRelatedChangesModel = resolve(
+    this,
+    relatedChangesModelToken
+  );
+
   constructor() {
     super();
     subscribe(
@@ -97,6 +92,31 @@
       () => this.getChangeModel().latestPatchNum$,
       x => (this.latestPatchNum = x)
     );
+    subscribe(
+      this,
+      () => this.getRelatedChangesModel().relatedChanges$,
+      x => (this.relatedChanges = x ?? [])
+    );
+    subscribe(
+      this,
+      () => this.getRelatedChangesModel().submittedTogether$,
+      x => (this.submittedTogether = x)
+    );
+    subscribe(
+      this,
+      () => this.getRelatedChangesModel().cherryPicks$,
+      x => (this.cherryPickChanges = x ?? [])
+    );
+    subscribe(
+      this,
+      () => this.getRelatedChangesModel().conflictingChanges$,
+      x => (this.conflictingChanges = x ?? [])
+    );
+    subscribe(
+      this,
+      () => this.getRelatedChangesModel().sameTopicChanges$,
+      x => (this.sameTopicChanges = x ?? [])
+    );
   }
 
   static override get styles() {
@@ -586,72 +606,6 @@
     return html`<span class="marker space"></span>`;
   }
 
-  reload(getRelatedChanges?: Promise<RelatedChangesInfo | undefined>) {
-    const change = this.change;
-    if (!change) return Promise.reject(new Error('change missing'));
-    if (!this.latestPatchNum)
-      return Promise.reject(new Error('latestPatchNum missing'));
-    if (!getRelatedChanges) {
-      getRelatedChanges = this.restApiService.getRelatedChanges(
-        change._number,
-        this.latestPatchNum
-      );
-    }
-    const promises: Array<Promise<void>> = [
-      getRelatedChanges.then(response => {
-        if (!response) {
-          throw new Error('getRelatedChanges returned undefined response');
-        }
-        this.relatedChanges = response?.changes ?? [];
-      }),
-      this.restApiService
-        .getChangesSubmittedTogether(change._number)
-        .then(response => {
-          this.submittedTogether = response;
-        }),
-      this.restApiService
-        .getChangeCherryPicks(change.project, change.change_id, change._number)
-        .then(response => {
-          this.cherryPickChanges = response || [];
-        }),
-    ];
-
-    // Get conflicts if change is open and is mergeable.
-    // Mergeable is output of restApiServict.getMergeable from gr-change-view
-    if (changeIsOpen(change) && this.mergeable) {
-      promises.push(
-        this.restApiService
-          .getChangeConflicts(change._number)
-          .then(response => {
-            this.conflictingChanges = response ?? [];
-          })
-      );
-    }
-    if (change.topic) {
-      const changeTopic = change.topic;
-      promises.push(
-        this.restApiService.getConfig().then(config => {
-          if (config && !config.change.submit_whole_topic) {
-            return this.restApiService
-              .getChangesWithSameTopic(changeTopic, {
-                openChangesOnly: true,
-                changeToExclude: change._number,
-              })
-              .then(response => {
-                if (changeTopic === this.change?.topic) {
-                  this.sameTopicChanges = response ?? [];
-                }
-              });
-          }
-          this.sameTopicChanges = [];
-          return Promise.resolve();
-        })
-      );
-    }
-
-    return Promise.all(promises);
-  }
-
   /**
    * Do the given objects describe the same change? Compares the changes by
    * their numbers.
diff --git a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_test.ts b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_test.ts
index 571b5b5..24a8217 100644
--- a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_test.ts
+++ b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_test.ts
@@ -4,10 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 import {fixture, html, assert} from '@open-wc/testing';
-import {SinonStubbedMember} from 'sinon';
 import {PluginApi} from '../../../api/plugin';
-import {ChangeStatus} from '../../../constants/constants';
-import {RestApiService} from '../../../services/gr-rest-api/gr-rest-api';
 import '../../../test/common-test-setup';
 import {testResolver} from '../../../test/common-test-setup';
 import {
@@ -19,12 +16,7 @@
   createRevision,
   createSubmittedTogetherInfo,
 } from '../../../test/test-data-generators';
-import {
-  query,
-  queryAndAssert,
-  stubRestApi,
-  waitEventLoop,
-} from '../../../test/test-utils';
+import {query, queryAndAssert, waitEventLoop} from '../../../test/test-utils';
 import {
   ChangeId,
   ChangeInfo,
@@ -196,16 +188,10 @@
     });
 
     test('render', async () => {
-      stubRestApi('getRelatedChanges').returns(
-        Promise.resolve(relatedChangeInfo)
-      );
-      stubRestApi('getChangesSubmittedTogether').returns(
-        Promise.resolve(submittedTogether)
-      );
-      stubRestApi('getChangeCherryPicks').returns(
-        Promise.resolve([createChange()])
-      );
-      await element.reload();
+      element.relatedChanges = relatedChangeInfo.changes;
+      element.submittedTogether = submittedTogether;
+      element.cherryPickChanges = [createChange()];
+      await element.updateComplete;
 
       assert.shadowDom.equal(
         element,
@@ -262,10 +248,9 @@
     });
 
     test('first list', async () => {
-      stubRestApi('getRelatedChanges').returns(
-        Promise.resolve(relatedChangeInfo)
-      );
-      await element.reload();
+      element.relatedChanges = relatedChangeInfo.changes;
+      await element.updateComplete;
+
       const section = queryAndAssert<HTMLElement>(element, '#relatedChanges');
       const relatedChanges = queryAndAssert<GrRelatedCollapse>(
         section,
@@ -275,13 +260,10 @@
     });
 
     test('first empty second non-empty', async () => {
-      stubRestApi('getRelatedChanges').returns(
-        Promise.resolve(createRelatedChangesInfo())
-      );
-      stubRestApi('getChangesSubmittedTogether').returns(
-        Promise.resolve(submittedTogether)
-      );
-      await element.reload();
+      element.relatedChanges = createRelatedChangesInfo().changes;
+      element.submittedTogether = submittedTogether;
+      await element.updateComplete;
+
       const relatedChanges = query<HTMLElement>(element, '#relatedChanges');
       assert.notExists(relatedChanges);
       const submittedTogetherSection = queryAndAssert<GrRelatedCollapse>(
@@ -292,16 +274,10 @@
     });
 
     test('first non-empty second empty third non-empty', async () => {
-      stubRestApi('getRelatedChanges').returns(
-        Promise.resolve(relatedChangeInfo)
-      );
-      stubRestApi('getChangesSubmittedTogether').returns(
-        Promise.resolve(createSubmittedTogetherInfo())
-      );
-      stubRestApi('getChangeCherryPicks').returns(
-        Promise.resolve([createChange()])
-      );
-      await element.reload();
+      element.relatedChanges = relatedChangeInfo.changes;
+      element.submittedTogether = createSubmittedTogetherInfo();
+      element.cherryPickChanges = [createChange()];
+      await element.updateComplete;
 
       const relatedChanges = queryAndAssert<GrRelatedCollapse>(
         queryAndAssert<HTMLElement>(element, '#relatedChanges'),
@@ -364,67 +340,6 @@
     assert.equal(getChangeNumber(change2), 1);
   });
 
-  suite('get conflicts tests', () => {
-    let element: GrRelatedChangesList;
-    let conflictsStub: SinonStubbedMember<RestApiService['getChangeConflicts']>;
-
-    setup(async () => {
-      element = await fixture(
-        html`<gr-related-changes-list></gr-related-changes-list>`
-      );
-      conflictsStub = stubRestApi('getChangeConflicts').returns(
-        Promise.resolve(undefined)
-      );
-    });
-
-    test('request conflicts if open and mergeable', () => {
-      element.latestPatchNum = 7 as PatchSetNumber;
-      element.change = {
-        ...createParsedChange(),
-        change_id: '123' as ChangeId,
-        status: ChangeStatus.NEW,
-      };
-      element.mergeable = true;
-      element.reload();
-      assert.isTrue(conflictsStub.called);
-    });
-
-    test('does not request conflicts if closed and mergeable', () => {
-      element.latestPatchNum = 7 as PatchSetNumber;
-      element.change = {
-        ...createParsedChange(),
-        change_id: '123' as ChangeId,
-        status: ChangeStatus.NEW,
-      };
-      element.reload();
-      assert.isFalse(conflictsStub.called);
-    });
-
-    test('does not request conflicts if open and not mergeable', () => {
-      element.latestPatchNum = 7 as PatchSetNumber;
-      element.change = {
-        ...createParsedChange(),
-        change_id: '123' as ChangeId,
-        status: ChangeStatus.NEW,
-      };
-      element.mergeable = false;
-      element.reload();
-      assert.isFalse(conflictsStub.called);
-    });
-
-    test('doesnt request conflicts if closed and not mergeable', () => {
-      element.latestPatchNum = 7 as PatchSetNumber;
-      element.change = {
-        ...createParsedChange(),
-        change_id: '123' as ChangeId,
-        status: ChangeStatus.NEW,
-      };
-      element.mergeable = false;
-      element.reload();
-      assert.isFalse(conflictsStub.called);
-    });
-  });
-
   test('connected revisions', () => {
     const change: ParsedChangeInfo = {
       ...createParsedChange(),
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog-it_test.ts b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog-it_test.ts
index a20135b..4f951f3 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog-it_test.ts
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog-it_test.ts
@@ -25,6 +25,8 @@
 import {testResolver} from '../../../test/common-test-setup';
 import {pluginLoaderToken} from '../../shared/gr-js-api-interface/gr-plugin-loader';
 import {GrComment} from '../../shared/gr-comment/gr-comment';
+import {createNewPatchsetLevel} from '../../../utils/comment-util';
+import {commentsModelToken} from '../../../models/comments/comments-model';
 
 suite('gr-reply-dialog-it tests', () => {
   let element: GrReplyDialog;
@@ -62,6 +64,9 @@
       'Code-Review': ['-1', ' 0', '+1'],
       Verified: ['-1', ' 0', '+1'],
     };
+    testResolver(commentsModelToken).addNewDraft(
+      createNewPatchsetLevel(latestPatchNum, '', false)
+    );
   };
 
   setup(async () => {
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts
index c0383fa..f41236b 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts
@@ -71,7 +71,6 @@
   queryAndAssert,
 } from '../../../utils/common-util';
 import {
-  createNewPatchsetLevel,
   getFirstComment,
   isPatchsetLevel,
   isUnresolved,
@@ -89,7 +88,6 @@
   fire,
   fireNoBubble,
   fireIronAnnounce,
-  fireReload,
   fireServerError,
 } from '../../../utils/event-util';
 import {ErrorCallback} from '../../../api/rest';
@@ -642,7 +640,7 @@
     );
     subscribe(
       this,
-      () => this.getCommentsModel().draftThreads$,
+      () => this.getCommentsModel().draftThreadsSaved$,
       threads =>
         (this.draftCommentThreads = threads.filter(
           t => !(isDraft(getFirstComment(t)) && isPatchsetLevel(t))
@@ -699,20 +697,6 @@
     });
   }
 
-  override updated() {
-    if (!this.patchsetLevelComment && this.latestPatchNum) {
-      // TODO: This should rather be done in the comments model. It should
-      // ensure that a patchset level draft is always present.
-      this.getCommentsModel().addNewDraft(
-        createNewPatchsetLevel(
-          this.latestPatchNum,
-          this.patchsetLevelDraftMessage,
-          !this.patchsetLevelDraftIsResolved
-        )
-      );
-    }
-  }
-
   override willUpdate(changedProperties: PropertyValues) {
     if (changedProperties.has('ccPendingConfirmation')) {
       this.pendingConfirmationUpdated(this.ccPendingConfirmation);
@@ -1353,6 +1337,7 @@
 
   // visible for testing
   async send(includeComments: boolean, startReview: boolean) {
+    // The change model will end this timing when the change was reloaded.
     this.reporting.time(Timing.SEND_REPLY);
     const labels = this.getLabelScores().getLabelValues();
 
@@ -1944,7 +1929,7 @@
   }
 
   _reload() {
-    fireReload(this, true);
+    this.getChangeModel().navigateToChangeResetReload();
     this.cancel();
   }
 
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.ts b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.ts
index 3e20d9a..c4a978c 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.ts
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.ts
@@ -69,6 +69,7 @@
   commentsModelToken,
 } from '../../../models/comments/comments-model';
 import {isOwner} from '../../../utils/change-util';
+import {createNewPatchsetLevel} from '../../../utils/comment-util';
 
 function cloneableResponse(status: number, text: string) {
   return {
@@ -153,9 +154,12 @@
       Verified: ['-1', ' 0', '+1'],
     };
     element.draftCommentThreads = [];
+    commentsModel = testResolver(commentsModelToken);
+    commentsModel.addNewDraft(
+      createNewPatchsetLevel(latestPatchNum, '', false)
+    );
 
     await element.updateComplete;
-    commentsModel = testResolver(commentsModelToken);
   });
 
   function stubSaveReview(
diff --git a/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard.ts b/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard.ts
index 2766114..98f65c0 100644
--- a/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard.ts
+++ b/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard.ts
@@ -327,7 +327,7 @@
         review
       )
       .then(() => {
-        fireReload(this, true);
+        fireReload(this);
       });
   }
 
diff --git a/polygerrit-ui/app/elements/core/gr-router/gr-router.ts b/polygerrit-ui/app/elements/core/gr-router/gr-router.ts
index 304f9ea..aa6bb7a4 100644
--- a/polygerrit-ui/app/elements/core/gr-router/gr-router.ts
+++ b/polygerrit-ui/app/elements/core/gr-router/gr-router.ts
@@ -1326,10 +1326,10 @@
     };
 
     const queryMap = new URLSearchParams(ctx.querystring);
-    if (queryMap.has('forceReload')) state.forceReload = true;
     if (queryMap.has('openReplyDialog')) state.openReplyDialog = true;
 
     const tab = queryMap.get('tab');
+    if (queryMap.has('forceReload')) state.forceReload = true;
     if (tab) state.tab = tab;
     const checksPatchset = Number(queryMap.get('checksPatchset'));
     if (Number.isInteger(checksPatchset) && checksPatchset > 0) {
@@ -1422,6 +1422,8 @@
       view: GerritView.CHANGE,
       childView: ChangeChildView.OVERVIEW,
     };
+    const queryMap = new URLSearchParams(ctx.querystring);
+    if (queryMap.has('forceReload')) state.forceReload = true;
     assertIsDefined(state.repo);
     this.reporting.setRepoName(state.repo);
     this.reporting.setChangeId(changeNum);
@@ -1443,6 +1445,8 @@
       childView: ChangeChildView.DIFF,
       diffView: {path: ctx.params[8]},
     };
+    const queryMap = new URLSearchParams(ctx.querystring);
+    if (queryMap.has('forceReload')) state.forceReload = true;
     const address = this.parseLineAddress(ctx.hash);
     if (address) {
       state.diffView!.leftSide = address.leftSide;
@@ -1493,6 +1497,8 @@
       childView: ChangeChildView.EDIT,
       editView: {path: ctx.params[3], lineNum: Number(ctx.hash)},
     };
+    const queryMap = new URLSearchParams(ctx.querystring);
+    if (queryMap.has('forceReload')) state.forceReload = true;
     this.normalizePatchRangeParams(state);
     // Note that router model view must be updated before view models.
     this.setState(state);
@@ -1516,14 +1522,7 @@
     };
     const tab = queryMap.get('tab');
     if (tab) state.tab = tab;
-    if (queryMap.has('forceReload')) {
-      state.forceReload = true;
-      history.replaceState(
-        null,
-        '',
-        location.href.replace(/[?&]forceReload=true/, '')
-      );
-    }
+    if (queryMap.has('forceReload')) state.forceReload = true;
     this.normalizePatchRangeParams(state);
     // Note that router model view must be updated before view models.
     this.setState(state);
diff --git a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts
index d98cce1..8bcbb2b 100644
--- a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts
+++ b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts
@@ -38,6 +38,7 @@
 import {anyLineTooLong} from '../../../embed/diff/gr-diff/gr-diff-utils';
 import {fireReload} from '../../../utils/event-util';
 import {when} from 'lit/directives/when.js';
+import {Timing} from '../../../constants/reporting';
 
 interface FilePreview {
   filepath: string;
@@ -103,6 +104,8 @@
 
   private readonly getNavigation = resolve(this, navigationToken);
 
+  private readonly reporting = getAppContext().reportingService;
+
   private readonly syntaxLayer = new GrSyntaxLayerWorker(
     resolve(this, highlightServiceToken),
     () => getAppContext().reportingService
@@ -276,7 +279,9 @@
   private async showSelectedFixSuggestion(fixSuggestion: FixSuggestionInfo) {
     this.currentFix = fixSuggestion;
     this.loading = true;
+    this.reporting.time(Timing.PREVIEW_FIX_LOAD);
     await this.fetchFixPreview(fixSuggestion);
+    this.reporting.timeEnd(Timing.PREVIEW_FIX_LOAD);
     this.loading = false;
   }
 
@@ -386,6 +391,7 @@
       throw new Error('Not all required properties are set.');
     }
     this.isApplyFixLoading = true;
+    this.reporting.time(Timing.APPLY_FIX_LOAD);
     let res;
     if (this.fixSuggestions?.[0].fix_id === PROVIDED_FIX_ID) {
       res = await this.restApiService.applyFixSuggestion(
@@ -411,6 +417,7 @@
       this.close(true);
     }
     this.isApplyFixLoading = false;
+    this.reporting.timeEnd(Timing.APPLY_FIX_LOAD);
   }
 }
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts
index 4687fc1..bdb634b 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts
@@ -59,7 +59,7 @@
 import {CommentSide, DiffViewMode, Side} from '../../../constants/constants';
 import {GrApplyFixDialog} from '../gr-apply-fix-dialog/gr-apply-fix-dialog';
 import {OpenFixPreviewEvent, ValueChangedEvent} from '../../../types/events';
-import {fireAlert, fire, fireTitleChange} from '../../../utils/event-util';
+import {fireAlert, fire} from '../../../utils/event-util';
 import {assertIsDefined, queryAndAssert} from '../../../utils/common-util';
 import {toggleClass, whenVisible} from '../../../utils/dom-util';
 import {CursorMoveResult} from '../../../api/core';
@@ -115,12 +115,6 @@
 @customElement('gr-diff-view')
 export class GrDiffView extends LitElement {
   /**
-   * Fired when the title of the page should change.
-   *
-   * @event title-change
-   */
-
-  /**
    * Fired when user tries to navigate away while comments are pending save.
    *
    * @event show-alert
@@ -187,21 +181,7 @@
   @state()
   files: Files = {sortedPaths: [], changeFilesByPath: {}};
 
-  // Private but used in tests
-  // Use path getter/setter.
-  _path?: string;
-
-  get path() {
-    return this._path;
-  }
-
-  set path(path: string | undefined) {
-    if (this._path === path) return;
-    const oldPath = this._path;
-    this._path = path;
-    this.pathChanged();
-    this.requestUpdate('path', oldPath);
-  }
+  @state() path?: string;
 
   /** Allows us to react when the user switches to the DIFF view. */
   // Private but used in tests.
@@ -1404,12 +1384,6 @@
     };
   }
 
-  private pathChanged() {
-    if (this.path) {
-      fireTitleChange(this, computeTruncatedPath(this.path));
-    }
-  }
-
   // Private but used in tests
   formatFilesForDropdown(): DropdownItem[] {
     if (!this.files) return [];
diff --git a/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select.ts b/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select.ts
index e1dfd1f..76d67af 100644
--- a/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select.ts
+++ b/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select.ts
@@ -14,7 +14,6 @@
   getParentIndex,
   getRevisionByPatchNum,
   isMergeParent,
-  sortRevisions,
   PatchSet,
   convertToPatchSetNum,
 } from '../../../utils/patch-set-util';
@@ -48,7 +47,6 @@
 import {changeModelToken} from '../../../models/change/change-model';
 import {changeViewModelToken} from '../../../models/views/change';
 import {fireNoBubbleNoCompose} from '../../../utils/event-util';
-import {KnownExperimentId} from '../../../services/flags/flags';
 
 // Maximum length for patch set descriptions.
 const PATCH_DESC_MAX_LENGTH = 500;
@@ -127,8 +125,6 @@
 
   private readonly getViewModel = resolve(this, changeViewModelToken);
 
-  private readonly flagsService = getAppContext().flagsService;
-
   constructor() {
     super();
     subscribe(
@@ -159,7 +155,7 @@
     subscribe(
       this,
       () => this.getChangeModel().revisions$,
-      x => (this.sortedRevisions = sortRevisions(Object.values(x || {})))
+      x => (this.sortedRevisions = x)
     );
     subscribe(
       this,
@@ -327,16 +323,7 @@
   }
 
   private computeText(patchNum: PatchSetNum, prefix: string, sha: string) {
-    if (
-      this.flagsService.isEnabled(KnownExperimentId.COMMENTS_CHIPS_IN_FILE_LIST)
-    ) {
-      return `${prefix}${patchNum} | ${sha}`;
-    }
-    return (
-      `${prefix}${patchNum}` +
-      `${this.computePatchSetCommentsString(patchNum)}` +
-      ` | ${sha}`
-    );
+    return `${prefix}${patchNum} | ${sha}`;
   }
 
   private createDropdownEntry(
@@ -350,17 +337,13 @@
       mobileText: this.computeMobileText(patchNum),
       bottomText: `${this.computePatchSetDescription(patchNum)}`,
       value: patchNum,
-    };
-    if (
-      this.flagsService.isEnabled(KnownExperimentId.COMMENTS_CHIPS_IN_FILE_LIST)
-    ) {
-      entry.commentThreads = this.changeComments?.computeCommentThreads(
+      commentThreads: this.changeComments?.computeCommentThreads(
         {
           patchNum,
         },
         true
-      );
-    }
+      ),
+    };
     const date = this.computePatchSetDate(patchNum);
     if (date) {
       entry.date = date;
diff --git a/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select_test.ts b/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select_test.ts
index 6051131..b4ab043 100644
--- a/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select_test.ts
+++ b/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select_test.ts
@@ -147,6 +147,7 @@
         mobileText: EDIT,
         bottomText: '',
         value: EDIT,
+        commentThreads: [],
       },
       {
         disabled: true,
@@ -156,6 +157,7 @@
         bottomText: '',
         value: 3,
         date: '2020-02-01 01:02:03.000000000' as Timestamp,
+        commentThreads: [],
       } as DropdownItem,
       {
         disabled: true,
@@ -165,6 +167,7 @@
         bottomText: '',
         value: 2,
         date: '2020-02-01 01:02:03.000000000' as Timestamp,
+        commentThreads: [],
       } as DropdownItem,
       {
         disabled: true,
@@ -174,6 +177,7 @@
         bottomText: '',
         value: 1,
         date: '2020-02-01 01:02:03.000000000' as Timestamp,
+        commentThreads: [],
       } as DropdownItem,
       {
         text: 'Base',
@@ -287,6 +291,7 @@
         mobileText: EDIT,
         bottomText: '',
         value: EDIT,
+        commentThreads: [],
       },
       {
         disabled: false,
@@ -296,6 +301,7 @@
         bottomText: '',
         value: 3,
         date: '2020-02-01 01:02:03.000000000' as Timestamp,
+        commentThreads: [],
       } as DropdownItem,
       {
         disabled: false,
@@ -305,6 +311,7 @@
         bottomText: 'description',
         value: 2,
         date: '2020-02-01 01:02:03.000000000' as Timestamp,
+        commentThreads: [],
       } as DropdownItem,
       {
         disabled: true,
@@ -314,6 +321,7 @@
         bottomText: '',
         value: 1,
         date: '2020-02-01 01:02:03.000000000' as Timestamp,
+        commentThreads: [],
       } as DropdownItem,
     ];
 
diff --git a/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.ts b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.ts
index 6dbdca6..a8bc84c 100644
--- a/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.ts
+++ b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.ts
@@ -45,7 +45,7 @@
 
   override connectedCallback() {
     super.connectedCallback();
-    fireTitleChange(this, 'Documentation Search');
+    fireTitleChange('Documentation Search');
   }
 
   static override get styles() {
diff --git a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts
index 0fc754c..5786112 100644
--- a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts
+++ b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts
@@ -18,7 +18,7 @@
   GrAutocomplete,
 } from '../../shared/gr-autocomplete/gr-autocomplete';
 import {getAppContext} from '../../../services/app-context';
-import {fireAlert, fireReload} from '../../../utils/event-util';
+import {fireAlert} from '../../../utils/event-util';
 import {
   assertIsDefined,
   query as queryUtil,
@@ -34,6 +34,7 @@
 import {modalStyles} from '../../../styles/gr-modal-styles';
 import {whenVisible} from '../../../utils/dom-util';
 import {throwingErrorCallback} from '../../shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper';
+import {changeModelToken} from '../../../models/change/change-model';
 
 @customElement('gr-edit-controls')
 export class GrEditControls extends LitElement {
@@ -77,6 +78,8 @@
 
   private readonly restApiService = getAppContext().restApiService;
 
+  private readonly getChangeModel = resolve(this, changeModelToken);
+
   private readonly getNavigation = resolve(this, navigationToken);
 
   static override get styles() {
@@ -451,7 +454,7 @@
           return;
         }
         this.closeDialog(this.openDialog);
-        fireReload(this, true);
+        this.getChangeModel().navigateToChangeResetReload();
       });
   }
 
@@ -471,7 +474,7 @@
           return;
         }
         this.closeDialog(dialog);
-        fireReload(this, true);
+        this.getChangeModel().navigateToChangeResetReload();
       });
   };
 
@@ -489,7 +492,7 @@
           return;
         }
         this.closeDialog(dialog);
-        fireReload(this, true);
+        this.getChangeModel().navigateToChangeResetReload();
       });
   };
 
@@ -507,7 +510,7 @@
           return;
         }
         this.closeDialog(dialog);
-        fireReload(this, true);
+        this.getChangeModel().navigateToChangeResetReload();
       });
   };
 
diff --git a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.ts b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.ts
index 0729f21..0e6778a 100644
--- a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.ts
+++ b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.ts
@@ -26,8 +26,12 @@
 import {fixture, html, assert} from '@open-wc/testing';
 import {GrButton} from '../../shared/gr-button/gr-button';
 import '../../shared/gr-dialog/gr-dialog';
-import {waitForEventOnce} from '../../../utils/event-util';
 import {testResolver} from '../../../test/common-test-setup';
+import {
+  ChangeModel,
+  changeModelToken,
+} from '../../../models/change/change-model';
+import {SinonStubbedMember} from 'sinon';
 
 suite('gr-edit-controls tests', () => {
   let element: GrEditControls;
@@ -36,6 +40,9 @@
   let closeDialogSpy: sinon.SinonSpy;
   let hideDialogStub: sinon.SinonStub;
   let queryStub: sinon.SinonStub;
+  let navigateResetStub: SinonStubbedMember<
+    ChangeModel['navigateToChangeResetReload']
+  >;
 
   setup(async () => {
     element = await fixture<GrEditControls>(html`
@@ -47,6 +54,10 @@
     closeDialogSpy = sinon.spy(element, 'closeDialog');
     hideDialogStub = sinon.stub(element, 'hideAllDialogs');
     queryStub = stubRestApi('queryChangeFiles').returns(Promise.resolve([]));
+    navigateResetStub = sinon.stub(
+      testResolver(changeModelToken),
+      'navigateToChangeResetReload'
+    );
     await element.updateComplete;
   });
 
@@ -298,7 +309,7 @@
       assert.isTrue(deleteStub.called);
       await deleteStub.lastCall.returnValue;
       assert.equal(element.path, '');
-      assert.equal(eventStub.firstCall.args[0].type, 'reload');
+      assert.equal(navigateResetStub.callCount, 1);
       assert.isTrue(closeDialogSpy.called);
     });
 
@@ -397,7 +408,7 @@
 
       await renameStub.lastCall.returnValue;
       assert.equal(element.path, '');
-      assert.equal(eventStub.firstCall.args[0].type, 'reload');
+      assert.equal(navigateResetStub.callCount, 1);
       assert.isTrue(closeDialogSpy.called);
     });
 
@@ -485,7 +496,7 @@
       assert.equal(restoreStub.lastCall.args[1], 'src/test.cpp');
       return restoreStub.lastCall.returnValue.then(() => {
         assert.equal(element.path, '');
-        assert.equal(eventStub.firstCall.args[0].type, 'reload');
+        assert.equal(navigateResetStub.callCount, 1);
         assert.isTrue(closeDialogSpy.called);
       });
     });
@@ -553,7 +564,8 @@
       assert.equal(fileStub.lastCall.args[0], 1);
       assert.equal(fileStub.lastCall.args[1], 'test.php');
       assert.equal(fileStub.lastCall.args[2], 'base64');
-      await waitForEventOnce(element, 'reload');
+      await waitUntil(() => navigateResetStub.called);
+      assert.equal(navigateResetStub.callCount, 1);
     });
   });
 
diff --git a/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.ts b/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.ts
index 878c5e9..f37a3d9 100644
--- a/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.ts
+++ b/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.ts
@@ -9,7 +9,6 @@
 import '../../shared/gr-editable-label/gr-editable-label';
 import '../gr-default-editor/gr-default-editor';
 import {navigationToken} from '../../core/gr-navigation/gr-navigation';
-import {computeTruncatedPath} from '../../../utils/path-list-util';
 import {
   EditPreferencesInfo,
   Base64FileContent,
@@ -17,11 +16,7 @@
 } from '../../../types/common';
 import {ParsedChangeInfo} from '../../../types/types';
 import {HttpMethod, NotifyType} from '../../../constants/constants';
-import {
-  fireAlert,
-  fireTitleChange,
-  fireReload,
-} from '../../../utils/event-util';
+import {fireAlert} from '../../../utils/event-util';
 import {getAppContext} from '../../../services/app-context';
 import {ErrorCallback} from '../../../api/rest';
 import {assertIsDefined} from '../../../utils/common-util';
@@ -57,12 +52,6 @@
 @customElement('gr-editor-view')
 export class GrEditorView extends LitElement {
   /**
-   * Fired when the title of the page should change.
-   *
-   * @event title-change
-   */
-
-  /**
    * Fired to notify the user of
    *
    * @event show-alert
@@ -333,17 +322,6 @@
   viewStateChanged() {
     if (this.viewState?.childView !== ChangeChildView.EDIT) return;
 
-    // NOTE: This may be called before attachment (e.g. while parentElement is
-    // null). Fire title-change in an async so that, if attachment to the DOM
-    // has been queued, the event can bubble up to the handler in gr-app.
-    setTimeout(() => {
-      if (!this.viewState) return;
-      const title = `Editing ${computeTruncatedPath(
-        this.viewState.editView?.path
-      )}`;
-      fireTitleChange(this, title);
-    });
-
     const promises = [];
     promises.push(this.getFileData());
     return Promise.all(promises);
@@ -512,13 +490,7 @@
         )
         .then(() => {
           assertIsDefined(this.change, 'change');
-          // TODO: `forceReload: true` does not seem to work as expected: The patchset is not
-          // updated. Thus we are also calling `fireReload()` here. That can probably be
-          // cleaned up once the change-view was migrated to fully relying on the change model.
-          fireReload(this);
-          this.getNavigation().setUrl(
-            createChangeUrl({change: this.change, forceReload: true})
-          );
+          this.getChangeModel().navigateToChangeResetReload();
         });
     });
   };
diff --git a/polygerrit-ui/app/elements/gr-app-element.ts b/polygerrit-ui/app/elements/gr-app-element.ts
index 98f1f25..75bfca2 100644
--- a/polygerrit-ui/app/elements/gr-app-element.ts
+++ b/polygerrit-ui/app/elements/gr-app-element.ts
@@ -118,7 +118,7 @@
 
   @state() private version?: string;
 
-  @state() private view?: GerritView;
+  @state() view?: GerritView;
 
   // TODO: Introduce a wrapper element for CHANGE, DIFF, EDIT view.
   @state() private childView?: ChangeChildView;
@@ -177,7 +177,7 @@
     document.addEventListener('page-error', e => {
       this.handlePageError(e);
     });
-    this.addEventListener('title-change', e => {
+    document.addEventListener('title-change', e => {
       this.handleTitleChange(e);
     });
     this.addEventListener('dialog-change', e => {
@@ -549,15 +549,21 @@
 
   private renderPluginScreen() {
     if (this.view !== GerritView.PLUGIN_SCREEN) return nothing;
+    if (!this.params) return nothing;
     const pluginViewState = this.params as PluginViewState;
-    return html`
-      <gr-endpoint-decorator .name=${this.computePluginScreenName()}>
-        <gr-endpoint-param
-          name="token"
-          .value=${pluginViewState.screen}
-        ></gr-endpoint-param>
-      </gr-endpoint-decorator>
-    `;
+    const pluginScreenName = this.computePluginScreenName();
+
+    return keyed(
+      pluginScreenName,
+      html`
+        <gr-endpoint-decorator .name=${pluginScreenName}>
+          <gr-endpoint-param
+            name="token"
+            .value=${pluginViewState.screen}
+          ></gr-endpoint-param>
+        </gr-endpoint-decorator>
+      `
+    );
   }
 
   private renderCLAView() {
diff --git a/polygerrit-ui/app/elements/gr-app-element_test.ts b/polygerrit-ui/app/elements/gr-app-element_test.ts
new file mode 100644
index 0000000..ec415ff
--- /dev/null
+++ b/polygerrit-ui/app/elements/gr-app-element_test.ts
@@ -0,0 +1,100 @@
+/**
+ * @license
+ * Copyright 2023 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+import '../test/common-test-setup';
+import './gr-app';
+import {fixture, html, assert} from '@open-wc/testing';
+import {GrAppElement} from './gr-app-element';
+import {queryAndAssert} from '../utils/common-util';
+import {GerritView} from '../services/router/router-model';
+import {PluginViewState} from '../models/views/plugin';
+import {GrEndpointDecorator} from './plugins/gr-endpoint-decorator/gr-endpoint-decorator';
+
+suite('gr-app-element tests', () => {
+  let element: GrAppElement;
+
+  setup(async () => {
+    element = await fixture<GrAppElement>(
+      html`<gr-app-element></gr-app-element>`
+    );
+    await element.updateComplete;
+  });
+
+  test('renders', () => {
+    assert.shadowDom.equal(
+      element,
+      /* HTML */ `
+        <gr-css-mixins> </gr-css-mixins>
+        <gr-endpoint-decorator name="banner"> </gr-endpoint-decorator>
+        <gr-main-header loggedin id="mainHeader" role="banner">
+        </gr-main-header>
+        <main>
+          <div class="errorView" id="errorView">
+            <div class="errorEmoji"></div>
+            <div class="errorText"></div>
+            <div class="errorMoreInfo"></div>
+          </div>
+        </main>
+        <footer>
+          <div>
+            Powered by
+            <a
+              href="https://www.gerritcodereview.com/"
+              rel="noopener"
+              target="_blank"
+            >
+              Gerrit Code Review
+            </a>
+            ()
+            <gr-endpoint-decorator name="footer-left"> </gr-endpoint-decorator>
+          </div>
+          <div>
+            Press “?” for keyboard shortcuts
+            <gr-endpoint-decorator name="footer-right"> </gr-endpoint-decorator>
+          </div>
+        </footer>
+        <gr-notifications-prompt> </gr-notifications-prompt>
+        <gr-endpoint-decorator name="plugin-overlay"> </gr-endpoint-decorator>
+        <gr-error-manager id="errorManager"> </gr-error-manager>
+        <gr-plugin-host id="plugins"> </gr-plugin-host>
+      `
+    );
+  });
+
+  test('renders plugin screen, changes endpoint instance', async () => {
+    element.view = GerritView.PLUGIN_SCREEN;
+    element.params = {
+      view: GerritView.PLUGIN_SCREEN,
+      screen: 'test-screen-1',
+      plugin: 'test-plugin',
+    } as PluginViewState;
+    await element.updateComplete;
+
+    const main1 = queryAndAssert(element, 'main');
+    const endpoint1 = queryAndAssert<GrEndpointDecorator>(
+      main1,
+      'gr-endpoint-decorator'
+    );
+    assert.equal(endpoint1.name, 'test-plugin-screen-test-screen-1');
+
+    element.params = {
+      view: GerritView.PLUGIN_SCREEN,
+      screen: 'test-screen-2',
+      plugin: 'test-plugin',
+    } as PluginViewState;
+    await element.updateComplete;
+
+    const main2 = queryAndAssert(element, 'main');
+    const endpoint2 = queryAndAssert<GrEndpointDecorator>(
+      main2,
+      'gr-endpoint-decorator'
+    );
+    assert.equal(endpoint2.name, 'test-plugin-screen-test-screen-2');
+
+    // Plugin screen endpoints have a variable name. Lit must not re-use the
+    // same element instance. (Issue 16884)
+    assert.isFalse(endpoint1 === endpoint2);
+  });
+});
diff --git a/polygerrit-ui/app/elements/gr-app-global-var-init.ts b/polygerrit-ui/app/elements/gr-app-global-var-init.ts
index d6a14ed..6589ee8 100644
--- a/polygerrit-ui/app/elements/gr-app-global-var-init.ts
+++ b/polygerrit-ui/app/elements/gr-app-global-var-init.ts
@@ -21,6 +21,7 @@
   initErrorReporter,
   initWebVitals,
   initClickReporter,
+  initInteractionReporter,
 } from '../services/gr-reporting/gr-reporting_impl';
 import {Finalizable} from '../services/registry';
 
@@ -36,6 +37,7 @@
     initWebVitals(reportingService);
     initErrorReporter(reportingService);
     initClickReporter(reportingService);
+    initInteractionReporter(reportingService);
   }
   window.GrAnnotation = GrAnnotation;
   window.GrPluginActionContext = GrPluginActionContext;
diff --git a/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view.ts b/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view.ts
index 2f835f7..a2b61e0 100644
--- a/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view.ts
+++ b/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view.ts
@@ -53,7 +53,7 @@
     super.connectedCallback();
     this.loadData();
 
-    fireTitleChange(this, 'New Contributor Agreement');
+    fireTitleChange('New Contributor Agreement');
   }
 
   static override get styles() {
diff --git a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.ts b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.ts
index 2695ea7..24a18c9 100644
--- a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.ts
+++ b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.ts
@@ -81,12 +81,6 @@
 @customElement('gr-settings-view')
 export class GrSettingsView extends LitElement {
   /**
-   * Fired when the title of the page should change.
-   *
-   * @event title-change
-   */
-
-  /**
    * Fired with email confirmation text, or when the page reloads.
    *
    * @event show-alert
@@ -261,7 +255,7 @@
     // Polymer 2: anchor tag won't work on shadow DOM
     // we need to manually calling scrollIntoView when hash changed
     document.addEventListener('location-change', this.handleLocationChange);
-    fireTitleChange(this, 'Settings');
+    fireTitleChange('Settings');
   }
 
   override firstUpdated() {
diff --git a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_test.ts b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_test.ts
index a0d7fab..0bcb09c 100644
--- a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_test.ts
+++ b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_test.ts
@@ -544,10 +544,8 @@
 
   test('calls the title-change event', async () => {
     const titleChangedStub = sinon.stub();
-
-    // Create a new view.
     const newElement = document.createElement('gr-settings-view');
-    newElement.addEventListener('title-change', titleChangedStub);
+    document.addEventListener('title-change', titleChangedStub);
 
     const div = await fixture(html`<div></div>`);
     div.appendChild(newElement);
diff --git a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
index d790e8c..5947cc3 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
@@ -1193,7 +1193,9 @@
     // a discard or a save action.
     const messageToSave = this.messageText.trimEnd();
     if (messageToSave === '') {
-      await this.getCommentsModel().discardDraft(id(this.comment));
+      if (!this.permanentEditingMode || this.somethingToSave()) {
+        await this.getCommentsModel().discardDraft(id(this.comment));
+      }
     } else {
       // No need to make a backend call when nothing has changed.
       while (this.somethingToSave()) {
diff --git a/polygerrit-ui/app/elements/shared/gr-copy-clipboard/gr-copy-clipboard.ts b/polygerrit-ui/app/elements/shared/gr-copy-clipboard/gr-copy-clipboard.ts
index 5b26ede..292da58 100644
--- a/polygerrit-ui/app/elements/shared/gr-copy-clipboard/gr-copy-clipboard.ts
+++ b/polygerrit-ui/app/elements/shared/gr-copy-clipboard/gr-copy-clipboard.ts
@@ -17,6 +17,8 @@
 import {customElement, property, query} from 'lit/decorators.js';
 import {GrButton} from '../gr-button/gr-button';
 import {GrIcon} from '../gr-icon/gr-icon';
+import {getAppContext} from '../../../services/app-context';
+import {Timing} from '../../../constants/reporting';
 
 const COPY_TIMEOUT_MS = 1000;
 
@@ -46,6 +48,8 @@
   @query('#icon')
   iconEl!: GrIcon;
 
+  private readonly reporting = getAppContext().reportingService;
+
   static override get styles() {
     return [
       css`
@@ -141,7 +145,12 @@
     this.text = queryAndAssert<HTMLInputElement>(this, '#input').value;
     assertIsDefined(this.text, 'text');
     this.iconEl.icon = 'check';
-    copyToClipbard(this.text, this.copyTargetName ?? 'Link');
+    this.reporting.time(Timing.COPY_TO_CLIPBOARD);
+    copyToClipbard(this.text, this.copyTargetName ?? 'Link').finally(() => {
+      this.reporting.timeEnd(Timing.COPY_TO_CLIPBOARD, {
+        copyTargetName: this.copyTargetName,
+      });
+    });
     setTimeout(() => (this.iconEl.icon = 'content_copy'), COPY_TIMEOUT_MS);
   }
 }
diff --git a/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account-contents.ts b/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account-contents.ts
index 14c2c15..394015e 100644
--- a/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account-contents.ts
+++ b/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account-contents.ts
@@ -43,7 +43,7 @@
 import {configModelToken} from '../../../models/config/config-model';
 import {createSearchUrl} from '../../../models/views/search';
 import {createDashboardUrl} from '../../../models/views/dashboard';
-import {fire} from '../../../utils/event-util';
+import {fire, fireReload} from '../../../utils/event-util';
 import {userModelToken} from '../../../models/user/user-model';
 
 @customElement('gr-hovercard-account-contents')
@@ -445,7 +445,7 @@
               this.getReviewerState(this.change!)
           );
         }
-        fire(this, 'reload', {clearPatchset: true});
+        fireReload(this);
       });
   }
 
@@ -464,7 +464,7 @@
         if (!response || !response.ok) {
           throw new Error('something went wrong when removing user');
         }
-        fire(this, 'reload', {clearPatchset: true});
+        fireReload(this);
         return response;
       });
   }
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-change-actions-js-api_test.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-change-actions-js-api_test.ts
index ae93977..4977ec5 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-change-actions-js-api_test.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-change-actions-js-api_test.ts
@@ -56,7 +56,6 @@
         <gr-change-actions></gr-change-actions>
       `);
       element.change = {} as ChangeViewChangeInfo;
-      element._hasKnownChainState = false;
       window.Gerrit.install(
         p => {
           plugin = p;
diff --git a/polygerrit-ui/app/elements/shared/gr-weblink/gr-weblink.ts b/polygerrit-ui/app/elements/shared/gr-weblink/gr-weblink.ts
index 63a1dc4..fb6372c 100644
--- a/polygerrit-ui/app/elements/shared/gr-weblink/gr-weblink.ts
+++ b/polygerrit-ui/app/elements/shared/gr-weblink/gr-weblink.ts
@@ -30,6 +30,7 @@
           display: inline-block;
           vertical-align: top;
           line-height: var(--line-height-normal);
+          margin-right: var(--spacing-s);
         }
         a {
           color: var(--link-color);
diff --git a/polygerrit-ui/app/embed/diff/gr-diff/gr-diff-group.ts b/polygerrit-ui/app/embed/diff/gr-diff/gr-diff-group.ts
index 5a1ded2..3b2fa81 100644
--- a/polygerrit-ui/app/embed/diff/gr-diff/gr-diff-group.ts
+++ b/polygerrit-ui/app/embed/diff/gr-diff/gr-diff-group.ts
@@ -441,11 +441,17 @@
   }
 
   startLine(side: Side): LineNumber {
-    if (this.type === GrDiffGroupType.CONTEXT_CONTROL) {
+    // For both CONTEXT_CONTROL groups and SKIP groups the `lines` array will
+    // be empty. So we have to use `lineRange` instead of looking at the first
+    // line.
+    if (this.type === GrDiffGroupType.CONTEXT_CONTROL || this.skip) {
       return side === Side.LEFT
         ? this.lineRange.left.start_line
         : this.lineRange.right.start_line;
     }
+    // For "normal" groups we could also use the `lineRange`, but for FILE or
+    // LOST lines we want to return FILE or LOST. The `lineRange` contains
+    // numbers only.
     return this.lines[0].lineNumber(side);
   }
 
diff --git a/polygerrit-ui/app/embed/diff/gr-diff/gr-diff-group_test.ts b/polygerrit-ui/app/embed/diff/gr-diff/gr-diff-group_test.ts
index 4a19282..06bf92920 100644
--- a/polygerrit-ui/app/embed/diff/gr-diff/gr-diff-group_test.ts
+++ b/polygerrit-ui/app/embed/diff/gr-diff/gr-diff-group_test.ts
@@ -275,6 +275,17 @@
       assert.equal(group.startLine(Side.RIGHT), 4);
     });
 
+    test('SKIP', () => {
+      const group = new GrDiffGroup({
+        type: GrDiffGroupType.BOTH,
+        skip: 10,
+        offsetLeft: 3,
+        offsetRight: 6,
+      });
+      assert.equal(group.startLine(Side.LEFT), 3);
+      assert.equal(group.startLine(Side.RIGHT), 6);
+    });
+
     test('FILE', () => {
       const lines: GrDiffLine[] = [];
       lines.push(new GrDiffLine(GrDiffLineType.BOTH, 'FILE', 'FILE'));
diff --git a/polygerrit-ui/app/models/change/change-model.ts b/polygerrit-ui/app/models/change/change-model.ts
index b6b9de7..6d111aa 100644
--- a/polygerrit-ui/app/models/change/change-model.ts
+++ b/polygerrit-ui/app/models/change/change-model.ts
@@ -5,6 +5,7 @@
  */
 import {
   BasePatchSetNum,
+  ChangeInfo,
   EditInfo,
   EDIT,
   PARENT,
@@ -13,25 +14,20 @@
   PreferencesInfo,
   RevisionPatchSetNum,
   PatchSetNumber,
+  CommitId,
 } from '../../types/common';
-import {DefaultBase} from '../../constants/constants';
-import {combineLatest, from, fromEvent, Observable, forkJoin, of} from 'rxjs';
-import {
-  map,
-  filter,
-  withLatestFrom,
-  startWith,
-  switchMap,
-} from 'rxjs/operators';
+import {ChangeStatus, DefaultBase} from '../../constants/constants';
+import {combineLatest, from, Observable, forkJoin, of} from 'rxjs';
+import {map, filter, withLatestFrom, switchMap} from 'rxjs/operators';
 import {
   computeAllPatchSets,
   computeLatestPatchNum,
   computeLatestPatchNumWithEdit,
+  findEdit,
+  sortRevisions,
 } from '../../utils/patch-set-util';
-import {ParsedChangeInfo} from '../../types/types';
-import {fireAlert} from '../../utils/event-util';
-
-import {ChangeInfo} from '../../types/common';
+import {isDefined, ParsedChangeInfo} from '../../types/types';
+import {fireAlert, fireTitleChange} from '../../utils/event-util';
 import {RestApiService} from '../../services/gr-rest-api/gr-rest-api';
 import {select} from '../../utils/observable-util';
 import {assertIsDefined} from '../../utils/common-util';
@@ -40,12 +36,18 @@
 import {define} from '../dependency';
 import {isOwner} from '../../utils/change-util';
 import {
+  ChangeChildView,
   ChangeViewModel,
   createChangeUrl,
   createDiffUrl,
   createEditUrl,
 } from '../views/change';
 import {NavigationService} from '../../elements/core/gr-navigation/gr-navigation';
+import {getRevertCreatedChangeIds} from '../../utils/message-util';
+import {computeTruncatedPath} from '../../utils/path-list-util';
+import {PluginLoader} from '../../elements/shared/gr-js-api-interface/gr-plugin-loader';
+import {ReportingService} from '../../services/gr-reporting/gr-reporting';
+import {Timing} from '../../constants/reporting';
 
 export enum LoadingStatus {
   NOT_LOADED = 'NOT_LOADED',
@@ -69,6 +71,39 @@
    * Undefined means it's still loading and empty set means no files reviewed.
    */
   reviewedFiles?: string[];
+  /**
+   * Either filled from `change.mergeable`, or from a dedicated REST API call.
+   * Is initially `undefined`, such that you can identify whether this
+   * information has already been loaded once for this change or not. Will never
+   * go back to `undefined` after being set for a change.
+   */
+  mergeable?: boolean;
+}
+
+/**
+ * `change.revisions` is a dictionary mapping the revision sha to RevisionInfo,
+ * but the info object itself does not contain the sha, which is a problem when
+ * working with just the info objects.
+ *
+ * So we are iterating over the map here and are assigning the sha map key to
+ * the property `revision.commit.commit`.
+ *
+ * As usual we are treating data objects as immutable, so we are doind a lot of
+ * cloning here.
+ */
+export function updateRevisionsWithCommitShas(changeInput?: ParsedChangeInfo) {
+  if (!changeInput?.revisions) return changeInput;
+  const changeOutput = {...changeInput, revisions: {...changeInput.revisions}};
+  for (const sha of Object.keys(changeOutput.revisions)) {
+    const revision = changeOutput.revisions[sha];
+    if (revision?.commit && !revision.commit.commit) {
+      changeOutput.revisions[sha] = {
+        ...revision,
+        commit: {...revision.commit, commit: sha as CommitId},
+      };
+    }
+  }
+  return changeOutput;
 }
 
 /**
@@ -168,20 +203,36 @@
     changeState => changeState.loadingStatus
   );
 
+  public readonly loading$ = select(
+    this.changeLoadingStatus$,
+    status =>
+      status === LoadingStatus.LOADING || status === LoadingStatus.RELOADING
+  );
+
   public readonly reviewedFiles$ = select(
     this.state$,
     changeState => changeState?.reviewedFiles
   );
 
+  public readonly mergeable$ = select(
+    this.state$,
+    changeState => changeState.mergeable
+  );
+
   public readonly changeNum$ = select(this.change$, change => change?._number);
 
+  public readonly changeId$ = select(this.change$, change => change?.change_id);
+
   public readonly repo$ = select(this.change$, change => change?.project);
 
+  public readonly topic$ = select(this.change$, change => change?.topic);
+
+  public readonly status$ = select(this.change$, change => change?.status);
+
   public readonly labels$ = select(this.change$, change => change?.labels);
 
-  public readonly revisions$ = select(
-    this.change$,
-    change => change?.revisions
+  public readonly revisions$ = select(this.change$, change =>
+    sortRevisions(Object.values(change?.revisions || {}))
   );
 
   public readonly patchsets$ = select(this.change$, change =>
@@ -264,49 +315,56 @@
         computeBase(viewModelBasePatchNum, patchNum, change, preferences)
     );
 
+  private selectRevision(
+    revisionNum$: Observable<RevisionPatchSetNum | undefined>
+  ) {
+    return select(
+      combineLatest([this.revisions$, revisionNum$]),
+      ([revisions, patchNum]) => {
+        if (!revisions || !patchNum) return undefined;
+        return Object.values(revisions).find(
+          revision => revision._number === patchNum
+        );
+      }
+    );
+  }
+
+  public readonly revision$ = this.selectRevision(this.patchNum$);
+
+  public readonly latestRevision$ = this.selectRevision(this.latestPatchNum$);
+
   public readonly isOwner$: Observable<boolean> = select(
     combineLatest([this.change$, this.userModel.account$]),
     ([change, account]) => isOwner(change, account)
   );
 
-  // For usage in `combineLatest` we need `startWith` such that reload$ has an
-  // initial value.
-  readonly reload$: Observable<unknown> = fromEvent(document, 'reload').pipe(
-    startWith(undefined)
+  public readonly messages$ = select(this.change$, change => change?.messages);
+
+  public readonly revertingChangeIds$ = select(this.messages$, messages =>
+    getRevertCreatedChangeIds(messages ?? [])
   );
 
   constructor(
     private readonly navigation: NavigationService,
     private readonly viewModel: ChangeViewModel,
     private readonly restApiService: RestApiService,
-    private readonly userModel: UserModel
+    private readonly userModel: UserModel,
+    private readonly pluginLoader: PluginLoader,
+    private readonly reporting: ReportingService
   ) {
     super(initialState);
     this.subscriptions = [
-      combineLatest([this.viewModel.changeNum$, this.reload$])
-        .pipe(
-          map(([changeNum, _]) => changeNum),
-          switchMap(changeNum => {
-            if (changeNum !== undefined) this.updateStateLoading(changeNum);
-            const change = from(this.restApiService.getChangeDetail(changeNum));
-            const edit = from(this.restApiService.getChangeEdit(changeNum));
-            return forkJoin([change, edit]);
-          }),
-          withLatestFrom(this.viewModel.patchNum$),
-          map(([[change, edit], patchNum]) =>
-            updateChangeWithEdit(change, edit, patchNum)
-          )
-        )
-        .subscribe(change => {
-          // The change service is currently a singleton, so we have to be
-          // careful to avoid situations where the application state is
-          // partially set for the old change where the user is coming from,
-          // and partially for the new change where the user is navigating to.
-          // So setting the change explicitly to undefined when the user
-          // moves away from diff and change pages (changeNum === undefined)
-          // helps with that.
-          this.updateStateChange(change ?? undefined);
-        }),
+      this.loadChange(),
+      this.loadMergeable(),
+      this.loadReviewedFiles(),
+      this.setOverviewTitle(),
+      this.setDiffTitle(),
+      this.setEditTitle(),
+      this.reportChangeReload(),
+      this.reportSendReply(),
+      this.fireShowChange(),
+      this.refuseEditForOpenChange(),
+      this.refuseEditForClosedChange(),
       this.change$.subscribe(change => (this.change = change)),
       this.patchNum$.subscribe(patchNum => (this.patchNum = patchNum)),
       this.basePatchNum$.subscribe(
@@ -315,20 +373,215 @@
       this.latestPatchNum$.subscribe(
         latestPatchNum => (this.latestPatchNum = latestPatchNum)
       ),
-      combineLatest([this.patchNum$, this.changeNum$, this.userModel.loggedIn$])
-        .pipe(
-          switchMap(([patchNum, changeNum, loggedIn]) => {
-            if (!changeNum || !patchNum || !loggedIn) {
-              this.updateStateReviewedFiles([]);
-              return of(undefined);
-            }
-            return from(this.fetchReviewedFiles(patchNum, changeNum));
-          })
-        )
-        .subscribe(),
     ];
   }
 
+  private reportSendReply() {
+    return this.changeLoadingStatus$.subscribe(loadingStatus => {
+      // We are ending the timer on each change load, because ending a timer
+      // that was not started is a no-op. :-)
+      if (loadingStatus === LoadingStatus.LOADED) {
+        this.reporting.timeEnd(Timing.SEND_REPLY);
+      }
+    });
+  }
+
+  private reportChangeReload() {
+    return this.changeLoadingStatus$.subscribe(loadingStatus => {
+      if (
+        loadingStatus === LoadingStatus.LOADING ||
+        loadingStatus === LoadingStatus.RELOADING
+      ) {
+        this.reporting.time(Timing.CHANGE_RELOAD);
+      }
+      if (
+        loadingStatus === LoadingStatus.LOADED ||
+        loadingStatus === LoadingStatus.NOT_LOADED
+      ) {
+        this.reporting.timeEnd(Timing.CHANGE_RELOAD);
+      }
+    });
+  }
+
+  private fireShowChange() {
+    return combineLatest([
+      this.viewModel.childView$,
+      this.change$,
+      this.patchNum$,
+      this.mergeable$,
+    ])
+      .pipe(
+        filter(
+          ([childView, change, patchNum, mergeable]) =>
+            childView === ChangeChildView.OVERVIEW &&
+            !!change &&
+            !!patchNum &&
+            mergeable !== undefined
+        )
+      )
+      .subscribe(([_, change, patchNum, mergeable]) => {
+        this.pluginLoader.jsApiService.handleShowChange({
+          change,
+          patchNum,
+          // `?? null` is for the TypeScript compiler only. We have a
+          // `mergeable !== undefined` filter above, so this cannot happen.
+          // It would be nice to change `ShowChangeDetail` to accept `undefined`
+          // instaed of `null`, but that would be a Plugin API change ...
+          info: {mergeable: mergeable ?? null},
+        });
+      });
+  }
+
+  private refuseEditForOpenChange() {
+    return combineLatest([this.revisions$, this.patchNum$, this.status$])
+      .pipe(
+        filter(
+          ([revisions, patchNum, status]) =>
+            status === ChangeStatus.NEW &&
+            revisions.length > 0 &&
+            patchNum === EDIT
+        )
+      )
+      .subscribe(([revisions]) => {
+        const editRev = findEdit(revisions);
+        if (!editRev) {
+          const msg = 'Change edit not found. Please create a change edit.';
+          fireAlert(document, msg);
+          this.navigateToChangeResetReload();
+        }
+      });
+  }
+
+  private refuseEditForClosedChange() {
+    return combineLatest([
+      this.revisions$,
+      this.viewModel.edit$,
+      this.patchNum$,
+      this.status$,
+    ])
+      .pipe(
+        filter(
+          ([revisions, edit, patchNum, status]) =>
+            (status === ChangeStatus.ABANDONED ||
+              status === ChangeStatus.MERGED) &&
+            revisions.length > 0 &&
+            (patchNum === EDIT || edit)
+        )
+      )
+      .subscribe(([revisions]) => {
+        const editRev = findEdit(revisions);
+        if (!editRev) {
+          const msg =
+            'Change edits cannot be created if change is merged ' +
+            'or abandoned. Redirecting to non edit mode.';
+          fireAlert(document, msg);
+          this.navigateToChangeResetReload();
+        }
+      });
+  }
+
+  private setOverviewTitle() {
+    return combineLatest([this.viewModel.childView$, this.change$])
+      .pipe(
+        filter(([childView, _]) => childView === ChangeChildView.OVERVIEW),
+        map(([_, change]) => change),
+        filter(isDefined)
+      )
+      .subscribe(change => {
+        const title = `${change.subject} (${change._number})`;
+        fireTitleChange(title);
+      });
+  }
+
+  private setDiffTitle() {
+    return combineLatest([this.viewModel.childView$, this.viewModel.diffPath$])
+      .pipe(
+        filter(([childView, _]) => childView === ChangeChildView.DIFF),
+        map(([_, diffPath]) => diffPath),
+        filter(isDefined)
+      )
+      .subscribe(diffPath => {
+        const title = computeTruncatedPath(diffPath);
+        fireTitleChange(title);
+      });
+  }
+
+  private setEditTitle() {
+    return combineLatest([this.viewModel.childView$, this.viewModel.editPath$])
+      .pipe(
+        filter(([childView, _]) => childView === ChangeChildView.EDIT),
+        map(([_, editPath]) => editPath),
+        filter(isDefined)
+      )
+      .subscribe(editPath => {
+        const title = `Editing ${computeTruncatedPath(editPath)}`;
+        fireTitleChange(title);
+      });
+  }
+
+  private loadReviewedFiles() {
+    return combineLatest([
+      this.patchNum$,
+      this.changeNum$,
+      this.userModel.loggedIn$,
+    ])
+      .pipe(
+        switchMap(([patchNum, changeNum, loggedIn]) => {
+          if (!changeNum || !patchNum || !loggedIn) {
+            this.updateStateReviewedFiles([]);
+            return of(undefined);
+          }
+          return from(this.fetchReviewedFiles(patchNum, changeNum));
+        })
+      )
+      .subscribe();
+  }
+
+  private loadMergeable() {
+    return this.change$
+      .pipe(
+        switchMap(change => {
+          if (change?._number === undefined) return of(undefined);
+          if (change.mergeable !== undefined) return of(change.mergeable);
+          if (change.status === ChangeStatus.MERGED) return of(false);
+          if (change.status === ChangeStatus.ABANDONED) return of(false);
+          return from(
+            this.restApiService
+              .getMergeable(change._number)
+              .then(mergableInfo => mergableInfo?.mergeable ?? false)
+          );
+        })
+      )
+      .subscribe(mergeable => this.updateState({mergeable}));
+  }
+
+  private loadChange() {
+    return this.viewModel.changeNum$
+      .pipe(
+        switchMap(changeNum => {
+          if (changeNum !== undefined) this.updateStateLoading(changeNum);
+          const change = from(this.restApiService.getChangeDetail(changeNum));
+          const edit = from(this.restApiService.getChangeEdit(changeNum));
+          return forkJoin([change, edit]);
+        }),
+        withLatestFrom(this.viewModel.patchNum$),
+        map(([[change, edit], patchNum]) =>
+          updateChangeWithEdit(change, edit, patchNum)
+        ),
+        map(updateRevisionsWithCommitShas)
+      )
+      .subscribe(change => {
+        // The change service is currently a singleton, so we have to be
+        // careful to avoid situations where the application state is
+        // partially set for the old change where the user is coming from,
+        // and partially for the new change where the user is navigating to.
+        // So setting the change explicitly to undefined when the user
+        // moves away from diff and change pages (changeNum === undefined)
+        // helps with that.
+        this.updateStateChange(change ?? undefined);
+      });
+  }
+
   updateStateReviewedFiles(reviewedFiles: string[]) {
     this.updateState({reviewedFiles});
   }
@@ -430,12 +683,27 @@
     });
   }
 
+  // Mainly used for navigating from DIFF to OVERVIEW.
   navigateToChange(openReplyDialog = false) {
     const url = this.changeUrl(openReplyDialog);
     if (!url) return;
     this.navigation.setUrl(url);
   }
 
+  /**
+   * Wipes all URL parameters and other view state and goes to the change
+   * overview page, forcing a reload.
+   *
+   * This will also wipe the `patchNum`, so will always go to the latest
+   * patchset.
+   */
+  navigateToChangeResetReload() {
+    if (!this.change) return;
+    const url = createChangeUrl({change: this.change, forceReload: true});
+    if (!url) return;
+    this.navigation.setUrl(url);
+  }
+
   editUrl(editView: {path: string; lineNum?: number}) {
     if (!this.change) return;
     return createEditUrl({
diff --git a/polygerrit-ui/app/models/change/change-model_test.ts b/polygerrit-ui/app/models/change/change-model_test.ts
index c11c15b..e5d2e36 100644
--- a/polygerrit-ui/app/models/change/change-model_test.ts
+++ b/polygerrit-ui/app/models/change/change-model_test.ts
@@ -7,10 +7,12 @@
 import {ChangeStatus} from '../../constants/constants';
 import '../../test/common-test-setup';
 import {
+  TEST_NUMERIC_CHANGE_ID,
   createChange,
   createChangeMessageInfo,
   createChangeViewState,
   createEditInfo,
+  createMergeable,
   createParsedChange,
   createRevision,
 } from '../../test/test-data-generators';
@@ -29,13 +31,34 @@
 } from '../../types/common';
 import {ParsedChangeInfo} from '../../types/types';
 import {getAppContext} from '../../services/app-context';
-import {ChangeState, LoadingStatus, updateChangeWithEdit} from './change-model';
+import {
+  ChangeState,
+  LoadingStatus,
+  updateChangeWithEdit,
+  updateRevisionsWithCommitShas,
+} from './change-model';
 import {ChangeModel} from './change-model';
 import {assert} from '@open-wc/testing';
 import {testResolver} from '../../test/common-test-setup';
 import {userModelToken} from '../user/user-model';
-import {changeViewModelToken} from '../views/change';
+import {
+  ChangeChildView,
+  ChangeViewModel,
+  changeViewModelToken,
+} from '../views/change';
 import {navigationToken} from '../../elements/core/gr-navigation/gr-navigation';
+import {SinonStub} from 'sinon';
+import {pluginLoaderToken} from '../../elements/shared/gr-js-api-interface/gr-plugin-loader';
+import {ShowChangeDetail} from '../../elements/shared/gr-js-api-interface/gr-js-api-types';
+
+suite('updateRevisionsWithCommitShas() tests', () => {
+  test('undefined edit', async () => {
+    const change = createParsedChange();
+    const updated = updateRevisionsWithCommitShas(change);
+    assert.equal(change?.revisions?.['abc'].commit?.commit, undefined);
+    assert.equal(updated?.revisions?.['abc'].commit?.commit, 'abc' as CommitId);
+  });
+});
 
 suite('updateChangeWithEdit() tests', () => {
   test('undefined change', async () => {
@@ -69,6 +92,7 @@
 });
 
 suite('change model tests', () => {
+  let changeViewModel: ChangeViewModel;
   let changeModel: ChangeModel;
   let knownChange: ParsedChangeInfo;
   const testCompleted = new Subject<void>();
@@ -84,25 +108,20 @@
   }
 
   setup(() => {
+    changeViewModel = testResolver(changeViewModelToken);
     changeModel = new ChangeModel(
       testResolver(navigationToken),
-      testResolver(changeViewModelToken),
+      changeViewModel,
       getAppContext().restApiService,
-      testResolver(userModelToken)
+      testResolver(userModelToken),
+      testResolver(pluginLoaderToken),
+      getAppContext().reportingService
     );
     knownChange = {
       ...createChange(),
       revisions: {
-        sha1: {
-          ...createRevision(1),
-          description: 'patch 1',
-          _number: 1 as PatchSetNumber,
-        },
-        sha2: {
-          ...createRevision(2),
-          description: 'patch 2',
-          _number: 2 as PatchSetNumber,
-        },
+        sha1: {...createRevision(1), description: 'patch 1'},
+        sha2: {...createRevision(2), description: 'patch 2'},
       },
       status: ChangeStatus.NEW,
       current_revision: 'abc' as CommitId,
@@ -115,6 +134,114 @@
     changeModel.finalize();
   });
 
+  suite('mergeability', async () => {
+    let getMergeableStub: SinonStub;
+    let mergeableApiResponse = false;
+
+    setup(() => {
+      getMergeableStub = stubRestApi('getMergeable').callsFake(() =>
+        Promise.resolve(createMergeable(mergeableApiResponse))
+      );
+    });
+
+    test('mergeability initially undefined', async () => {
+      waitUntilObserved(
+        changeModel.mergeable$,
+        mergeable => mergeable === undefined
+      );
+      assert.isFalse(getMergeableStub.called);
+    });
+
+    test('mergeability true from change', async () => {
+      changeModel.updateStateChange({...knownChange, mergeable: true});
+
+      waitUntilObserved(
+        changeModel.mergeable$,
+        mergeable => mergeable === true
+      );
+      assert.isFalse(getMergeableStub.called);
+    });
+
+    test('mergeability false from change', async () => {
+      changeModel.updateStateChange({...knownChange, mergeable: false});
+
+      waitUntilObserved(
+        changeModel.mergeable$,
+        mergeable => mergeable === true
+      );
+      assert.isFalse(getMergeableStub.called);
+    });
+
+    test('mergeability false for MERGED change', async () => {
+      changeModel.updateStateChange({
+        ...knownChange,
+        status: ChangeStatus.MERGED,
+      });
+
+      waitUntilObserved(
+        changeModel.mergeable$,
+        mergeable => mergeable === false
+      );
+      assert.isFalse(getMergeableStub.called);
+    });
+
+    test('mergeability false for ABANDONED change', async () => {
+      changeModel.updateStateChange({
+        ...knownChange,
+        status: ChangeStatus.ABANDONED,
+      });
+
+      waitUntilObserved(
+        changeModel.mergeable$,
+        mergeable => mergeable === false
+      );
+      assert.isFalse(getMergeableStub.called);
+    });
+
+    test('mergeability true from API', async () => {
+      mergeableApiResponse = true;
+      changeModel.updateStateChange(knownChange);
+
+      waitUntilObserved(
+        changeModel.mergeable$,
+        mergeable => mergeable === true
+      );
+      assert.isTrue(getMergeableStub.calledOnce);
+    });
+
+    test('mergeability false from API', async () => {
+      mergeableApiResponse = false;
+      changeModel.updateStateChange(knownChange);
+
+      waitUntilObserved(
+        changeModel.mergeable$,
+        mergeable => mergeable === false
+      );
+      assert.isTrue(getMergeableStub.calledOnce);
+    });
+  });
+
+  test('fireShowChange', async () => {
+    const pluginLoader = testResolver(pluginLoaderToken);
+    const jsApiService = pluginLoader.jsApiService;
+    const showChangeStub = sinon.stub(jsApiService, 'handleShowChange');
+
+    changeViewModel.updateState({
+      childView: ChangeChildView.OVERVIEW,
+      patchNum: 1 as PatchSetNumber,
+    });
+    changeModel.updateState({
+      change: createParsedChange(),
+      mergeable: true,
+    });
+
+    assert.isTrue(showChangeStub.calledOnce);
+    const detail: ShowChangeDetail = showChangeStub.lastCall.firstArg;
+    assert.equal(detail.change?._number, createParsedChange()._number);
+    assert.equal(detail.patchNum, 1 as PatchSetNumber);
+    assert.equal(detail.info.mergeable, true);
+  });
+
   test('load a change', async () => {
     const promise = mockPromise<ParsedChangeInfo | undefined>();
     const stub = stubRestApi('getChangeDetail').callsFake(() => promise);
@@ -132,7 +259,7 @@
     promise.resolve(knownChange);
     state = await waitForLoadingStatus(LoadingStatus.LOADED);
     assert.equal(stub.callCount, 1);
-    assert.equal(state?.change, knownChange);
+    assert.deepEqual(state?.change, updateRevisionsWithCommitShas(knownChange));
   });
 
   test('reload a change', async () => {
@@ -143,17 +270,20 @@
     testResolver(changeViewModelToken).setState(createChangeViewState());
     promise.resolve(knownChange);
     state = await waitForLoadingStatus(LoadingStatus.LOADED);
+    assert.equal(stub.callCount, 1);
 
     // Reloading same change
     document.dispatchEvent(new CustomEvent('reload'));
     state = await waitForLoadingStatus(LoadingStatus.RELOADING);
-    assert.equal(stub.callCount, 2);
-    assert.equal(state?.change, knownChange);
+    assert.equal(stub.callCount, 3);
+    assert.equal(stub.getCall(1).firstArg, undefined);
+    assert.equal(stub.getCall(2).firstArg, TEST_NUMERIC_CHANGE_ID);
+    assert.deepEqual(state?.change, updateRevisionsWithCommitShas(knownChange));
 
     promise.resolve(knownChange);
     state = await waitForLoadingStatus(LoadingStatus.LOADED);
-    assert.equal(stub.callCount, 2);
-    assert.equal(state?.change, knownChange);
+    assert.equal(stub.callCount, 3);
+    assert.deepEqual(state?.change, updateRevisionsWithCommitShas(knownChange));
   });
 
   test('navigating to another change', async () => {
@@ -183,7 +313,7 @@
     promise.resolve(otherChange);
     state = await waitForLoadingStatus(LoadingStatus.LOADED);
     assert.equal(stub.callCount, 2);
-    assert.equal(state?.change, otherChange);
+    assert.deepEqual(state?.change, updateRevisionsWithCommitShas(otherChange));
   });
 
   test('navigating to dashboard', async () => {
@@ -211,7 +341,7 @@
     testResolver(changeViewModelToken).setState(createChangeViewState());
     state = await waitForLoadingStatus(LoadingStatus.LOADED);
     assert.equal(stub.callCount, 3);
-    assert.equal(state?.change, knownChange);
+    assert.deepEqual(state?.change, updateRevisionsWithCommitShas(knownChange));
   });
 
   test('changeModel.fetchChangeUpdates on latest', async () => {
@@ -294,4 +424,28 @@
     changeModel.updateStateChange(createParsedChange());
     assert.equal(spy.callCount, 2);
   });
+
+  test('revision$ selector latest', async () => {
+    changeViewModel.updateState({patchNum: undefined});
+    changeModel.updateState({change: knownChange});
+    await waitUntilObserved(changeModel.revision$, x => x?._number === 2);
+  });
+
+  test('revision$ selector 1', async () => {
+    changeViewModel.updateState({patchNum: 1 as PatchSetNumber});
+    changeModel.updateState({change: knownChange});
+    await waitUntilObserved(changeModel.revision$, x => x?._number === 1);
+  });
+
+  test('latestRevision$ selector latest', async () => {
+    changeViewModel.updateState({patchNum: undefined});
+    changeModel.updateState({change: knownChange});
+    await waitUntilObserved(changeModel.latestRevision$, x => x?._number === 2);
+  });
+
+  test('latestRevision$ selector 1', async () => {
+    changeViewModel.updateState({patchNum: 1 as PatchSetNumber});
+    changeModel.updateState({change: knownChange});
+    await waitUntilObserved(changeModel.latestRevision$, x => x?._number === 2);
+  });
 });
diff --git a/polygerrit-ui/app/models/change/files-model.ts b/polygerrit-ui/app/models/change/files-model.ts
index b7ff16f..c01b718 100644
--- a/polygerrit-ui/app/models/change/files-model.ts
+++ b/polygerrit-ui/app/models/change/files-model.ts
@@ -22,6 +22,8 @@
 import {define} from '../dependency';
 import {ChangeModel} from './change-model';
 import {CommentsModel} from '../comments/comments-model';
+import {Timing} from '../../constants/reporting';
+import {ReportingService} from '../../services/gr-reporting/gr-reporting';
 
 export type FileNameToNormalizedFileInfoMap = {
   [name: string]: NormalizedFileInfo;
@@ -141,10 +143,13 @@
   constructor(
     readonly changeModel: ChangeModel,
     readonly commentsModel: CommentsModel,
-    readonly restApiService: RestApiService
+    readonly restApiService: RestApiService,
+    private readonly reporting: ReportingService
   ) {
     super(initialState);
     this.subscriptions = [
+      this.reportChangeDataStart(),
+      this.reportChangeDataEnd(),
       this.subscribeToFiles(
         (psLeft, psRight) => {
           return {basePatchNum: psLeft, patchNum: psRight};
@@ -176,6 +181,26 @@
     ];
   }
 
+  private reportChangeDataStart() {
+    return combineLatest([this.changeModel.loading$]).subscribe(
+      ([changeLoading]) => {
+        if (changeLoading) {
+          this.reporting.time(Timing.CHANGE_DATA);
+        }
+      }
+    );
+  }
+
+  private reportChangeDataEnd() {
+    return combineLatest([this.changeModel.loading$, this.files$]).subscribe(
+      ([changeLoading, files]) => {
+        if (!changeLoading && files.length > 0) {
+          this.reporting.timeEnd(Timing.CHANGE_DATA);
+        }
+      }
+    );
+  }
+
   private subscribeToFiles(
     rangeChooser: (
       basePatchNum: BasePatchSetNum,
@@ -184,13 +209,12 @@
     filesToState: (files: NormalizedFileInfo[]) => Partial<FilesState>
   ) {
     return combineLatest([
-      this.changeModel.reload$,
       this.changeModel.changeNum$,
       this.changeModel.basePatchNum$,
       this.changeModel.patchNum$,
     ])
       .pipe(
-        switchMap(([_, changeNum, basePatchNum, patchNum]) => {
+        switchMap(([changeNum, basePatchNum, patchNum]) => {
           if (!changeNum || !patchNum) return of({});
           const range = rangeChooser(basePatchNum, patchNum);
           if (!range) return of({});
diff --git a/polygerrit-ui/app/models/change/related-changes-model.ts b/polygerrit-ui/app/models/change/related-changes-model.ts
new file mode 100644
index 0000000..9ae4295
--- /dev/null
+++ b/polygerrit-ui/app/models/change/related-changes-model.ts
@@ -0,0 +1,242 @@
+/**
+ * @license
+ * Copyright 2023 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+import {
+  ChangeInfo,
+  RelatedChangeAndCommitInfo,
+  SubmittedTogetherInfo,
+} from '../../types/common';
+import {RestApiService} from '../../services/gr-rest-api/gr-rest-api';
+import {select} from '../../utils/observable-util';
+import {Model} from '../model';
+import {define} from '../dependency';
+import {ChangeModel} from './change-model';
+import {combineLatest, forkJoin, from, of} from 'rxjs';
+import {map, switchMap} from 'rxjs/operators';
+import {ConfigModel} from '../config/config-model';
+import {ChangeStatus} from '../../api/rest-api';
+import {isDefined} from '../../types/types';
+
+export interface RelatedChangesState {
+  /** `undefined` means "not yet loaded". */
+  relatedChanges?: RelatedChangeAndCommitInfo[];
+  submittedTogether?: SubmittedTogetherInfo;
+  cherryPicks?: ChangeInfo[];
+  conflictingChanges?: ChangeInfo[];
+  sameTopicChanges?: ChangeInfo[];
+  revertingChanges: ChangeInfo[];
+}
+
+const initialState: RelatedChangesState = {
+  relatedChanges: undefined,
+  submittedTogether: undefined,
+  cherryPicks: undefined,
+  conflictingChanges: undefined,
+  sameTopicChanges: undefined,
+  revertingChanges: [],
+};
+
+export const relatedChangesModelToken = define<RelatedChangesModel>(
+  'related-changes-model'
+);
+
+export class RelatedChangesModel extends Model<RelatedChangesState> {
+  public readonly relatedChanges$ = select(
+    this.state$,
+    state => state.relatedChanges
+  );
+
+  public readonly submittedTogether$ = select(
+    this.state$,
+    state => state.submittedTogether
+  );
+
+  public readonly cherryPicks$ = select(
+    this.state$,
+    state => state.cherryPicks
+  );
+
+  public readonly conflictingChanges$ = select(
+    this.state$,
+    state => state.conflictingChanges
+  );
+
+  public readonly sameTopicChanges$ = select(
+    this.state$,
+    state => state.sameTopicChanges
+  );
+
+  /**
+   * Emits all changes that have reverted the current change, based on
+   * information from parsed change messages. Abandoned changes are not
+   * included.
+   */
+  public readonly revertingChanges$ = select(
+    this.state$,
+    state => state.revertingChanges
+  );
+
+  /**
+   * Emits one reverting change (if there is any) from revertingChanges$.
+   * It prefers MERGED changes. Otherwise the choice is random.
+   */
+  public readonly revertingChange$ = select(
+    this.revertingChanges$,
+    revertingChanges => {
+      if (revertingChanges.length === 0) return undefined;
+      const submittedRevert = revertingChanges.find(
+        c => c.status === ChangeStatus.MERGED
+      );
+      if (submittedRevert) return submittedRevert;
+      return revertingChanges[0];
+    }
+  );
+
+  /**
+   * Determines whether the change has a parent change. If there
+   * is a relation chain, and the change id is not the last item of the
+   * relation chain, then there is a parent.
+   */
+  public readonly hasParent$ = select(
+    combineLatest([this.changeModel.change$, this.relatedChanges$]),
+    ([change, relatedChanges]) => {
+      if (!change) return undefined;
+      if (relatedChanges === undefined) return undefined;
+      if (relatedChanges.length === 0) return false;
+      const lastChangeId = relatedChanges[relatedChanges.length - 1].change_id;
+      return lastChangeId !== change.change_id;
+    }
+  );
+
+  constructor(
+    readonly changeModel: ChangeModel,
+    readonly configModel: ConfigModel,
+    readonly restApiService: RestApiService
+  ) {
+    super(initialState);
+    this.subscriptions = [
+      this.loadRelatedChanges(),
+      this.loadSubmittedTogether(),
+      this.loadCherryPicks(),
+      this.loadConflictingChanges(),
+      this.loadSameTopicChanges(),
+      this.loadRevertingChanges(),
+    ];
+  }
+
+  private loadRelatedChanges() {
+    return combineLatest([
+      this.changeModel.changeNum$,
+      this.changeModel.latestPatchNum$,
+    ])
+      .pipe(
+        switchMap(([changeNum, latestPatchNum]) => {
+          if (!changeNum || !latestPatchNum) return of(undefined);
+          return from(
+            this.restApiService
+              .getRelatedChanges(changeNum, latestPatchNum)
+              .then(info => info?.changes ?? [])
+          );
+        })
+      )
+      .subscribe(relatedChanges => {
+        this.updateState({relatedChanges});
+      });
+  }
+
+  private loadSubmittedTogether() {
+    return this.changeModel.changeNum$
+      .pipe(
+        switchMap(changeNum => {
+          if (!changeNum) return of(undefined);
+          return from(
+            this.restApiService.getChangesSubmittedTogether(changeNum)
+          );
+        })
+      )
+      .subscribe(submittedTogether => {
+        this.updateState({submittedTogether});
+      });
+  }
+
+  private loadCherryPicks() {
+    return combineLatest([
+      this.changeModel.changeNum$,
+      this.changeModel.changeId$,
+      this.changeModel.repo$,
+    ])
+      .pipe(
+        switchMap(([changeNum, changeId, repo]) => {
+          if (!changeNum || !changeId || !repo) return of(undefined);
+          return from(
+            this.restApiService.getChangeCherryPicks(repo, changeId, changeNum)
+          );
+        })
+      )
+      .subscribe(cherryPicks => {
+        this.updateState({cherryPicks});
+      });
+  }
+
+  private loadConflictingChanges() {
+    return combineLatest([
+      this.changeModel.changeNum$,
+      this.changeModel.status$,
+      this.changeModel.mergeable$,
+    ])
+      .pipe(
+        switchMap(([changeNum, status, mergeable]) => {
+          if (!changeNum || !status || !mergeable) return of(undefined);
+          if (status !== ChangeStatus.NEW) return of(undefined);
+          return from(this.restApiService.getChangeConflicts(changeNum));
+        })
+      )
+      .subscribe(conflictingChanges => {
+        this.updateState({conflictingChanges});
+      });
+  }
+
+  private loadSameTopicChanges() {
+    return combineLatest([
+      this.changeModel.changeNum$,
+      this.changeModel.topic$,
+      this.configModel.serverConfig$,
+    ])
+      .pipe(
+        switchMap(([changeNum, topic, config]) => {
+          if (!changeNum || !topic || !config) return of(undefined);
+          if (config.change.submit_whole_topic) return of(undefined);
+          return from(
+            this.restApiService.getChangesWithSameTopic(topic, {
+              openChangesOnly: true,
+              changeToExclude: changeNum,
+            })
+          );
+        })
+      )
+      .subscribe(sameTopicChanges => {
+        this.updateState({sameTopicChanges});
+      });
+  }
+
+  private loadRevertingChanges() {
+    return this.changeModel.revertingChangeIds$
+      .pipe(
+        switchMap(changeIds => {
+          if (!changeIds?.length) return of([]);
+          return forkJoin(
+            changeIds.map(changeId =>
+              from(this.restApiService.getChange(changeId))
+            )
+          );
+        }),
+        map(changes => changes.filter(isDefined)),
+        map(changes => changes.filter(c => c.status !== ChangeStatus.ABANDONED))
+      )
+      .subscribe(revertingChanges => {
+        this.updateState({revertingChanges});
+      });
+  }
+}
diff --git a/polygerrit-ui/app/models/change/related-changes-model_test.ts b/polygerrit-ui/app/models/change/related-changes-model_test.ts
new file mode 100644
index 0000000..295f284
--- /dev/null
+++ b/polygerrit-ui/app/models/change/related-changes-model_test.ts
@@ -0,0 +1,286 @@
+/**
+ * @license
+ * Copyright 2023 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+import '../../test/common-test-setup';
+import {getAppContext} from '../../services/app-context';
+import {ChangeModel, changeModelToken} from '../change/change-model';
+import {assert} from '@open-wc/testing';
+import {testResolver} from '../../test/common-test-setup';
+import {RelatedChangesModel} from './related-changes-model';
+import {configModelToken} from '../config/config-model';
+import {SinonStub} from 'sinon';
+import {
+  ChangeInfo,
+  RelatedChangesInfo,
+  SubmittedTogetherInfo,
+} from '../../types/common';
+import {stubRestApi, waitUntilObserved} from '../../test/test-utils';
+import {
+  createParsedChange,
+  createRelatedChangesInfo,
+  createRelatedChangeAndCommitInfo,
+  createChange,
+  createChangeMessage,
+} from '../../test/test-data-generators';
+import {ChangeStatus, ReviewInputTag, TopicName} from '../../api/rest-api';
+import {MessageTag} from '../../constants/constants';
+
+suite('related-changes-model tests', () => {
+  let model: RelatedChangesModel;
+  let changeModel: ChangeModel;
+
+  setup(async () => {
+    changeModel = testResolver(changeModelToken);
+    model = new RelatedChangesModel(
+      changeModel,
+      testResolver(configModelToken),
+      getAppContext().restApiService
+    );
+    await waitUntilObserved(changeModel.change$, c => c === undefined);
+  });
+
+  teardown(() => {
+    model.finalize();
+  });
+
+  test('register and fetch', async () => {
+    assert.equal('', '');
+  });
+
+  suite('related changes and hasParent', async () => {
+    let getRelatedChangesStub: SinonStub;
+    let getRelatedChangesResponse: RelatedChangesInfo;
+    let hasParent: boolean | undefined;
+
+    setup(() => {
+      getRelatedChangesStub = stubRestApi('getRelatedChanges').callsFake(() =>
+        Promise.resolve(getRelatedChangesResponse)
+      );
+      model.hasParent$.subscribe(x => (hasParent = x));
+    });
+
+    test('relatedChanges initially undefined', async () => {
+      await waitUntilObserved(
+        model.relatedChanges$,
+        relatedChanges => relatedChanges === undefined
+      );
+      assert.isFalse(getRelatedChangesStub.called);
+      assert.isUndefined(hasParent);
+    });
+
+    test('relatedChanges loading empty', async () => {
+      changeModel.updateStateChange({...createParsedChange()});
+
+      await waitUntilObserved(
+        model.relatedChanges$,
+        relatedChanges => relatedChanges?.length === 0
+      );
+      assert.isTrue(getRelatedChangesStub.calledOnce);
+      assert.isFalse(hasParent);
+    });
+
+    test('relatedChanges loading one change', async () => {
+      getRelatedChangesResponse = {
+        ...createRelatedChangesInfo(),
+        changes: [createRelatedChangeAndCommitInfo()],
+      };
+      changeModel.updateStateChange({...createParsedChange()});
+
+      await waitUntilObserved(
+        model.relatedChanges$,
+        relatedChanges => relatedChanges?.length === 1
+      );
+      assert.isTrue(getRelatedChangesStub.calledOnce);
+      assert.isTrue(hasParent);
+    });
+  });
+
+  suite('loadSubmittedTogether', async () => {
+    let getChangesSubmittedTogetherStub: SinonStub;
+    let getChangesSubmittedTogetherResponse: SubmittedTogetherInfo;
+
+    setup(() => {
+      getChangesSubmittedTogetherStub = stubRestApi(
+        'getChangesSubmittedTogether'
+      ).callsFake(() => Promise.resolve(getChangesSubmittedTogetherResponse));
+    });
+
+    test('submittedTogether initially undefined', async () => {
+      await waitUntilObserved(
+        model.submittedTogether$,
+        submittedTogether => submittedTogether === undefined
+      );
+      assert.isFalse(getChangesSubmittedTogetherStub.called);
+    });
+
+    test('submittedTogether emits', async () => {
+      getChangesSubmittedTogetherResponse = {
+        changes: [createChange()],
+        non_visible_changes: 0,
+      };
+      changeModel.updateStateChange({...createParsedChange()});
+
+      await waitUntilObserved(
+        model.submittedTogether$,
+        submittedTogether => submittedTogether?.changes?.length === 1
+      );
+      assert.isTrue(getChangesSubmittedTogetherStub.calledOnce);
+    });
+  });
+
+  suite('loadCherryPicks', async () => {
+    let getChangeCherryPicksStub: SinonStub;
+    let getChangeCherryPicksResponse: ChangeInfo[];
+
+    setup(() => {
+      getChangeCherryPicksStub = stubRestApi('getChangeCherryPicks').callsFake(
+        () => Promise.resolve(getChangeCherryPicksResponse)
+      );
+    });
+
+    test('cherryPicks initially undefined', async () => {
+      await waitUntilObserved(
+        model.cherryPicks$,
+        cherryPicks => cherryPicks === undefined
+      );
+      assert.isFalse(getChangeCherryPicksStub.called);
+    });
+
+    test('cherryPicks emits', async () => {
+      getChangeCherryPicksResponse = [createChange()];
+      changeModel.updateStateChange({...createParsedChange()});
+
+      await waitUntilObserved(
+        model.cherryPicks$,
+        cherryPicks => cherryPicks?.length === 1
+      );
+      assert.isTrue(getChangeCherryPicksStub.calledOnce);
+    });
+  });
+
+  suite('loadConflictingChanges', async () => {
+    let getChangeConflictsStub: SinonStub;
+    let getChangeConflictsResponse: ChangeInfo[];
+
+    setup(() => {
+      getChangeConflictsStub = stubRestApi('getChangeConflicts').callsFake(() =>
+        Promise.resolve(getChangeConflictsResponse)
+      );
+    });
+
+    test('conflictingChanges initially undefined', async () => {
+      await waitUntilObserved(
+        model.conflictingChanges$,
+        conflictingChanges => conflictingChanges === undefined
+      );
+      assert.isFalse(getChangeConflictsStub.called);
+    });
+
+    test('conflictingChanges not loaded for merged changes', async () => {
+      getChangeConflictsResponse = [createChange()];
+      changeModel.updateStateChange({
+        ...createParsedChange(),
+        mergeable: true,
+        status: ChangeStatus.MERGED,
+      });
+
+      await waitUntilObserved(
+        model.conflictingChanges$,
+        conflictingChanges => conflictingChanges === undefined
+      );
+      assert.isFalse(getChangeConflictsStub.called);
+    });
+
+    test('conflictingChanges emits', async () => {
+      getChangeConflictsResponse = [createChange()];
+      changeModel.updateStateChange({...createParsedChange(), mergeable: true});
+
+      await waitUntilObserved(
+        model.conflictingChanges$,
+        conflictingChanges => conflictingChanges?.length === 1
+      );
+      assert.isTrue(getChangeConflictsStub.calledOnce);
+    });
+  });
+
+  suite('loadSameTopicChanges', async () => {
+    let getChangesWithSameTopicStub: SinonStub;
+    let getChangesWithSameTopicResponse: ChangeInfo[];
+
+    setup(() => {
+      getChangesWithSameTopicStub = stubRestApi(
+        'getChangesWithSameTopic'
+      ).callsFake(() => Promise.resolve(getChangesWithSameTopicResponse));
+    });
+
+    test('sameTopicChanges initially undefined', async () => {
+      await waitUntilObserved(
+        model.sameTopicChanges$,
+        sameTopicChanges => sameTopicChanges === undefined
+      );
+      assert.isFalse(getChangesWithSameTopicStub.called);
+    });
+
+    test('sameTopicChanges emits', async () => {
+      getChangesWithSameTopicResponse = [createChange()];
+      changeModel.updateStateChange({
+        ...createParsedChange(),
+        topic: 'test-topic' as TopicName,
+      });
+
+      await waitUntilObserved(
+        model.sameTopicChanges$,
+        sameTopicChanges => sameTopicChanges?.length === 1
+      );
+      assert.isTrue(getChangesWithSameTopicStub.calledOnce);
+    });
+  });
+
+  suite('loadRevertingChanges', async () => {
+    let getChangeStub: SinonStub;
+
+    setup(() => {
+      getChangeStub = stubRestApi('getChange').callsFake(() =>
+        Promise.resolve(createChange())
+      );
+    });
+
+    test('revertingChanges initially empty', async () => {
+      await waitUntilObserved(
+        model.revertingChanges$,
+        revertingChanges => revertingChanges.length === 0
+      );
+      assert.isFalse(getChangeStub.called);
+    });
+
+    test('revertingChanges empty when change does not contain a revert message', async () => {
+      changeModel.updateStateChange(createParsedChange());
+      await waitUntilObserved(
+        model.revertingChanges$,
+        revertingChanges => revertingChanges.length === 0
+      );
+      assert.isFalse(getChangeStub.called);
+    });
+
+    test('revertingChanges emits', async () => {
+      changeModel.updateStateChange({
+        ...createParsedChange(),
+        messages: [
+          {
+            ...createChangeMessage(),
+            message: 'Created a revert of this change as 123',
+            tag: MessageTag.TAG_REVERT as ReviewInputTag,
+          },
+        ],
+      });
+
+      await waitUntilObserved(
+        model.revertingChanges$,
+        revertingChanges => revertingChanges?.length === 1
+      );
+      assert.isTrue(getChangeStub.calledOnce);
+    });
+  });
+});
diff --git a/polygerrit-ui/app/models/checks/checks-model.ts b/polygerrit-ui/app/models/checks/checks-model.ts
index 2aa4aa4..729d46f 100644
--- a/polygerrit-ui/app/models/checks/checks-model.ts
+++ b/polygerrit-ui/app/models/checks/checks-model.ts
@@ -195,8 +195,6 @@
 
   private readonly documentVisibilityChange$ = new BehaviorSubject(undefined);
 
-  private readonly reloadListener: () => void;
-
   private readonly visibilityChangeListener: () => void;
 
   public checksSelectedPatchsetNumber$ = select(
@@ -414,8 +412,6 @@
       'visibilitychange',
       this.visibilityChangeListener
     );
-    this.reloadListener = () => this.reloadAll();
-    document.addEventListener('reload', this.reloadListener);
   }
 
   private reportStats(state: {[name: string]: ChecksProviderState}) {
@@ -459,7 +455,6 @@
   }
 
   override finalize() {
-    document.removeEventListener('reload', this.reloadListener);
     document.removeEventListener(
       'visibilitychange',
       this.visibilityChangeListener
diff --git a/polygerrit-ui/app/models/comments/comments-model.ts b/polygerrit-ui/app/models/comments/comments-model.ts
index 2c18a09..ac832a1 100644
--- a/polygerrit-ui/app/models/comments/comments-model.ts
+++ b/polygerrit-ui/app/models/comments/comments-model.ts
@@ -24,8 +24,10 @@
 import {
   addPath,
   createNew,
+  createNewPatchsetLevel,
   id,
   isDraftThread,
+  isNewThread,
   reportingDetails,
 } from '../../utils/comment-util';
 import {deepEqual} from '../../utils/deep-util';
@@ -280,12 +282,21 @@
     commentState => commentState.drafts
   );
 
+  public readonly draftsLoading$ = select(
+    this.drafts$,
+    drafts => drafts === undefined
+  );
+
   public readonly draftsArray$ = select(this.drafts$, drafts =>
     Object.values(drafts ?? {}).flat()
   );
 
+  public readonly draftsSaved$ = select(this.draftsArray$, drafts =>
+    drafts.filter(d => !isNew(d))
+  );
+
   public readonly draftsCount$ = select(
-    this.draftsArray$,
+    this.draftsSaved$,
     drafts => drafts.length
   );
 
@@ -382,8 +393,12 @@
     changeComments.getAllThreadsForChange()
   );
 
-  public readonly draftThreads$ = select(this.threads$, threads =>
-    threads.filter(isDraftThread)
+  public readonly threadsSaved$ = select(this.threads$, threads =>
+    threads.filter(t => !isNewThread(t))
+  );
+
+  public readonly draftThreadsSaved$ = select(this.threads$, threads =>
+    threads.filter(t => !isNewThread(t) && isDraftThread(t))
   );
 
   public readonly commentedPaths$ = select(
@@ -409,8 +424,6 @@
 
   private patchNum?: PatchSetNum;
 
-  private readonly reloadListener: () => void;
-
   private drafts: {[path: string]: DraftInfo[]} = {};
 
   private draftToastTask?: DelayedTask;
@@ -454,6 +467,16 @@
       this.changeModel.patchNum$.subscribe(x => (this.patchNum = x))
     );
     this.subscriptions.push(
+      combineLatest([
+        this.draftsLoading$,
+        this.patchsetLevelDrafts$,
+        this.changeModel.latestPatchNum$,
+      ]).subscribe(([loading, plDraft, latestPatchNum]) => {
+        if (loading || plDraft.length > 0 || !latestPatchNum) return;
+        this.addNewDraft(createNewPatchsetLevel(latestPatchNum, '', false));
+      })
+    );
+    this.subscriptions.push(
       this.changeViewModel.changeNum$.subscribe(changeNum => {
         this.changeNum = changeNum;
         this.setState({...initialState});
@@ -470,16 +493,6 @@
         this.reloadAllPortedComments();
       })
     );
-    this.reloadListener = () => {
-      this.reloadAllComments();
-      this.reloadAllPortedComments();
-    };
-    document.addEventListener('reload', this.reloadListener);
-  }
-
-  override finalize() {
-    document.removeEventListener('reload', this.reloadListener);
-    super.finalize();
   }
 
   // Note that this does *not* reload ported comments.
diff --git a/polygerrit-ui/app/models/views/change.ts b/polygerrit-ui/app/models/views/change.ts
index d2a0dd8..713d401 100644
--- a/polygerrit-ui/app/models/views/change.ts
+++ b/polygerrit-ui/app/models/views/change.ts
@@ -69,9 +69,16 @@
 
   /** for scrolling a Change Log message into view in gr-change-view */
   messageHash?: string;
-  /** for logging where the user came from */
+  /**
+   * For logging where the user came from. This is handled by the router, so
+   * this is not inspected by the model.
+   */
   usp?: string;
-  /** triggers all change related data to be reloaded */
+  /**
+   * Triggers all change related data to be reloaded. This is implemented by
+   * intercepting change view state updates and `forceReload` causing the view
+   * state to be wiped clean as `undefined` in an intermediate update.
+   */
   forceReload?: boolean;
   /** triggers opening the reply dialog */
   openReplyDialog?: boolean;
@@ -261,6 +268,20 @@
     state => state?.basePatchNum
   );
 
+  public readonly openReplyDialog$ = select(
+    this.state$,
+    state => state?.openReplyDialog
+  );
+
+  public readonly commentId$ = select(this.state$, state => state?.commentId);
+
+  public readonly edit$ = select(this.state$, state => !!state?.edit);
+
+  public readonly editPath$ = select(
+    this.state$,
+    state => state?.editView?.path
+  );
+
   public readonly diffPath$ = select(
     this.state$,
     state => state?.diffView?.path
@@ -278,7 +299,11 @@
 
   public readonly childView$ = select(this.state$, state => state?.childView);
 
-  public readonly tab$ = select(this.state$, state => state?.tab);
+  public readonly tab$ = select(this.state$, state => {
+    if (state?.commentId) return Tab.COMMENT_THREADS;
+    if (state?.tab) return state.tab;
+    return Tab.FILES;
+  });
 
   public readonly checksPatchset$ = select(
     this.state$,
@@ -310,6 +335,39 @@
         });
       }
     });
+    document.addEventListener('reload', this.reload);
+  }
+
+  override finalize(): void {
+    document.removeEventListener('reload', this.reload);
+  }
+
+  /**
+   * Calling this is the same as firing the 'reload' event. This is also the
+   * same as adding `forceReload` parameter in the URL. See below.
+   */
+  reload = () => {
+    const state = this.getState();
+    if (state !== undefined) this.forceLoad(state);
+  };
+
+  /**
+   * This is the destination of where the `reload()` method, the `reload` event
+   * and the `forceReload` URL parameter all end up.
+   */
+  private forceLoad(state: ChangeViewState) {
+    this.setState(undefined);
+    // We have to do this in a timeout, because we need the `undefined` value to
+    // be processed by all observers first and thus have the "reset" completed.
+    setTimeout(() => this.setState({...state, forceReload: undefined}));
+  }
+
+  override setState(state: ChangeViewState | undefined): void {
+    if (state?.forceReload) {
+      this.forceLoad(state);
+    } else {
+      super.setState(state);
+    }
   }
 
   toggleSelectedCheckRun(checkName: string) {
diff --git a/polygerrit-ui/app/services/app-context-init.ts b/polygerrit-ui/app/services/app-context-init.ts
index 3b9d3bb..8589ae3 100644
--- a/polygerrit-ui/app/services/app-context-init.ts
+++ b/polygerrit-ui/app/services/app-context-init.ts
@@ -68,6 +68,10 @@
   ServiceWorkerInstaller,
   serviceWorkerInstallerToken,
 } from './service-worker-installer';
+import {
+  RelatedChangesModel,
+  relatedChangesModelToken,
+} from '../models/change/related-changes-model';
 
 /**
  * The AppContext lazy initializator for all services
@@ -151,7 +155,9 @@
           resolver(navigationToken),
           resolver(changeViewModelToken),
           appContext.restApiService,
-          resolver(userModelToken)
+          resolver(userModelToken),
+          resolver(pluginLoaderToken),
+          appContext.reportingService
         ),
     ],
     [
@@ -172,7 +178,8 @@
         new FilesModel(
           resolver(changeModelToken),
           resolver(commentsModelToken),
-          appContext.restApiService
+          appContext.restApiService,
+          appContext.reportingService
         ),
     ],
     [
@@ -181,6 +188,15 @@
         new ConfigModel(resolver(changeModelToken), appContext.restApiService),
     ],
     [
+      relatedChangesModelToken,
+      () =>
+        new RelatedChangesModel(
+          resolver(changeModelToken),
+          resolver(configModelToken),
+          appContext.restApiService
+        ),
+    ],
+    [
       pluginLoaderToken,
       () =>
         new PluginLoader(
diff --git a/polygerrit-ui/app/services/flags/flags.ts b/polygerrit-ui/app/services/flags/flags.ts
index 973960e..7488e79 100644
--- a/polygerrit-ui/app/services/flags/flags.ts
+++ b/polygerrit-ui/app/services/flags/flags.ts
@@ -19,5 +19,4 @@
   PUSH_NOTIFICATIONS_DEVELOPER = 'UiFeature__push_notifications_developer',
   PUSH_NOTIFICATIONS = 'UiFeature__push_notifications',
   SUGGEST_EDIT = 'UiFeature__suggest_edit',
-  COMMENTS_CHIPS_IN_FILE_LIST = 'UiFeature__comments_chips_in_file_list',
 }
diff --git a/polygerrit-ui/app/services/gr-reporting/gr-reporting_impl.ts b/polygerrit-ui/app/services/gr-reporting/gr-reporting_impl.ts
index 55bb64c..350f199 100644
--- a/polygerrit-ui/app/services/gr-reporting/gr-reporting_impl.ts
+++ b/polygerrit-ui/app/services/gr-reporting/gr-reporting_impl.ts
@@ -203,6 +203,62 @@
   });
 }
 
+/**
+ * Reports generic user interaction every x seconds to detect, if the user is
+ * present and is using the application somehow. If you just look at
+ * `document.visibilityState`, then the user may have left the browser open
+ * without locking the screen. So it helps to know whether some interaction is
+ * actually happening.
+ */
+export class InteractionReporter implements Finalizable {
+  /** Accumulates event names until the next round of interaction reporting. */
+  private interactionEvents = new Set<string>();
+
+  /** Allows clearing the interval timer. Mostly useful for tests. */
+  private intervalId?: number;
+
+  constructor(
+    private readonly reportingService: ReportingService,
+    private readonly reportingIntervalMs = 10 * 1000
+  ) {
+    const events = ['mousemove', 'scroll', 'wheel', 'keydown', 'pointerdown'];
+    for (const eventName of events) {
+      document.addEventListener(eventName, () =>
+        this.interactionEvents.add(eventName)
+      );
+    }
+
+    this.intervalId = window.setInterval(
+      () => this.report(),
+      this.reportingIntervalMs
+    );
+  }
+
+  finalize() {
+    window.clearInterval(this.intervalId);
+  }
+
+  private report() {
+    const active = this.interactionEvents.size > 0;
+    if (active) {
+      this.reportingService.reportInteraction(Interaction.USER_ACTIVE, {
+        events: [...this.interactionEvents],
+      });
+    } else if (document.visibilityState === 'visible') {
+      this.reportingService.reportInteraction(Interaction.USER_PASSIVE, {});
+    }
+    this.interactionEvents.clear();
+  }
+}
+
+let interactionReporter: InteractionReporter;
+
+export function initInteractionReporter(reportingService: ReportingService) {
+  if (!interactionReporter) {
+    interactionReporter = new InteractionReporter(reportingService);
+  }
+}
+
 export function initWebVitals(reportingService: ReportingService) {
   function reportWebVitalMetric(name: Timing, metric: Metric) {
     let score = metric.value;
diff --git a/polygerrit-ui/app/services/gr-reporting/gr-reporting_test.ts b/polygerrit-ui/app/services/gr-reporting/gr-reporting_test.ts
index 9c5e20d..2d3dfe2 100644
--- a/polygerrit-ui/app/services/gr-reporting/gr-reporting_test.ts
+++ b/polygerrit-ui/app/services/gr-reporting/gr-reporting_test.ts
@@ -8,11 +8,14 @@
   GrReporting,
   DEFAULT_STARTUP_TIMERS,
   initErrorReporter,
+  InteractionReporter,
 } from './gr-reporting_impl';
 import {getAppContext} from '../app-context';
 import {Deduping} from '../../api/reporting';
-import {SinonFakeTimers} from 'sinon';
+import {SinonFakeTimers, SinonStub} from 'sinon';
 import {assert} from '@open-wc/testing';
+import {grReportingMock} from './gr-reporting_mock';
+import {Interaction} from '../../constants/reporting';
 
 suite('gr-reporting tests', () => {
   // We have to type as any because we access
@@ -563,3 +566,62 @@
     });
   });
 });
+
+suite('InteractionReporter', () => {
+  let interactionReporter: InteractionReporter;
+  let clock: SinonFakeTimers;
+  let stub: SinonStub;
+  let activeCalls: number[] = [];
+  let passiveCalls: number[] = [];
+
+  setup(() => {
+    clock = sinon.useFakeTimers(0);
+    activeCalls = [];
+    passiveCalls = [];
+    const reporting = grReportingMock;
+    stub = sinon
+      .stub(reporting, 'reportInteraction')
+      .callsFake((interaction: string | Interaction) => {
+        if (interaction === Interaction.USER_ACTIVE) {
+          activeCalls.push(clock.now);
+        }
+        if (interaction === Interaction.USER_PASSIVE) {
+          passiveCalls.push(clock.now);
+        }
+      });
+    interactionReporter = new InteractionReporter(reporting, 1000);
+  });
+
+  teardown(() => {
+    clock.restore();
+    interactionReporter.finalize();
+  });
+
+  test('interaction example', () => {
+    clock.tick(500);
+    clock.tick(1000);
+    document.dispatchEvent(new MouseEvent('mousemove'));
+    clock.tick(1000);
+    document.dispatchEvent(new MouseEvent('mousemove'));
+    document.dispatchEvent(new MouseEvent('scroll'));
+    document.dispatchEvent(new MouseEvent('wheel'));
+    clock.tick(1000);
+    clock.tick(1000);
+    clock.tick(1000);
+    document.dispatchEvent(new MouseEvent('mousemove'));
+    clock.tick(1000);
+    document.dispatchEvent(new MouseEvent('mousemove'));
+    clock.tick(1000);
+
+    assert.sameOrderedMembers(activeCalls, [2000, 3000, 6000, 7000]);
+    assert.sameOrderedMembers(passiveCalls, [1000, 4000, 5000]);
+
+    assert.isUndefined(stub.getCall(0).args[1].events);
+    assert.sameMembers(stub.getCall(1).args[1].events, ['mousemove']);
+    assert.sameMembers(stub.getCall(2).args[1].events, [
+      'mousemove',
+      'scroll',
+      'wheel',
+    ]);
+  });
+});
diff --git a/polygerrit-ui/app/test/mocks/gr-rest-api_mock.ts b/polygerrit-ui/app/test/mocks/gr-rest-api_mock.ts
index b60ace5..f8e4160 100644
--- a/polygerrit-ui/app/test/mocks/gr-rest-api_mock.ts
+++ b/polygerrit-ui/app/test/mocks/gr-rest-api_mock.ts
@@ -67,6 +67,7 @@
   createChange,
   createCommit,
   createConfig,
+  createMergeable,
   createPreferences,
   createServerInfo,
   createSubmittedTogetherInfo,
@@ -368,7 +369,7 @@
     return Promise.resolve(true);
   },
   getMergeable(): Promise<MergeableInfo | undefined> {
-    throw new Error('getMergeable() not implemented by RestApiMock.');
+    return Promise.resolve(createMergeable());
   },
   getPlugins(): Promise<{[p: string]: PluginInfo} | undefined> {
     return Promise.resolve({});
diff --git a/polygerrit-ui/app/test/test-data-generators.ts b/polygerrit-ui/app/test/test-data-generators.ts
index a92e932..dce8e4b 100644
--- a/polygerrit-ui/app/test/test-data-generators.ts
+++ b/polygerrit-ui/app/test/test-data-generators.ts
@@ -672,10 +672,10 @@
   };
 }
 
-export function createMergeable(): MergeableInfo {
+export function createMergeable(mergeable = false): MergeableInfo {
   return {
     submit_type: SubmitType.MERGE_IF_NECESSARY,
-    mergeable: false,
+    mergeable,
   };
 }
 
diff --git a/polygerrit-ui/app/test/test-utils.ts b/polygerrit-ui/app/test/test-utils.ts
index d897423..6e20dd4 100644
--- a/polygerrit-ui/app/test/test-utils.ts
+++ b/polygerrit-ui/app/test/test-utils.ts
@@ -16,8 +16,9 @@
 import {assert} from '@open-wc/testing';
 import {Route, ViewState} from '../models/views/base';
 import {PageContext} from '../elements/core/gr-router/gr-page';
+import {waitUntil} from '../utils/async-util';
 export {query, queryAll, queryAndAssert} from '../utils/common-util';
-export {mockPromise} from '../utils/async-util';
+export {mockPromise, waitUntil} from '../utils/async-util';
 export type {MockPromise} from '../utils/async-util';
 
 export function isHidden(el: Element | undefined | null) {
@@ -149,32 +150,6 @@
   return queryAndAssert<E>(el, selector);
 }
 
-export async function waitUntil(
-  predicate: (() => boolean) | (() => Promise<boolean>),
-  message = 'The waitUntil() predicate is still false after 1000 ms.',
-  timeout_ms = 1000
-): Promise<void> {
-  const start = Date.now();
-  let sleep = 0;
-  if (await predicate()) return Promise.resolve();
-  const error = new Error(message);
-  return new Promise((resolve, reject) => {
-    const waiter = async () => {
-      if (await predicate()) {
-        resolve();
-        return;
-      }
-      if (Date.now() - start >= timeout_ms) {
-        reject(error);
-        return;
-      }
-      setTimeout(waiter, sleep);
-      sleep = sleep === 0 ? 1 : sleep * 4;
-    };
-    waiter();
-  });
-}
-
 export async function waitUntilVisible(element: Element): Promise<void> {
   return new Promise(resolve => {
     whenVisible(element, () => resolve());
diff --git a/polygerrit-ui/app/types/events.ts b/polygerrit-ui/app/types/events.ts
index 4bf0c78..922d779 100644
--- a/polygerrit-ui/app/types/events.ts
+++ b/polygerrit-ui/app/types/events.ts
@@ -52,14 +52,13 @@
     'open-fix-preview': OpenFixPreviewEvent;
     'reply-to-comment': ReplyToCommentEvent;
     // prettier-ignore
-    'reload': ReloadEvent;
+    'reload': CustomEvent<{}>;
     'remove-reviewer': RemoveReviewerEvent;
     'show-alert': ShowAlertEvent;
     'show-error': ShowErrorEvent;
     'show-tab': SwitchTabEvent;
     'show-secondary-tab': SwitchTabEvent;
     'tap-item': TapItemEvent;
-    'title-change': TitleChangeEvent;
   }
 }
 
@@ -69,11 +68,12 @@
     'network-error': NetworkErrorEvent;
     'page-error': PageErrorEvent;
     // prettier-ignore
-    'reload': ReloadEvent;
+    'reload': CustomEvent<{}>;
     'server-error': ServerErrorEvent;
     'show-alert': ShowAlertEvent;
     'show-error': ShowErrorEvent;
     'auth-error': AuthErrorEvent;
+    'title-change': TitleChangeEvent;
   }
 }
 
@@ -186,11 +186,6 @@
 }
 export type PageErrorEvent = CustomEvent<PageErrorEventDetail>;
 
-export interface ReloadEventDetail {
-  clearPatchset: boolean;
-}
-export type ReloadEvent = CustomEvent<ReloadEventDetail>;
-
 export interface RemoveAccountEventDetail {
   account: AccountInfo;
 }
diff --git a/polygerrit-ui/app/utils/async-util.ts b/polygerrit-ui/app/utils/async-util.ts
index 2dde07a..32a6867 100644
--- a/polygerrit-ui/app/utils/async-util.ts
+++ b/polygerrit-ui/app/utils/async-util.ts
@@ -371,3 +371,29 @@
     setTimeout(resolve, timeoutMs);
   });
 }
+
+export async function waitUntil(
+  predicate: (() => boolean) | (() => Promise<boolean>),
+  message = 'The waitUntil() predicate is still false after 1000 ms.',
+  timeout_ms = 1000
+): Promise<void> {
+  if (await predicate()) return Promise.resolve();
+  const start = Date.now();
+  let sleep = 10;
+  const error = new Error(message);
+  return new Promise((resolve, reject) => {
+    const waiter = async () => {
+      if (await predicate()) {
+        resolve();
+        return;
+      }
+      if (Date.now() - start >= timeout_ms) {
+        reject(error);
+        return;
+      }
+      setTimeout(waiter, sleep);
+      sleep *= 2;
+    };
+    waiter();
+  });
+}
diff --git a/polygerrit-ui/app/utils/change-util.ts b/polygerrit-ui/app/utils/change-util.ts
index 5dda8d6..4490afa 100644
--- a/polygerrit-ui/app/utils/change-util.ts
+++ b/polygerrit-ui/app/utils/change-util.ts
@@ -20,6 +20,8 @@
 interface ChangeStatusesOptions {
   mergeable: boolean; // This can be wrong! See WARNING above
   submitEnabled: boolean; // This can be wrong! See WARNING above
+  /** Is there a reverting change and if so, what status has it? */
+  revertingChangeStatus?: ChangeStatus;
 }
 
 export const ChangeDiffType = {
@@ -158,6 +160,12 @@
 ): ChangeStates[] {
   const states = [];
   if (change.status === ChangeStatus.MERGED) {
+    if (options?.revertingChangeStatus === ChangeStatus.MERGED) {
+      return [ChangeStates.MERGED, ChangeStates.REVERT_SUBMITTED];
+    }
+    if (options?.revertingChangeStatus !== undefined) {
+      return [ChangeStates.MERGED, ChangeStates.REVERT_CREATED];
+    }
     return [ChangeStates.MERGED];
   }
   if (change.status === ChangeStatus.ABANDONED) {
diff --git a/polygerrit-ui/app/utils/change-util_test.ts b/polygerrit-ui/app/utils/change-util_test.ts
index ccaa1db..f768145 100644
--- a/polygerrit-ui/app/utils/change-util_test.ts
+++ b/polygerrit-ui/app/utils/change-util_test.ts
@@ -129,6 +129,32 @@
     assert.deepEqual(changeStatuses(change), [ChangeStates.MERGED]);
   });
 
+  test('Merged and Reverted status', () => {
+    const change = {
+      ...createChange(),
+      revisions: createRevisions(1),
+      current_revision: 'rev1' as CommitId,
+      status: ChangeStatus.MERGED,
+    };
+    assert.deepEqual(changeStatuses(change), [ChangeStates.MERGED]);
+    assert.deepEqual(
+      changeStatuses(change, {
+        revertingChangeStatus: ChangeStatus.NEW,
+        mergeable: true,
+        submitEnabled: true,
+      }),
+      [ChangeStates.MERGED, ChangeStates.REVERT_CREATED]
+    );
+    assert.deepEqual(
+      changeStatuses(change, {
+        revertingChangeStatus: ChangeStatus.MERGED,
+        mergeable: true,
+        submitEnabled: true,
+      }),
+      [ChangeStates.MERGED, ChangeStates.REVERT_SUBMITTED]
+    );
+  });
+
   test('Abandoned status', () => {
     const change = {
       ...createChange(),
diff --git a/polygerrit-ui/app/utils/comment-util.ts b/polygerrit-ui/app/utils/comment-util.ts
index 802d15d..4646bf6 100644
--- a/polygerrit-ui/app/utils/comment-util.ts
+++ b/polygerrit-ui/app/utils/comment-util.ts
@@ -238,6 +238,14 @@
   return isDraft(getLastComment(thread));
 }
 
+/**
+ * Returns true, if the thread consists only of one comment that has not yet
+ * been saved to the backend.
+ */
+export function isNewThread(thread: CommentThread): boolean {
+  return isNew(getFirstComment(thread));
+}
+
 export function isMentionedThread(
   thread: CommentThread,
   account?: AccountInfo
@@ -427,8 +435,8 @@
 }
 
 /**
- * Add state:SAVED to all drafts returned from server so that they can be told
- * apart from published comments easily.
+ * Add `savingState: SavingState.OK` to all drafts returned from server so that
+ * they can be told apart from published comments easily.
  */
 export function addDraftProp(
   draftsByPath: {[path: string]: CommentInfo[]} = {}
diff --git a/polygerrit-ui/app/utils/comment-util_test.ts b/polygerrit-ui/app/utils/comment-util_test.ts
index ab21c67..7bf0c1e 100644
--- a/polygerrit-ui/app/utils/comment-util_test.ts
+++ b/polygerrit-ui/app/utils/comment-util_test.ts
@@ -16,6 +16,8 @@
   createUserFixSuggestion,
   PROVIDED_FIX_ID,
   getMentionedThreads,
+  isNewThread,
+  createNew,
 } from './comment-util';
 import {
   createAccountWithEmail,
@@ -72,6 +74,17 @@
     );
   });
 
+  test('isNewThread', () => {
+    let thread = createCommentThread([createComment()]);
+    assert.isFalse(isNewThread(thread));
+
+    thread = createCommentThread([createComment(), createNew()]);
+    assert.isFalse(isNewThread(thread));
+
+    thread = createCommentThread([createNew()]);
+    assert.isTrue(isNewThread(thread));
+  });
+
   suite('getPatchRangeForCommentUrl', () => {
     test('comment created with side=PARENT does not navigate to latest ps', () => {
       const comment = {
diff --git a/polygerrit-ui/app/utils/event-util.ts b/polygerrit-ui/app/utils/event-util.ts
index 3704557..af545e7 100644
--- a/polygerrit-ui/app/utils/event-util.ts
+++ b/polygerrit-ui/app/utils/event-util.ts
@@ -95,8 +95,8 @@
   fire(document, 'network-error', {error});
 }
 
-export function fireTitleChange(target: EventTarget, title: string) {
-  fire(target, 'title-change', {title});
+export function fireTitleChange(title: string) {
+  fire(document, 'title-change', {title});
 }
 
 // TODO(milutin) - remove once new gr-dialog will do it out of the box
@@ -122,8 +122,8 @@
   fire(target, 'show-tab', detail);
 }
 
-export function fireReload(target: EventTarget, clearPatchset?: boolean) {
-  fire(target, 'reload', {clearPatchset: !!clearPatchset});
+export function fireReload(target: EventTarget) {
+  fire(target, 'reload', {});
 }
 
 export function waitForEventOnce<K extends keyof HTMLElementEventMap>(
diff --git a/polygerrit-ui/app/utils/message-util_test.ts b/polygerrit-ui/app/utils/message-util_test.ts
new file mode 100644
index 0000000..22a5e4d
--- /dev/null
+++ b/polygerrit-ui/app/utils/message-util_test.ts
@@ -0,0 +1,37 @@
+/**
+ * @license
+ * Copyright 2023 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+import {getRevertCreatedChangeIds} from './message-util';
+import {assert} from '@open-wc/testing';
+import {MessageTag} from '../constants/constants';
+import {ChangeId, ReviewInputTag} from '../api/rest-api';
+import {createChangeMessage} from '../test/test-data-generators';
+
+suite('message-util tests', () => {
+  test('getRevertCreatedChangeIds', () => {
+    const messages = [
+      {
+        ...createChangeMessage(),
+        message: 'Created a revert of this change as 123',
+        tag: MessageTag.TAG_REVERT as ReviewInputTag,
+      },
+      {
+        ...createChangeMessage(),
+        message: 'Created a revert of this change as xyz',
+        tag: MessageTag.TAG_REVERT as ReviewInputTag,
+      },
+      {
+        ...createChangeMessage(),
+        message: 'Created a revert of this change as abc',
+        tag: undefined,
+      },
+    ];
+
+    assert.deepEqual(getRevertCreatedChangeIds(messages), [
+      '123' as ChangeId,
+      'xyz' as ChangeId,
+    ]);
+  });
+});
diff --git a/polygerrit-ui/app/utils/patch-set-util.ts b/polygerrit-ui/app/utils/patch-set-util.ts
index 7e16ad9..7f3b6eb 100644
--- a/polygerrit-ui/app/utils/patch-set-util.ts
+++ b/polygerrit-ui/app/utils/patch-set-util.ts
@@ -35,11 +35,6 @@
   wip?: boolean;
 }
 
-interface PatchRange {
-  patchNum?: RevisionPatchSetNum;
-  basePatchNum?: BasePatchSetNum;
-}
-
 /**
  * Whether the given patch is a numbered parent of a merge (i.e. a negative
  * number).
@@ -294,10 +289,6 @@
   return allPatchSets[0].num === EDIT;
 }
 
-export function hasEditPatchsetLoaded(patchRange: PatchRange) {
-  return patchRange.patchNum === EDIT;
-}
-
 /**
  * @param revisions A sorted array of revisions.
  *
diff --git a/resources/com/google/gerrit/httpd/auth/ldap/LoginForm.html b/resources/com/google/gerrit/httpd/auth/ldap/LoginForm.html
index 593ea45..08c890d 100644
--- a/resources/com/google/gerrit/httpd/auth/ldap/LoginForm.html
+++ b/resources/com/google/gerrit/httpd/auth/ldap/LoginForm.html
@@ -43,6 +43,7 @@
             <input name="rememberme" id="f_remember"
                    type="checkbox"
                    value="1"
+                   checked="checked"
                    tabindex="3" />
             <label for="f_remember">Remember me</label>
           </td>
diff --git a/tools/BUILD b/tools/BUILD
index e25dcc5..e05a705 100644
--- a/tools/BUILD
+++ b/tools/BUILD
@@ -76,6 +76,7 @@
         "-Xep:BadImport:ERROR",
         "-Xep:BadInstanceof:ERROR",
         "-Xep:BadShiftAmount:ERROR",
+        "-Xep:BanJNDI:WARN",
         "-Xep:BanSerializableRead:ERROR",
         "-Xep:BigDecimalEquals:ERROR",
         "-Xep:BigDecimalLiteralDouble:ERROR",
@@ -187,6 +188,7 @@
         "-Xep:ImmutableAnnotationChecker:ERROR",
         "-Xep:ImmutableEnumChecker:ERROR",
         "-Xep:ImmutableModification:ERROR",
+        "-Xep:ImpossibleNullComparison:WARN",
         "-Xep:Incomparable:ERROR",
         "-Xep:IncompatibleArgumentType:ERROR",
         "-Xep:IncompatibleModifiers:ERROR",
@@ -255,7 +257,7 @@
         "-Xep:JodaWithDurationAddedLong:ERROR",
         "-Xep:LiteByteStringUtf8:ERROR",
         "-Xep:LiteEnumValueOf:ERROR",
-        "-Xep:LiteProtoToString:ERROR",
+        "-Xep:LiteProtoToString:WARN",
         "-Xep:LocalDateTemporalAmount:ERROR",
         "-Xep:LockNotBeforeTry:ERROR",
         "-Xep:LockOnBoxedPrimitive:ERROR",
@@ -287,7 +289,7 @@
         "-Xep:MultipleParallelOrSequentialCalls:ERROR",
         "-Xep:MultipleUnaryOperatorsInMethodCall:ERROR",
         "-Xep:MustBeClosedChecker:ERROR",
-        "-Xep:MutableConstantField:ERROR",
+        "-Xep:MutableConstantField:WARN",
         "-Xep:MutablePublicArray:ERROR",
         "-Xep:NCopiesOfChar:ERROR",
         "-Xep:NarrowingCompoundAssignment:ERROR",
@@ -340,7 +342,7 @@
         "-Xep:ProtoTimestampGetSecondsGetNano:ERROR",
         "-Xep:ProtoTruthMixedDescriptors:ERROR",
         "-Xep:ProtocolBufferOrdinal:ERROR",
-        "-Xep:ProvidesMethodOutsideOfModule:ERROR",
+        "-Xep:ProvidesMethodOutsideOfModule:WARN",
         "-Xep:RandomCast:ERROR",
         "-Xep:RandomModInteger:ERROR",
         "-Xep:ReachabilityFenceUsage:ERROR",
diff --git a/tools/nongoogle.bzl b/tools/nongoogle.bzl
index 7f26ef3..df62019 100644
--- a/tools/nongoogle.bzl
+++ b/tools/nongoogle.bzl
@@ -243,36 +243,36 @@
         sha1 = "64cba89cf87c1d84cb8c81d06f0b9c482f10b4dc",
     )
 
-    LUCENE_VERS = "7.7.3"
+    LUCENE_VERS = "8.11.2"
 
     maven_jar(
         name = "lucene-core",
         artifact = "org.apache.lucene:lucene-core:" + LUCENE_VERS,
-        sha1 = "5faa5ae56f7599019fce6184accc6c968b7519e7",
+        sha1 = "57438c3f31e0e440de149294890eee88e030ea6d",
     )
 
     maven_jar(
         name = "lucene-analyzers-common",
         artifact = "org.apache.lucene:lucene-analyzers-common:" + LUCENE_VERS,
-        sha1 = "0a76cbf5e21bbbb0c2d6288b042450236248214e",
+        sha1 = "07a74c5c2dd082b08c644a9016bc6ff66c8f27cc",
     )
 
     maven_jar(
         name = "backward-codecs",
         artifact = "org.apache.lucene:lucene-backward-codecs:" + LUCENE_VERS,
-        sha1 = "40207d0dd023a0e2868a23dd87d72f1a3cdbb893",
+        sha1 = "a5d0f0db405d607cc13265819b8d2ef0c81c0819",
     )
 
     maven_jar(
         name = "lucene-misc",
         artifact = "org.apache.lucene:lucene-misc:" + LUCENE_VERS,
-        sha1 = "3aca078edf983059722fe61a81b7b7bd5ecdb222",
+        sha1 = "9c7204f923465a96a20ac9e49cdca0cfcde64851",
     )
 
     maven_jar(
         name = "lucene-queryparser",
         artifact = "org.apache.lucene:lucene-queryparser:" + LUCENE_VERS,
-        sha1 = "685fc6166d29eb3e3441ae066873bb442aa02df1",
+        sha1 = "1886e3a27a8d4a73eb8fad54ea93a160b099bc60",
     )
 
     # JGit's transitive dependencies