diff --git a/Documentation/access-control.txt b/Documentation/access-control.txt
index d3f5d77..13e3a53 100644
--- a/Documentation/access-control.txt
+++ b/Documentation/access-control.txt
@@ -5,6 +5,12 @@
 to those groups.  Access rights cannot be granted to individual
 users.
 
+To view/edit the access controls for a specific project, first
+navigate to the projects page: for example,
+https://gerrit-review.googlesource.com/admin/repos/ . Then click on
+the individual project, and then click Access. This will bring you
+to a url that looks like
+https://gerrit-review.googlesource.com/admin/repos/gerrit,access
 
 [[system_groups]]
 == System Groups
diff --git a/Documentation/config-cla.txt b/Documentation/config-cla.txt
index 2234808..2c7b194 100644
--- a/Documentation/config-cla.txt
+++ b/Documentation/config-cla.txt
@@ -25,13 +25,15 @@
 ----
 
 Contributor agreements are defined as contributor-agreement sections in
-`project.config`:
+`project.config` of `All-Projects`:
 ----
   [contributor-agreement "Individual"]
     description = If you are going to be contributing code on your own, this is the one you want. You can sign this one online.
     agreementUrl = static/cla_individual.html
     autoVerify = group CLA Accepted - Individual
     accepted = group CLA Accepted - Individual
+    matchProjects = ^/.*$
+    excludeProjects = ^/not/my/project/
 ----
 
 Each `contributor-agreement` section within the `project.config` file must
@@ -75,6 +77,16 @@
 contributor agreement has been accepted. The groups' UUID must also
 appear in the `groups` file.
 
+[[contributor-agreement.name.matchProjects]]contributor-agreement.<name>.matchProjects::
++
+List of project regular expressions identifying projects where the
+agreement is required. Defaults to every project when omitted.
+
+[[contributor-agreement.name.excludeProjects]]contributor-agreement.<name>.excludeProjects::
++
+List of project regular expressions identifying projects where the
+agreement does not apply. Defaults to empty. i.e. no projects excluded.
+
 GERRIT
 ------
 Part of link:index.html[Gerrit Code Review]
diff --git a/Documentation/dev-bazel.txt b/Documentation/dev-bazel.txt
index 0ecc820..a68c3ac 100644
--- a/Documentation/dev-bazel.txt
+++ b/Documentation/dev-bazel.txt
@@ -258,8 +258,10 @@
   bazel test //javatests/com/google/gerrit/acceptance/rest/account:rest_account
 ----
 
-To run the tests against NoteDb backend with write
-to NoteDb, but not read from it:
+The tests run with NoteDb fully enabled by default.
+
+To run the tests against NoteDb backend with write to NoteDb, but not read from
+it:
 
 ----
   bazel test --test_env=GERRIT_NOTEDB=WRITE //...
@@ -277,10 +279,10 @@
   bazel test --test_env=GERRIT_NOTEDB=PRIMARY //...
 ----
 
-Primary storage NoteDb and ReviewDb disabled:
+NoteDb entirely disabled:
 
 ----
-  bazel test --test_env=GERRIT_NOTEDB=ON //...
+  bazel test --test_env=GERRIT_NOTEDB=OFF //...
 ----
 
 To run only tests that do not use SSH:
diff --git a/Documentation/dev-intellij.txt b/Documentation/dev-intellij.txt
index 8bedd08..5ec6ae8 100644
--- a/Documentation/dev-intellij.txt
+++ b/Documentation/dev-intellij.txt
@@ -177,9 +177,9 @@
 plugin manages a project, it intercepts the creation and creates a Bazel test
 run configuration instead, which can be used just like the standard ones.
 
-TIP: If you would like to execute a test in NoteDb mode, add
-`--test_env=GERRIT_NOTEDB=READ_WRITE` to the *Bazel flags* of your run
-configuration.
+TIP: Tests run with NoteDb enabled by default. If you would like to execute a
+test with NoteDb turned off, add `--test_env=GERRIT_NOTEDB=OFF` to the *Bazel
+flags* of your run configuration.
 
 [[remote-debug]]
 === Debugging a remote Gerrit server
diff --git a/Documentation/metrics.txt b/Documentation/metrics.txt
index 37d6d01..db6f883 100644
--- a/Documentation/metrics.txt
+++ b/Documentation/metrics.txt
@@ -177,6 +177,10 @@
 * `plugin/latency`: Latency for plugin invocation.
 * `plugin/error_count`: Number of plugin errors.
 
+=== Group
+
+* `group/guess_relevant_groups_latency`: Latency for guessing relevant groups.
+
 === Replication Plugin
 
 * `plugins/replication/replication_latency`: Time spent pushing to remote
diff --git a/Documentation/replace_macros.py b/Documentation/replace_macros.py
index 6f90697..309a135 100755
--- a/Documentation/replace_macros.py
+++ b/Documentation/replace_macros.py
@@ -89,7 +89,7 @@
 </button>
 <script type="text/javascript">
 var f = function() {
-  window.location = '../#/Documentation/' +
+  window.location = '../#/Documentation/q/' +
     encodeURIComponent(document.getElementById("docSearch").value);
 }
 document.getElementById("searchBox").onclick = f;
diff --git a/Documentation/rest-api-changes.txt b/Documentation/rest-api-changes.txt
index 1829c6b..b1c9a88 100644
--- a/Documentation/rest-api-changes.txt
+++ b/Documentation/rest-api-changes.txt
@@ -5769,8 +5769,12 @@
 Number of inserted lines.
 |`deletions`          ||
 Number of deleted lines.
+|`total_comment_count`  |optional|
+Total number of inline comments across all patch sets. Not set if the current
+change index doesn't have the data.
 |`unresolved_comment_count`  |optional|
-Number of unresolved comments. Not set if the current change index doesn't have the data.
+Number of unresolved inline comment threads across all patch sets. Not set if
+the current change index doesn't have the data.
 |`_number`            ||The legacy numeric ID of the change.
 |`owner`              ||
 The owner of the change as an link:rest-api-accounts.html#account-info[
diff --git a/Documentation/rest-api-projects.txt b/Documentation/rest-api-projects.txt
index 3214761..49ab36f 100644
--- a/Documentation/rest-api-projects.txt
+++ b/Documentation/rest-api-projects.txt
@@ -1358,25 +1358,6 @@
 Ref(ref)::
 The branch for which to check access. This must be given if `perm` is specified.
 
-[[check-access-post]]
-=== Check Access (POST)
-
-This endpoint can also be accessed as a POST request (deprecated). In
-this case, the input for the access checks must be provided in the
-request body inside a link:#access-check-input[AccessCheckInput]
-entity.
-
-.Request
-----
-  POST /projects/MyProject/check.access HTTP/1.0
-  Content-Type: application/json; charset=UTF-8
-
-  {
-    "account": "Kristen.Burns@gerritcodereview.com",
-    "ref": "refs/heads/secret/bla"
-  }
-----
-
 [[index]]
 === Index project
 
@@ -2936,21 +2917,6 @@
 |`message`                   |optional|A clarifying message if `status` is not 200.
 |=========================================
 
-[[access-check-input]]
-=== AccessCheckInput
-The `AccessCheckInput` entity is either an account or
-(account, ref) tuple for which we want to check access.
-
-[options="header",cols="1,^1,5"]
-|=========================================
-|Field Name                  ||Description
-|`account`                   ||The account for which to check access
-|`ref`                       |optional|The refname for which to check
-access
-|`permission`                |optional|The ref permission for which to
-check. This defaults to `read`. If given, it `ref` must be given too.
-|=========================================
-
 [[auto_closeable_changes_check_input]]
 === AutoCloseableChangesCheckInput
 The `AutoCloseableChangesCheckInput` entity contains options for running
diff --git a/WORKSPACE b/WORKSPACE
index b2b3b6f..a5dbbaf 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -15,9 +15,9 @@
 
 http_archive(
     name = "io_bazel_rules_closure",
-    sha256 = "4dd84dd2bdd6c9f56cb5a475d504ea31d199c34309e202e9379501d01c3067e5",
-    strip_prefix = "rules_closure-3103a773820b59b76345f94c231cb213e0d404e2",
-    urls = ["https://github.com/bazelbuild/rules_closure/archive/3103a773820b59b76345f94c231cb213e0d404e2.tar.gz"],
+    sha256 = "5b4b610ea4892116b6126fa689218535629305590c43fbd68034d831953a9989",
+    strip_prefix = "rules_closure-409a86250c457ca15cafde35eb169e4c2601570e",
+    urls = ["https://github.com/bazelbuild/rules_closure/archive/409a86250c457ca15cafde35eb169e4c2601570e.zip"],
 )
 
 # File is specific to Polymer and copied from the Closure Github -- should be
@@ -48,8 +48,8 @@
 # Golang support for PolyGerrit local dev server.
 http_archive(
     name = "io_bazel_rules_go",
-    sha256 = "97cf62bdef33519412167fd1e4b0810a318a7c234f5f8dc4f53e2da86241c492",
-    urls = ["https://github.com/bazelbuild/rules_go/releases/download/0.15.3/rules_go-0.15.3.tar.gz"],
+    sha256 = "ee5fe78fe417c685ecb77a0a725dc9f6040ae5beb44a0ba4ddb55453aad23a8a",
+    url = "https://github.com/bazelbuild/rules_go/releases/download/0.16.0/rules_go-0.16.0.tar.gz",
 )
 
 load("@io_bazel_rules_go//go:def.bzl", "go_register_toolchains", "go_rules_dependencies")
@@ -108,24 +108,24 @@
     sha1 = "83cd2cd674a217ade95a4bb83a8a14f351f48bd0",
 )
 
-GUICE_VERS = "4.2.1"
+GUICE_VERS = "4.2.2"
 
 maven_jar(
     name = "guice-library",
     artifact = "com.google.inject:guice:" + GUICE_VERS,
-    sha1 = "f77dfd89318fe3ff293bafceaa75fbf66e4e4b10",
+    sha1 = "6dacbe18e5eaa7f6c9c36db33b42e7985e94ce77",
 )
 
 maven_jar(
     name = "guice-assistedinject",
     artifact = "com.google.inject.extensions:guice-assistedinject:" + GUICE_VERS,
-    sha1 = "d327e4aee7c96f08cd657c17da231a1f4a8999ac",
+    sha1 = "c33fb10080d58446f752b4fcfff8a5fabb80a449",
 )
 
 maven_jar(
     name = "guice-servlet",
     artifact = "com.google.inject.extensions:guice-servlet:" + GUICE_VERS,
-    sha1 = "3927e462f923b0c672fdb045c5645bca4beab5c0",
+    sha1 = "0d0054bdd812224078357a9b11409e43d182a046",
 )
 
 maven_jar(
@@ -586,36 +586,36 @@
     sha1 = "5e3bda828a80c7a21dfbe2308d1755759c2fd7b4",
 )
 
-OW2_VERS = "6.2.1"
+OW2_VERS = "7.0"
 
 maven_jar(
     name = "ow2-asm",
     artifact = "org.ow2.asm:asm:" + OW2_VERS,
-    sha1 = "c01b6798f81b0fc2c5faa70cbe468c275d4b50c7",
+    sha1 = "d74d4ba0dee443f68fb2dcb7fcdb945a2cd89912",
 )
 
 maven_jar(
     name = "ow2-asm-analysis",
     artifact = "org.ow2.asm:asm-analysis:" + OW2_VERS,
-    sha1 = "e8b876c5ccf226cae2f44ed2c436ad3407d0ec1d",
+    sha1 = "4b310d20d6f1c6b7197a75f1b5d69f169bc8ac1f",
 )
 
 maven_jar(
     name = "ow2-asm-commons",
     artifact = "org.ow2.asm:asm-commons:" + OW2_VERS,
-    sha1 = "eaf31376d741a3e2017248a4c759209fe25c77d3",
+    sha1 = "478006d07b7c561ae3a92ddc1829bca81ae0cdd1",
 )
 
 maven_jar(
     name = "ow2-asm-tree",
     artifact = "org.ow2.asm:asm-tree:" + OW2_VERS,
-    sha1 = "332b022092ecec53cdb6272dc436884b2d940615",
+    sha1 = "29bc62dcb85573af6e62e5b2d735ef65966c4180",
 )
 
 maven_jar(
     name = "ow2-asm-util",
     artifact = "org.ow2.asm:asm-util:" + OW2_VERS,
-    sha1 = "400d664d7c92a659d988c00cb65150d1b30cf339",
+    sha1 = "18d4d07010c24405129a6dbb0e92057f8779fb9d",
 )
 
 AUTO_VALUE_VERSION = "1.6.2"
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/Dispatcher.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/Dispatcher.java
index c9346f4..4b84864 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/Dispatcher.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/Dispatcher.java
@@ -236,7 +236,7 @@
     if (matchPrefix(QUERY, token)) {
       query(token);
 
-    } else if (matchPrefix("/Documentation/", token)) {
+    } else if (matchPrefix("/Documentation/q/", token)) {
       docSearch(token);
 
     } else if (matchPrefix("/c/", token)) {
diff --git a/java/com/google/gerrit/acceptance/AbstractDaemonTest.java b/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
index 496ee5b..d168919 100644
--- a/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
+++ b/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
@@ -50,6 +50,7 @@
 import com.google.gerrit.common.data.PermissionRule;
 import com.google.gerrit.common.data.PermissionRule.Action;
 import com.google.gerrit.extensions.api.GerritApi;
+import com.google.gerrit.extensions.api.changes.RelatedChangeAndCommitInfo;
 import com.google.gerrit.extensions.api.changes.ReviewInput;
 import com.google.gerrit.extensions.api.changes.RevisionApi;
 import com.google.gerrit.extensions.api.changes.SubmittedTogetherInfo;
@@ -252,6 +253,7 @@
   @Inject protected MetaDataUpdate.Server metaDataUpdateFactory;
   @Inject protected PatchSetUtil psUtil;
   @Inject protected ProjectCache projectCache;
+  @Inject protected ProjectConfig.Factory projectConfigFactory;
   @Inject protected ProjectResetter.Builder.Factory projectResetter;
   @Inject protected Provider<InternalChangeQuery> queryProvider;
   @Inject protected PushOneCommit.Factory pushFactory;
@@ -268,6 +270,7 @@
   protected Project.NameKey project;
   protected RestSession adminRestSession;
   protected RestSession userRestSession;
+  protected RestSession anonymousRestSession;
   protected ReviewDb db;
   protected SshSession adminSshSession;
   protected SshSession userSshSession;
@@ -444,6 +447,7 @@
 
     adminRestSession = new RestSession(server, admin);
     userRestSession = new RestSession(server, user);
+    anonymousRestSession = new RestSession(server, null);
 
     initSsh();
 
@@ -997,7 +1001,7 @@
 
   protected void setUseContributorAgreements(InheritableBoolean value) throws Exception {
     try (MetaDataUpdate md = metaDataUpdateFactory.create(project)) {
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
       config.getProject().setBooleanConfig(BooleanProjectConfig.USE_CONTRIBUTOR_AGREEMENTS, value);
       config.commit(md);
       projectCache.evict(config.getProject());
@@ -1006,7 +1010,7 @@
 
   protected void setUseSignedOffBy(InheritableBoolean value) throws Exception {
     try (MetaDataUpdate md = metaDataUpdateFactory.create(project)) {
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
       config.getProject().setBooleanConfig(BooleanProjectConfig.USE_SIGNED_OFF_BY, value);
       config.commit(md);
       projectCache.evict(config.getProject());
@@ -1015,7 +1019,7 @@
 
   protected void setRequireChangeId(InheritableBoolean value) throws Exception {
     try (MetaDataUpdate md = metaDataUpdateFactory.create(project)) {
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
       config.getProject().setBooleanConfig(BooleanProjectConfig.REQUIRE_CHANGE_ID, value);
       config.commit(md);
       projectCache.evict(config.getProject());
@@ -1077,7 +1081,7 @@
       throws RepositoryNotFoundException, IOException, ConfigInvalidException {
     try (MetaDataUpdate md = metaDataUpdateFactory.create(project)) {
       md.setMessage(String.format("Grant %s on %s", permission, ref));
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
       AccessSection s = config.getAccessSection(ref, true);
       Permission p = s.getPermission(permission, true);
       PermissionRule rule = Util.newRule(config, groupUUID);
@@ -1101,7 +1105,7 @@
     String permission = Permission.LABEL + label;
     try (MetaDataUpdate md = metaDataUpdateFactory.create(project)) {
       md.setMessage(String.format("Grant %s on %s", permission, ref));
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
       AccessSection s = config.getAccessSection(ref, true);
       Permission p = s.getPermission(permission, true);
       p.setExclusiveGroup(exclusive);
@@ -1119,7 +1123,7 @@
       throws IOException, ConfigInvalidException {
     try (MetaDataUpdate md = metaDataUpdateFactory.create(project)) {
       md.setMessage(String.format("Remove %s on %s", permission, ref));
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
       AccessSection s = config.getAccessSection(ref, true);
       Permission p = s.getPermission(permission, true);
       p.clearRules();
@@ -1244,14 +1248,14 @@
   protected ContributorAgreement configureContributorAgreement(boolean autoVerify)
       throws Exception {
     ContributorAgreement ca;
+    String g = createGroup(autoVerify ? "cla-test-group" : "cla-test-no-auto-verify-group");
+    GroupApi groupApi = gApi.groups().id(g);
+    groupApi.description("CLA test group");
+    InternalGroup caGroup = group(new AccountGroup.UUID(groupApi.detail().id));
+    GroupReference groupRef = new GroupReference(caGroup.getGroupUUID(), caGroup.getName());
+    PermissionRule rule = new PermissionRule(groupRef);
+    rule.setAction(PermissionRule.Action.ALLOW);
     if (autoVerify) {
-      String g = createGroup("cla-test-group");
-      GroupApi groupApi = gApi.groups().id(g);
-      groupApi.description("CLA test group");
-      InternalGroup caGroup = group(new AccountGroup.UUID(groupApi.detail().id));
-      GroupReference groupRef = new GroupReference(caGroup.getGroupUUID(), caGroup.getName());
-      PermissionRule rule = new PermissionRule(groupRef);
-      rule.setAction(PermissionRule.Action.ALLOW);
       ca = new ContributorAgreement("cla-test");
       ca.setAutoVerify(groupRef);
       ca.setAccepted(ImmutableList.of(rule));
@@ -1260,6 +1264,8 @@
     }
     ca.setDescription("description");
     ca.setAgreementUrl("agreement-url");
+    ca.setAccepted(ImmutableList.of(rule));
+    ca.setExcludeProjectsRegexes(ImmutableList.of("ExcludedProject"));
 
     try (ProjectConfigUpdate u = updateProject(allProjects)) {
       u.getConfig().replace(ca);
@@ -1667,7 +1673,7 @@
 
     private ProjectConfigUpdate(Project.NameKey projectName) throws Exception {
       metaDataUpdate = metaDataUpdateFactory.create(projectName);
-      projectConfig = ProjectConfig.read(metaDataUpdate);
+      projectConfig = projectConfigFactory.read(metaDataUpdate);
     }
 
     public ProjectConfig getConfig() {
@@ -1714,4 +1720,13 @@
     comments.sort(Comparator.comparing(c -> c.id));
     return comments;
   }
+
+  protected List<RelatedChangeAndCommitInfo> getRelated(PatchSet.Id ps) throws Exception {
+    return getRelated(ps.getParentKey(), ps.get());
+  }
+
+  protected List<RelatedChangeAndCommitInfo> getRelated(Change.Id changeId, int ps)
+      throws Exception {
+    return gApi.changes().id(changeId.get()).revision(ps).related().changes;
+  }
 }
diff --git a/java/com/google/gerrit/acceptance/HttpSession.java b/java/com/google/gerrit/acceptance/HttpSession.java
index fe446f4..fdd1fce 100644
--- a/java/com/google/gerrit/acceptance/HttpSession.java
+++ b/java/com/google/gerrit/acceptance/HttpSession.java
@@ -19,8 +19,10 @@
 import java.io.IOException;
 import java.net.URI;
 import org.apache.http.HttpHost;
+import org.apache.http.client.HttpClient;
 import org.apache.http.client.fluent.Executor;
 import org.apache.http.client.fluent.Request;
+import org.apache.http.impl.client.HttpClientBuilder;
 
 public class HttpSession {
   protected TestAccount account;
@@ -30,7 +32,8 @@
   public HttpSession(GerritServer server, @Nullable TestAccount account) {
     this.url = CharMatcher.is('/').trimTrailingFrom(server.getUrl());
     URI uri = URI.create(url);
-    this.executor = Executor.newInstance();
+    HttpClient noRedirectClient = HttpClientBuilder.create().disableRedirectHandling().build();
+    this.executor = Executor.newInstance(noRedirectClient);
     this.account = account;
     if (account != null) {
       executor.auth(
diff --git a/java/com/google/gerrit/acceptance/RestResponse.java b/java/com/google/gerrit/acceptance/RestResponse.java
index da08215..e8de5c6 100644
--- a/java/com/google/gerrit/acceptance/RestResponse.java
+++ b/java/com/google/gerrit/acceptance/RestResponse.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.acceptance;
 
+import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.google.gerrit.httpd.restapi.RestApiServlet.JSON_MAGIC;
 import static java.nio.charset.StandardCharsets.UTF_8;
@@ -21,6 +22,7 @@
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.Reader;
+import java.net.URI;
 import org.apache.http.HttpStatus;
 
 public class RestResponse extends HttpResponse {
@@ -83,4 +85,9 @@
   public void assertPreconditionFailed() throws Exception {
     assertStatus(HttpStatus.SC_PRECONDITION_FAILED);
   }
+
+  public void assertTemporaryRedirect(String path) throws Exception {
+    assertStatus(HttpStatus.SC_MOVED_TEMPORARILY);
+    assertThat(URI.create(getHeader("Location")).getPath()).isEqualTo(path);
+  }
 }
diff --git a/java/com/google/gerrit/common/data/ContributorAgreement.java b/java/com/google/gerrit/common/data/ContributorAgreement.java
index b43dbfa..a6e8cdd 100644
--- a/java/com/google/gerrit/common/data/ContributorAgreement.java
+++ b/java/com/google/gerrit/common/data/ContributorAgreement.java
@@ -25,6 +25,8 @@
   protected List<PermissionRule> accepted;
   protected GroupReference autoVerify;
   protected String agreementUrl;
+  protected List<String> excludeProjectsRegexes;
+  protected List<String> matchProjectsRegexes;
 
   protected ContributorAgreement() {}
 
@@ -75,6 +77,28 @@
     this.agreementUrl = agreementUrl;
   }
 
+  public List<String> getExcludeProjectsRegexes() {
+    if (excludeProjectsRegexes == null) {
+      excludeProjectsRegexes = new ArrayList<>();
+    }
+    return excludeProjectsRegexes;
+  }
+
+  public void setExcludeProjectsRegexes(List<String> excludeProjectsRegexes) {
+    this.excludeProjectsRegexes = excludeProjectsRegexes;
+  }
+
+  public List<String> getMatchProjectsRegexes() {
+    if (matchProjectsRegexes == null) {
+      matchProjectsRegexes = new ArrayList<>();
+    }
+    return matchProjectsRegexes;
+  }
+
+  public void setMatchProjectsRegexes(List<String> matchProjectsRegexes) {
+    this.matchProjectsRegexes = matchProjectsRegexes;
+  }
+
   @Override
   public int compareTo(ContributorAgreement o) {
     return getName().compareTo(o.getName());
diff --git a/java/com/google/gerrit/extensions/api/changes/ChangeApi.java b/java/com/google/gerrit/extensions/api/changes/ChangeApi.java
index 0150e1e..dfa2128 100644
--- a/java/com/google/gerrit/extensions/api/changes/ChangeApi.java
+++ b/java/com/google/gerrit/extensions/api/changes/ChangeApi.java
@@ -49,17 +49,21 @@
    * @return API for accessing the revision.
    * @throws RestApiException if an error occurred.
    */
-  RevisionApi current() throws RestApiException;
+  default RevisionApi current() throws RestApiException {
+    return revision("current");
+  }
 
   /**
    * Look up a revision of a change by number.
    *
    * @see #current()
    */
-  RevisionApi revision(int id) throws RestApiException;
+  default RevisionApi revision(int id) throws RestApiException {
+    return revision(Integer.toString(id));
+  }
 
   /**
-   * Look up a revision of a change by commit SHA-1.
+   * Look up a revision of a change by commit SHA-1 or other supported revision string.
    *
    * @see #current()
    */
@@ -79,15 +83,23 @@
    */
   ReviewerApi reviewer(String id) throws RestApiException;
 
-  void abandon() throws RestApiException;
+  default void abandon() throws RestApiException {
+    abandon(new AbandonInput());
+  }
 
   void abandon(AbandonInput in) throws RestApiException;
 
-  void restore() throws RestApiException;
+  default void restore() throws RestApiException {
+    restore(new RestoreInput());
+  }
 
   void restore(RestoreInput in) throws RestApiException;
 
-  void move(String destination) throws RestApiException;
+  default void move(String destination) throws RestApiException {
+    MoveInput in = new MoveInput();
+    in.destinationBranch = destination;
+    move(in);
+  }
 
   void move(MoveInput in) throws RestApiException;
 
@@ -132,7 +144,9 @@
    *
    * @see Changes#id(int)
    */
-  ChangeApi revert() throws RestApiException;
+  default ChangeApi revert() throws RestApiException {
+    return revert(new RevertInput());
+  }
 
   /**
    * Create a new change that reverts this change.
@@ -144,10 +158,17 @@
   /** Create a merge patch set for the change. */
   ChangeInfo createMergePatchSet(MergePatchSetInput in) throws RestApiException;
 
-  List<ChangeInfo> submittedTogether() throws RestApiException;
+  default List<ChangeInfo> submittedTogether() throws RestApiException {
+    SubmittedTogetherInfo info =
+        submittedTogether(
+            EnumSet.noneOf(ListChangesOption.class), EnumSet.noneOf(SubmittedTogetherOption.class));
+    return info.changes;
+  }
 
-  SubmittedTogetherInfo submittedTogether(EnumSet<SubmittedTogetherOption> options)
-      throws RestApiException;
+  default SubmittedTogetherInfo submittedTogether(EnumSet<SubmittedTogetherOption> options)
+      throws RestApiException {
+    return submittedTogether(EnumSet.noneOf(ListChangesOption.class), options);
+  }
 
   SubmittedTogetherInfo submittedTogether(
       EnumSet<ListChangesOption> listOptions, EnumSet<SubmittedTogetherOption> submitOptions)
@@ -155,10 +176,14 @@
 
   /** Publishes a draft change. */
   @Deprecated
-  void publish() throws RestApiException;
+  default void publish() throws RestApiException {
+    throw new UnsupportedOperationException("draft workflow is discontinued");
+  }
 
   /** Rebase the current revision of a change using default options. */
-  void rebase() throws RestApiException;
+  default void rebase() throws RestApiException {
+    rebase(new RebaseInput());
+  }
 
   /** Rebase the current revision of a change. */
   void rebase(RebaseInput in) throws RestApiException;
@@ -172,13 +197,19 @@
 
   IncludedInInfo includedIn() throws RestApiException;
 
-  AddReviewerResult addReviewer(AddReviewerInput in) throws RestApiException;
+  default AddReviewerResult addReviewer(String reviewer) throws RestApiException {
+    AddReviewerInput in = new AddReviewerInput();
+    in.reviewer = reviewer;
+    return addReviewer(in);
+  }
 
-  AddReviewerResult addReviewer(String in) throws RestApiException;
+  AddReviewerResult addReviewer(AddReviewerInput in) throws RestApiException;
 
   SuggestedReviewersRequest suggestReviewers() throws RestApiException;
 
-  SuggestedReviewersRequest suggestReviewers(String query) throws RestApiException;
+  default SuggestedReviewersRequest suggestReviewers(String query) throws RestApiException {
+    return suggestReviewers().withQuery(query);
+  }
 
   ChangeInfo get(EnumSet<ListChangesOption> options) throws RestApiException;
 
@@ -198,10 +229,16 @@
    *   <li>{@code SKIP_MERGEABLE} is omitted, so the {@code mergeable} bit <em>is</em> set.
    * </ul>
    */
-  ChangeInfo get() throws RestApiException;
+  default ChangeInfo get() throws RestApiException {
+    return get(
+        EnumSet.complementOf(
+            EnumSet.of(ListChangesOption.CHECK, ListChangesOption.SKIP_MERGEABLE)));
+  }
 
   /** {@link #get(ListChangesOption...)} with no options included. */
-  ChangeInfo info() throws RestApiException;
+  default ChangeInfo info() throws RestApiException {
+    return get(EnumSet.noneOf(ListChangesOption.class));
+  }
 
   /**
    * Retrieve change edit when exists.
@@ -210,7 +247,9 @@
    *     ChangeEditApi#get()}.
    */
   @Deprecated
-  EditInfo getEdit() throws RestApiException;
+  default EditInfo getEdit() throws RestApiException {
+    return edit().get().orElse(null);
+  }
 
   /**
    * Provides access to an API regarding the change edit of this change.
@@ -221,7 +260,11 @@
   ChangeEditApi edit() throws RestApiException;
 
   /** Create a new patch set with a new commit message. */
-  void setMessage(String message) throws RestApiException;
+  default void setMessage(String message) throws RestApiException {
+    CommitMessageInput in = new CommitMessageInput();
+    in.message = message;
+    setMessage(in);
+  }
 
   /** Create a new patch set with a new commit message. */
   void setMessage(CommitMessageInput in) throws RestApiException;
@@ -347,16 +390,6 @@
     }
 
     @Override
-    public RevisionApi current() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
-    public RevisionApi revision(int id) throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public ReviewerApi reviewer(String id) throws RestApiException {
       throw new NotImplementedException();
     }
@@ -367,31 +400,16 @@
     }
 
     @Override
-    public void abandon() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public void abandon(AbandonInput in) throws RestApiException {
       throw new NotImplementedException();
     }
 
     @Override
-    public void restore() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public void restore(RestoreInput in) throws RestApiException {
       throw new NotImplementedException();
     }
 
     @Override
-    public void move(String destination) throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public void move(MoveInput in) throws RestApiException {
       throw new NotImplementedException();
     }
@@ -412,27 +430,11 @@
     }
 
     @Override
-    public ChangeApi revert() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public ChangeApi revert(RevertInput in) throws RestApiException {
       throw new NotImplementedException();
     }
 
     @Override
-    public void publish() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Deprecated
-    @Override
-    public void rebase() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public void rebase(RebaseInput in) throws RestApiException {
       throw new NotImplementedException();
     }
@@ -463,51 +465,21 @@
     }
 
     @Override
-    public AddReviewerResult addReviewer(String in) throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public SuggestedReviewersRequest suggestReviewers() throws RestApiException {
       throw new NotImplementedException();
     }
 
     @Override
-    public SuggestedReviewersRequest suggestReviewers(String query) throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public ChangeInfo get(EnumSet<ListChangesOption> options) throws RestApiException {
       throw new NotImplementedException();
     }
 
     @Override
-    public ChangeInfo get() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
-    public ChangeInfo info() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
-    public void setMessage(String message) throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public void setMessage(CommitMessageInput in) throws RestApiException {
       throw new NotImplementedException();
     }
 
     @Override
-    public EditInfo getEdit() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public ChangeEditApi edit() throws RestApiException {
       throw new NotImplementedException();
     }
diff --git a/java/com/google/gerrit/extensions/api/changes/RelatedChangeAndCommitInfo.java b/java/com/google/gerrit/extensions/api/changes/RelatedChangeAndCommitInfo.java
new file mode 100644
index 0000000..5bf22aa
--- /dev/null
+++ b/java/com/google/gerrit/extensions/api/changes/RelatedChangeAndCommitInfo.java
@@ -0,0 +1,43 @@
+// Copyright (C) 2018 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.extensions.api.changes;
+
+import com.google.common.base.MoreObjects;
+import com.google.gerrit.extensions.common.CommitInfo;
+
+public class RelatedChangeAndCommitInfo {
+  public String project;
+  public String changeId;
+  public CommitInfo commit;
+  public Integer _changeNumber;
+  public Integer _revisionNumber;
+  public Integer _currentRevisionNumber;
+  public String status;
+
+  public RelatedChangeAndCommitInfo() {}
+
+  @Override
+  public String toString() {
+    return MoreObjects.toStringHelper(this)
+        .add("project", project)
+        .add("changeId", changeId)
+        .add("commit", commit)
+        .add("_changeNumber", _changeNumber)
+        .add("_revisionNumber", _revisionNumber)
+        .add("_currentRevisionNumber", _currentRevisionNumber)
+        .add("status", status)
+        .toString();
+  }
+}
diff --git a/java/com/google/gerrit/extensions/api/changes/RelatedChangesInfo.java b/java/com/google/gerrit/extensions/api/changes/RelatedChangesInfo.java
new file mode 100644
index 0000000..e1e70f3
--- /dev/null
+++ b/java/com/google/gerrit/extensions/api/changes/RelatedChangesInfo.java
@@ -0,0 +1,21 @@
+// Copyright (C) 2018 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.extensions.api.changes;
+
+import java.util.List;
+
+public class RelatedChangesInfo {
+  public List<RelatedChangeAndCommitInfo> changes;
+}
diff --git a/java/com/google/gerrit/extensions/api/changes/RevisionApi.java b/java/com/google/gerrit/extensions/api/changes/RevisionApi.java
index 4658eb3..14dc589 100644
--- a/java/com/google/gerrit/extensions/api/changes/RevisionApi.java
+++ b/java/com/google/gerrit/extensions/api/changes/RevisionApi.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.extensions.api.changes;
 
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.extensions.client.SubmitType;
 import com.google.gerrit.extensions.common.ActionInfo;
 import com.google.gerrit.extensions.common.CherryPickChangeInfo;
@@ -34,7 +35,9 @@
 
 public interface RevisionApi {
   @Deprecated
-  void delete() throws RestApiException;
+  default void delete() throws RestApiException {
+    throw new UnsupportedOperationException("draft workflow is discontinued");
+  }
 
   String description() throws RestApiException;
 
@@ -42,22 +45,32 @@
 
   ReviewResult review(ReviewInput in) throws RestApiException;
 
-  void submit() throws RestApiException;
+  default void submit() throws RestApiException {
+    SubmitInput in = new SubmitInput();
+    submit(in);
+  }
 
   void submit(SubmitInput in) throws RestApiException;
 
-  BinaryResult submitPreview() throws RestApiException;
+  default BinaryResult submitPreview() throws RestApiException {
+    return submitPreview("zip");
+  }
 
   BinaryResult submitPreview(String format) throws RestApiException;
 
   @Deprecated
-  void publish() throws RestApiException;
+  default void publish() throws RestApiException {
+    throw new UnsupportedOperationException("draft workflow is discontinued");
+  }
 
   ChangeApi cherryPick(CherryPickInput in) throws RestApiException;
 
   CherryPickChangeInfo cherryPickAsInfo(CherryPickInput in) throws RestApiException;
 
-  ChangeApi rebase() throws RestApiException;
+  default ChangeApi rebase() throws RestApiException {
+    RebaseInput in = new RebaseInput();
+    return rebase(in);
+  }
 
   ChangeApi rebase(RebaseInput in) throws RestApiException;
 
@@ -69,9 +82,11 @@
 
   Set<String> reviewed() throws RestApiException;
 
-  Map<String, FileInfo> files() throws RestApiException;
+  default Map<String, FileInfo> files() throws RestApiException {
+    return files(null);
+  }
 
-  Map<String, FileInfo> files(String base) throws RestApiException;
+  Map<String, FileInfo> files(@Nullable String base) throws RestApiException;
 
   Map<String, FileInfo> files(int parentNum) throws RestApiException;
 
@@ -133,6 +148,8 @@
 
   MergeListRequest getMergeList() throws RestApiException;
 
+  RelatedChangesInfo related() throws RestApiException;
+
   abstract class MergeListRequest {
     private boolean addLinks;
     private int uninterestingParent = 1;
@@ -163,33 +180,16 @@
    * interface.
    */
   class NotImplemented implements RevisionApi {
-    @Deprecated
-    @Override
-    public void delete() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
     @Override
     public ReviewResult review(ReviewInput in) throws RestApiException {
       throw new NotImplementedException();
     }
 
     @Override
-    public void submit() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public void submit(SubmitInput in) throws RestApiException {
       throw new NotImplementedException();
     }
 
-    @Deprecated
-    @Override
-    public void publish() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
     @Override
     public ChangeApi cherryPick(CherryPickInput in) throws RestApiException {
       throw new NotImplementedException();
@@ -201,11 +201,6 @@
     }
 
     @Override
-    public ChangeApi rebase() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public ChangeApi rebase(RebaseInput in) throws RestApiException {
       throw new NotImplementedException();
     }
@@ -251,11 +246,6 @@
     }
 
     @Override
-    public Map<String, FileInfo> files() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public List<String> queryFiles(String query) throws RestApiException {
       throw new NotImplementedException();
     }
@@ -346,11 +336,6 @@
     }
 
     @Override
-    public BinaryResult submitPreview() throws RestApiException {
-      throw new NotImplementedException();
-    }
-
-    @Override
     public BinaryResult submitPreview(String format) throws RestApiException {
       throw new NotImplementedException();
     }
@@ -371,6 +356,11 @@
     }
 
     @Override
+    public RelatedChangesInfo related() throws RestApiException {
+      throw new NotImplementedException();
+    }
+
+    @Override
     public void description(String description) throws RestApiException {
       throw new NotImplementedException();
     }
diff --git a/java/com/google/gerrit/extensions/api/projects/RefInfo.java b/java/com/google/gerrit/extensions/api/projects/RefInfo.java
index c573600..d5695fd 100644
--- a/java/com/google/gerrit/extensions/api/projects/RefInfo.java
+++ b/java/com/google/gerrit/extensions/api/projects/RefInfo.java
@@ -14,8 +14,15 @@
 
 package com.google.gerrit.extensions.api.projects;
 
+import com.google.common.base.MoreObjects;
+
 public class RefInfo {
   public String ref;
   public String revision;
   public Boolean canDelete;
+
+  @Override
+  public String toString() {
+    return MoreObjects.toStringHelper(this).add("ref", ref).add("revision", revision).toString();
+  }
 }
diff --git a/java/com/google/gerrit/extensions/common/ChangeInfo.java b/java/com/google/gerrit/extensions/common/ChangeInfo.java
index 945c239..9a739ef 100644
--- a/java/com/google/gerrit/extensions/common/ChangeInfo.java
+++ b/java/com/google/gerrit/extensions/common/ChangeInfo.java
@@ -46,6 +46,7 @@
   public Boolean submittable;
   public Integer insertions;
   public Integer deletions;
+  public Integer totalCommentCount;
   public Integer unresolvedCommentCount;
   public Boolean isPrivate;
   public Boolean workInProgress;
diff --git a/java/com/google/gerrit/extensions/common/CommitInfo.java b/java/com/google/gerrit/extensions/common/CommitInfo.java
index 213b366..1fd8755 100644
--- a/java/com/google/gerrit/extensions/common/CommitInfo.java
+++ b/java/com/google/gerrit/extensions/common/CommitInfo.java
@@ -16,6 +16,8 @@
 
 import static java.util.stream.Collectors.joining;
 
+import com.google.common.base.MoreObjects;
+import com.google.common.base.MoreObjects.ToStringHelper;
 import java.util.List;
 import java.util.Objects;
 
@@ -50,17 +52,18 @@
 
   @Override
   public String toString() {
-    // Using something like the raw commit format might be nice, but we can't depend on JGit here.
-    StringBuilder sb = new StringBuilder().append(getClass().getSimpleName()).append('{');
-    sb.append(commit);
-    sb.append(", parents=").append(parents.stream().map(p -> p.commit).collect(joining(", ")));
-    sb.append(", author=").append(author);
-    sb.append(", committer=").append(committer);
-    sb.append(", subject=").append(subject);
-    sb.append(", message=").append(message);
-    if (webLinks != null) {
-      sb.append(", webLinks=").append(webLinks);
+    ToStringHelper helper = MoreObjects.toStringHelper(this).addValue(commit);
+    if (parents != null) {
+      helper.add("parents", parents.stream().map(p -> p.commit).collect(joining(", ")));
     }
-    return sb.append('}').toString();
+    helper
+        .add("author", author)
+        .add("committer", committer)
+        .add("subject", subject)
+        .add("message", message);
+    if (webLinks != null) {
+      helper.add("webLinks", webLinks);
+    }
+    return helper.toString();
   }
 }
diff --git a/java/com/google/gerrit/httpd/NumericChangeIdRedirectServlet.java b/java/com/google/gerrit/httpd/NumericChangeIdRedirectServlet.java
new file mode 100644
index 0000000..164f957
--- /dev/null
+++ b/java/com/google/gerrit/httpd/NumericChangeIdRedirectServlet.java
@@ -0,0 +1,71 @@
+// Copyright (C) 2018 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.httpd;
+
+import com.google.gerrit.common.PageLinks;
+import com.google.gerrit.extensions.restapi.ResourceConflictException;
+import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.server.change.ChangeResource;
+import com.google.gerrit.server.permissions.PermissionBackendException;
+import com.google.gerrit.server.restapi.change.ChangesCollection;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+import java.io.IOException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/** Redirects {@code domain.tld/123} to {@code domain.tld/c/project/+/123}. */
+@Singleton
+public class NumericChangeIdRedirectServlet extends HttpServlet {
+  private static final long serialVersionUID = 1L;
+
+  private final ChangesCollection changesCollection;
+
+  @Inject
+  NumericChangeIdRedirectServlet(ChangesCollection changesCollection) {
+    this.changesCollection = changesCollection;
+  }
+
+  @Override
+  protected void doGet(HttpServletRequest req, HttpServletResponse rsp) throws IOException {
+    String idString = req.getPathInfo();
+    if (idString.endsWith("/")) {
+      idString = idString.substring(0, idString.length() - 1);
+    }
+    Change.Id id;
+    try {
+      id = Change.Id.parse(idString);
+    } catch (IllegalArgumentException e) {
+      rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
+      return;
+    }
+
+    ChangeResource changeResource;
+    try {
+      changeResource = changesCollection.parse(id);
+    } catch (ResourceConflictException | ResourceNotFoundException e) {
+      rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
+      return;
+    } catch (OrmException | PermissionBackendException e) {
+      throw new IOException("Unable to lookup change " + id.id, e);
+    }
+    String path =
+        PageLinks.toChange(changeResource.getProject(), changeResource.getChange().getId());
+    UrlModule.toGerrit(path, req, rsp);
+  }
+}
diff --git a/java/com/google/gerrit/httpd/UrlModule.java b/java/com/google/gerrit/httpd/UrlModule.java
index 1dd176a..183b2bd 100644
--- a/java/com/google/gerrit/httpd/UrlModule.java
+++ b/java/com/google/gerrit/httpd/UrlModule.java
@@ -87,7 +87,7 @@
     serveRegex("^/settings/?$").with(screen(PageLinks.SETTINGS));
     serveRegex("^/register$").with(registerScreen(false));
     serveRegex("^/register/(.+)$").with(registerScreen(true));
-    serveRegex("^/([1-9][0-9]*)/?$").with(directChangeById());
+    serveRegex("^/([1-9][0-9]*)/?$").with(NumericChangeIdRedirectServlet.class);
     serveRegex("^/p/(.*)$").with(queryProjectNew());
     serveRegex("^/r/(.+)/?$").with(DirectChangeByCommit.class);
 
@@ -164,30 +164,6 @@
         });
   }
 
-  private Key<HttpServlet> directChangeById() {
-    return key(
-        new HttpServlet() {
-          private static final long serialVersionUID = 1L;
-
-          @Override
-          protected void doGet(HttpServletRequest req, HttpServletResponse rsp) throws IOException {
-            try {
-              String idString = req.getPathInfo();
-              if (idString.endsWith("/")) {
-                idString = idString.substring(0, idString.length() - 1);
-              }
-              Change.Id id = Change.Id.parse(idString);
-              // User accessed Gerrit with /1234, so we have no project yet.
-              // TODO(hiesel) Replace with a preflight request to obtain project before we deprecate
-              // the numeric change id.
-              toGerrit(PageLinks.toChange(null, id), req, rsp);
-            } catch (IllegalArgumentException err) {
-              rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
-            }
-          }
-        });
-  }
-
   private Key<HttpServlet> queryProjectNew() {
     return key(
         new HttpServlet() {
diff --git a/java/com/google/gerrit/httpd/raw/StaticModule.java b/java/com/google/gerrit/httpd/raw/StaticModule.java
index 124ad1c..062d776 100644
--- a/java/com/google/gerrit/httpd/raw/StaticModule.java
+++ b/java/com/google/gerrit/httpd/raw/StaticModule.java
@@ -71,7 +71,15 @@
    */
   public static final ImmutableList<String> POLYGERRIT_INDEX_PATHS =
       ImmutableList.of(
-          "/", "/c/*", "/p/*", "/q/*", "/x/*", "/admin/*", "/dashboard/*", "/settings/*");
+          "/",
+          "/c/*",
+          "/p/*",
+          "/q/*",
+          "/x/*",
+          "/admin/*",
+          "/dashboard/*",
+          "/settings/*",
+          "/Documentation/q/*");
   // TODO(dborowitz): These fragments conflict with the REST API
   // namespace, so they will need to use a different path.
   // "/groups/*",
diff --git a/java/com/google/gerrit/httpd/rpc/project/ChangeProjectAccess.java b/java/com/google/gerrit/httpd/rpc/project/ChangeProjectAccess.java
index 24efb86..dd6622a 100644
--- a/java/com/google/gerrit/httpd/rpc/project/ChangeProjectAccess.java
+++ b/java/com/google/gerrit/httpd/rpc/project/ChangeProjectAccess.java
@@ -62,6 +62,7 @@
       ProjectAccessFactory.Factory projectAccessFactory,
       ProjectCache projectCache,
       GroupBackend groupBackend,
+      ProjectConfig.Factory projectConfigFactory,
       MetaDataUpdate.User metaDataUpdateFactory,
       AllProjectsName allProjects,
       Provider<SetParent> setParent,
@@ -77,6 +78,7 @@
       @Nullable @Assisted String message) {
     super(
         groupBackend,
+        projectConfigFactory,
         metaDataUpdateFactory,
         allProjects,
         setParent,
diff --git a/java/com/google/gerrit/httpd/rpc/project/ProjectAccessFactory.java b/java/com/google/gerrit/httpd/rpc/project/ProjectAccessFactory.java
index 6193e45..4c4959a 100644
--- a/java/com/google/gerrit/httpd/rpc/project/ProjectAccessFactory.java
+++ b/java/com/google/gerrit/httpd/rpc/project/ProjectAccessFactory.java
@@ -71,6 +71,7 @@
   private final GroupControl.Factory groupControlFactory;
   private final MetaDataUpdate.Server metaDataUpdateFactory;
   private final AllProjectsName allProjectsName;
+  private final ProjectConfig.Factory projectConfigFactory;
 
   private final Project.NameKey projectName;
   private WebLinks webLinks;
@@ -83,6 +84,7 @@
       GroupControl.Factory groupControlFactory,
       MetaDataUpdate.Server metaDataUpdateFactory,
       AllProjectsName allProjectsName,
+      ProjectConfig.Factory projectConfigFactory,
       WebLinks webLinks,
       @Assisted final Project.NameKey name) {
     this.groupBackend = groupBackend;
@@ -91,6 +93,7 @@
     this.groupControlFactory = groupControlFactory;
     this.metaDataUpdateFactory = metaDataUpdateFactory;
     this.allProjectsName = allProjectsName;
+    this.projectConfigFactory = projectConfigFactory;
     this.webLinks = webLinks;
 
     this.projectName = name;
@@ -108,7 +111,7 @@
     //
     ProjectConfig config;
     try (MetaDataUpdate md = metaDataUpdateFactory.create(projectName)) {
-      config = ProjectConfig.read(md);
+      config = projectConfigFactory.read(md);
       if (config.updateGroupNames(groupBackend)) {
         md.setMessage("Update group names\n");
         config.commit(md);
diff --git a/java/com/google/gerrit/httpd/rpc/project/ProjectAccessHandler.java b/java/com/google/gerrit/httpd/rpc/project/ProjectAccessHandler.java
index 44c8966..074f6a8 100644
--- a/java/com/google/gerrit/httpd/rpc/project/ProjectAccessHandler.java
+++ b/java/com/google/gerrit/httpd/rpc/project/ProjectAccessHandler.java
@@ -31,6 +31,7 @@
 import com.google.gerrit.extensions.restapi.UnprocessableEntityException;
 import com.google.gerrit.httpd.rpc.Handler;
 import com.google.gerrit.reviewdb.client.Project;
+import com.google.gerrit.reviewdb.client.Project.NameKey;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.account.GroupBackend;
 import com.google.gerrit.server.account.GroupBackends;
@@ -58,6 +59,7 @@
 public abstract class ProjectAccessHandler<T> extends Handler<T> {
 
   protected final GroupBackend groupBackend;
+  protected final ProjectConfig.Factory projectConfigFactory;
   protected final Project.NameKey projectName;
   protected final ObjectId base;
   protected final CurrentUser user;
@@ -77,14 +79,15 @@
 
   protected ProjectAccessHandler(
       GroupBackend groupBackend,
+      ProjectConfig.Factory projectConfigFactory,
       MetaDataUpdate.User metaDataUpdateFactory,
       AllProjectsName allProjects,
       Provider<SetParent> setParent,
       CurrentUser user,
-      Project.NameKey projectName,
+      NameKey projectName,
       ObjectId base,
       List<AccessSection> sectionList,
-      Project.NameKey parentProjectName,
+      NameKey parentProjectName,
       String message,
       ContributorAgreementsChecker contributorAgreements,
       PermissionBackend permissionBackend,
@@ -102,6 +105,7 @@
     this.message = message;
     this.contributorAgreements = contributorAgreements;
     this.permissionBackend = permissionBackend;
+    this.projectConfigFactory = projectConfigFactory;
     this.checkIfOwner = checkIfOwner;
   }
 
@@ -113,7 +117,7 @@
     contributorAgreements.check(projectName, user);
 
     try (MetaDataUpdate md = metaDataUpdateFactory.create(projectName)) {
-      ProjectConfig config = ProjectConfig.read(md, base);
+      ProjectConfig config = projectConfigFactory.read(md, base);
       Set<String> toDelete = scanSectionNames(config);
       PermissionBackend.ForProject forProject = permissionBackend.user(user).project(projectName);
 
diff --git a/java/com/google/gerrit/httpd/rpc/project/ReviewProjectAccess.java b/java/com/google/gerrit/httpd/rpc/project/ReviewProjectAccess.java
index 6a43a1d..9e8592a 100644
--- a/java/com/google/gerrit/httpd/rpc/project/ReviewProjectAccess.java
+++ b/java/com/google/gerrit/httpd/rpc/project/ReviewProjectAccess.java
@@ -88,6 +88,7 @@
   ReviewProjectAccess(
       PermissionBackend permissionBackend,
       GroupBackend groupBackend,
+      ProjectConfig.Factory projectConfigFactory,
       MetaDataUpdate.User metaDataUpdateFactory,
       ReviewDb db,
       Provider<PostReviewers> reviewersProvider,
@@ -108,6 +109,7 @@
       @Nullable @Assisted String message) {
     super(
         groupBackend,
+        projectConfigFactory,
         metaDataUpdateFactory,
         allProjects,
         setParent,
diff --git a/java/com/google/gerrit/lucene/LuceneChangeIndex.java b/java/com/google/gerrit/lucene/LuceneChangeIndex.java
index 66db468..b208a31 100644
--- a/java/com/google/gerrit/lucene/LuceneChangeIndex.java
+++ b/java/com/google/gerrit/lucene/LuceneChangeIndex.java
@@ -76,6 +76,7 @@
 import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
+import java.util.function.Consumer;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexableField;
@@ -129,6 +130,7 @@
       ChangeField.STORED_SUBMIT_RECORD_LENIENT.getName();
   private static final String SUBMIT_RECORD_STRICT_FIELD =
       ChangeField.STORED_SUBMIT_RECORD_STRICT.getName();
+  private static final String TOTAL_COMMENT_COUNT_FIELD = ChangeField.TOTAL_COMMENT_COUNT.getName();
   private static final String UNRESOLVED_COMMENT_COUNT_FIELD =
       ChangeField.UNRESOLVED_COMMENT_COUNT.getName();
 
@@ -504,6 +506,7 @@
     }
 
     decodeUnresolvedCommentCount(doc, cd);
+    decodeTotalCommentCount(doc, cd);
     return cd;
   }
 
@@ -633,9 +636,18 @@
 
   private void decodeUnresolvedCommentCount(
       ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    IndexableField f = Iterables.getFirst(doc.get(UNRESOLVED_COMMENT_COUNT_FIELD), null);
+    decodeIntField(doc, UNRESOLVED_COMMENT_COUNT_FIELD, cd::setUnresolvedCommentCount);
+  }
+
+  private void decodeTotalCommentCount(ListMultimap<String, IndexableField> doc, ChangeData cd) {
+    decodeIntField(doc, TOTAL_COMMENT_COUNT_FIELD, cd::setTotalCommentCount);
+  }
+
+  private static void decodeIntField(
+      ListMultimap<String, IndexableField> doc, String fieldName, Consumer<Integer> consumer) {
+    IndexableField f = Iterables.getFirst(doc.get(fieldName), null);
     if (f != null && f.numericValue() != null) {
-      cd.setUnresolvedCommentCount(f.numericValue().intValue());
+      consumer.accept(f.numericValue().intValue());
     }
   }
 
diff --git a/java/com/google/gerrit/pgm/http/jetty/HttpLog.java b/java/com/google/gerrit/pgm/http/jetty/HttpLog.java
index b7ec2be..dab9d7e 100644
--- a/java/com/google/gerrit/pgm/http/jetty/HttpLog.java
+++ b/java/com/google/gerrit/pgm/http/jetty/HttpLog.java
@@ -45,6 +45,7 @@
   protected static final String P_PROTOCOL = "Version";
   protected static final String P_STATUS = "Status";
   protected static final String P_CONTENT_LENGTH = "Content-Length";
+  protected static final String P_LATENCY = "Latency";
   protected static final String P_REFERER = "Referer";
   protected static final String P_USER_AGENT = "User-Agent";
 
@@ -94,6 +95,7 @@
     set(event, P_PROTOCOL, req.getProtocol());
     set(event, P_STATUS, rsp.getStatus());
     set(event, P_CONTENT_LENGTH, rsp.getContentCount());
+    set(event, P_LATENCY, System.currentTimeMillis() - req.getTimeStamp());
     set(event, P_REFERER, req.getHeader("Referer"));
     set(event, P_USER_AGENT, req.getHeader("User-Agent"));
 
diff --git a/java/com/google/gerrit/pgm/http/jetty/HttpLogLayout.java b/java/com/google/gerrit/pgm/http/jetty/HttpLogLayout.java
index 2eea88d..bd7d998 100644
--- a/java/com/google/gerrit/pgm/http/jetty/HttpLogLayout.java
+++ b/java/com/google/gerrit/pgm/http/jetty/HttpLogLayout.java
@@ -67,6 +67,9 @@
     opt(buf, event, HttpLog.P_CONTENT_LENGTH);
 
     buf.append(' ');
+    opt(buf, event, HttpLog.P_LATENCY);
+
+    buf.append(' ');
     dq_opt(buf, event, HttpLog.P_REFERER);
 
     buf.append(' ');
diff --git a/java/com/google/gerrit/server/CreateGroupPermissionSyncer.java b/java/com/google/gerrit/server/CreateGroupPermissionSyncer.java
index ee0138c..94ce924 100644
--- a/java/com/google/gerrit/server/CreateGroupPermissionSyncer.java
+++ b/java/com/google/gerrit/server/CreateGroupPermissionSyncer.java
@@ -57,17 +57,20 @@
   private final AllUsersName allUsers;
   private final ProjectCache projectCache;
   private final Provider<MetaDataUpdate.Server> metaDataUpdateFactory;
+  private final ProjectConfig.Factory projectConfigFactory;
 
   @Inject
   CreateGroupPermissionSyncer(
       AllProjectsName allProjects,
       AllUsersName allUsers,
       ProjectCache projectCache,
-      Provider<MetaDataUpdate.Server> metaDataUpdateFactory) {
+      Provider<MetaDataUpdate.Server> metaDataUpdateFactory,
+      ProjectConfig.Factory projectConfigFactory) {
     this.allProjects = allProjects;
     this.allUsers = allUsers;
     this.projectCache = projectCache;
     this.metaDataUpdateFactory = metaDataUpdateFactory;
+    this.projectConfigFactory = projectConfigFactory;
   }
 
   /**
@@ -102,7 +105,7 @@
     }
 
     try (MetaDataUpdate md = metaDataUpdateFactory.get().create(allUsers)) {
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
       AccessSection createGroupAccessSection =
           config.getAccessSection(RefNames.REFS_GROUPS + "*", true);
       if (createGroupsGlobal.isEmpty()) {
diff --git a/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java b/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java
index 358a3a8..0f731ed 100644
--- a/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java
+++ b/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java
@@ -43,7 +43,6 @@
 import com.google.gerrit.extensions.common.ChangeMessageInfo;
 import com.google.gerrit.extensions.common.CommentInfo;
 import com.google.gerrit.extensions.common.CommitMessageInput;
-import com.google.gerrit.extensions.common.EditInfo;
 import com.google.gerrit.extensions.common.Input;
 import com.google.gerrit.extensions.common.MergePatchSetInput;
 import com.google.gerrit.extensions.common.PureRevertInfo;
@@ -256,16 +255,6 @@
   }
 
   @Override
-  public RevisionApi current() throws RestApiException {
-    return revision("current");
-  }
-
-  @Override
-  public RevisionApi revision(int id) throws RestApiException {
-    return revision(String.valueOf(id));
-  }
-
-  @Override
   public RevisionApi revision(String id) throws RestApiException {
     try {
       return revisionApi.create(revisions.parse(change, IdString.fromDecoded(id)));
@@ -284,11 +273,6 @@
   }
 
   @Override
-  public void abandon() throws RestApiException {
-    abandon(new AbandonInput());
-  }
-
-  @Override
   public void abandon(AbandonInput in) throws RestApiException {
     try {
       abandon.apply(change, in);
@@ -298,11 +282,6 @@
   }
 
   @Override
-  public void restore() throws RestApiException {
-    restore(new RestoreInput());
-  }
-
-  @Override
   public void restore(RestoreInput in) throws RestApiException {
     try {
       restore.apply(change, in);
@@ -312,13 +291,6 @@
   }
 
   @Override
-  public void move(String destination) throws RestApiException {
-    MoveInput in = new MoveInput();
-    in.destinationBranch = destination;
-    move(in);
-  }
-
-  @Override
   public void move(MoveInput in) throws RestApiException {
     try {
       move.apply(change, in);
@@ -360,11 +332,6 @@
   }
 
   @Override
-  public ChangeApi revert() throws RestApiException {
-    return revert(new RevertInput());
-  }
-
-  @Override
   public ChangeApi revert(RevertInput in) throws RestApiException {
     try {
       return changeApi.id(revert.apply(change, in)._number);
@@ -383,20 +350,6 @@
   }
 
   @Override
-  public List<ChangeInfo> submittedTogether() throws RestApiException {
-    SubmittedTogetherInfo info =
-        submittedTogether(
-            EnumSet.noneOf(ListChangesOption.class), EnumSet.noneOf(SubmittedTogetherOption.class));
-    return info.changes;
-  }
-
-  @Override
-  public SubmittedTogetherInfo submittedTogether(EnumSet<SubmittedTogetherOption> options)
-      throws RestApiException {
-    return submittedTogether(EnumSet.noneOf(ListChangesOption.class), options);
-  }
-
-  @Override
   public SubmittedTogetherInfo submittedTogether(
       EnumSet<ListChangesOption> listOptions, EnumSet<SubmittedTogetherOption> submitOptions)
       throws RestApiException {
@@ -411,17 +364,6 @@
     }
   }
 
-  @Deprecated
-  @Override
-  public void publish() throws RestApiException {
-    throw new UnsupportedOperationException("draft workflow is discontinued");
-  }
-
-  @Override
-  public void rebase() throws RestApiException {
-    rebase(new RebaseInput());
-  }
-
   @Override
   public void rebase(RebaseInput in) throws RestApiException {
     try {
@@ -466,13 +408,6 @@
   }
 
   @Override
-  public AddReviewerResult addReviewer(String reviewer) throws RestApiException {
-    AddReviewerInput in = new AddReviewerInput();
-    in.reviewer = reviewer;
-    return addReviewer(in);
-  }
-
-  @Override
   public AddReviewerResult addReviewer(AddReviewerInput in) throws RestApiException {
     try {
       return postReviewers.apply(change, in);
@@ -491,11 +426,6 @@
     };
   }
 
-  @Override
-  public SuggestedReviewersRequest suggestReviewers(String query) throws RestApiException {
-    return suggestReviewers().withQuery(query);
-  }
-
   private List<SuggestedReviewerInfo> suggestReviewers(SuggestedReviewersRequest r)
       throws RestApiException {
     try {
@@ -517,30 +447,11 @@
   }
 
   @Override
-  public ChangeInfo get() throws RestApiException {
-    return get(
-        EnumSet.complementOf(
-            EnumSet.of(ListChangesOption.CHECK, ListChangesOption.SKIP_MERGEABLE)));
-  }
-
-  @Override
-  public EditInfo getEdit() throws RestApiException {
-    return edit().get().orElse(null);
-  }
-
-  @Override
   public ChangeEditApi edit() throws RestApiException {
     return changeEditApi.create(change);
   }
 
   @Override
-  public void setMessage(String msg) throws RestApiException {
-    CommitMessageInput in = new CommitMessageInput();
-    in.message = msg;
-    setMessage(in);
-  }
-
-  @Override
   public void setMessage(CommitMessageInput in) throws RestApiException {
     try {
       putMessage.apply(change, in);
@@ -550,11 +461,6 @@
   }
 
   @Override
-  public ChangeInfo info() throws RestApiException {
-    return get(EnumSet.noneOf(ListChangesOption.class));
-  }
-
-  @Override
   public void setHashtags(HashtagsInput input) throws RestApiException {
     try {
       postHashtags.apply(change, input);
diff --git a/java/com/google/gerrit/server/api/changes/RevisionApiImpl.java b/java/com/google/gerrit/server/api/changes/RevisionApiImpl.java
index 33f211d..f8a2ecb 100644
--- a/java/com/google/gerrit/server/api/changes/RevisionApiImpl.java
+++ b/java/com/google/gerrit/server/api/changes/RevisionApiImpl.java
@@ -18,6 +18,7 @@
 import static com.google.gerrit.server.api.ApiUtil.asRestApiException;
 
 import com.google.common.collect.ImmutableSet;
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.extensions.api.changes.ChangeApi;
 import com.google.gerrit.extensions.api.changes.Changes;
 import com.google.gerrit.extensions.api.changes.CherryPickInput;
@@ -26,6 +27,7 @@
 import com.google.gerrit.extensions.api.changes.DraftInput;
 import com.google.gerrit.extensions.api.changes.FileApi;
 import com.google.gerrit.extensions.api.changes.RebaseInput;
+import com.google.gerrit.extensions.api.changes.RelatedChangesInfo;
 import com.google.gerrit.extensions.api.changes.ReviewInput;
 import com.google.gerrit.extensions.api.changes.ReviewResult;
 import com.google.gerrit.extensions.api.changes.RevisionApi;
@@ -64,6 +66,7 @@
 import com.google.gerrit.server.restapi.change.GetDescription;
 import com.google.gerrit.server.restapi.change.GetMergeList;
 import com.google.gerrit.server.restapi.change.GetPatch;
+import com.google.gerrit.server.restapi.change.GetRelated;
 import com.google.gerrit.server.restapi.change.GetRevisionActions;
 import com.google.gerrit.server.restapi.change.ListRevisionComments;
 import com.google.gerrit.server.restapi.change.ListRevisionDrafts;
@@ -129,6 +132,7 @@
   private final TestSubmitType.Get getSubmitType;
   private final Provider<TestSubmitRule> testSubmitRule;
   private final Provider<GetMergeList> getMergeList;
+  private final GetRelated getRelated;
   private final PutDescription putDescription;
   private final GetDescription getDescription;
 
@@ -169,6 +173,7 @@
       TestSubmitType.Get getSubmitType,
       Provider<TestSubmitRule> testSubmitRule,
       Provider<GetMergeList> getMergeList,
+      GetRelated getRelated,
       PutDescription putDescription,
       GetDescription getDescription,
       @Assisted RevisionResource r) {
@@ -207,6 +212,7 @@
     this.getSubmitType = getSubmitType;
     this.testSubmitRule = testSubmitRule;
     this.getMergeList = getMergeList;
+    this.getRelated = getRelated;
     this.putDescription = putDescription;
     this.getDescription = getDescription;
     this.revision = r;
@@ -222,12 +228,6 @@
   }
 
   @Override
-  public void submit() throws RestApiException {
-    SubmitInput in = new SubmitInput();
-    submit(in);
-  }
-
-  @Override
   public void submit(SubmitInput in) throws RestApiException {
     try {
       submit.apply(revision, in);
@@ -237,11 +237,6 @@
   }
 
   @Override
-  public BinaryResult submitPreview() throws RestApiException {
-    return submitPreview("zip");
-  }
-
-  @Override
   public BinaryResult submitPreview(String format) throws RestApiException {
     try {
       submitPreview.setFormat(format);
@@ -252,22 +247,6 @@
   }
 
   @Override
-  public void publish() throws RestApiException {
-    throw new UnsupportedOperationException("draft workflow is discontinued");
-  }
-
-  @Override
-  public void delete() throws RestApiException {
-    throw new UnsupportedOperationException("draft workflow is discontinued");
-  }
-
-  @Override
-  public ChangeApi rebase() throws RestApiException {
-    RebaseInput in = new RebaseInput();
-    return rebase(in);
-  }
-
-  @Override
   public ChangeApi rebase(RebaseInput in) throws RestApiException {
     try {
       return changes.id(rebase.apply(revision, in)._number);
@@ -361,17 +340,7 @@
 
   @SuppressWarnings("unchecked")
   @Override
-  public Map<String, FileInfo> files() throws RestApiException {
-    try {
-      return (Map<String, FileInfo>) listFiles.apply(revision).value();
-    } catch (Exception e) {
-      throw asRestApiException("Cannot retrieve files", e);
-    }
-  }
-
-  @SuppressWarnings("unchecked")
-  @Override
-  public Map<String, FileInfo> files(String base) throws RestApiException {
+  public Map<String, FileInfo> files(@Nullable String base) throws RestApiException {
     try {
       return (Map<String, FileInfo>) listFiles.setBase(base).apply(revision).value();
     } catch (Exception e) {
@@ -590,6 +559,15 @@
   }
 
   @Override
+  public RelatedChangesInfo related() throws RestApiException {
+    try {
+      return getRelated.apply(revision);
+    } catch (Exception e) {
+      throw asRestApiException("Cannot get related changes", e);
+    }
+  }
+
+  @Override
   public void description(String description) throws RestApiException {
     DescriptionInput in = new DescriptionInput();
     in.description = description;
diff --git a/java/com/google/gerrit/server/change/ChangeJson.java b/java/com/google/gerrit/server/change/ChangeJson.java
index c64cd12..b7049a7 100644
--- a/java/com/google/gerrit/server/change/ChangeJson.java
+++ b/java/com/google/gerrit/server/change/ChangeJson.java
@@ -535,6 +535,7 @@
     out.created = in.getCreatedOn();
     out.updated = in.getLastUpdatedOn();
     out._number = in.getId().get();
+    out.totalCommentCount = cd.totalCommentCount();
     out.unresolvedCommentCount = cd.unresolvedCommentCount();
 
     if (user.isIdentifiedUser()) {
diff --git a/java/com/google/gerrit/server/change/RebaseChangeOp.java b/java/com/google/gerrit/server/change/RebaseChangeOp.java
index 1f216f0..dac8fec 100644
--- a/java/com/google/gerrit/server/change/RebaseChangeOp.java
+++ b/java/com/google/gerrit/server/change/RebaseChangeOp.java
@@ -20,12 +20,14 @@
 import com.google.gerrit.extensions.restapi.MergeConflictException;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.extensions.restapi.RestApiException;
+import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.client.RevId;
 import com.google.gerrit.server.ChangeUtil;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.change.RebaseUtil.Base;
+import com.google.gerrit.server.git.GroupCollector;
 import com.google.gerrit.server.git.MergeUtil;
 import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.permissions.PermissionBackendException;
@@ -199,8 +201,14 @@
               + " was rebased");
     }
 
-    if (base != null) {
-      patchSetInserter.setGroups(base.patchSet().getGroups());
+    if (base != null && base.notes().getChange().getStatus() != Change.Status.MERGED) {
+      if (base.notes().getChange().getStatus() != Change.Status.MERGED) {
+        // Add to end of relation chain for open base change.
+        patchSetInserter.setGroups(base.patchSet().getGroups());
+      } else {
+        // If the base is merged, start a new relation chain.
+        patchSetInserter.setGroups(GroupCollector.getDefaultGroups(rebasedCommit));
+      }
     }
     patchSetInserter.updateRepo(ctx);
   }
diff --git a/java/com/google/gerrit/server/config/ProjectConfigEntry.java b/java/com/google/gerrit/server/config/ProjectConfigEntry.java
index 5515f0e..92ae10a 100644
--- a/java/com/google/gerrit/server/config/ProjectConfigEntry.java
+++ b/java/com/google/gerrit/server/config/ProjectConfigEntry.java
@@ -302,12 +302,16 @@
 
     private final GitRepositoryManager repoManager;
     private final DynamicMap<ProjectConfigEntry> pluginConfigEntries;
+    private final ProjectConfig.Factory projectConfigFactory;
 
     @Inject
     UpdateChecker(
-        GitRepositoryManager repoManager, DynamicMap<ProjectConfigEntry> pluginConfigEntries) {
+        GitRepositoryManager repoManager,
+        DynamicMap<ProjectConfigEntry> pluginConfigEntries,
+        ProjectConfig.Factory projectConfigFactory) {
       this.repoManager = repoManager;
       this.pluginConfigEntries = pluginConfigEntries;
+      this.projectConfigFactory = projectConfigFactory;
     }
 
     @Override
@@ -361,7 +365,7 @@
         return null;
       }
       try (Repository repo = repoManager.openRepository(p)) {
-        ProjectConfig pc = new ProjectConfig(p);
+        ProjectConfig pc = projectConfigFactory.create(p);
         pc.load(repo, id);
         return pc;
       }
diff --git a/java/com/google/gerrit/server/git/DefaultAdvertiseRefsHook.java b/java/com/google/gerrit/server/git/DefaultAdvertiseRefsHook.java
index ef5e65b..be8fcdb 100644
--- a/java/com/google/gerrit/server/git/DefaultAdvertiseRefsHook.java
+++ b/java/com/google/gerrit/server/git/DefaultAdvertiseRefsHook.java
@@ -14,8 +14,11 @@
 
 package com.google.gerrit.server.git;
 
+import com.google.common.collect.ImmutableMap;
 import com.google.gerrit.server.permissions.PermissionBackend;
 import com.google.gerrit.server.permissions.PermissionBackendException;
+import java.io.IOException;
+import java.util.List;
 import java.util.Map;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.Repository;
@@ -28,7 +31,6 @@
  * implements {@link org.eclipse.jgit.transport.AdvertiseRefsHook}.
  */
 public class DefaultAdvertiseRefsHook extends AbstractAdvertiseRefsHook {
-
   private final PermissionBackend.ForProject perm;
   private final PermissionBackend.RefFilterOptions opts;
 
@@ -42,9 +44,24 @@
   protected Map<String, Ref> getAdvertisedRefs(Repository repo, RevWalk revWalk)
       throws ServiceMayNotContinueException {
     try {
-      return perm.filter(repo.getAllRefs(), repo, opts);
-    } catch (PermissionBackendException e) {
-      throw new ServiceMayNotContinueException(e);
+      Map<String, Ref> refs;
+      List<String> prefixes = opts.prefixes();
+      if (prefixes.isEmpty() || prefixes.get(0).isEmpty()) {
+        refs = repo.getAllRefs();
+      } else {
+        ImmutableMap.Builder<String, Ref> b = new ImmutableMap.Builder<>();
+        for (String prefix : prefixes) {
+          for (Ref ref : repo.getRefDatabase().getRefsByPrefix(prefix)) {
+            b.put(ref.getName(), ref);
+          }
+        }
+        refs = b.build();
+      }
+      return perm.filter(refs, repo, opts);
+    } catch (IOException | PermissionBackendException e) {
+      ServiceMayNotContinueException ex = new ServiceMayNotContinueException();
+      ex.initCause(e);
+      throw ex;
     }
   }
 }
diff --git a/java/com/google/gerrit/server/git/MultiBaseLocalDiskRepositoryManager.java b/java/com/google/gerrit/server/git/MultiBaseLocalDiskRepositoryManager.java
index 6fafe4e..01e85cf 100644
--- a/java/com/google/gerrit/server/git/MultiBaseLocalDiskRepositoryManager.java
+++ b/java/com/google/gerrit/server/git/MultiBaseLocalDiskRepositoryManager.java
@@ -17,7 +17,7 @@
 import static com.google.common.base.Preconditions.checkState;
 
 import com.google.gerrit.lifecycle.LifecycleModule;
-import com.google.gerrit.reviewdb.client.Project.NameKey;
+import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.config.RepositoryConfig;
 import com.google.gerrit.server.config.SitePaths;
@@ -54,7 +54,7 @@
   }
 
   @Override
-  public Path getBasePath(NameKey name) {
+  public Path getBasePath(Project.NameKey name) {
     Path alternateBasePath = config.getBasePath(name);
     return alternateBasePath != null ? alternateBasePath : super.getBasePath(name);
   }
diff --git a/java/com/google/gerrit/server/git/receive/ReceiveCommits.java b/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
index 6267590..c747533 100644
--- a/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
+++ b/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
@@ -321,6 +321,7 @@
   private final SetHashtagsOp.Factory hashtagsFactory;
   private final SubmoduleOp.Factory subOpFactory;
   private final TagCache tagCache;
+  private final ProjectConfig.Factory projectConfigFactory;
 
   // Assisted injected fields.
   private final AllRefsWatcher allRefsWatcher;
@@ -365,6 +366,7 @@
       AccountResolver accountResolver,
       AllProjectsName allProjectsName,
       BatchUpdate.Factory batchUpdateFactory,
+      ProjectConfig.Factory projectConfigFactory,
       @GerritServerConfig Config cfg,
       ChangeEditUtil editUtil,
       ChangeIndexer indexer,
@@ -437,6 +439,7 @@
     this.seq = seq;
     this.subOpFactory = subOpFactory;
     this.tagCache = tagCache;
+    this.projectConfigFactory = projectConfigFactory;
 
     // Assisted injected fields.
     this.allRefsWatcher = allRefsWatcher;
@@ -1055,7 +1058,7 @@
       case UPDATE:
       case UPDATE_NONFASTFORWARD:
         try {
-          ProjectConfig cfg = new ProjectConfig(project.getNameKey());
+          ProjectConfig cfg = projectConfigFactory.create(project.getNameKey());
           cfg.load(project.getNameKey(), receivePack.getRevWalk(), cmd.getNewId());
           if (!cfg.getValidationErrors().isEmpty()) {
             addError("Invalid project configuration:");
diff --git a/java/com/google/gerrit/server/git/validators/CommitValidators.java b/java/com/google/gerrit/server/git/validators/CommitValidators.java
index 9f75c07..e3dfa75 100644
--- a/java/com/google/gerrit/server/git/validators/CommitValidators.java
+++ b/java/com/google/gerrit/server/git/validators/CommitValidators.java
@@ -98,6 +98,7 @@
     private final AccountValidator accountValidator;
     private final String installCommitMsgHookCommand;
     private final ProjectCache projectCache;
+    private final ProjectConfig.Factory projectConfigFactory;
 
     @Inject
     Factory(
@@ -110,7 +111,8 @@
         AllProjectsName allProjects,
         ExternalIdsConsistencyChecker externalIdsConsistencyChecker,
         AccountValidator accountValidator,
-        ProjectCache projectCache) {
+        ProjectCache projectCache,
+        ProjectConfig.Factory projectConfigFactory) {
       this.gerritIdent = gerritIdent;
       this.urlFormatter = urlFormatter;
       this.pluginValidators = pluginValidators;
@@ -122,6 +124,7 @@
       this.installCommitMsgHookCommand =
           cfg != null ? cfg.getString("gerrit", null, "installCommitMsgHookCommand") : null;
       this.projectCache = projectCache;
+      this.projectConfigFactory = projectConfigFactory;
     }
 
     public CommitValidators forReceiveCommits(
@@ -145,7 +148,7 @@
               new SignedOffByValidator(user, perm, projectState),
               new ChangeIdValidator(
                   projectState, user, urlFormatter, installCommitMsgHookCommand, sshInfo, change),
-              new ConfigValidator(branch, user, rw, allUsers, allProjects),
+              new ConfigValidator(projectConfigFactory, branch, user, rw, allUsers, allProjects),
               new BannedCommitsValidator(rejectCommits),
               new PluginCommitValidationListener(pluginValidators),
               new ExternalIdUpdateListener(allUsers, externalIdsConsistencyChecker),
@@ -172,7 +175,7 @@
               new SignedOffByValidator(user, perm, projectCache.checkedGet(branch.getParentKey())),
               new ChangeIdValidator(
                   projectState, user, urlFormatter, installCommitMsgHookCommand, sshInfo, change),
-              new ConfigValidator(branch, user, rw, allUsers, allProjects),
+              new ConfigValidator(projectConfigFactory, branch, user, rw, allUsers, allProjects),
               new PluginCommitValidationListener(pluginValidators),
               new ExternalIdUpdateListener(allUsers, externalIdsConsistencyChecker),
               new AccountCommitValidator(repoManager, allUsers, accountValidator),
@@ -331,7 +334,8 @@
             .append(getCommitMessageHookInstallationHint())
             .append("\n")
             .append("and then amend the commit:\n")
-            .append("  git commit --amend\n");
+            .append("  git commit --amend\n")
+            .append("Finally, push your changes again\n");
       }
       return new CommitValidationMessage(sb.toString(), Type.ERROR);
     }
@@ -378,6 +382,7 @@
 
   /** If this is the special project configuration branch, validate the config. */
   public static class ConfigValidator implements CommitValidationListener {
+    private final ProjectConfig.Factory projectConfigFactory;
     private final Branch.NameKey branch;
     private final IdentifiedUser user;
     private final RevWalk rw;
@@ -385,11 +390,13 @@
     private final AllProjectsName allProjects;
 
     public ConfigValidator(
+        ProjectConfig.Factory projectConfigFactory,
         Branch.NameKey branch,
         IdentifiedUser user,
         RevWalk rw,
         AllUsersName allUsers,
         AllProjectsName allProjects) {
+      this.projectConfigFactory = projectConfigFactory;
       this.branch = branch;
       this.user = user;
       this.rw = rw;
@@ -404,7 +411,7 @@
         List<CommitValidationMessage> messages = new ArrayList<>();
 
         try {
-          ProjectConfig cfg = new ProjectConfig(receiveEvent.project.getNameKey());
+          ProjectConfig cfg = projectConfigFactory.create(receiveEvent.project.getNameKey());
           cfg.load(rw, receiveEvent.command.getNewId());
           if (!cfg.getValidationErrors().isEmpty()) {
             addError("Invalid project configuration:", messages);
diff --git a/java/com/google/gerrit/server/git/validators/MergeValidators.java b/java/com/google/gerrit/server/git/validators/MergeValidators.java
index 0422c51..56a641f 100644
--- a/java/com/google/gerrit/server/git/validators/MergeValidators.java
+++ b/java/com/google/gerrit/server/git/validators/MergeValidators.java
@@ -127,6 +127,7 @@
     private final ProjectCache projectCache;
     private final PermissionBackend permissionBackend;
     private final DynamicMap<ProjectConfigEntry> pluginConfigEntries;
+    private final ProjectConfig.Factory projectConfigFactory;
     private final boolean allowProjectOwnersToChangeParent;
 
     public interface Factory {
@@ -140,12 +141,14 @@
         ProjectCache projectCache,
         PermissionBackend permissionBackend,
         DynamicMap<ProjectConfigEntry> pluginConfigEntries,
+        ProjectConfig.Factory projectConfigFactory,
         @GerritServerConfig Config config) {
       this.allProjectsName = allProjectsName;
       this.allUsersName = allUsersName;
       this.projectCache = projectCache;
       this.permissionBackend = permissionBackend;
       this.pluginConfigEntries = pluginConfigEntries;
+      this.projectConfigFactory = projectConfigFactory;
       this.allowProjectOwnersToChangeParent =
           config.getBoolean("receive", "allowProjectOwnersToChangeParent", false);
     }
@@ -162,7 +165,7 @@
       if (RefNames.REFS_CONFIG.equals(destBranch.get())) {
         final Project.NameKey newParent;
         try {
-          ProjectConfig cfg = new ProjectConfig(destProject.getNameKey());
+          ProjectConfig cfg = projectConfigFactory.create(destProject.getNameKey());
           cfg.load(destProject.getNameKey(), repo, commit);
           newParent = cfg.getProject().getParent(allProjectsName);
           final Project.NameKey oldParent = destProject.getProject().getParent(allProjectsName);
diff --git a/java/com/google/gerrit/server/group/db/RenameGroupOp.java b/java/com/google/gerrit/server/group/db/RenameGroupOp.java
index eada57d..e002192 100644
--- a/java/com/google/gerrit/server/group/db/RenameGroupOp.java
+++ b/java/com/google/gerrit/server/group/db/RenameGroupOp.java
@@ -49,6 +49,7 @@
 
   private final ProjectCache projectCache;
   private final MetaDataUpdate.Server metaDataUpdateFactory;
+  private final ProjectConfig.Factory projectConfigFactory;
 
   private final PersonIdent author;
   private final AccountGroup.UUID uuid;
@@ -63,6 +64,7 @@
       WorkQueue workQueue,
       ProjectCache projectCache,
       MetaDataUpdate.Server metaDataUpdateFactory,
+      ProjectConfig.Factory projectConfigFactory,
       @Assisted("author") PersonIdent author,
       @Assisted AccountGroup.UUID uuid,
       @Assisted("oldName") String oldName,
@@ -70,6 +72,7 @@
     super(workQueue);
     this.projectCache = projectCache;
     this.metaDataUpdateFactory = metaDataUpdateFactory;
+    this.projectConfigFactory = projectConfigFactory;
 
     this.author = author;
     this.uuid = uuid;
@@ -109,7 +112,7 @@
   private void rename(MetaDataUpdate md) throws IOException, ConfigInvalidException {
     boolean success = false;
     for (int attempts = 0; !success && attempts < MAX_TRIES; attempts++) {
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
 
       // The group isn't referenced, or its name has been fixed already.
       //
diff --git a/java/com/google/gerrit/server/index/change/ChangeField.java b/java/com/google/gerrit/server/index/change/ChangeField.java
index 5d12e79..b79a1c2 100644
--- a/java/com/google/gerrit/server/index/change/ChangeField.java
+++ b/java/com/google/gerrit/server/index/change/ChangeField.java
@@ -508,11 +508,15 @@
                           cd.messages().stream().map(ChangeMessage::getMessage))
                       .collect(toSet()));
 
-  /** Number of unresolved comments of the change. */
+  /** Number of unresolved comment threads of the change, including robot comments. */
   public static final FieldDef<ChangeData, Integer> UNRESOLVED_COMMENT_COUNT =
       intRange(ChangeQueryBuilder.FIELD_UNRESOLVED_COMMENT_COUNT)
           .build(ChangeData::unresolvedCommentCount);
 
+  /** Total number of published inline comments of the change, including robot comments. */
+  public static final FieldDef<ChangeData, Integer> TOTAL_COMMENT_COUNT =
+      intRange("total_comments").build(ChangeData::totalCommentCount);
+
   /** Whether the change is mergeable. */
   public static final FieldDef<ChangeData, String> MERGEABLE =
       exact(ChangeQueryBuilder.FIELD_MERGEABLE)
diff --git a/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java b/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java
index 2000cd1..9016fd1 100644
--- a/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java
+++ b/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java
@@ -99,7 +99,9 @@
   @Deprecated static final Schema<ChangeData> V49 = schema(V48);
 
   // Bump Lucene version requires reindexing
-  static final Schema<ChangeData> V50 = schema(V49);
+  @Deprecated static final Schema<ChangeData> V50 = schema(V49);
+
+  static final Schema<ChangeData> V51 = schema(V50, ChangeField.TOTAL_COMMENT_COUNT);
 
   public static final String NAME = "changes";
   public static final ChangeSchemaDefinitions INSTANCE = new ChangeSchemaDefinitions();
diff --git a/java/com/google/gerrit/server/permissions/PermissionBackend.java b/java/com/google/gerrit/server/permissions/PermissionBackend.java
index db3c961..bea760c 100644
--- a/java/com/google/gerrit/server/permissions/PermissionBackend.java
+++ b/java/com/google/gerrit/server/permissions/PermissionBackend.java
@@ -18,6 +18,7 @@
 import static java.util.stream.Collectors.toSet;
 
 import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Sets;
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.common.data.LabelType;
@@ -40,6 +41,7 @@
 import java.util.Collections;
 import java.util.EnumSet;
 import java.util.Iterator;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import org.eclipse.jgit.errors.RepositoryNotFoundException;
@@ -367,12 +369,19 @@
     /** Separately add reachable tags. */
     public abstract boolean filterTagsSeparately();
 
+    /**
+     * Select only refs with names matching prefixes per {@link
+     * org.eclipse.jgit.lib.RefDatabase#getRefsByPrefix}.
+     */
+    public abstract ImmutableList<String> prefixes();
+
     public abstract Builder toBuilder();
 
     public static Builder builder() {
       return new AutoValue_PermissionBackend_RefFilterOptions.Builder()
           .setFilterMeta(false)
-          .setFilterTagsSeparately(false);
+          .setFilterTagsSeparately(false)
+          .setPrefixes(Collections.singletonList(""));
     }
 
     @AutoValue.Builder
@@ -381,6 +390,8 @@
 
       public abstract Builder setFilterTagsSeparately(boolean val);
 
+      public abstract Builder setPrefixes(List<String> prefixes);
+
       public abstract RefFilterOptions build();
     }
 
diff --git a/java/com/google/gerrit/server/plugincontext/PluginSetEntryContext.java b/java/com/google/gerrit/server/plugincontext/PluginSetEntryContext.java
index afffbef..2268c07 100644
--- a/java/com/google/gerrit/server/plugincontext/PluginSetEntryContext.java
+++ b/java/com/google/gerrit/server/plugincontext/PluginSetEntryContext.java
@@ -103,8 +103,9 @@
    *
    * <p>Should only be used in exceptional cases to get direct access to the extension
    * implementation. If possible the extension should be invoked through {@link
-   * #run(ExtensionImplConsumer)}, {@link #run(ExtensionImplConsumer, Class)}, {@link
-   * #call(ExtensionImplFunction)} and {@link #call(CheckedExtensionImplFunction, Class)}.
+   * #run(PluginContext.ExtensionImplConsumer)}, {@link #run(PluginContext.ExtensionImplConsumer,
+   * java.lang.Class)}, {@link #call(PluginContext.ExtensionImplFunction)} and {@link
+   * #call(PluginContext.CheckedExtensionImplFunction, java.lang.Class)}.
    *
    * @return the implementation of this extension
    */
diff --git a/java/com/google/gerrit/server/plugins/JarScanner.java b/java/com/google/gerrit/server/plugins/JarScanner.java
index 1a9b859..486e264 100644
--- a/java/com/google/gerrit/server/plugins/JarScanner.java
+++ b/java/com/google/gerrit/server/plugins/JarScanner.java
@@ -195,7 +195,7 @@
     Collection<String> exports;
 
     private ClassData(Collection<String> exports) {
-      super(Opcodes.ASM6);
+      super(Opcodes.ASM7);
       this.exports = exports;
     }
 
@@ -263,7 +263,7 @@
 
   private abstract static class AbstractAnnotationVisitor extends AnnotationVisitor {
     AbstractAnnotationVisitor() {
-      super(Opcodes.ASM6);
+      super(Opcodes.ASM7);
     }
 
     @Override
diff --git a/java/com/google/gerrit/server/project/ContributorAgreementsChecker.java b/java/com/google/gerrit/server/project/ContributorAgreementsChecker.java
index fc342db..4ed1c0c 100644
--- a/java/com/google/gerrit/server/project/ContributorAgreementsChecker.java
+++ b/java/com/google/gerrit/server/project/ContributorAgreementsChecker.java
@@ -14,6 +14,9 @@
 
 package com.google.gerrit.server.project;
 
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+
 import com.google.gerrit.common.data.ContributorAgreement;
 import com.google.gerrit.common.data.PermissionRule;
 import com.google.gerrit.common.data.PermissionRule.Action;
@@ -34,6 +37,8 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import java.util.regex.Pattern;
+import java.util.regex.PatternSyntaxException;
 
 @Singleton
 public class ContributorAgreementsChecker {
@@ -93,6 +98,20 @@
       List<AccountGroup.UUID> groupIds;
       groupIds = okGroupIds;
 
+      // matchProjects defaults to match all projects when missing.
+      List<String> matchProjectsRegexes = ca.getMatchProjectsRegexes();
+      if (!matchProjectsRegexes.isEmpty()
+          && !projectMatchesAnyPattern(project.get(), matchProjectsRegexes)) {
+        // Doesn't match, isn't checked.
+        continue;
+      }
+      // excludeProjects defaults to exclude no projects when missing.
+      List<String> excludeProjectsRegexes = ca.getExcludeProjectsRegexes();
+      if (!excludeProjectsRegexes.isEmpty()
+          && projectMatchesAnyPattern(project.get(), excludeProjectsRegexes)) {
+        // Matches, isn't checked.
+        continue;
+      }
       for (PermissionRule rule : ca.getAccepted()) {
         if ((rule.getAction() == Action.ALLOW)
             && (rule.getGroup() != null)
@@ -102,7 +121,7 @@
       }
     }
 
-    if (!iUser.getEffectiveGroups().containsAnyOf(okGroupIds)) {
+    if (!okGroupIds.isEmpty() && !iUser.getEffectiveGroups().containsAnyOf(okGroupIds)) {
       final StringBuilder msg = new StringBuilder();
       msg.append("No Contributor Agreement on file for user ")
           .append(iUser.getNameEmail())
@@ -114,4 +133,23 @@
       throw new AuthException(msg.toString());
     }
   }
+
+  private boolean projectMatchesAnyPattern(String projectName, List<String> regexes) {
+    checkNotNull(regexes);
+    checkArgument(!regexes.isEmpty());
+    for (String patternString : regexes) {
+      Pattern pattern;
+      try {
+        pattern = Pattern.compile(patternString);
+      } catch (PatternSyntaxException e) {
+        // Should never happen: Regular expressions validated when reading project.config.
+        throw new IllegalStateException(
+            "Invalid matchProjects or excludeProjects clause in project.config", e);
+      }
+      if (pattern.matcher(projectName).find()) {
+        return true;
+      }
+    }
+    return false;
+  }
 }
diff --git a/java/com/google/gerrit/server/project/CreateProjectArgs.java b/java/com/google/gerrit/server/project/CreateProjectArgs.java
index a68bd84..df31c19 100644
--- a/java/com/google/gerrit/server/project/CreateProjectArgs.java
+++ b/java/com/google/gerrit/server/project/CreateProjectArgs.java
@@ -49,6 +49,7 @@
     enableSignedPush = InheritableBoolean.INHERIT;
     requireSignedPush = InheritableBoolean.INHERIT;
     submitType = SubmitType.MERGE_IF_NECESSARY;
+    rejectEmptyCommit = InheritableBoolean.INHERIT;
   }
 
   public Project.NameKey getProject() {
diff --git a/java/com/google/gerrit/server/project/ProjectCacheImpl.java b/java/com/google/gerrit/server/project/ProjectCacheImpl.java
index aa455e6..ddeeb8a 100644
--- a/java/com/google/gerrit/server/project/ProjectCacheImpl.java
+++ b/java/com/google/gerrit/server/project/ProjectCacheImpl.java
@@ -25,6 +25,10 @@
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.index.project.ProjectIndexer;
 import com.google.gerrit.lifecycle.LifecycleModule;
+import com.google.gerrit.metrics.Description;
+import com.google.gerrit.metrics.Description.Units;
+import com.google.gerrit.metrics.MetricMaker;
+import com.google.gerrit.metrics.Timer0;
 import com.google.gerrit.reviewdb.client.AccountGroup;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.cache.CacheModule;
@@ -89,6 +93,7 @@
   private final Lock listLock;
   private final ProjectCacheClock clock;
   private final Provider<ProjectIndexer> indexer;
+  private final Timer0 guessRelevantGroupsLatency;
 
   @Inject
   ProjectCacheImpl(
@@ -97,7 +102,8 @@
       @Named(CACHE_NAME) LoadingCache<String, ProjectState> byName,
       @Named(CACHE_LIST) LoadingCache<ListKey, ImmutableSortedSet<Project.NameKey>> list,
       ProjectCacheClock clock,
-      Provider<ProjectIndexer> indexer) {
+      Provider<ProjectIndexer> indexer,
+      MetricMaker metricMaker) {
     this.allProjectsName = allProjectsName;
     this.allUsersName = allUsersName;
     this.byName = byName;
@@ -105,6 +111,13 @@
     this.listLock = new ReentrantLock(true /* fair */);
     this.clock = clock;
     this.indexer = indexer;
+
+    this.guessRelevantGroupsLatency =
+        metricMaker.newTimer(
+            "group/guess_relevant_groups_latency",
+            new Description("Latency for guessing relevant groups")
+                .setCumulative()
+                .setUnit(Units.NANOSECONDS));
   }
 
   @Override
@@ -234,15 +247,17 @@
 
   @Override
   public Set<AccountGroup.UUID> guessRelevantGroupUUIDs() {
-    return all()
-        .stream()
-        .map(n -> byName.getIfPresent(n.get()))
-        .filter(Objects::nonNull)
-        .flatMap(p -> p.getConfig().getAllGroupUUIDs().stream())
-        // getAllGroupUUIDs shouldn't really return null UUIDs, but harden
-        // against them just in case there is a bug or corner case.
-        .filter(id -> id != null && id.get() != null)
-        .collect(toSet());
+    try (Timer0.Context ignored = guessRelevantGroupsLatency.start()) {
+      return all()
+          .stream()
+          .map(n -> byName.getIfPresent(n.get()))
+          .filter(Objects::nonNull)
+          .flatMap(p -> p.getConfig().getAllGroupUUIDs().stream())
+          // getAllGroupUUIDs shouldn't really return null UUIDs, but harden
+          // against them just in case there is a bug or corner case.
+          .filter(id -> id != null && id.get() != null)
+          .collect(toSet());
+    }
   }
 
   @Override
@@ -262,12 +277,18 @@
     private final ProjectState.Factory projectStateFactory;
     private final GitRepositoryManager mgr;
     private final ProjectCacheClock clock;
+    private final ProjectConfig.Factory projectConfigFactory;
 
     @Inject
-    Loader(ProjectState.Factory psf, GitRepositoryManager g, ProjectCacheClock clock) {
+    Loader(
+        ProjectState.Factory psf,
+        GitRepositoryManager g,
+        ProjectCacheClock clock,
+        ProjectConfig.Factory projectConfigFactory) {
       projectStateFactory = psf;
       mgr = g;
       this.clock = clock;
+      this.projectConfigFactory = projectConfigFactory;
     }
 
     @Override
@@ -276,7 +297,7 @@
         long now = clock.read();
         Project.NameKey key = new Project.NameKey(projectName);
         try (Repository git = mgr.openRepository(key)) {
-          ProjectConfig cfg = new ProjectConfig(key);
+          ProjectConfig cfg = projectConfigFactory.create(key);
           cfg.load(key, git);
 
           ProjectState state = projectStateFactory.create(cfg);
diff --git a/java/com/google/gerrit/server/project/ProjectConfig.java b/java/com/google/gerrit/server/project/ProjectConfig.java
index bccc415..74c0f3b 100644
--- a/java/com/google/gerrit/server/project/ProjectConfig.java
+++ b/java/com/google/gerrit/server/project/ProjectConfig.java
@@ -59,6 +59,7 @@
 import com.google.gerrit.server.git.ValidationError;
 import com.google.gerrit.server.git.meta.MetaDataUpdate;
 import com.google.gerrit.server.git.meta.VersionedMetaData;
+import com.google.inject.Singleton;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -127,6 +128,8 @@
   private static final String KEY_ACCEPTED = "accepted";
   private static final String KEY_AUTO_VERIFY = "autoVerify";
   private static final String KEY_AGREEMENT_URL = "agreementUrl";
+  private static final String KEY_MATCH_PROJECTS = "matchProjects";
+  private static final String KEY_EXCLUDE_PROJECTS = "excludeProjects";
 
   private static final String NOTIFY = "notify";
   private static final String KEY_EMAIL = "email";
@@ -165,6 +168,29 @@
 
   private static final Pattern EXCLUSIVE_PERMISSIONS_SPLIT_PATTERN = Pattern.compile("[, \t]{1,}");
 
+  // Don't use an assisted factory, since instances created by an assisted factory retain references
+  // to their enclosing injector. Instances of ProjectConfig are cached for a long time in the
+  // ProjectCache, so this would retain lots more memory.
+  @Singleton
+  public static class Factory {
+    public ProjectConfig create(Project.NameKey projectName) {
+      return new ProjectConfig(projectName);
+    }
+
+    public ProjectConfig read(MetaDataUpdate update) throws IOException, ConfigInvalidException {
+      ProjectConfig r = create(update.getProjectName());
+      r.load(update);
+      return r;
+    }
+
+    public ProjectConfig read(MetaDataUpdate update, ObjectId id)
+        throws IOException, ConfigInvalidException {
+      ProjectConfig r = create(update.getProjectName());
+      r.load(update, id);
+      return r;
+    }
+  }
+
   private Project project;
   private AccountsSection accountsSection;
   private GroupList groupList;
@@ -186,20 +212,6 @@
   private Map<String, List<String>> extensionPanelSections;
   private Map<String, GroupReference> groupsByName;
 
-  public static ProjectConfig read(MetaDataUpdate update)
-      throws IOException, ConfigInvalidException {
-    ProjectConfig r = new ProjectConfig(update.getProjectName());
-    r.load(update);
-    return r;
-  }
-
-  public static ProjectConfig read(MetaDataUpdate update, ObjectId id)
-      throws IOException, ConfigInvalidException {
-    ProjectConfig r = new ProjectConfig(update.getProjectName());
-    r.load(update, id);
-    return r;
-  }
-
   public static CommentLinkInfoImpl buildCommentLink(Config cfg, String name, boolean allowRaw)
       throws IllegalArgumentException {
     String match = cfg.getString(COMMENTLINK, name, KEY_MATCH);
@@ -241,7 +253,7 @@
     commentLinkSections.add(commentLink);
   }
 
-  public ProjectConfig(Project.NameKey projectName) {
+  private ProjectConfig(Project.NameKey projectName) {
     this.projectName = projectName;
   }
 
@@ -593,6 +605,9 @@
       ca.setAgreementUrl(rc.getString(CONTRIBUTOR_AGREEMENT, name, KEY_AGREEMENT_URL));
       ca.setAccepted(
           loadPermissionRules(rc, CONTRIBUTOR_AGREEMENT, name, KEY_ACCEPTED, groupsByName, false));
+      ca.setExcludeProjectsRegexes(
+          loadPatterns(rc, CONTRIBUTOR_AGREEMENT, name, KEY_EXCLUDE_PROJECTS));
+      ca.setMatchProjectsRegexes(loadPatterns(rc, CONTRIBUTOR_AGREEMENT, name, KEY_MATCH_PROJECTS));
 
       List<PermissionRule> rules =
           loadPermissionRules(
@@ -753,6 +768,22 @@
     }
   }
 
+  private ImmutableList<String> loadPatterns(
+      Config rc, String section, String subsection, String varName) {
+    ImmutableList.Builder<String> patterns = ImmutableList.builder();
+    for (String patternString : rc.getStringList(section, subsection, varName)) {
+      try {
+        // While one could just use getStringList directly, compiling first will cause the server
+        // to fail fast if any of the patterns are invalid.
+        patterns.add(Pattern.compile(patternString).pattern());
+      } catch (PatternSyntaxException e) {
+        error(new ValidationError(PROJECT_CONFIG, "Invalid regular expression: " + e.getMessage()));
+        continue;
+      }
+    }
+    return patterns.build();
+  }
+
   private ImmutableList<PermissionRule> loadPermissionRules(
       Config rc,
       String section,
@@ -1163,6 +1194,16 @@
           ca.getName(),
           KEY_ACCEPTED,
           ruleToStringList(ca.getAccepted(), keepGroups));
+      rc.setStringList(
+          CONTRIBUTOR_AGREEMENT,
+          ca.getName(),
+          KEY_EXCLUDE_PROJECTS,
+          patternToStringList(ca.getExcludeProjectsRegexes()));
+      rc.setStringList(
+          CONTRIBUTOR_AGREEMENT,
+          ca.getName(),
+          KEY_MATCH_PROJECTS,
+          patternToStringList(ca.getMatchProjectsRegexes()));
     }
   }
 
@@ -1206,6 +1247,10 @@
     }
   }
 
+  private List<String> patternToStringList(List<String> list) {
+    return list;
+  }
+
   private List<String> ruleToStringList(
       List<PermissionRule> list, Set<AccountGroup.UUID> keepGroups) {
     List<String> rules = new ArrayList<>();
diff --git a/java/com/google/gerrit/server/project/SectionMatcher.java b/java/com/google/gerrit/server/project/SectionMatcher.java
index 11b1f37..3095f2f 100644
--- a/java/com/google/gerrit/server/project/SectionMatcher.java
+++ b/java/com/google/gerrit/server/project/SectionMatcher.java
@@ -16,7 +16,6 @@
 
 import com.google.gerrit.common.data.AccessSection;
 import com.google.gerrit.reviewdb.client.Project;
-import com.google.gerrit.reviewdb.client.Project.NameKey;
 import com.google.gerrit.server.CurrentUser;
 
 /**
@@ -57,7 +56,7 @@
     return matcher;
   }
 
-  public NameKey getProject() {
+  public Project.NameKey getProject() {
     return project;
   }
 }
diff --git a/java/com/google/gerrit/server/query/change/ChangeData.java b/java/com/google/gerrit/server/query/change/ChangeData.java
index 83d68db..0f5d938 100644
--- a/java/com/google/gerrit/server/query/change/ChangeData.java
+++ b/java/com/google/gerrit/server/query/change/ChangeData.java
@@ -30,6 +30,7 @@
 import com.google.common.collect.ListMultimap;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
+import com.google.common.primitives.Ints;
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.common.data.LabelTypes;
 import com.google.gerrit.common.data.SubmitRecord;
@@ -391,6 +392,7 @@
   private PersonIdent committer;
   private int parentCount;
   private Integer unresolvedCommentCount;
+  private Integer totalCommentCount;
   private LabelTypes labelTypes;
 
   private ImmutableList<byte[]> refStates;
@@ -925,6 +927,23 @@
     this.unresolvedCommentCount = count;
   }
 
+  public Integer totalCommentCount() throws OrmException {
+    if (totalCommentCount == null) {
+      if (!lazyLoad) {
+        return null;
+      }
+
+      // Fail on overflow.
+      totalCommentCount =
+          Ints.checkedCast((long) publishedComments().size() + robotComments().size());
+    }
+    return totalCommentCount;
+  }
+
+  public void setTotalCommentCount(Integer count) {
+    this.totalCommentCount = count;
+  }
+
   public List<ChangeMessage> messages() throws OrmException {
     if (messages == null) {
       if (!lazyLoad) {
diff --git a/java/com/google/gerrit/server/query/change/ChangeIsVisibleToPredicate.java b/java/com/google/gerrit/server/query/change/ChangeIsVisibleToPredicate.java
index f81ea15..d682b93 100644
--- a/java/com/google/gerrit/server/query/change/ChangeIsVisibleToPredicate.java
+++ b/java/com/google/gerrit/server/query/change/ChangeIsVisibleToPredicate.java
@@ -29,6 +29,7 @@
 import com.google.gerrit.server.project.ProjectCache;
 import com.google.gerrit.server.project.ProjectState;
 import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
 import com.google.inject.Provider;
 import java.io.IOException;
 import org.eclipse.jgit.errors.RepositoryNotFoundException;
@@ -43,6 +44,7 @@
   protected final ProjectCache projectCache;
   private final Provider<AnonymousUser> anonymousUserProvider;
 
+  @Inject
   public ChangeIsVisibleToPredicate(
       Provider<ReviewDb> db,
       ChangeNotes.Factory notesFactory,
diff --git a/java/com/google/gerrit/server/restapi/change/ChangesCollection.java b/java/com/google/gerrit/server/restapi/change/ChangesCollection.java
index 561c27c..30d93be 100644
--- a/java/com/google/gerrit/server/restapi/change/ChangesCollection.java
+++ b/java/com/google/gerrit/server/restapi/change/ChangesCollection.java
@@ -17,6 +17,7 @@
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.IdString;
+import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.RestCollection;
@@ -101,7 +102,8 @@
   }
 
   public ChangeResource parse(Change.Id id)
-      throws RestApiException, OrmException, PermissionBackendException, IOException {
+      throws ResourceConflictException, ResourceNotFoundException, OrmException,
+          PermissionBackendException, IOException {
     List<ChangeNotes> notes = changeFinder.find(id);
     if (notes.isEmpty()) {
       throw new ResourceNotFoundException(toIdString(id));
@@ -139,7 +141,7 @@
   }
 
   private void checkProjectStatePermitsRead(Project.NameKey project)
-      throws IOException, RestApiException {
+      throws IOException, ResourceNotFoundException, ResourceConflictException {
     ProjectState projectState = projectCache.checkedGet(project);
     if (projectState == null) {
       throw new ResourceNotFoundException("project not found: " + project.get());
diff --git a/java/com/google/gerrit/server/restapi/change/Files.java b/java/com/google/gerrit/server/restapi/change/Files.java
index 1bb6bf2..b374fdc 100644
--- a/java/com/google/gerrit/server/restapi/change/Files.java
+++ b/java/com/google/gerrit/server/restapi/change/Files.java
@@ -18,6 +18,7 @@
 import com.google.common.flogger.FluentLogger;
 import com.google.common.hash.Hasher;
 import com.google.common.hash.Hashing;
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.extensions.common.FileInfo;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.restapi.AuthException;
@@ -332,7 +333,7 @@
       return this;
     }
 
-    public ListFiles setBase(String base) {
+    public ListFiles setBase(@Nullable String base) {
       this.base = base;
       return this;
     }
diff --git a/java/com/google/gerrit/server/restapi/change/GetRelated.java b/java/com/google/gerrit/server/restapi/change/GetRelated.java
index 3313136..30fbf39 100644
--- a/java/com/google/gerrit/server/restapi/change/GetRelated.java
+++ b/java/com/google/gerrit/server/restapi/change/GetRelated.java
@@ -17,9 +17,10 @@
 import static java.util.stream.Collectors.toSet;
 
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.MoreObjects;
 import com.google.common.collect.Lists;
 import com.google.gerrit.common.Nullable;
+import com.google.gerrit.extensions.api.changes.RelatedChangeAndCommitInfo;
+import com.google.gerrit.extensions.api.changes.RelatedChangesInfo;
 import com.google.gerrit.extensions.common.CommitInfo;
 import com.google.gerrit.extensions.restapi.RestReadView;
 import com.google.gerrit.index.IndexConfig;
@@ -70,15 +71,15 @@
   }
 
   @Override
-  public RelatedInfo apply(RevisionResource rsrc)
+  public RelatedChangesInfo apply(RevisionResource rsrc)
       throws RepositoryNotFoundException, IOException, OrmException, NoSuchProjectException,
           PermissionBackendException {
-    RelatedInfo relatedInfo = new RelatedInfo();
-    relatedInfo.changes = getRelated(rsrc);
-    return relatedInfo;
+    RelatedChangesInfo relatedChangesInfo = new RelatedChangesInfo();
+    relatedChangesInfo.changes = getRelated(rsrc);
+    return relatedChangesInfo;
   }
 
-  private List<ChangeAndCommit> getRelated(RevisionResource rsrc)
+  private List<RelatedChangeAndCommitInfo> getRelated(RevisionResource rsrc)
       throws OrmException, IOException, PermissionBackendException {
     Set<String> groups = getAllGroups(rsrc.getNotes(), db.get(), psUtil);
     if (groups.isEmpty()) {
@@ -94,7 +95,7 @@
     if (cds.size() == 1 && cds.get(0).getId().equals(rsrc.getChange().getId())) {
       return Collections.emptyList();
     }
-    List<ChangeAndCommit> result = new ArrayList<>(cds.size());
+    List<RelatedChangeAndCommitInfo> result = new ArrayList<>(cds.size());
 
     boolean isEdit = rsrc.getEdit().isPresent();
     PatchSet basePs = isEdit ? rsrc.getEdit().get().getBasePatchSet() : rsrc.getPatchSet();
@@ -111,11 +112,11 @@
       } else {
         commit = d.commit();
       }
-      result.add(new ChangeAndCommit(rsrc.getProject(), d.data().change(), ps, commit));
+      result.add(newChangeAndCommit(rsrc.getProject(), d.data().change(), ps, commit));
     }
 
     if (result.size() == 1) {
-      ChangeAndCommit r = result.get(0);
+      RelatedChangeAndCommitInfo r = result.get(0);
       if (r.commit != null && r.commit.commit.equals(rsrc.getPatchSet().getRevision().get())) {
         return Collections.emptyList();
       }
@@ -143,69 +144,30 @@
     }
   }
 
-  public static class RelatedInfo {
-    public List<ChangeAndCommit> changes;
-  }
+  static RelatedChangeAndCommitInfo newChangeAndCommit(
+      Project.NameKey project, @Nullable Change change, @Nullable PatchSet ps, RevCommit c) {
+    RelatedChangeAndCommitInfo info = new RelatedChangeAndCommitInfo();
+    info.project = project.get();
 
-  public static class ChangeAndCommit {
-    public String project;
-    public String changeId;
-    public CommitInfo commit;
-    public Integer _changeNumber;
-    public Integer _revisionNumber;
-    public Integer _currentRevisionNumber;
-    public String status;
-
-    public ChangeAndCommit() {}
-
-    ChangeAndCommit(
-        Project.NameKey project, @Nullable Change change, @Nullable PatchSet ps, RevCommit c) {
-      this.project = project.get();
-
-      if (change != null) {
-        changeId = change.getKey().get();
-        _changeNumber = change.getChangeId();
-        _revisionNumber = ps != null ? ps.getPatchSetId() : null;
-        PatchSet.Id curr = change.currentPatchSetId();
-        _currentRevisionNumber = curr != null ? curr.get() : null;
-        status = change.getStatus().asChangeStatus().toString();
-      }
-
-      commit = new CommitInfo();
-      commit.commit = c.name();
-      commit.parents = Lists.newArrayListWithCapacity(c.getParentCount());
-      for (int i = 0; i < c.getParentCount(); i++) {
-        CommitInfo p = new CommitInfo();
-        p.commit = c.getParent(i).name();
-        commit.parents.add(p);
-      }
-      commit.author = CommonConverters.toGitPerson(c.getAuthorIdent());
-      commit.subject = c.getShortMessage();
+    if (change != null) {
+      info.changeId = change.getKey().get();
+      info._changeNumber = change.getChangeId();
+      info._revisionNumber = ps != null ? ps.getPatchSetId() : null;
+      PatchSet.Id curr = change.currentPatchSetId();
+      info._currentRevisionNumber = curr != null ? curr.get() : null;
+      info.status = change.getStatus().asChangeStatus().toString();
     }
 
-    @Override
-    public String toString() {
-      return MoreObjects.toStringHelper(this)
-          .add("project", project)
-          .add("changeId", changeId)
-          .add("commit", toString(commit))
-          .add("_changeNumber", _changeNumber)
-          .add("_revisionNumber", _revisionNumber)
-          .add("_currentRevisionNumber", _currentRevisionNumber)
-          .add("status", status)
-          .toString();
+    info.commit = new CommitInfo();
+    info.commit.commit = c.name();
+    info.commit.parents = Lists.newArrayListWithCapacity(c.getParentCount());
+    for (int i = 0; i < c.getParentCount(); i++) {
+      CommitInfo p = new CommitInfo();
+      p.commit = c.getParent(i).name();
+      info.commit.parents.add(p);
     }
-
-    private static String toString(CommitInfo commit) {
-      return MoreObjects.toStringHelper(commit)
-          .add("commit", commit.commit)
-          .add("parent", commit.parents)
-          .add("author", commit.author)
-          .add("committer", commit.committer)
-          .add("subject", commit.subject)
-          .add("message", commit.message)
-          .add("webLinks", commit.webLinks)
-          .toString();
-    }
+    info.commit.author = CommonConverters.toGitPerson(c.getAuthorIdent());
+    info.commit.subject = c.getShortMessage();
+    return info;
   }
 }
diff --git a/java/com/google/gerrit/server/restapi/change/Move.java b/java/com/google/gerrit/server/restapi/change/Move.java
index 013d3e9..df1d9b9 100644
--- a/java/com/google/gerrit/server/restapi/change/Move.java
+++ b/java/com/google/gerrit/server/restapi/change/Move.java
@@ -27,6 +27,7 @@
 import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.BadRequestException;
+import com.google.gerrit.extensions.restapi.MethodNotAllowedException;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.webui.UiAction;
@@ -47,6 +48,7 @@
 import com.google.gerrit.server.PatchSetUtil;
 import com.google.gerrit.server.change.ChangeJson;
 import com.google.gerrit.server.change.ChangeResource;
+import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.notedb.ChangeUpdate;
 import com.google.gerrit.server.permissions.PermissionBackend;
@@ -68,6 +70,7 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
+import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
@@ -87,6 +90,7 @@
   private final PatchSetUtil psUtil;
   private final ApprovalsUtil approvalsUtil;
   private final ProjectCache projectCache;
+  private final boolean moveEnabled;
 
   @Inject
   Move(
@@ -99,7 +103,8 @@
       RetryHelper retryHelper,
       PatchSetUtil psUtil,
       ApprovalsUtil approvalsUtil,
-      ProjectCache projectCache) {
+      ProjectCache projectCache,
+      @GerritServerConfig Config gerritConfig) {
     super(retryHelper);
     this.permissionBackend = permissionBackend;
     this.dbProvider = dbProvider;
@@ -110,6 +115,7 @@
     this.psUtil = psUtil;
     this.approvalsUtil = approvalsUtil;
     this.projectCache = projectCache;
+    this.moveEnabled = gerritConfig.getBoolean("change", null, "move", true);
   }
 
   @Override
@@ -117,6 +123,12 @@
       BatchUpdate.Factory updateFactory, ChangeResource rsrc, MoveInput input)
       throws RestApiException, OrmException, UpdateException, PermissionBackendException,
           IOException {
+    if (!moveEnabled) {
+      // This will be removed with the above config once we reach consensus for the move change
+      // behavior. See: https://bugs.chromium.org/p/gerrit/issues/detail?id=9877
+      throw new MethodNotAllowedException("move changes endpoint is disabled");
+    }
+
     Change change = rsrc.getChange();
     Project.NameKey project = rsrc.getProject();
     IdentifiedUser caller = rsrc.getUser().asIdentifiedUser();
diff --git a/java/com/google/gerrit/server/restapi/project/CreateAccessChange.java b/java/com/google/gerrit/server/restapi/project/CreateAccessChange.java
index feb37c0..f679610 100644
--- a/java/com/google/gerrit/server/restapi/project/CreateAccessChange.java
+++ b/java/com/google/gerrit/server/restapi/project/CreateAccessChange.java
@@ -68,6 +68,7 @@
   private final SetAccessUtil setAccess;
   private final ChangeJson.Factory jsonFactory;
   private final ProjectCache projectCache;
+  private final ProjectConfig.Factory projectConfigFactory;
 
   @Inject
   CreateAccessChange(
@@ -79,7 +80,8 @@
       Provider<ReviewDb> db,
       SetAccessUtil accessUtil,
       ChangeJson.Factory jsonFactory,
-      ProjectCache projectCache) {
+      ProjectCache projectCache,
+      ProjectConfig.Factory projectConfigFactory) {
     this.permissionBackend = permissionBackend;
     this.seq = seq;
     this.changeInserterFactory = changeInserterFactory;
@@ -89,6 +91,7 @@
     this.setAccess = accessUtil;
     this.jsonFactory = jsonFactory;
     this.projectCache = projectCache;
+    this.projectConfigFactory = projectConfigFactory;
   }
 
   @Override
@@ -117,7 +120,7 @@
         input.parent == null ? null : new Project.NameKey(input.parent);
 
     try (MetaDataUpdate md = metaDataUpdateUser.create(rsrc.getNameKey())) {
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
       ObjectId oldCommit = config.getRevision();
       String oldCommitSha1 = oldCommit == null ? null : oldCommit.getName();
 
diff --git a/java/com/google/gerrit/server/restapi/project/CreateProject.java b/java/com/google/gerrit/server/restapi/project/CreateProject.java
index 5620370..60a24d8 100644
--- a/java/com/google/gerrit/server/restapi/project/CreateProject.java
+++ b/java/com/google/gerrit/server/restapi/project/CreateProject.java
@@ -109,12 +109,13 @@
   private final MetaDataUpdate.User metaDataUpdateFactory;
   private final GitReferenceUpdated referenceUpdated;
   private final RepositoryConfig repositoryCfg;
-  private final PersonIdent serverIdent;
+  private final Provider<PersonIdent> serverIdent;
   private final Provider<IdentifiedUser> identifiedUser;
   private final Provider<PutConfig> putConfig;
   private final AllProjectsName allProjects;
   private final AllUsersName allUsers;
   private final PluginItemContext<ProjectNameLockManager> lockManager;
+  private final ProjectConfig.Factory projectConfigFactory;
 
   @Inject
   CreateProject(
@@ -130,12 +131,13 @@
       MetaDataUpdate.User metaDataUpdateFactory,
       GitReferenceUpdated referenceUpdated,
       RepositoryConfig repositoryCfg,
-      @GerritPersonIdent PersonIdent serverIdent,
+      @GerritPersonIdent Provider<PersonIdent> serverIdent,
       Provider<IdentifiedUser> identifiedUser,
       Provider<PutConfig> putConfig,
       AllProjectsName allProjects,
       AllUsersName allUsers,
-      PluginItemContext<ProjectNameLockManager> lockManager) {
+      PluginItemContext<ProjectNameLockManager> lockManager,
+      ProjectConfig.Factory projectConfigFactory) {
     this.projectsCollection = projectsCollection;
     this.groupResolver = groupResolver;
     this.projectCreationValidationListeners = projectCreationValidationListeners;
@@ -154,6 +156,7 @@
     this.allProjects = allProjects;
     this.allUsers = allUsers;
     this.lockManager = lockManager;
+    this.projectConfigFactory = projectConfigFactory;
   }
 
   @Override
@@ -286,7 +289,7 @@
   private void createProjectConfig(CreateProjectArgs args)
       throws IOException, ConfigInvalidException {
     try (MetaDataUpdate md = metaDataUpdateFactory.create(args.getProject())) {
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
 
       Project newProject = config.getProject();
       newProject.setDescription(args.projectDescription);
@@ -354,7 +357,7 @@
       CommitBuilder cb = new CommitBuilder();
       cb.setTreeId(oi.insert(Constants.OBJ_TREE, new byte[] {}));
       cb.setAuthor(metaDataUpdateFactory.getUserPersonIdent());
-      cb.setCommitter(serverIdent);
+      cb.setCommitter(serverIdent.get());
       cb.setMessage("Initial empty repository\n");
 
       ObjectId id = oi.insert(cb);
diff --git a/java/com/google/gerrit/server/restapi/project/GetAccess.java b/java/com/google/gerrit/server/restapi/project/GetAccess.java
index a6b9404..8875d40 100644
--- a/java/com/google/gerrit/server/restapi/project/GetAccess.java
+++ b/java/com/google/gerrit/server/restapi/project/GetAccess.java
@@ -95,6 +95,7 @@
   private final MetaDataUpdate.Server metaDataUpdateFactory;
   private final GroupBackend groupBackend;
   private final WebLinks webLinks;
+  private final ProjectConfig.Factory projectConfigFactory;
 
   @Inject
   public GetAccess(
@@ -105,7 +106,8 @@
       MetaDataUpdate.Server metaDataUpdateFactory,
       ProjectJson projectJson,
       GroupBackend groupBackend,
-      WebLinks webLinks) {
+      WebLinks webLinks,
+      ProjectConfig.Factory projectConfigFactory) {
     this.user = self;
     this.permissionBackend = permissionBackend;
     this.allProjectsName = allProjectsName;
@@ -114,6 +116,7 @@
     this.metaDataUpdateFactory = metaDataUpdateFactory;
     this.groupBackend = groupBackend;
     this.webLinks = webLinks;
+    this.projectConfigFactory = projectConfigFactory;
   }
 
   public ProjectAccessInfo apply(Project.NameKey nameKey)
@@ -141,7 +144,7 @@
 
     ProjectConfig config;
     try (MetaDataUpdate md = metaDataUpdateFactory.create(projectName)) {
-      config = ProjectConfig.read(md);
+      config = projectConfigFactory.read(md);
       info.configWebLinks = new ArrayList<>();
 
       // config may have a null revision if the repo doesn't have its own refs/meta/config.
diff --git a/java/com/google/gerrit/server/restapi/project/Module.java b/java/com/google/gerrit/server/restapi/project/Module.java
index 8c8ab49..de5661d 100644
--- a/java/com/google/gerrit/server/restapi/project/Module.java
+++ b/java/com/google/gerrit/server/restapi/project/Module.java
@@ -55,7 +55,6 @@
     get(PROJECT_KIND, "access").to(GetAccess.class);
     post(PROJECT_KIND, "access").to(SetAccess.class);
     put(PROJECT_KIND, "access:review").to(CreateAccessChange.class);
-    post(PROJECT_KIND, "check.access").to(CheckAccess.class);
     get(PROJECT_KIND, "check.access").to(CheckAccessReadView.class);
 
     post(PROJECT_KIND, "check").to(Check.class);
diff --git a/java/com/google/gerrit/server/restapi/project/PutConfig.java b/java/com/google/gerrit/server/restapi/project/PutConfig.java
index 76ea0c9..921a591 100644
--- a/java/com/google/gerrit/server/restapi/project/PutConfig.java
+++ b/java/com/google/gerrit/server/restapi/project/PutConfig.java
@@ -47,6 +47,7 @@
 import com.google.gerrit.server.project.ProjectConfig;
 import com.google.gerrit.server.project.ProjectResource;
 import com.google.gerrit.server.project.ProjectState;
+import com.google.gerrit.server.project.ProjectState.Factory;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
@@ -77,20 +78,22 @@
   private final DynamicMap<RestView<ProjectResource>> views;
   private final Provider<CurrentUser> user;
   private final PermissionBackend permissionBackend;
+  private final ProjectConfig.Factory projectConfigFactory;
 
   @Inject
   PutConfig(
       @EnableSignedPush boolean serverEnableSignedPush,
       Provider<MetaDataUpdate.User> metaDataUpdateFactory,
       ProjectCache projectCache,
-      ProjectState.Factory projectStateFactory,
+      Factory projectStateFactory,
       DynamicMap<ProjectConfigEntry> pluginConfigEntries,
       PluginConfigFactory cfgFactory,
       AllProjectsName allProjects,
       UiActions uiActions,
       DynamicMap<RestView<ProjectResource>> views,
       Provider<CurrentUser> user,
-      PermissionBackend permissionBackend) {
+      PermissionBackend permissionBackend,
+      ProjectConfig.Factory projectConfigFactory) {
     this.serverEnableSignedPush = serverEnableSignedPush;
     this.metaDataUpdateFactory = metaDataUpdateFactory;
     this.projectCache = projectCache;
@@ -102,6 +105,7 @@
     this.views = views;
     this.user = user;
     this.permissionBackend = permissionBackend;
+    this.projectConfigFactory = projectConfigFactory;
   }
 
   @Override
@@ -122,7 +126,7 @@
     }
 
     try (MetaDataUpdate md = metaDataUpdateFactory.get().create(projectName)) {
-      ProjectConfig projectConfig = ProjectConfig.read(md);
+      ProjectConfig projectConfig = projectConfigFactory.read(md);
       Project p = projectConfig.getProject();
 
       p.setDescription(Strings.emptyToNull(input.description));
@@ -164,7 +168,7 @@
         throw new ResourceConflictException("Cannot update " + projectName);
       }
 
-      ProjectState state = projectStateFactory.create(ProjectConfig.read(md));
+      ProjectState state = projectStateFactory.create(projectConfigFactory.read(md));
       return new ConfigInfoImpl(
           serverEnableSignedPush,
           state,
diff --git a/java/com/google/gerrit/server/restapi/project/PutDescription.java b/java/com/google/gerrit/server/restapi/project/PutDescription.java
index 1c74021..081669a 100644
--- a/java/com/google/gerrit/server/restapi/project/PutDescription.java
+++ b/java/com/google/gerrit/server/restapi/project/PutDescription.java
@@ -42,15 +42,18 @@
   private final ProjectCache cache;
   private final MetaDataUpdate.Server updateFactory;
   private final PermissionBackend permissionBackend;
+  private final ProjectConfig.Factory projectConfigFactory;
 
   @Inject
   PutDescription(
       ProjectCache cache,
       MetaDataUpdate.Server updateFactory,
-      PermissionBackend permissionBackend) {
+      PermissionBackend permissionBackend,
+      ProjectConfig.Factory projectConfigFactory) {
     this.cache = cache;
     this.updateFactory = updateFactory;
     this.permissionBackend = permissionBackend;
+    this.projectConfigFactory = projectConfigFactory;
   }
 
   @Override
@@ -68,7 +71,7 @@
         .check(ProjectPermission.WRITE_CONFIG);
 
     try (MetaDataUpdate md = updateFactory.create(resource.getNameKey())) {
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
       Project project = config.getProject();
       project.setDescription(Strings.emptyToNull(input.description));
 
diff --git a/java/com/google/gerrit/server/restapi/project/SetAccess.java b/java/com/google/gerrit/server/restapi/project/SetAccess.java
index c9d69a5..19e89a9 100644
--- a/java/com/google/gerrit/server/restapi/project/SetAccess.java
+++ b/java/com/google/gerrit/server/restapi/project/SetAccess.java
@@ -56,6 +56,7 @@
   private final Provider<IdentifiedUser> identifiedUser;
   private final SetAccessUtil accessUtil;
   private final CreateGroupPermissionSyncer createGroupPermissionSyncer;
+  private final ProjectConfig.Factory projectConfigFactory;
 
   @Inject
   private SetAccess(
@@ -66,7 +67,8 @@
       GetAccess getAccess,
       Provider<IdentifiedUser> identifiedUser,
       SetAccessUtil accessUtil,
-      CreateGroupPermissionSyncer createGroupPermissionSyncer) {
+      CreateGroupPermissionSyncer createGroupPermissionSyncer,
+      ProjectConfig.Factory projectConfigFactory) {
     this.groupBackend = groupBackend;
     this.permissionBackend = permissionBackend;
     this.metaDataUpdateFactory = metaDataUpdateFactory;
@@ -75,6 +77,7 @@
     this.identifiedUser = identifiedUser;
     this.accessUtil = accessUtil;
     this.createGroupPermissionSyncer = createGroupPermissionSyncer;
+    this.projectConfigFactory = projectConfigFactory;
   }
 
   @Override
@@ -89,7 +92,7 @@
     List<AccessSection> removals = accessUtil.getAccessSections(input.remove);
     List<AccessSection> additions = accessUtil.getAccessSections(input.add);
     try (MetaDataUpdate md = metaDataUpdateUser.create(rsrc.getNameKey())) {
-      config = ProjectConfig.read(md);
+      config = projectConfigFactory.read(md);
 
       // Check that the user has the right permissions.
       boolean checkedAdmin = false;
diff --git a/java/com/google/gerrit/server/restapi/project/SetDefaultDashboard.java b/java/com/google/gerrit/server/restapi/project/SetDefaultDashboard.java
index ef292e5..0f346df 100644
--- a/java/com/google/gerrit/server/restapi/project/SetDefaultDashboard.java
+++ b/java/com/google/gerrit/server/restapi/project/SetDefaultDashboard.java
@@ -47,6 +47,7 @@
   private final DashboardsCollection dashboards;
   private final Provider<GetDashboard> get;
   private final PermissionBackend permissionBackend;
+  private final ProjectConfig.Factory projectConfigFactory;
 
   @Option(name = "--inherited", usage = "set dashboard inherited by children")
   boolean inherited;
@@ -57,12 +58,14 @@
       MetaDataUpdate.Server updateFactory,
       DashboardsCollection dashboards,
       Provider<GetDashboard> get,
-      PermissionBackend permissionBackend) {
+      PermissionBackend permissionBackend,
+      ProjectConfig.Factory projectConfigFactory) {
     this.cache = cache;
     this.updateFactory = updateFactory;
     this.dashboards = dashboards;
     this.get = get;
     this.permissionBackend = permissionBackend;
+    this.projectConfigFactory = projectConfigFactory;
   }
 
   @Override
@@ -93,7 +96,7 @@
     }
 
     try (MetaDataUpdate md = updateFactory.create(rsrc.getProjectState().getNameKey())) {
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
       Project project = config.getProject();
       if (inherited) {
         project.setDefaultDashboard(input.id);
diff --git a/java/com/google/gerrit/server/restapi/project/SetParent.java b/java/com/google/gerrit/server/restapi/project/SetParent.java
index ca7e7aa..15cb7f8 100644
--- a/java/com/google/gerrit/server/restapi/project/SetParent.java
+++ b/java/com/google/gerrit/server/restapi/project/SetParent.java
@@ -60,6 +60,7 @@
   private final MetaDataUpdate.Server updateFactory;
   private final AllProjectsName allProjects;
   private final AllUsersName allUsers;
+  private final ProjectConfig.Factory projectConfigFactory;
   private volatile boolean allowProjectOwnersToChangeParent;
 
   @Inject
@@ -69,12 +70,14 @@
       MetaDataUpdate.Server updateFactory,
       AllProjectsName allProjects,
       AllUsersName allUsers,
+      ProjectConfig.Factory projectConfigFactory,
       @GerritServerConfig Config config) {
     this.cache = cache;
     this.permissionBackend = permissionBackend;
     this.updateFactory = updateFactory;
     this.allProjects = allProjects;
     this.allUsers = allUsers;
+    this.projectConfigFactory = projectConfigFactory;
     this.allowProjectOwnersToChangeParent =
         config.getBoolean("receive", "allowProjectOwnersToChangeParent", false);
   }
@@ -96,7 +99,7 @@
         MoreObjects.firstNonNull(Strings.emptyToNull(input.parent), allProjects.get());
     validateParentUpdate(rsrc.getProjectState().getNameKey(), user, parentName, checkIfAdmin);
     try (MetaDataUpdate md = updateFactory.create(rsrc.getNameKey())) {
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
       Project project = config.getProject();
       project.setParentName(parentName);
 
diff --git a/java/com/google/gerrit/server/rules/StoredValues.java b/java/com/google/gerrit/server/rules/StoredValues.java
index 8b9cfe3..a712635 100644
--- a/java/com/google/gerrit/server/rules/StoredValues.java
+++ b/java/com/google/gerrit/server/rules/StoredValues.java
@@ -110,6 +110,18 @@
         }
       };
 
+  // Accessing GitRepositoryManager could be slow.
+  // It should be minimized or cached to reduce pause time
+  // when evaluating Prolog submit rules.
+  public static final StoredValue<GitRepositoryManager> REPO_MANAGER =
+      new StoredValue<GitRepositoryManager>() {
+        @Override
+        public GitRepositoryManager createValue(Prolog engine) {
+          PrologEnvironment env = (PrologEnvironment) engine.control;
+          return env.getArgs().getGitRepositoryManager();
+        }
+      };
+
   public static final StoredValue<Repository> REPOSITORY =
       new StoredValue<Repository>() {
         @Override
diff --git a/java/com/google/gerrit/server/schema/AllProjectsCreator.java b/java/com/google/gerrit/server/schema/AllProjectsCreator.java
index 348f88c..85965ef 100644
--- a/java/com/google/gerrit/server/schema/AllProjectsCreator.java
+++ b/java/com/google/gerrit/server/schema/AllProjectsCreator.java
@@ -73,6 +73,7 @@
   private final AllProjectsName allProjectsName;
   private final PersonIdent serverUser;
   private final NotesMigration notesMigration;
+  private final ProjectConfig.Factory projectConfigFactory;
   private final GroupReference anonymous;
   private final GroupReference registered;
   private final GroupReference owners;
@@ -90,11 +91,13 @@
       AllProjectsName allProjectsName,
       @GerritPersonIdent PersonIdent serverUser,
       NotesMigration notesMigration,
-      SystemGroupBackend systemGroupBackend) {
+      SystemGroupBackend systemGroupBackend,
+      ProjectConfig.Factory projectConfigFactory) {
     this.repositoryManager = repositoryManager;
     this.allProjectsName = allProjectsName;
     this.serverUser = serverUser;
     this.notesMigration = notesMigration;
+    this.projectConfigFactory = projectConfigFactory;
 
     this.anonymous = systemGroupBackend.getGroup(ANONYMOUS_USERS);
     this.registered = systemGroupBackend.getGroup(REGISTERED_USERS);
@@ -170,7 +173,7 @@
               Strings.emptyToNull(message),
               "Initialized Gerrit Code Review " + Version.getVersion()));
 
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
       Project p = config.getProject();
       p.setDescription("Access inherited by all other projects.");
       p.setBooleanConfig(BooleanProjectConfig.REQUIRE_CHANGE_ID, InheritableBoolean.TRUE);
diff --git a/java/com/google/gerrit/server/schema/AllUsersCreator.java b/java/com/google/gerrit/server/schema/AllUsersCreator.java
index 3779d0d..3b1124d 100644
--- a/java/com/google/gerrit/server/schema/AllUsersCreator.java
+++ b/java/com/google/gerrit/server/schema/AllUsersCreator.java
@@ -35,6 +35,7 @@
 import com.google.gerrit.server.git.meta.MetaDataUpdate;
 import com.google.gerrit.server.group.SystemGroupBackend;
 import com.google.gerrit.server.project.ProjectConfig;
+import com.google.gerrit.server.project.ProjectConfig.Factory;
 import com.google.gerrit.server.project.RefPattern;
 import com.google.inject.Inject;
 import java.io.IOException;
@@ -50,6 +51,7 @@
   private final GitRepositoryManager mgr;
   private final AllUsersName allUsersName;
   private final PersonIdent serverUser;
+  private final ProjectConfig.Factory projectConfigFactory;
   private final GroupReference registered;
 
   @Nullable private GroupReference admin;
@@ -60,11 +62,13 @@
       GitRepositoryManager mgr,
       AllUsersName allUsersName,
       SystemGroupBackend systemGroupBackend,
-      @GerritPersonIdent PersonIdent serverUser) {
+      @GerritPersonIdent PersonIdent serverUser,
+      Factory projectConfigFactory) {
     this.mgr = mgr;
     this.allUsersName = allUsersName;
     this.serverUser = serverUser;
     this.registered = systemGroupBackend.getGroup(REGISTERED_USERS);
+    this.projectConfigFactory = projectConfigFactory;
     this.codeReviewLabel = getDefaultCodeReviewLabel();
   }
 
@@ -107,7 +111,7 @@
       md.getCommitBuilder().setCommitter(serverUser);
       md.setMessage("Initialized Gerrit Code Review " + Version.getVersion());
 
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
       Project project = config.getProject();
       project.setDescription("Individual user settings and preferences.");
 
diff --git a/java/com/google/gerrit/server/schema/Schema_108.java b/java/com/google/gerrit/server/schema/Schema_108.java
index 4e62460..b37fab3 100644
--- a/java/com/google/gerrit/server/schema/Schema_108.java
+++ b/java/com/google/gerrit/server/schema/Schema_108.java
@@ -24,7 +24,6 @@
 import com.google.gerrit.reviewdb.client.Change.Status;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.client.Project;
-import com.google.gerrit.reviewdb.client.Project.NameKey;
 import com.google.gerrit.reviewdb.client.RefNames;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.git.GitRepositoryManager;
@@ -145,8 +144,8 @@
 
   private SetMultimap<Project.NameKey, Change.Id> getOpenChangesByProject(ReviewDb db, UpdateUI ui)
       throws OrmException {
-    SortedSet<NameKey> projects = repoManager.list();
-    SortedSet<NameKey> nonExistentProjects = Sets.newTreeSet();
+    SortedSet<Project.NameKey> projects = repoManager.list();
+    SortedSet<Project.NameKey> nonExistentProjects = Sets.newTreeSet();
     SetMultimap<Project.NameKey, Change.Id> openByProject =
         MultimapBuilder.hashKeys().hashSetValues().build();
     for (Change c : db.changes().all()) {
@@ -155,7 +154,7 @@
         continue;
       }
 
-      NameKey projectKey = c.getProject();
+      Project.NameKey projectKey = c.getProject();
       if (!projects.contains(projectKey)) {
         nonExistentProjects.add(projectKey);
       } else {
diff --git a/java/com/google/gerrit/server/schema/Schema_120.java b/java/com/google/gerrit/server/schema/Schema_120.java
index f2f3b99..15e34ab 100644
--- a/java/com/google/gerrit/server/schema/Schema_120.java
+++ b/java/com/google/gerrit/server/schema/Schema_120.java
@@ -42,15 +42,18 @@
 public class Schema_120 extends SchemaVersion {
 
   private final GitRepositoryManager mgr;
+  private final ProjectConfig.Factory projectConfigFactory;
   private final PersonIdent serverUser;
 
   @Inject
   Schema_120(
       Provider<Schema_119> prior,
       GitRepositoryManager mgr,
+      ProjectConfig.Factory projectConfigFactory,
       @GerritPersonIdent PersonIdent serverUser) {
     super(prior);
     this.mgr = mgr;
+    this.projectConfigFactory = projectConfigFactory;
     this.serverUser = serverUser;
   }
 
@@ -64,7 +67,7 @@
         md.getCommitBuilder().setAuthor(serverUser);
         md.getCommitBuilder().setCommitter(serverUser);
         md.setMessage("Added superproject subscription during upgrade");
-        ProjectConfig pc = ProjectConfig.read(md);
+        ProjectConfig pc = projectConfigFactory.read(md);
 
         SubscribeSection s = null;
         for (SubscribeSection s1 : pc.getSubscribeSections(subbranch)) {
diff --git a/java/com/google/gerrit/server/schema/Schema_125.java b/java/com/google/gerrit/server/schema/Schema_125.java
index 7aab7c7..474d7ac 100644
--- a/java/com/google/gerrit/server/schema/Schema_125.java
+++ b/java/com/google/gerrit/server/schema/Schema_125.java
@@ -57,6 +57,7 @@
   private final AllUsersName allUsersName;
   private final AllProjectsName allProjectsName;
   private final SystemGroupBackend systemGroupBackend;
+  private final ProjectConfig.Factory projectConfigFactory;
   private final PersonIdent serverUser;
 
   @Inject
@@ -66,12 +67,14 @@
       AllUsersName allUsersName,
       AllProjectsName allProjectsName,
       SystemGroupBackend systemGroupBackend,
+      ProjectConfig.Factory projectConfigFactory,
       @GerritPersonIdent PersonIdent serverUser) {
     super(prior);
     this.repoManager = repoManager;
     this.allUsersName = allUsersName;
     this.allProjectsName = allProjectsName;
     this.systemGroupBackend = systemGroupBackend;
+    this.projectConfigFactory = projectConfigFactory;
     this.serverUser = serverUser;
   }
 
@@ -79,7 +82,7 @@
   protected void migrateData(ReviewDb db, UpdateUI ui) throws OrmException {
     try (Repository git = repoManager.openRepository(allUsersName);
         MetaDataUpdate md = new MetaDataUpdate(GitReferenceUpdated.DISABLED, allUsersName, git)) {
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
 
       config
           .getAccessSection(RefNames.REFS_USERS + "*", true)
@@ -114,7 +117,7 @@
     while (parent != null) {
       try (Repository git = repoManager.openRepository(parent);
           MetaDataUpdate md = new MetaDataUpdate(GitReferenceUpdated.DISABLED, parent, git)) {
-        ProjectConfig parentConfig = ProjectConfig.read(md);
+        ProjectConfig parentConfig = projectConfigFactory.read(md);
         for (LabelType lt : parentConfig.getLabelSections().values()) {
           if (!labelTypes.containsKey(lt.getName())) {
             labelTypes.put(lt.getName(), lt);
diff --git a/java/com/google/gerrit/server/schema/Schema_126.java b/java/com/google/gerrit/server/schema/Schema_126.java
index 5dbda72..23de169 100644
--- a/java/com/google/gerrit/server/schema/Schema_126.java
+++ b/java/com/google/gerrit/server/schema/Schema_126.java
@@ -44,6 +44,7 @@
   private final GitRepositoryManager repoManager;
   private final AllUsersName allUsersName;
   private final SystemGroupBackend systemGroupBackend;
+  private final ProjectConfig.Factory projectConfigFactory;
   private final PersonIdent serverUser;
 
   @Inject
@@ -52,11 +53,13 @@
       GitRepositoryManager repoManager,
       AllUsersName allUsersName,
       SystemGroupBackend systemGroupBackend,
+      ProjectConfig.Factory projectConfigFactory,
       @GerritPersonIdent PersonIdent serverUser) {
     super(prior);
     this.repoManager = repoManager;
     this.allUsersName = allUsersName;
     this.systemGroupBackend = systemGroupBackend;
+    this.projectConfigFactory = projectConfigFactory;
     this.serverUser = serverUser;
   }
 
@@ -64,7 +67,7 @@
   protected void migrateData(ReviewDb db, UpdateUI ui) throws OrmException {
     try (Repository git = repoManager.openRepository(allUsersName);
         MetaDataUpdate md = new MetaDataUpdate(GitReferenceUpdated.DISABLED, allUsersName, git)) {
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
 
       String refsUsersShardedId = RefNames.REFS_USERS + "${" + RefPattern.USERID_SHARDED + "}";
       config.remove(config.getAccessSection(refsUsersShardedId));
diff --git a/java/com/google/gerrit/server/schema/Schema_128.java b/java/com/google/gerrit/server/schema/Schema_128.java
index bd6b76a..4f5f962 100644
--- a/java/com/google/gerrit/server/schema/Schema_128.java
+++ b/java/com/google/gerrit/server/schema/Schema_128.java
@@ -42,6 +42,7 @@
   private final GitRepositoryManager repoManager;
   private final AllProjectsName allProjectsName;
   private final SystemGroupBackend systemGroupBackend;
+  private final ProjectConfig.Factory projectConfigFactory;
   private final PersonIdent serverUser;
 
   @Inject
@@ -50,11 +51,13 @@
       GitRepositoryManager repoManager,
       AllProjectsName allProjectsName,
       SystemGroupBackend systemGroupBackend,
+      ProjectConfig.Factory projectConfigFactory,
       @GerritPersonIdent PersonIdent serverUser) {
     super(prior);
     this.repoManager = repoManager;
     this.allProjectsName = allProjectsName;
     this.systemGroupBackend = systemGroupBackend;
+    this.projectConfigFactory = projectConfigFactory;
     this.serverUser = serverUser;
   }
 
@@ -63,7 +66,7 @@
     try (Repository git = repoManager.openRepository(allProjectsName);
         MetaDataUpdate md =
             new MetaDataUpdate(GitReferenceUpdated.DISABLED, allProjectsName, git)) {
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
 
       GroupReference registered = systemGroupBackend.getGroup(REGISTERED_USERS);
       AccessSection refsFor = config.getAccessSection("refs/for/*", true);
diff --git a/java/com/google/gerrit/server/schema/Schema_131.java b/java/com/google/gerrit/server/schema/Schema_131.java
index 3755211..e496096 100644
--- a/java/com/google/gerrit/server/schema/Schema_131.java
+++ b/java/com/google/gerrit/server/schema/Schema_131.java
@@ -38,15 +38,18 @@
       "Rename 'Push Annotated/Signed Tag' permission to 'Create Annotated/Signed Tag'";
 
   private final GitRepositoryManager repoManager;
+  private final ProjectConfig.Factory projectConfigFactory;
   private final PersonIdent serverUser;
 
   @Inject
   Schema_131(
       Provider<Schema_130> prior,
       GitRepositoryManager repoManager,
+      ProjectConfig.Factory projectConfigFactory,
       @GerritPersonIdent PersonIdent serverUser) {
     super(prior);
     this.repoManager = repoManager;
+    this.projectConfigFactory = projectConfigFactory;
     this.serverUser = serverUser;
   }
 
@@ -58,7 +61,7 @@
     for (Project.NameKey projectName : repoList) {
       try (Repository git = repoManager.openRepository(projectName);
           MetaDataUpdate md = new MetaDataUpdate(GitReferenceUpdated.DISABLED, projectName, git)) {
-        ProjectConfig config = ProjectConfig.read(md);
+        ProjectConfig config = projectConfigFactory.read(md);
         if (config.hasLegacyPermissions()) {
           md.getCommitBuilder().setAuthor(serverUser);
           md.getCommitBuilder().setCommitter(serverUser);
diff --git a/java/com/google/gerrit/server/schema/Schema_135.java b/java/com/google/gerrit/server/schema/Schema_135.java
index 66224c2..6281251 100644
--- a/java/com/google/gerrit/server/schema/Schema_135.java
+++ b/java/com/google/gerrit/server/schema/Schema_135.java
@@ -48,6 +48,7 @@
   private final GitRepositoryManager repoManager;
   private final AllProjectsName allProjectsName;
   private final SystemGroupBackend systemGroupBackend;
+  private final ProjectConfig.Factory projectConfigFactory;
   private final PersonIdent serverUser;
 
   @Inject
@@ -56,11 +57,13 @@
       GitRepositoryManager repoManager,
       AllProjectsName allProjectsName,
       SystemGroupBackend systemGroupBackend,
+      ProjectConfig.Factory projectConfigFactory,
       @GerritPersonIdent PersonIdent serverUser) {
     super(prior);
     this.repoManager = repoManager;
     this.allProjectsName = allProjectsName;
     this.systemGroupBackend = systemGroupBackend;
+    this.projectConfigFactory = projectConfigFactory;
     this.serverUser = serverUser;
   }
 
@@ -69,7 +72,7 @@
     try (Repository git = repoManager.openRepository(allProjectsName);
         MetaDataUpdate md =
             new MetaDataUpdate(GitReferenceUpdated.DISABLED, allProjectsName, git)) {
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
 
       AccessSection meta = config.getAccessSection(RefNames.REFS_CONFIG, true);
       Permission createRefsMetaConfigPermission = meta.getPermission(Permission.CREATE, true);
diff --git a/java/com/google/gerrit/server/schema/Schema_162.java b/java/com/google/gerrit/server/schema/Schema_162.java
index 7406bc6..85220c7 100644
--- a/java/com/google/gerrit/server/schema/Schema_162.java
+++ b/java/com/google/gerrit/server/schema/Schema_162.java
@@ -34,6 +34,7 @@
   private final GitRepositoryManager repoManager;
   private final AllProjectsName allProjectsName;
   private final AllUsersName allUsersName;
+  private final ProjectConfig.Factory projectConfigFactory;
   private final PersonIdent serverUser;
 
   @Inject
@@ -42,11 +43,13 @@
       GitRepositoryManager repoManager,
       AllProjectsName allProjectsName,
       AllUsersName allUsersName,
+      ProjectConfig.Factory projectConfigFactory,
       @GerritPersonIdent PersonIdent serverUser) {
     super(prior);
     this.repoManager = repoManager;
     this.allProjectsName = allProjectsName;
     this.allUsersName = allUsersName;
+    this.projectConfigFactory = projectConfigFactory;
     this.serverUser = serverUser;
   }
 
@@ -54,7 +57,7 @@
   protected void migrateData(ReviewDb db, UpdateUI ui) throws OrmException {
     try (Repository git = repoManager.openRepository(allUsersName);
         MetaDataUpdate md = new MetaDataUpdate(GitReferenceUpdated.DISABLED, allUsersName, git)) {
-      ProjectConfig cfg = ProjectConfig.read(md);
+      ProjectConfig cfg = projectConfigFactory.read(md);
       if (allProjectsName.equals(cfg.getProject().getParent(allProjectsName))) {
         return;
       }
diff --git a/java/com/google/gerrit/server/schema/Schema_164.java b/java/com/google/gerrit/server/schema/Schema_164.java
index 8525478..818f84c 100644
--- a/java/com/google/gerrit/server/schema/Schema_164.java
+++ b/java/com/google/gerrit/server/schema/Schema_164.java
@@ -44,6 +44,7 @@
   private final GitRepositoryManager repoManager;
   private final AllUsersName allUsersName;
   private final SystemGroupBackend systemGroupBackend;
+  private final ProjectConfig.Factory projectConfigFactory;
   private final PersonIdent serverUser;
 
   @Inject
@@ -52,11 +53,13 @@
       GitRepositoryManager repoManager,
       AllUsersName allUsersName,
       SystemGroupBackend systemGroupBackend,
+      ProjectConfig.Factory projectConfigFactory,
       @GerritPersonIdent PersonIdent serverUser) {
     super(prior);
     this.repoManager = repoManager;
     this.allUsersName = allUsersName;
     this.systemGroupBackend = systemGroupBackend;
+    this.projectConfigFactory = projectConfigFactory;
     this.serverUser = serverUser;
   }
 
@@ -68,7 +71,7 @@
       md.getCommitBuilder().setCommitter(serverUser);
       md.setMessage(COMMIT_MSG);
 
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
       AccessSection groups = config.getAccessSection(RefNames.REFS_GROUPS + "*", true);
       grant(
           config,
diff --git a/java/com/google/gerrit/server/schema/Schema_165.java b/java/com/google/gerrit/server/schema/Schema_165.java
index cd6da55..b4f9523 100644
--- a/java/com/google/gerrit/server/schema/Schema_165.java
+++ b/java/com/google/gerrit/server/schema/Schema_165.java
@@ -48,6 +48,7 @@
   private final GitRepositoryManager repoManager;
   private final AllUsersName allUsersName;
   private final SystemGroupBackend systemGroupBackend;
+  private final ProjectConfig.Factory projectConfigFactory;
   private final PersonIdent serverUser;
 
   @Inject
@@ -56,11 +57,13 @@
       GitRepositoryManager repoManager,
       AllUsersName allUsersName,
       SystemGroupBackend systemGroupBackend,
+      ProjectConfig.Factory projectConfigFactory,
       @GerritPersonIdent PersonIdent serverUser) {
     super(prior);
     this.repoManager = repoManager;
     this.allUsersName = allUsersName;
     this.systemGroupBackend = systemGroupBackend;
+    this.projectConfigFactory = projectConfigFactory;
     this.serverUser = serverUser;
   }
 
@@ -68,7 +71,7 @@
   protected void migrateData(ReviewDb db, UpdateUI ui) throws OrmException, SQLException {
     try (Repository git = repoManager.openRepository(allUsersName);
         MetaDataUpdate md = new MetaDataUpdate(GitReferenceUpdated.DISABLED, allUsersName, git)) {
-      ProjectConfig config = ProjectConfig.read(md);
+      ProjectConfig config = projectConfigFactory.read(md);
       Optional<Permission> permission = findDefaultPermission(config);
       if (!permission.isPresent()) {
         // the default permission was not found, hence it cannot be fixed
diff --git a/java/com/google/gerrit/server/submit/LocalMergeSuperSetComputation.java b/java/com/google/gerrit/server/submit/LocalMergeSuperSetComputation.java
index 9efb976..66463be 100644
--- a/java/com/google/gerrit/server/submit/LocalMergeSuperSetComputation.java
+++ b/java/com/google/gerrit/server/submit/LocalMergeSuperSetComputation.java
@@ -37,6 +37,7 @@
 import com.google.gerrit.server.project.ProjectCache;
 import com.google.gerrit.server.project.ProjectState;
 import com.google.gerrit.server.query.change.ChangeData;
+import com.google.gerrit.server.query.change.ChangeIsVisibleToPredicate;
 import com.google.gerrit.server.query.change.InternalChangeQuery;
 import com.google.gerrit.server.submit.MergeOpRepoManager.OpenRepo;
 import com.google.gwtorm.server.OrmException;
@@ -87,20 +88,23 @@
 
   private final PermissionBackend permissionBackend;
   private final Provider<InternalChangeQuery> queryProvider;
-  private final Map<QueryKey, List<ChangeData>> queryCache;
+  private final Map<QueryKey, ImmutableList<ChangeData>> queryCache;
   private final Map<Branch.NameKey, Optional<RevCommit>> heads;
   private final ProjectCache projectCache;
+  private final ChangeIsVisibleToPredicate changeIsVisibleToPredicate;
 
   @Inject
   LocalMergeSuperSetComputation(
       PermissionBackend permissionBackend,
       Provider<InternalChangeQuery> queryProvider,
-      ProjectCache projectCache) {
+      ProjectCache projectCache,
+      ChangeIsVisibleToPredicate changeIsVisibleToPredicate) {
     this.projectCache = projectCache;
     this.permissionBackend = permissionBackend;
     this.queryProvider = queryProvider;
     this.queryCache = new HashMap<>();
     this.heads = new HashMap<>();
+    this.changeIsVisibleToPredicate = changeIsVisibleToPredicate;
   }
 
   @Override
@@ -147,10 +151,11 @@
 
       Set<String> visibleHashes =
           walkChangesByHashes(visibleCommits, Collections.emptySet(), or, b);
-      Iterables.addAll(visibleChanges, byCommitsOnBranchNotMerged(or, db, b, visibleHashes));
-
       Set<String> nonVisibleHashes = walkChangesByHashes(nonVisibleCommits, visibleHashes, or, b);
-      Iterables.addAll(nonVisibleChanges, byCommitsOnBranchNotMerged(or, db, b, nonVisibleHashes));
+
+      ChangeSet partialSet = byCommitsOnBranchNotMerged(or, db, b, visibleHashes, nonVisibleHashes);
+      Iterables.addAll(visibleChanges, partialSet.changes());
+      Iterables.addAll(nonVisibleChanges, partialSet.nonVisibleChanges());
     }
 
     return new ChangeSet(visibleChanges, nonVisibleChanges);
@@ -206,24 +211,41 @@
     return str.type;
   }
 
-  private List<ChangeData> byCommitsOnBranchNotMerged(
+  private ChangeSet byCommitsOnBranchNotMerged(
+      OpenRepo or,
+      ReviewDb db,
+      Branch.NameKey branch,
+      Set<String> visibleHashes,
+      Set<String> nonVisibleHashes)
+      throws OrmException, IOException {
+    List<ChangeData> potentiallyVisibleChanges =
+        byCommitsOnBranchNotMerged(or, db, branch, visibleHashes);
+    List<ChangeData> invisibleChanges =
+        new ArrayList<>(byCommitsOnBranchNotMerged(or, db, branch, nonVisibleHashes));
+    List<ChangeData> visibleChanges = new ArrayList<>(potentiallyVisibleChanges.size());
+    for (ChangeData cd : potentiallyVisibleChanges) {
+      if (changeIsVisibleToPredicate.match(cd)) {
+        visibleChanges.add(cd);
+      } else {
+        invisibleChanges.add(cd);
+      }
+    }
+    return new ChangeSet(visibleChanges, invisibleChanges);
+  }
+
+  private ImmutableList<ChangeData> byCommitsOnBranchNotMerged(
       OpenRepo or, ReviewDb db, Branch.NameKey branch, Set<String> hashes)
       throws OrmException, IOException {
     if (hashes.isEmpty()) {
       return ImmutableList.of();
     }
     QueryKey k = QueryKey.create(branch, hashes);
-    List<ChangeData> cached = queryCache.get(k);
-    if (cached != null) {
-      return cached;
+    if (queryCache.containsKey(k)) {
+      return queryCache.get(k);
     }
-
-    List<ChangeData> result = new ArrayList<>();
-    Iterable<ChangeData> destChanges =
-        queryProvider.get().byCommitsOnBranchNotMerged(or.repo, db, branch, hashes);
-    for (ChangeData chd : destChanges) {
-      result.add(chd);
-    }
+    ImmutableList<ChangeData> result =
+        ImmutableList.copyOf(
+            queryProvider.get().byCommitsOnBranchNotMerged(or.repo, db, branch, hashes));
     queryCache.put(k, result);
     return result;
   }
diff --git a/java/com/google/gerrit/server/submit/SubmitStrategy.java b/java/com/google/gerrit/server/submit/SubmitStrategy.java
index 4cefd7d..6511d25 100644
--- a/java/com/google/gerrit/server/submit/SubmitStrategy.java
+++ b/java/com/google/gerrit/server/submit/SubmitStrategy.java
@@ -46,6 +46,7 @@
 import com.google.gerrit.server.logging.RequestId;
 import com.google.gerrit.server.patch.PatchSetInfoFactory;
 import com.google.gerrit.server.project.ProjectCache;
+import com.google.gerrit.server.project.ProjectConfig;
 import com.google.gerrit.server.project.ProjectState;
 import com.google.gerrit.server.query.change.InternalChangeQuery;
 import com.google.gerrit.server.submit.MergeOp.CommitStatus;
@@ -115,6 +116,7 @@
     final OnSubmitValidators.Factory onSubmitValidatorsFactory;
     final TagCache tagCache;
     final Provider<InternalChangeQuery> queryProvider;
+    final ProjectConfig.Factory projectConfigFactory;
 
     final Branch.NameKey destBranch;
     final CodeReviewRevWalk rw;
@@ -154,6 +156,7 @@
         OnSubmitValidators.Factory onSubmitValidatorsFactory,
         TagCache tagCache,
         Provider<InternalChangeQuery> queryProvider,
+        ProjectConfig.Factory projectConfigFactory,
         @Assisted Branch.NameKey destBranch,
         @Assisted CommitStatus commitStatus,
         @Assisted CodeReviewRevWalk rw,
@@ -176,6 +179,7 @@
       this.repoManager = repoManager;
       this.cmUtil = cmUtil;
       this.labelNormalizer = labelNormalizer;
+      this.projectConfigFactory = projectConfigFactory;
       this.patchSetInfoFactory = patchSetInfoFactory;
       this.psUtil = psUtil;
       this.projectCache = projectCache;
diff --git a/java/com/google/gerrit/server/submit/SubmitStrategyOp.java b/java/com/google/gerrit/server/submit/SubmitStrategyOp.java
index 8a4fbfb..3be4c31 100644
--- a/java/com/google/gerrit/server/submit/SubmitStrategyOp.java
+++ b/java/com/google/gerrit/server/submit/SubmitStrategyOp.java
@@ -145,7 +145,7 @@
     if (RefNames.REFS_CONFIG.equals(refName)) {
       logger.atFine().log("Loading new configuration from %s", RefNames.REFS_CONFIG);
       try {
-        ProjectConfig cfg = new ProjectConfig(getProject());
+        ProjectConfig cfg = args.projectConfigFactory.create(getProject());
         cfg.load(ctx.getRevWalk(), commit);
       } catch (Exception e) {
         throw new IntegrationException(
diff --git a/java/com/google/gerrit/testing/NoteDbMode.java b/java/com/google/gerrit/testing/NoteDbMode.java
index d4a7c7e..e46acc3 100644
--- a/java/com/google/gerrit/testing/NoteDbMode.java
+++ b/java/com/google/gerrit/testing/NoteDbMode.java
@@ -52,7 +52,7 @@
       value = System.getProperty(SYS_PROP);
     }
     if (Strings.isNullOrEmpty(value)) {
-      return OFF;
+      return ON;
     }
     value = value.toUpperCase().replace("-", "_");
     NoteDbMode mode = Enums.getIfPresent(NoteDbMode.class, value).orNull();
diff --git a/javatests/com/google/gerrit/acceptance/api/accounts/AgreementsIT.java b/javatests/com/google/gerrit/acceptance/api/accounts/AgreementsIT.java
index 7a4a901..c939ac1 100644
--- a/javatests/com/google/gerrit/acceptance/api/accounts/AgreementsIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/accounts/AgreementsIT.java
@@ -182,6 +182,28 @@
   }
 
   @Test
+  public void revertExcludedProjectChangeWithoutCLA() throws Exception {
+    // Contributor agreements configured with excludeProjects = ExcludedProject
+    // in AbstractDaemonTest.configureContributorAgreement(...)
+    assume().that(isContributorAgreementsEnabled()).isTrue();
+
+    // Create a change succeeds when agreement is not required
+    setUseContributorAgreements(InheritableBoolean.FALSE);
+    // Project name includes test method name which contains ExcludedProject
+    ChangeInfo change = gApi.changes().create(newChangeInput()).get();
+
+    // Approve and submit it
+    setApiUser(admin);
+    gApi.changes().id(change.changeId).current().review(ReviewInput.approve());
+    gApi.changes().id(change.changeId).current().submit(new SubmitInput());
+
+    // Revert in excluded project is allowed even when CLA is required but not signed
+    setApiUser(user);
+    setUseContributorAgreements(InheritableBoolean.TRUE);
+    gApi.changes().id(change.changeId).revert();
+  }
+
+  @Test
   public void cherrypickChangeWithoutCLA() throws Exception {
     assume().that(isContributorAgreementsEnabled()).isTrue();
 
@@ -240,6 +262,17 @@
     gApi.changes().create(newChangeInput());
   }
 
+  @Test
+  public void createExcludedProjectChangeIgnoresCLA() throws Exception {
+    // Contributor agreements configured with excludeProjects = ExcludedProject
+    // in AbstractDaemonTest.configureContributorAgreement(...)
+    assume().that(isContributorAgreementsEnabled()).isTrue();
+
+    // Create a change in excluded project is allowed even when CLA is required but not signed.
+    setUseContributorAgreements(InheritableBoolean.TRUE);
+    gApi.changes().create(newChangeInput());
+  }
+
   private void assertAgreement(AgreementInfo info, ContributorAgreement ca) {
     assertThat(info.name).isEqualTo(ca.getName());
     assertThat(info.description).isEqualTo(ca.getDescription());
diff --git a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
index 7063b27..30aef73 100644
--- a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
@@ -80,6 +80,7 @@
 import com.google.gerrit.extensions.api.changes.NotifyInfo;
 import com.google.gerrit.extensions.api.changes.RebaseInput;
 import com.google.gerrit.extensions.api.changes.RecipientType;
+import com.google.gerrit.extensions.api.changes.RelatedChangeAndCommitInfo;
 import com.google.gerrit.extensions.api.changes.RevertInput;
 import com.google.gerrit.extensions.api.changes.ReviewInput;
 import com.google.gerrit.extensions.api.changes.ReviewInput.DraftHandling;
@@ -124,6 +125,7 @@
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.UnprocessableEntityException;
+import com.google.gerrit.index.IndexConfig;
 import com.google.gerrit.mail.Address;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.AccountGroup;
@@ -139,8 +141,12 @@
 import com.google.gerrit.server.change.ChangeResource;
 import com.google.gerrit.server.git.ChangeMessageModifier;
 import com.google.gerrit.server.group.SystemGroupBackend;
+import com.google.gerrit.server.index.change.ChangeIndex;
+import com.google.gerrit.server.index.change.ChangeIndexCollection;
+import com.google.gerrit.server.index.change.IndexedChangeQuery;
 import com.google.gerrit.server.notedb.NoteDbChangeState.PrimaryStorage;
 import com.google.gerrit.server.project.testing.Util;
+import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.restapi.change.PostReview;
 import com.google.gerrit.server.update.BatchUpdate;
 import com.google.gerrit.server.update.BatchUpdateOp;
@@ -185,6 +191,9 @@
 
   @Inject private AccountOperations accountOperations;
 
+  @Inject private ChangeIndexCollection changeIndexCollection;
+  @Inject private IndexConfig indexConfig;
+
   private ChangeIndexedCounter changeIndexedCounter;
   private RegistrationHandle changeIndexedCounterHandle;
 
@@ -943,13 +952,77 @@
     RevisionInfo ri2 = ci2.revisions.get(ci2.currentRevision);
     assertThat(ri2.commit.parents.get(0).commit).isEqualTo(branchTip);
 
+    Change.Id id1 = r1.getChange().getId();
     RebaseInput in = new RebaseInput();
-    in.base = Integer.toString(r1.getChange().getId().get());
+    in.base = id1.toString();
     gApi.changes().id(r2.getChangeId()).rebase(in);
 
+    Change.Id id2 = r2.getChange().getId();
     ci2 = get(r2.getChangeId(), CURRENT_REVISION, CURRENT_COMMIT);
     ri2 = ci2.revisions.get(ci2.currentRevision);
     assertThat(ri2.commit.parents.get(0).commit).isEqualTo(r1.getCommit().name());
+
+    List<RelatedChangeAndCommitInfo> related = getRelated(id2, ri2._number);
+    assertThat(related).hasSize(2);
+    assertThat(related.get(0)._changeNumber).isEqualTo(id2.get());
+    assertThat(related.get(0)._revisionNumber).isEqualTo(2);
+    assertThat(related.get(1)._changeNumber).isEqualTo(id1.get());
+    assertThat(related.get(1)._revisionNumber).isEqualTo(1);
+  }
+
+  @Test
+  public void rebaseOnClosedChange() throws Exception {
+    String branchTip = testRepo.getRepository().exactRef("HEAD").getObjectId().name();
+    PushOneCommit.Result r1 = createChange();
+    testRepo.reset("HEAD~1");
+    PushOneCommit.Result r2 = createChange();
+
+    ChangeInfo ci2 = get(r2.getChangeId(), CURRENT_REVISION, CURRENT_COMMIT);
+    RevisionInfo ri2 = ci2.revisions.get(ci2.currentRevision);
+    assertThat(ri2.commit.parents.get(0).commit).isEqualTo(branchTip);
+
+    // Submit first change.
+    Change.Id id1 = r1.getChange().getId();
+    gApi.changes().id(id1.get()).current().review(ReviewInput.approve());
+    gApi.changes().id(id1.get()).current().submit();
+
+    // Rebase second change on first change.
+    RebaseInput in = new RebaseInput();
+    in.base = id1.toString();
+    gApi.changes().id(r2.getChangeId()).rebase(in);
+
+    Change.Id id2 = r2.getChange().getId();
+    ci2 = get(r2.getChangeId(), CURRENT_REVISION, CURRENT_COMMIT);
+    ri2 = ci2.revisions.get(ci2.currentRevision);
+    assertThat(ri2.commit.parents.get(0).commit).isEqualTo(r1.getCommit().name());
+
+    assertThat(getRelated(id2, ri2._number)).isEmpty();
+  }
+
+  @Test
+  public void rebaseFromRelationChainToClosedChange() throws Exception {
+    PushOneCommit.Result r1 = createChange();
+    testRepo.reset("HEAD~1");
+
+    createChange();
+    PushOneCommit.Result r3 = createChange();
+
+    // Submit first change.
+    Change.Id id1 = r1.getChange().getId();
+    gApi.changes().id(id1.get()).current().review(ReviewInput.approve());
+    gApi.changes().id(id1.get()).current().submit();
+
+    // Rebase third change on first change.
+    RebaseInput in = new RebaseInput();
+    in.base = id1.toString();
+    gApi.changes().id(r3.getChangeId()).rebase(in);
+
+    Change.Id id3 = r3.getChange().getId();
+    ChangeInfo ci3 = get(r3.getChangeId(), CURRENT_REVISION, CURRENT_COMMIT);
+    RevisionInfo ri3 = ci3.revisions.get(ci3.currentRevision);
+    assertThat(ri3.commit.parents.get(0).commit).isEqualTo(r1.getCommit().name());
+
+    assertThat(getRelated(id3, ri3._number)).isEmpty();
   }
 
   @Test
@@ -1244,6 +1317,23 @@
   }
 
   @Test
+  public void deleteChangeUpdatesIndex() throws Exception {
+    PushOneCommit.Result changeResult = createChange();
+    String changeId = changeResult.getChangeId();
+    Change.Id id = changeResult.getChange().getId();
+
+    ChangeIndex idx = changeIndexCollection.getSearchIndex();
+
+    Optional<ChangeData> result =
+        idx.get(id, IndexedChangeQuery.createOptions(indexConfig, 0, 1, ImmutableSet.of()));
+
+    assertThat(result.isPresent()).isTrue();
+    gApi.changes().id(changeId).delete();
+    result = idx.get(id, IndexedChangeQuery.createOptions(indexConfig, 0, 1, ImmutableSet.of()));
+    assertThat(result.isPresent()).isFalse();
+  }
+
+  @Test
   public void rebaseUpToDateChange() throws Exception {
     PushOneCommit.Result r = createChange();
     exception.expect(ResourceConflictException.class);
@@ -1602,7 +1692,7 @@
     PushOneCommit.Result result = createChange();
 
     String username = name("new-user");
-    gApi.accounts().create(username).setActive(false);
+    accountOperations.newAccount().username(username).inactive().create();
 
     AddReviewerInput in = new AddReviewerInput();
     in.reviewer = username;
@@ -1624,7 +1714,7 @@
     PushOneCommit.Result result = createChange();
 
     String username = "user@domain.com";
-    gApi.accounts().create(username).setActive(false);
+    accountOperations.newAccount().username(username).inactive().create();
 
     AddReviewerInput in = new AddReviewerInput();
     in.reviewer = username;
@@ -2006,7 +2096,7 @@
     ChangeResource rsrc = parseResource(r);
     String oldETag = rsrc.getETag();
 
-    gApi.accounts().id(admin.id.get()).setStatus("new status");
+    accountOperations.account(admin.id).forUpdate().status("new status").update();
     rsrc = parseResource(r);
     assertThat(rsrc.getETag()).isNotEqualTo(oldETag);
   }
diff --git a/javatests/com/google/gerrit/acceptance/api/project/ProjectIT.java b/javatests/com/google/gerrit/acceptance/api/project/ProjectIT.java
index 9fcbaa7..995f89b 100644
--- a/javatests/com/google/gerrit/acceptance/api/project/ProjectIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/project/ProjectIT.java
@@ -33,6 +33,7 @@
 import com.google.gerrit.acceptance.PushOneCommit;
 import com.google.gerrit.common.data.Permission;
 import com.google.gerrit.extensions.api.projects.BranchInput;
+import com.google.gerrit.extensions.api.projects.CommentLinkInfo;
 import com.google.gerrit.extensions.api.projects.ConfigInfo;
 import com.google.gerrit.extensions.api.projects.ConfigInput;
 import com.google.gerrit.extensions.api.projects.DescriptionInput;
@@ -51,7 +52,10 @@
 import com.google.gerrit.reviewdb.client.RefNames;
 import com.google.gerrit.server.group.SystemGroupBackend;
 import com.google.gerrit.server.index.IndexExecutor;
+import com.google.gerrit.server.project.CommentLinkInfoImpl;
 import com.google.inject.Inject;
+import java.util.HashMap;
+import java.util.Map;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.transport.PushResult;
 import org.eclipse.jgit.transport.RemoteRefUpdate.Status;
@@ -61,6 +65,13 @@
 
 @NoHttpd
 public class ProjectIT extends AbstractDaemonTest {
+  private static final String BUGZILLA = "bugzilla";
+  private static final String BUGZILLA_LINK = "http://bugzilla.example.com/?id=$2";
+  private static final String BUGZILLA_MATCH = "(bug\\\\s+#?)(\\\\d+)";
+  private static final String JIRA = "jira";
+  private static final String JIRA_LINK = "http://jira.example.com/?id=$2";
+  private static final String JIRA_MATCH = "(jira\\\\s+#?)(\\\\d+)";
+
   @Inject private DynamicSet<ProjectIndexedListener> projectIndexedListeners;
 
   @Inject
@@ -603,6 +614,31 @@
     setMaxObjectSize("100 foo");
   }
 
+  @Test
+  public void noCommentlinksByDefault() throws Exception {
+    assertThat(getConfig().commentlinks).isEmpty();
+  }
+
+  @Test
+  @GerritConfig(name = "commentlink.bugzilla.match", value = BUGZILLA_MATCH)
+  @GerritConfig(name = "commentlink.bugzilla.link", value = BUGZILLA_LINK)
+  @GerritConfig(name = "commentlink.jira.match", value = JIRA_MATCH)
+  @GerritConfig(name = "commentlink.jira.link", value = JIRA_LINK)
+  public void projectConfigUsesCommentlinksFromGlobalConfig() throws Exception {
+    Map<String, CommentLinkInfo> expected = new HashMap<>();
+    expected.put(BUGZILLA, commentLinkInfo(BUGZILLA, BUGZILLA_MATCH, BUGZILLA_LINK));
+    expected.put(JIRA, commentLinkInfo(JIRA, JIRA_MATCH, JIRA_LINK));
+    assertCommentLinks(getConfig(), expected);
+  }
+
+  private CommentLinkInfo commentLinkInfo(String name, String match, String link) {
+    return new CommentLinkInfoImpl(name, match, link, null /*html*/, null /*enabled*/);
+  }
+
+  private void assertCommentLinks(ConfigInfo actual, Map<String, CommentLinkInfo> expected) {
+    assertThat(actual.commentlinks).containsExactlyEntriesIn(expected);
+  }
+
   private ConfigInfo setConfig(Project.NameKey name, ConfigInput input) throws Exception {
     return gApi.projects().name(name.get()).config(input);
   }
diff --git a/javatests/com/google/gerrit/acceptance/api/revision/RobotCommentsIT.java b/javatests/com/google/gerrit/acceptance/api/revision/RobotCommentsIT.java
index cd20765..d713db6 100644
--- a/javatests/com/google/gerrit/acceptance/api/revision/RobotCommentsIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/revision/RobotCommentsIT.java
@@ -1024,7 +1024,7 @@
   }
 
   @Test
-  public void queryChangesWithUnresolvedCommentCount() throws Exception {
+  public void queryChangesWithCommentCounts() throws Exception {
     assume().that(notesMigration.readChanges()).isTrue();
 
     PushOneCommit.Result r1 = createChange();
@@ -1043,6 +1043,7 @@
       // if we allow users to resolve a robot comment, then this test should
       // be modified.
       assertThat(result.unresolvedCommentCount).isEqualTo(0);
+      assertThat(result.totalCommentCount).isEqualTo(1);
     } finally {
       enableDb(ctx);
     }
diff --git a/javatests/com/google/gerrit/acceptance/edit/ChangeEditIT.java b/javatests/com/google/gerrit/acceptance/edit/ChangeEditIT.java
index 91a1278..9ad14ee 100644
--- a/javatests/com/google/gerrit/acceptance/edit/ChangeEditIT.java
+++ b/javatests/com/google/gerrit/acceptance/edit/ChangeEditIT.java
@@ -239,6 +239,7 @@
 
   @Test
   public void publishEditRestWithoutCLA() throws Exception {
+    configureContributorAgreement(true);
     createArbitraryEditFor(changeId);
     setUseContributorAgreements(InheritableBoolean.TRUE);
     adminRestSession.post(urlPublish(changeId)).assertForbidden();
diff --git a/javatests/com/google/gerrit/acceptance/git/AbstractSubmoduleSubscription.java b/javatests/com/google/gerrit/acceptance/git/AbstractSubmoduleSubscription.java
index 943b052..66a09f8 100644
--- a/javatests/com/google/gerrit/acceptance/git/AbstractSubmoduleSubscription.java
+++ b/javatests/com/google/gerrit/acceptance/git/AbstractSubmoduleSubscription.java
@@ -189,7 +189,7 @@
     try (MetaDataUpdate md = metaDataUpdateFactory.create(sub)) {
       md.setMessage("Added superproject subscription");
       SubscribeSection s;
-      ProjectConfig pc = ProjectConfig.read(md);
+      ProjectConfig pc = projectConfigFactory.read(md);
       if (pc.getSubscribeSections().containsKey(superName)) {
         s = pc.getSubscribeSections().get(superName);
       } else {
diff --git a/javatests/com/google/gerrit/acceptance/rest/ProjectsRestApiBindingsIT.java b/javatests/com/google/gerrit/acceptance/rest/ProjectsRestApiBindingsIT.java
index 6563de3..ca8d3ce 100644
--- a/javatests/com/google/gerrit/acceptance/rest/ProjectsRestApiBindingsIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/ProjectsRestApiBindingsIT.java
@@ -60,7 +60,6 @@
           RestCall.post("/projects/%s/access"),
           RestCall.put("/projects/%s/access:review"),
           RestCall.get("/projects/%s/check.access"),
-          RestCall.post("/projects/%s/check.access"),
           RestCall.put("/projects/%s/ban"),
           RestCall.get("/projects/%s/statistics.git"),
           RestCall.post("/projects/%s/index"),
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/ChangeIdIT.java b/javatests/com/google/gerrit/acceptance/rest/change/ChangeIdIT.java
index a2ad7fc..3f1608c 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/ChangeIdIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/ChangeIdIT.java
@@ -18,6 +18,7 @@
 import com.google.gerrit.acceptance.PushOneCommit;
 import com.google.gerrit.acceptance.RestResponse;
 import com.google.gerrit.extensions.api.changes.ChangeApi;
+import com.google.gerrit.reviewdb.client.Change;
 import org.junit.Test;
 
 public class ChangeIdIT extends AbstractDaemonTest {
@@ -92,6 +93,43 @@
     res.assertNotFound();
   }
 
+  @Test
+  public void changeNumberRedirects() throws Exception {
+    // This test tests a redirect that is primarily intended for the UI (though the backend doesn't
+    // really care who the caller is). The redirect rewrites a shorthand change number URL (/123) to
+    // it's canonical long form (/c/project/+/123).
+    int changeId = createChange().getChange().getId().id;
+    RestResponse res = anonymousRestSession.get("/" + changeId);
+    res.assertTemporaryRedirect("/c/" + project.get() + "/+/" + changeId + "/");
+  }
+
+  @Test
+  public void changeNumberRedirectsWithTrailingSlash() throws Exception {
+    int changeId = createChange().getChange().getId().id;
+    RestResponse res = anonymousRestSession.get("/" + changeId + "/");
+    res.assertTemporaryRedirect("/c/" + project.get() + "/+/" + changeId + "/");
+  }
+
+  @Test
+  public void changeNumberOverflowNotFound() throws Exception {
+    RestResponse res = anonymousRestSession.get("/9" + Long.MAX_VALUE);
+    res.assertNotFound();
+  }
+
+  @Test
+  public void unknownChangeNumberNotFound() throws Exception {
+    RestResponse res = anonymousRestSession.get("/10");
+    res.assertNotFound();
+  }
+
+  @Test
+  public void hiddenChangeNotFound() throws Exception {
+    Change.Id changeId = createChange().getChange().getId();
+    gApi.changes().id(changeId.id).setPrivate(true, null);
+    RestResponse res = anonymousRestSession.get("/" + changeId.id);
+    res.assertNotFound();
+  }
+
   private static String changeDetail(String changeId) {
     return "/changes/" + changeId + "/detail";
   }
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/CorsIT.java b/javatests/com/google/gerrit/acceptance/rest/change/CorsIT.java
index 0af9708..6fd3bab 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/CorsIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/CorsIT.java
@@ -34,6 +34,7 @@
 import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.PushOneCommit.Result;
 import com.google.gerrit.acceptance.RestResponse;
+import com.google.gerrit.acceptance.RestSession;
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.restapi.RestApiException;
@@ -44,6 +45,7 @@
 import java.util.stream.Stream;
 import org.apache.http.Header;
 import org.apache.http.HttpResponse;
+import org.apache.http.HttpStatus;
 import org.apache.http.client.fluent.Executor;
 import org.apache.http.client.fluent.Request;
 import org.apache.http.cookie.Cookie;
@@ -99,6 +101,30 @@
   }
 
   @Test
+  public void originsOnNotFoundException() throws Exception {
+    String url = "/changes/999/detail";
+    check(url, true, "http://example.com", adminRestSession, 404);
+    check(url, false, "http://friendsly", adminRestSession, 404);
+  }
+
+  @Test
+  public void originsOnBadRequestException() throws Exception {
+    String url = "/config/server/caches/?format=NONSENSE";
+    check(url, true, "http://example.com", adminRestSession, 400);
+    check(url, false, "http://friendsly", adminRestSession, 400);
+  }
+
+  @Test
+  public void originsOnForbidden() throws Exception {
+    Result change = createChange();
+    // Make change private to hide it
+    gApi.changes().id(change.getChangeId()).setPrivate(true, "now private");
+    String url = "/changes/" + change.getChangeId() + "/detail";
+    check(url, true, "http://example.com", anonymousRestSession, 404);
+    check(url, false, "http://friendsly", anonymousRestSession, 404);
+  }
+
+  @Test
   public void putWithServerOriginAcceptedWithNoCorsResponseHeaders() throws Exception {
     Result change = createChange();
     String origin = adminRestSession.url();
@@ -247,9 +273,15 @@
   }
 
   private void check(String url, boolean accept, String origin) throws Exception {
+    check(url, accept, origin, adminRestSession, HttpStatus.SC_OK);
+  }
+
+  private void check(
+      String url, boolean accept, String origin, RestSession restSession, int httpStatusCode)
+      throws Exception {
     Header hdr = new BasicHeader(ORIGIN, origin);
-    RestResponse r = adminRestSession.getWithHeader(url, hdr);
-    r.assertOK();
+    RestResponse r = restSession.getWithHeader(url, hdr);
+    r.assertStatus(httpStatusCode);
     checkCors(r, accept, origin);
   }
 
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/MoveChangeIT.java b/javatests/com/google/gerrit/acceptance/rest/change/MoveChangeIT.java
index 206cc68..222973e 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/MoveChangeIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/MoveChangeIT.java
@@ -19,6 +19,7 @@
 import static com.google.gerrit.server.group.SystemGroupBackend.REGISTERED_USERS;
 
 import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.GerritConfig;
 import com.google.gerrit.acceptance.GitUtil;
 import com.google.gerrit.acceptance.NoHttpd;
 import com.google.gerrit.acceptance.PushOneCommit;
@@ -30,6 +31,7 @@
 import com.google.gerrit.extensions.api.projects.BranchInput;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.BadRequestException;
+import com.google.gerrit.extensions.restapi.MethodNotAllowedException;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.reviewdb.client.AccountGroup;
@@ -332,6 +334,16 @@
     move(r.getChangeId(), null);
   }
 
+  @Test
+  @GerritConfig(name = "change.move", value = "false")
+  public void moveCanBeDisabledByConfig() throws Exception {
+    PushOneCommit.Result r = createChange();
+
+    exception.expect(MethodNotAllowedException.class);
+    exception.expectMessage("move changes endpoint is disabled");
+    move(r.getChangeId(), null);
+  }
+
   private void move(int changeNum, String destination) throws RestApiException {
     gApi.changes().id(changeNum).move(destination);
   }
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/SubmitByMergeIfNecessaryIT.java b/javatests/com/google/gerrit/acceptance/rest/change/SubmitByMergeIfNecessaryIT.java
index c1dda00..229122b 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/SubmitByMergeIfNecessaryIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/SubmitByMergeIfNecessaryIT.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.acceptance.rest.change;
 
 import static com.google.common.truth.Truth.assertThat;
+import static com.google.common.truth.TruthJUnit.assume;
 import static com.google.gerrit.server.group.SystemGroupBackend.ANONYMOUS_USERS;
 import static com.google.gerrit.server.group.SystemGroupBackend.REGISTERED_USERS;
 
@@ -24,10 +25,9 @@
 import com.google.gerrit.extensions.api.changes.ChangeApi;
 import com.google.gerrit.extensions.api.changes.CherryPickInput;
 import com.google.gerrit.extensions.api.changes.ReviewInput;
-import com.google.gerrit.extensions.api.changes.SubmitInput;
 import com.google.gerrit.extensions.api.projects.BranchInput;
-import com.google.gerrit.extensions.client.ChangeStatus;
 import com.google.gerrit.extensions.client.SubmitType;
+import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.BinaryResult;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestApiException;
@@ -657,7 +657,7 @@
   }
 
   @Test
-  public void dependencyOnHiddenChangeShouldPreventMergeButDoesnt() throws Exception {
+  public void dependencyOnHiddenChangePreventsMerge() throws Exception {
     grantLabel("Code-Review", -2, 2, project, "refs/heads/*", false, REGISTERED_USERS, false);
     grant(project, "refs/*", Permission.SUBMIT, false, REGISTERED_USERS);
 
@@ -686,18 +686,80 @@
       assertThat(e.getMessage()).isEqualTo("Not found: " + changeResult.getChangeId());
     }
 
-    // Submit the second change which has a dependency on the first change which is not visible to
-    // the user. We would expect the submit to fail, but instead the submit succeeds and the hidden
-    // change gets submitted too.
-    // TODO(ekempin): Make this submit fail.
-    gApi.changes().id(change2Result.getChangeId()).current().submit(new SubmitInput());
+    // Submit is expected to fail.
+    try {
+      gApi.changes().id(change2Result.getChangeId()).current().submit();
+      fail("expected failure");
+    } catch (AuthException e) {
+      assertThat(e.getMessage())
+          .isEqualTo(
+              "A change to be submitted with "
+                  + change2Result.getChange().getId().id
+                  + " is not visible");
+    }
+    assertRefUpdatedEvents();
+    assertChangeMergedEvents();
+  }
 
-    // Verify that both changes have been submitted.
-    setApiUser(admin);
-    assertThat(gApi.changes().id(changeResult.getChangeId()).get().status)
-        .isEqualTo(ChangeStatus.MERGED);
-    assertThat(gApi.changes().id(change2Result.getChangeId()).get().status)
-        .isEqualTo(ChangeStatus.MERGED);
+  @Test
+  public void dependencyOnHiddenChangeUsingTopicPreventsMerge() throws Exception {
+    // Construct a topic where a change included by topic depends on a private change that is not
+    // visible to the submitting user
+    // (c1) --- topic --- (c2b)
+    //                      |
+    //                    (c2a) <= private
+    assume().that(isSubmitWholeTopicEnabled()).isTrue();
+
+    Project.NameKey p1 = createProject("project-where-we-submit");
+    Project.NameKey p2 = createProject("project-impacted-via-topic");
+
+    grantLabel("Code-Review", -2, 2, p1, "refs/heads/*", false, REGISTERED_USERS, false);
+    grant(p1, "refs/*", Permission.SUBMIT, false, REGISTERED_USERS);
+    grantLabel("Code-Review", -2, 2, p2, "refs/heads/*", false, REGISTERED_USERS, false);
+    grant(p2, "refs/*", Permission.SUBMIT, false, REGISTERED_USERS);
+
+    TestRepository<?> repo1 = cloneProject(p1);
+    TestRepository<?> repo2 = cloneProject(p2);
+
+    PushOneCommit.Result change1 =
+        createChange(repo1, "master", "A fresh change in repo1", "a.txt", "1", "topic-to-submit");
+    approve(change1.getChangeId());
+    PushOneCommit push =
+        pushFactory.create(
+            db, admin.getIdent(), repo2, "An ancestor change in repo2", "a.txt", "2");
+    PushOneCommit.Result change2a = push.to("refs/for/master");
+    approve(change2a.getChangeId());
+    PushOneCommit.Result change2b =
+        createChange(
+            repo2, "master", "A topic-linked change in repo2", "a.txt", "2", "topic-to-submit");
+    approve(change2b.getChangeId());
+
+    // Mark change2a private so that it's not visible to user.
+    gApi.changes().id(change2a.getChangeId()).setPrivate(true, "nobody should see this");
+
+    setApiUser(user);
+
+    // Verify that user cannot see change2a
+    try {
+      gApi.changes().id(change2a.getChangeId()).get();
+      fail("expected failure");
+    } catch (ResourceNotFoundException e) {
+      assertThat(e.getMessage()).isEqualTo("Not found: " + change2a.getChangeId());
+    }
+
+    // Submit is expected to fail.
+    try {
+      gApi.changes().id(change1.getChangeId()).current().submit();
+      fail("expected failure");
+    } catch (AuthException e) {
+      assertThat(e.getMessage())
+          .isEqualTo(
+              "A change to be submitted with "
+                  + change1.getChange().getId().id
+                  + " is not visible");
+    }
+    assertRefUpdatedEvents();
+    assertChangeMergedEvents();
   }
 
   @Test
diff --git a/javatests/com/google/gerrit/acceptance/server/change/CommentsIT.java b/javatests/com/google/gerrit/acceptance/server/change/CommentsIT.java
index 8b1f4bc..0d40a1c 100644
--- a/javatests/com/google/gerrit/acceptance/server/change/CommentsIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/change/CommentsIT.java
@@ -716,7 +716,7 @@
   }
 
   @Test
-  public void queryChangesWithUnresolvedCommentCount() throws Exception {
+  public void queryChangesWithCommentCount() throws Exception {
     // PS1 has three comments in three different threads, PS2 has one comment in one thread.
     PushOneCommit.Result result = createChange("change 1", FILE_NAME, "content 1");
     String changeId1 = result.getChangeId();
@@ -751,8 +751,11 @@
       ChangeInfo changeInfo2 = Iterables.getOnlyElement(query(changeId2));
       ChangeInfo changeInfo3 = Iterables.getOnlyElement(query(changeId3));
       assertThat(changeInfo1.unresolvedCommentCount).isEqualTo(2);
+      assertThat(changeInfo1.totalCommentCount).isEqualTo(4);
       assertThat(changeInfo2.unresolvedCommentCount).isEqualTo(0);
+      assertThat(changeInfo2.totalCommentCount).isEqualTo(2);
       assertThat(changeInfo3.unresolvedCommentCount).isEqualTo(1);
+      assertThat(changeInfo3.totalCommentCount).isEqualTo(2);
     } finally {
       enableDb(ctx);
     }
diff --git a/javatests/com/google/gerrit/acceptance/server/change/GetRelatedIT.java b/javatests/com/google/gerrit/acceptance/server/change/GetRelatedIT.java
index 5d3b223..8e8aeac 100644
--- a/javatests/com/google/gerrit/acceptance/server/change/GetRelatedIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/change/GetRelatedIT.java
@@ -24,9 +24,10 @@
 import com.google.common.collect.Iterables;
 import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.GerritConfig;
+import com.google.gerrit.acceptance.NoHttpd;
 import com.google.gerrit.acceptance.PushOneCommit;
-import com.google.gerrit.acceptance.RestResponse;
 import com.google.gerrit.common.RawInputUtil;
+import com.google.gerrit.extensions.api.changes.RelatedChangeAndCommitInfo;
 import com.google.gerrit.extensions.common.CommitInfo;
 import com.google.gerrit.extensions.common.EditInfo;
 import com.google.gerrit.index.IndexConfig;
@@ -35,8 +36,6 @@
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.restapi.change.ChangesCollection;
 import com.google.gerrit.server.restapi.change.GetRelated;
-import com.google.gerrit.server.restapi.change.GetRelated.ChangeAndCommit;
-import com.google.gerrit.server.restapi.change.GetRelated.RelatedInfo;
 import com.google.gerrit.server.update.BatchUpdate;
 import com.google.gerrit.server.update.BatchUpdateOp;
 import com.google.gerrit.server.update.ChangeContext;
@@ -56,6 +55,7 @@
 import org.junit.Before;
 import org.junit.Test;
 
+@NoHttpd
 public class GetRelatedIT extends AbstractDaemonTest {
   private static final int MAX_TERMS = 10;
 
@@ -577,17 +577,6 @@
     assertRelated(cd.change().currentPatchSetId());
   }
 
-  private List<ChangeAndCommit> getRelated(PatchSet.Id ps) throws Exception {
-    return getRelated(ps.getParentKey(), ps.get());
-  }
-
-  private List<ChangeAndCommit> getRelated(Change.Id changeId, int ps) throws Exception {
-    String url = String.format("/changes/%d/revisions/%d/related", changeId.get(), ps);
-    RestResponse r = adminRestSession.get(url);
-    r.assertOK();
-    return newGson().fromJson(r.getReader(), RelatedInfo.class).changes;
-  }
-
   private RevCommit parseBody(RevCommit c) throws Exception {
     testRepo.getRevWalk().parseBody(c);
     return c;
@@ -601,9 +590,9 @@
     return Iterables.getOnlyElement(queryProvider.get().byCommit(c));
   }
 
-  private ChangeAndCommit changeAndCommit(
+  private RelatedChangeAndCommitInfo changeAndCommit(
       PatchSet.Id psId, ObjectId commitId, int currentRevisionNum) {
-    ChangeAndCommit result = new ChangeAndCommit();
+    RelatedChangeAndCommitInfo result = new RelatedChangeAndCommitInfo();
     result.project = project.get();
     result._changeNumber = psId.getParentKey().get();
     result.commit = new CommitInfo();
@@ -631,13 +620,14 @@
     }
   }
 
-  private void assertRelated(PatchSet.Id psId, ChangeAndCommit... expected) throws Exception {
-    List<ChangeAndCommit> actual = getRelated(psId);
+  private void assertRelated(PatchSet.Id psId, RelatedChangeAndCommitInfo... expected)
+      throws Exception {
+    List<RelatedChangeAndCommitInfo> actual = getRelated(psId);
     assertThat(actual).named("related to " + psId).hasSize(expected.length);
     for (int i = 0; i < actual.size(); i++) {
       String name = "index " + i + " related to " + psId;
-      ChangeAndCommit a = actual.get(i);
-      ChangeAndCommit e = expected[i];
+      RelatedChangeAndCommitInfo a = actual.get(i);
+      RelatedChangeAndCommitInfo e = expected[i];
       assertThat(a.project).named("project of " + name).isEqualTo(e.project);
       assertThat(a._changeNumber).named("change ID of " + name).isEqualTo(e._changeNumber);
       // Don't bother checking changeId; assume _changeNumber is sufficient.
diff --git a/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java b/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java
index 9ff2c05..b8380f5 100644
--- a/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java
@@ -17,6 +17,7 @@
 import static com.google.common.truth.Truth.assertThat;
 
 import com.google.common.collect.Iterables;
+import com.google.gerrit.acceptance.testsuite.account.AccountOperations;
 import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.common.ChangeMessageInfo;
 import com.google.gerrit.extensions.common.CommentInfo;
@@ -33,6 +34,7 @@
 
 public class MailProcessorIT extends AbstractMailIT {
   @Inject private MailProcessor mailProcessor;
+  @Inject private AccountOperations accountOperations;
 
   @Test
   public void parseAndPersistChangeMessage() throws Exception {
@@ -163,16 +165,13 @@
     b.textContent(txt + textFooterForChange(changeInfo._number, ts));
 
     // Set account state to inactive
-    gApi.accounts().id("user").setActive(false);
+    accountOperations.account(user.id).forUpdate().inactive().update();
 
     mailProcessor.process(b.build());
     comments = gApi.changes().id(changeId).current().commentsAsList();
 
     // Check that comment size has not changed
     assertThat(comments).hasSize(2);
-
-    // Reset
-    gApi.accounts().id("user").setActive(true);
   }
 
   @Test
diff --git a/javatests/com/google/gerrit/server/change/LabelNormalizerTest.java b/javatests/com/google/gerrit/server/change/LabelNormalizerTest.java
index 5a067f1..eb6f189 100644
--- a/javatests/com/google/gerrit/server/change/LabelNormalizerTest.java
+++ b/javatests/com/google/gerrit/server/change/LabelNormalizerTest.java
@@ -74,6 +74,7 @@
   @Inject private SchemaCreator schemaCreator;
   @Inject protected ThreadLocalRequestContext requestContext;
   @Inject private ChangeNotes.Factory changeNotesFactory;
+  @Inject private ProjectConfig.Factory projectConfigFactory;
 
   private LifecycleManager lifecycle;
   private ReviewDb db;
@@ -198,7 +199,7 @@
 
   private ProjectConfig loadAllProjects() throws Exception {
     try (Repository repo = repoManager.openRepository(allProjects)) {
-      ProjectConfig pc = new ProjectConfig(allProjects);
+      ProjectConfig pc = projectConfigFactory.create(allProjects);
       pc.load(repo);
       return pc;
     }
diff --git a/javatests/com/google/gerrit/server/config/RepositoryConfigTest.java b/javatests/com/google/gerrit/server/config/RepositoryConfigTest.java
index 2edcf7c..3da35b2 100644
--- a/javatests/com/google/gerrit/server/config/RepositoryConfigTest.java
+++ b/javatests/com/google/gerrit/server/config/RepositoryConfigTest.java
@@ -19,7 +19,7 @@
 
 import com.google.common.collect.ImmutableList;
 import com.google.gerrit.extensions.client.SubmitType;
-import com.google.gerrit.reviewdb.client.Project.NameKey;
+import com.google.gerrit.reviewdb.client.Project;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.List;
@@ -41,35 +41,35 @@
   @Test
   public void defaultSubmitTypeWhenNotConfigured() {
     // Check expected value explicitly rather than depending on constant.
-    assertThat(repoCfg.getDefaultSubmitType(new NameKey("someProject")))
+    assertThat(repoCfg.getDefaultSubmitType(new Project.NameKey("someProject")))
         .isEqualTo(SubmitType.INHERIT);
   }
 
   @Test
   public void defaultSubmitTypeForStarFilter() {
     configureDefaultSubmitType("*", SubmitType.CHERRY_PICK);
-    assertThat(repoCfg.getDefaultSubmitType(new NameKey("someProject")))
+    assertThat(repoCfg.getDefaultSubmitType(new Project.NameKey("someProject")))
         .isEqualTo(SubmitType.CHERRY_PICK);
 
     configureDefaultSubmitType("*", SubmitType.FAST_FORWARD_ONLY);
-    assertThat(repoCfg.getDefaultSubmitType(new NameKey("someProject")))
+    assertThat(repoCfg.getDefaultSubmitType(new Project.NameKey("someProject")))
         .isEqualTo(SubmitType.FAST_FORWARD_ONLY);
 
     configureDefaultSubmitType("*", SubmitType.REBASE_IF_NECESSARY);
-    assertThat(repoCfg.getDefaultSubmitType(new NameKey("someProject")))
+    assertThat(repoCfg.getDefaultSubmitType(new Project.NameKey("someProject")))
         .isEqualTo(SubmitType.REBASE_IF_NECESSARY);
 
     configureDefaultSubmitType("*", SubmitType.REBASE_ALWAYS);
-    assertThat(repoCfg.getDefaultSubmitType(new NameKey("someProject")))
+    assertThat(repoCfg.getDefaultSubmitType(new Project.NameKey("someProject")))
         .isEqualTo(SubmitType.REBASE_ALWAYS);
   }
 
   @Test
   public void defaultSubmitTypeForSpecificFilter() {
     configureDefaultSubmitType("someProject", SubmitType.CHERRY_PICK);
-    assertThat(repoCfg.getDefaultSubmitType(new NameKey("someOtherProject")))
+    assertThat(repoCfg.getDefaultSubmitType(new Project.NameKey("someOtherProject")))
         .isEqualTo(RepositoryConfig.DEFAULT_SUBMIT_TYPE);
-    assertThat(repoCfg.getDefaultSubmitType(new NameKey("someProject")))
+    assertThat(repoCfg.getDefaultSubmitType(new Project.NameKey("someProject")))
         .isEqualTo(SubmitType.CHERRY_PICK);
   }
 
@@ -79,13 +79,13 @@
     configureDefaultSubmitType("somePath/*", SubmitType.CHERRY_PICK);
     configureDefaultSubmitType("*", SubmitType.MERGE_ALWAYS);
 
-    assertThat(repoCfg.getDefaultSubmitType(new NameKey("someProject")))
+    assertThat(repoCfg.getDefaultSubmitType(new Project.NameKey("someProject")))
         .isEqualTo(SubmitType.MERGE_ALWAYS);
 
-    assertThat(repoCfg.getDefaultSubmitType(new NameKey("somePath/someProject")))
+    assertThat(repoCfg.getDefaultSubmitType(new Project.NameKey("somePath/someProject")))
         .isEqualTo(SubmitType.CHERRY_PICK);
 
-    assertThat(repoCfg.getDefaultSubmitType(new NameKey("somePath/somePath/someProject")))
+    assertThat(repoCfg.getDefaultSubmitType(new Project.NameKey("somePath/somePath/someProject")))
         .isEqualTo(SubmitType.REBASE_IF_NECESSARY);
   }
 
@@ -99,14 +99,14 @@
 
   @Test
   public void ownerGroupsWhenNotConfigured() {
-    assertThat(repoCfg.getOwnerGroups(new NameKey("someProject"))).isEmpty();
+    assertThat(repoCfg.getOwnerGroups(new Project.NameKey("someProject"))).isEmpty();
   }
 
   @Test
   public void ownerGroupsForStarFilter() {
     ImmutableList<String> ownerGroups = ImmutableList.of("group1", "group2");
     configureOwnerGroups("*", ownerGroups);
-    assertThat(repoCfg.getOwnerGroups(new NameKey("someProject")))
+    assertThat(repoCfg.getOwnerGroups(new Project.NameKey("someProject")))
         .containsExactlyElementsIn(ownerGroups);
   }
 
@@ -114,8 +114,8 @@
   public void ownerGroupsForSpecificFilter() {
     ImmutableList<String> ownerGroups = ImmutableList.of("group1", "group2");
     configureOwnerGroups("someProject", ownerGroups);
-    assertThat(repoCfg.getOwnerGroups(new NameKey("someOtherProject"))).isEmpty();
-    assertThat(repoCfg.getOwnerGroups(new NameKey("someProject")))
+    assertThat(repoCfg.getOwnerGroups(new Project.NameKey("someOtherProject"))).isEmpty();
+    assertThat(repoCfg.getOwnerGroups(new Project.NameKey("someProject")))
         .containsExactlyElementsIn(ownerGroups);
   }
 
@@ -129,13 +129,13 @@
     configureOwnerGroups("somePath/*", ownerGroups2);
     configureOwnerGroups("somePath/somePath/*", ownerGroups3);
 
-    assertThat(repoCfg.getOwnerGroups(new NameKey("someProject")))
+    assertThat(repoCfg.getOwnerGroups(new Project.NameKey("someProject")))
         .containsExactlyElementsIn(ownerGroups1);
 
-    assertThat(repoCfg.getOwnerGroups(new NameKey("somePath/someProject")))
+    assertThat(repoCfg.getOwnerGroups(new Project.NameKey("somePath/someProject")))
         .containsExactlyElementsIn(ownerGroups2);
 
-    assertThat(repoCfg.getOwnerGroups(new NameKey("somePath/somePath/someProject")))
+    assertThat(repoCfg.getOwnerGroups(new Project.NameKey("somePath/somePath/someProject")))
         .containsExactlyElementsIn(ownerGroups3);
   }
 
@@ -149,22 +149,24 @@
 
   @Test
   public void basePathWhenNotConfigured() {
-    assertThat(repoCfg.getBasePath(new NameKey("someProject"))).isNull();
+    assertThat(repoCfg.getBasePath(new Project.NameKey("someProject"))).isNull();
   }
 
   @Test
   public void basePathForStarFilter() {
     String basePath = "/someAbsolutePath/someDirectory";
     configureBasePath("*", basePath);
-    assertThat(repoCfg.getBasePath(new NameKey("someProject")).toString()).isEqualTo(basePath);
+    assertThat(repoCfg.getBasePath(new Project.NameKey("someProject")).toString())
+        .isEqualTo(basePath);
   }
 
   @Test
   public void basePathForSpecificFilter() {
     String basePath = "/someAbsolutePath/someDirectory";
     configureBasePath("someProject", basePath);
-    assertThat(repoCfg.getBasePath(new NameKey("someOtherProject"))).isNull();
-    assertThat(repoCfg.getBasePath(new NameKey("someProject")).toString()).isEqualTo(basePath);
+    assertThat(repoCfg.getBasePath(new Project.NameKey("someOtherProject"))).isNull();
+    assertThat(repoCfg.getBasePath(new Project.NameKey("someProject")).toString())
+        .isEqualTo(basePath);
   }
 
   @Test
@@ -179,12 +181,14 @@
     configureBasePath("project/*", basePath3);
     configureBasePath("*", basePath4);
 
-    assertThat(repoCfg.getBasePath(new NameKey("project1")).toString()).isEqualTo(basePath1);
-    assertThat(repoCfg.getBasePath(new NameKey("project/project/someProject")).toString())
+    assertThat(repoCfg.getBasePath(new Project.NameKey("project1")).toString())
+        .isEqualTo(basePath1);
+    assertThat(repoCfg.getBasePath(new Project.NameKey("project/project/someProject")).toString())
         .isEqualTo(basePath2);
-    assertThat(repoCfg.getBasePath(new NameKey("project/someProject")).toString())
+    assertThat(repoCfg.getBasePath(new Project.NameKey("project/someProject")).toString())
         .isEqualTo(basePath3);
-    assertThat(repoCfg.getBasePath(new NameKey("someProject")).toString()).isEqualTo(basePath4);
+    assertThat(repoCfg.getBasePath(new Project.NameKey("someProject")).toString())
+        .isEqualTo(basePath4);
   }
 
   @Test
diff --git a/javatests/com/google/gerrit/server/permissions/RefControlTest.java b/javatests/com/google/gerrit/server/permissions/RefControlTest.java
index a3f9f93..1d2d04c 100644
--- a/javatests/com/google/gerrit/server/permissions/RefControlTest.java
+++ b/javatests/com/google/gerrit/server/permissions/RefControlTest.java
@@ -206,6 +206,7 @@
   @Inject private DefaultRefFilter.Factory refFilterFactory;
   @Inject private TransferConfig transferConfig;
   @Inject private MetricMaker metricMaker;
+  @Inject private ProjectConfig.Factory projectConfigFactory;
 
   @Before
   public void setUp() throws Exception {
@@ -274,7 +275,8 @@
 
     try {
       Repository repo = repoManager.createRepository(allProjectsName);
-      ProjectConfig allProjects = new ProjectConfig(new Project.NameKey(allProjectsName.get()));
+      ProjectConfig allProjects =
+          projectConfigFactory.create(new Project.NameKey(allProjectsName.get()));
       allProjects.load(repo);
       LabelType cr = Util.codeReview();
       allProjects.getLabelSections().put(cr.getName(), cr);
@@ -295,11 +297,11 @@
         CacheBuilder.newBuilder().build();
     sectionSorter = new PermissionCollection.Factory(new SectionSortCache(c), metricMaker);
 
-    parent = new ProjectConfig(parentKey);
+    parent = projectConfigFactory.create(parentKey);
     parent.load(newRepository(parentKey));
     add(parent);
 
-    local = new ProjectConfig(localKey);
+    local = projectConfigFactory.create(localKey);
     local.load(newRepository(localKey));
     add(local);
     local.getProject().setParentName(parentKey);
@@ -455,7 +457,7 @@
     allow(local, READ, DEVS, "refs/heads/*");
     assertCanAccess(user(local, "a", ADMIN));
 
-    local = new ProjectConfig(localKey);
+    local = projectConfigFactory.create(localKey);
     local.load(newRepository(localKey));
     local.getProject().setParentName(parentKey);
     allow(local, READ, DEVS, "refs/*");
diff --git a/javatests/com/google/gerrit/server/project/CommitsCollectionTest.java b/javatests/com/google/gerrit/server/project/CommitsCollectionTest.java
index b39208a..2ae9e90 100644
--- a/javatests/com/google/gerrit/server/project/CommitsCollectionTest.java
+++ b/javatests/com/google/gerrit/server/project/CommitsCollectionTest.java
@@ -57,6 +57,7 @@
   @Inject protected MetaDataUpdate.Server metaDataUpdateFactory;
   @Inject protected AllProjectsName allProjects;
   @Inject private CommitsCollection commits;
+  @Inject private ProjectConfig.Factory projectConfigFactory;
 
   private TestRepository<InMemoryRepository> repo;
   private ProjectConfig project;
@@ -70,7 +71,7 @@
 
     Project.NameKey name = new Project.NameKey("project");
     InMemoryRepository inMemoryRepo = repoManager.createRepository(name);
-    project = new ProjectConfig(name);
+    project = projectConfigFactory.create(name);
     project.load(inMemoryRepo);
     repo = new TestRepository<>(inMemoryRepo);
   }
diff --git a/javatests/com/google/gerrit/server/project/ProjectConfigTest.java b/javatests/com/google/gerrit/server/project/ProjectConfigTest.java
index 0e4ba10..764d49a 100644
--- a/javatests/com/google/gerrit/server/project/ProjectConfigTest.java
+++ b/javatests/com/google/gerrit/server/project/ProjectConfigTest.java
@@ -78,11 +78,13 @@
       new GroupReference(new AccountGroup.UUID("X"), "Developers");
   private final GroupReference staff = new GroupReference(new AccountGroup.UUID("Y"), "Staff");
 
+  private ProjectConfig.Factory factory;
   private Repository db;
   private TestRepository<?> tr;
 
   @Before
   public void setUp() throws Exception {
+    factory = new ProjectConfig.Factory();
     db = new InMemoryRepository(new DfsRepositoryDescription("repo"));
     tr = new TestRepository<>(db);
   }
@@ -104,6 +106,13 @@
                     + "  sameGroupVisibility = block group Staff\n"
                     + "[contributor-agreement \"Individual\"]\n"
                     + "  description = A simple description\n"
+                    + "  matchProjects = ^/ourproject\n"
+                    + "  matchProjects = ^/ourotherproject\n"
+                    + "  matchProjects = ^/someotherroot/ourproject\n"
+                    + "  excludeProjects = ^/theirproject\n"
+                    + "  excludeProjects = ^/theirotherproject\n"
+                    + "  excludeProjects = ^/someotherroot/theirproject\n"
+                    + "  excludeProjects = ^/someotherroot/theirotherproject\n"
                     + "  accepted = group Developers\n"
                     + "  accepted = group Staff\n"
                     + "  autoVerify = group Developers\n"
@@ -115,6 +124,14 @@
     ContributorAgreement ca = cfg.getContributorAgreement("Individual");
     assertThat(ca.getName()).isEqualTo("Individual");
     assertThat(ca.getDescription()).isEqualTo("A simple description");
+    assertThat(ca.getMatchProjectsRegexes())
+        .containsExactly("^/ourproject", "^/ourotherproject", "^/someotherroot/ourproject");
+    assertThat(ca.getExcludeProjectsRegexes())
+        .containsExactly(
+            "^/theirproject",
+            "^/theirotherproject",
+            "^/someotherroot/theirproject",
+            "^/someotherroot/theirotherproject");
     assertThat(ca.getAgreementUrl()).isEqualTo("http://www.example.com/agree");
     assertThat(ca.getAccepted()).hasSize(2);
     assertThat(ca.getAccepted().get(0).getGroup()).isEqualTo(developers);
@@ -256,6 +273,7 @@
                     + "  sameGroupVisibility = block group Staff\n"
                     + "[contributor-agreement \"Individual\"]\n"
                     + "  description = A simple description\n"
+                    + "  matchProjects = ^/ourproject\n"
                     + "  accepted = group Developers\n"
                     + "  autoVerify = group Developers\n"
                     + "  agreementUrl = http://www.example.com/agree\n"
@@ -273,6 +291,8 @@
     ContributorAgreement ca = cfg.getContributorAgreement("Individual");
     ca.setAccepted(Collections.singletonList(new PermissionRule(cfg.resolve(staff))));
     ca.setAutoVerify(null);
+    ca.setMatchProjectsRegexes(null);
+    ca.setExcludeProjectsRegexes(Collections.singletonList("^/theirproject"));
     ca.setDescription("A new description");
     rev = commit(cfg);
     assertThat(text(rev, "project.config"))
@@ -289,6 +309,7 @@
                 + "  description = A new description\n"
                 + "  accepted = group Staff\n"
                 + "  agreementUrl = http://www.example.com/agree\n"
+                + "\texcludeProjects = ^/theirproject\n"
                 + "[label \"CustomLabel\"]\n"
                 + LABEL_SCORES_CONFIG
                 + "\tfunction = MaxWithBlock\n" // label gets this function when it is created
@@ -385,7 +406,7 @@
 
   @Test
   public void readUnexistingPluginConfig() throws Exception {
-    ProjectConfig cfg = new ProjectConfig(new Project.NameKey("test"));
+    ProjectConfig cfg = factory.create(new Project.NameKey("test"));
     cfg.load(db);
     PluginConfig pluginCfg = cfg.getPluginConfig("somePlugin");
     assertThat(pluginCfg.getNames()).isEmpty();
@@ -573,7 +594,7 @@
   }
 
   private ProjectConfig read(RevCommit rev) throws IOException, ConfigInvalidException {
-    ProjectConfig cfg = new ProjectConfig(new Project.NameKey("test"));
+    ProjectConfig cfg = factory.create(new Project.NameKey("test"));
     cfg.load(db, rev);
     return cfg;
   }
diff --git a/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java b/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
index b9973e9..f362e5a 100644
--- a/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
+++ b/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
@@ -2378,6 +2378,12 @@
     cd.reviewers();
     cd.unresolvedCommentCount();
 
+    if (getSchemaVersion() < 51) {
+      assertMissingField(ChangeField.TOTAL_COMMENT_COUNT);
+    } else {
+      cd.totalCommentCount();
+    }
+
     // TODO(dborowitz): Swap out GitRepositoryManager somehow? Will probably be
     // necessary for NoteDb anyway.
     cd.isMergeable();
diff --git a/javatests/com/google/gerrit/server/schema/SchemaCreatorTest.java b/javatests/com/google/gerrit/server/schema/SchemaCreatorTest.java
index d3f69982..9cb9333 100644
--- a/javatests/com/google/gerrit/server/schema/SchemaCreatorTest.java
+++ b/javatests/com/google/gerrit/server/schema/SchemaCreatorTest.java
@@ -50,6 +50,8 @@
 
   @Inject private InMemoryDatabase db;
 
+  @Inject private ProjectConfig.Factory projectConfigFactory;
+
   @Before
   public void setUp() throws Exception {
     new InMemoryModule().inject(this);
@@ -85,7 +87,7 @@
 
   private LabelTypes getLabelTypes() throws Exception {
     db.create();
-    ProjectConfig c = new ProjectConfig(allProjects);
+    ProjectConfig c = projectConfigFactory.create(allProjects);
     try (Repository repo = repoManager.openRepository(allProjects)) {
       c.load(repo);
       return new LabelTypes(ImmutableList.copyOf(c.getLabelSections().values()));
diff --git a/javatests/com/google/gerrit/server/schema/Schema_161_to_162_Test.java b/javatests/com/google/gerrit/server/schema/Schema_161_to_162_Test.java
index 67d071d..10aabe8 100644
--- a/javatests/com/google/gerrit/server/schema/Schema_161_to_162_Test.java
+++ b/javatests/com/google/gerrit/server/schema/Schema_161_to_162_Test.java
@@ -47,6 +47,7 @@
   @Inject private GitRepositoryManager repoManager;
   @Inject private Schema_162 schema162;
   @Inject private ReviewDb db;
+  @Inject private ProjectConfig.Factory projectConfigFactory;
   @Inject @GerritPersonIdent private PersonIdent serverUser;
 
   @Test
@@ -73,7 +74,7 @@
 
     try (Repository git = repoManager.openRepository(allUsersName);
         MetaDataUpdate md = new MetaDataUpdate(GitReferenceUpdated.DISABLED, allUsersName, git)) {
-      ProjectConfig cfg = ProjectConfig.read(md);
+      ProjectConfig cfg = projectConfigFactory.read(md);
       cfg.getProject().setParentName(testProject);
       md.getCommitBuilder().setCommitter(serverUser);
       md.getCommitBuilder().setAuthor(serverUser);
diff --git a/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.html b/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.html
index 372e6be..2235ae1 100644
--- a/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.html
+++ b/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.html
@@ -55,14 +55,14 @@
       </tr>
       <template is="dom-repeat" items="[[sections]]" as="changeSection"
           index-as="sectionIndex">
-        <template is="dom-if" if="[[changeSection.sectionName]]">
+        <template is="dom-if" if="[[changeSection.name]]">
           <tr class="groupHeader">
             <td class="leftPadding"></td>
             <td class="star" hidden$="[[!showStar]]" hidden></td>
             <td class="cell"
                 colspan$="[[_computeColspan(changeTableColumns, labelNames)]]">
               <a href$="[[_sectionHref(changeSection.query)]]">
-                [[changeSection.sectionName]]
+                [[changeSection.name]]
               </a>
             </td>
           </tr>
diff --git a/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.js b/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.js
index de97e62..708a730 100644
--- a/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.js
+++ b/polygerrit-ui/app/elements/change-list/gr-change-list/gr-change-list.js
@@ -63,7 +63,7 @@
        * properties should not be used together.
        *
        * @type {!Array<{
-       *   sectionName: string,
+       *   name: string,
        *   query: string,
        *   results: !Array<!Object>
        * }>}
diff --git a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.js b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.js
index 775c046..3fc4089 100644
--- a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.js
+++ b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.js
@@ -207,7 +207,7 @@
               this._showNewUserHelp = lastResultSet.length == 0;
             }
             this._results = changes.map((results, i) => ({
-              sectionName: res.sections[i].name,
+              name: res.sections[i].name,
               query: res.sections[i].query,
               results,
               isOutgoing: res.sections[i].isOutgoing,
diff --git a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view_test.html b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view_test.html
index de74218..78fdee6 100644
--- a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view_test.html
+++ b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view_test.html
@@ -279,7 +279,7 @@
 
       return element._fetchDashboardChanges({sections}, false).then(() => {
         assert.equal(element._results.length, 1);
-        assert.equal(element._results[0].sectionName, 'test2');
+        assert.equal(element._results[0].name, 'test2');
       });
     });
 
diff --git a/polygerrit-ui/app/elements/change-list/gr-embed-dashboard/gr-embed-dashboard.html b/polygerrit-ui/app/elements/change-list/gr-embed-dashboard/gr-embed-dashboard.html
new file mode 100644
index 0000000..2394e24
--- /dev/null
+++ b/polygerrit-ui/app/elements/change-list/gr-embed-dashboard/gr-embed-dashboard.html
@@ -0,0 +1,41 @@
+<!--
+@license
+Copyright (C) 2018 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.
+-->
+
+<link rel="import" href="../../../bower_components/polymer/polymer.html">
+
+<link rel="import" href="../../change-list/gr-change-list/gr-change-list.html">
+<link rel="import" href="../gr-create-change-help/gr-create-change-help.html">
+
+<dom-module id="gr-embed-dashboard">
+  <template>
+    <gr-change-list
+        show-star
+        account="[[account]]"
+        preferences="[[preferences]]"
+        sections="[[sections]]">
+      <div id="emptyOutgoing" slot="empty-outgoing">
+        <template is="dom-if" if="[[showNewUserHelp]]">
+          <gr-create-change-help></gr-create-change-help>
+        </template>
+        <template is="dom-if" if="[[!showNewUserHelp]]">
+          No changes
+        </template>
+      </div>
+    </gr-change-list>
+  </template>
+  <script src="gr-embed-dashboard.js"></script>
+</dom-module>
diff --git a/polygerrit-ui/app/elements/change-list/gr-embed-dashboard/gr-embed-dashboard.js b/polygerrit-ui/app/elements/change-list/gr-embed-dashboard/gr-embed-dashboard.js
new file mode 100644
index 0000000..e31f9ad
--- /dev/null
+++ b/polygerrit-ui/app/elements/change-list/gr-embed-dashboard/gr-embed-dashboard.js
@@ -0,0 +1,29 @@
+/**
+ * @license
+ * Copyright (C) 2018 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.
+ */
+(function() {
+  'use strict';
+
+  Polymer({
+    is: 'gr-embed-dashboard',
+    properties: {
+      account: Object,
+      sections: Array,
+      preferences: Object,
+      showNewUserHelp: Boolean,
+    },
+  });
+})();
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html
index 3f5bd13..38f5f2f 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html
@@ -531,6 +531,7 @@
             patch-num="{{_patchRange.patchNum}}"
             base-patch-num="{{_patchRange.basePatchNum}}"
             files-expanded="[[_filesExpanded]]"
+            diff-prefs-disabled="[[_diffPrefsDisabled]]"
             on-open-diff-prefs="_handleOpenDiffPrefs"
             on-open-download-dialog="_handleOpenDownloadDialog"
             on-open-upload-help-dialog="_handleOpenUploadHelpDialog"
@@ -587,6 +588,7 @@
             change-comments="[[_changeComments]]"
             project-name="[[_change.project]]"
             show-reply-buttons="[[_loggedIn]]"
+            on-message-anchor-tap="_handleMessageAnchorTap"
             on-reply="_handleMessageReply"></gr-messages-list>
       </template>
       <template is="dom-if" if="[[!_showMessagesView]]">
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
index 42aae9c..24453be 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
@@ -44,6 +44,8 @@
 
   const TRAILING_WHITESPACE_REGEX = /[ \t]+$/gm;
 
+  const MSG_PREFIX = '#message-';
+
   const ReloadToastMessage = {
     NEWER_REVISION: 'A newer patch set has been uploaded',
     RESTORED: 'This change has been restored',
@@ -106,6 +108,14 @@
         type: Boolean,
         value: false,
       },
+      disableDiffPrefs: {
+        type: Boolean,
+        value: false,
+      },
+      _diffPrefsDisabled: {
+        type: Boolean,
+        computed: '_computeDiffPrefsDisabled(disableDiffPrefs, _loggedIn)',
+      },
       _commentThreads: Array,
       /** @type {?} */
       _serverConfig: {
@@ -720,10 +730,17 @@
       this.viewState.numFilesShown = numFilesShown;
     },
 
+    _handleMessageAnchorTap(e) {
+      const hash = MSG_PREFIX + e.detail.id;
+      const url = Gerrit.Nav.getUrlForChange(this._change,
+          this._patchRange.patchNum, this._patchRange.basePatchNum,
+          this._editMode, hash);
+      history.replaceState(null, '', url);
+    },
+
     _maybeScrollToMessage(hash) {
-      const msgPrefix = '#message-';
-      if (hash.startsWith(msgPrefix)) {
-        this.messagesList.scrollToMessage(hash.substr(msgPrefix.length));
+      if (hash.startsWith(MSG_PREFIX)) {
+        this.messagesList.scrollToMessage(hash.substr(MSG_PREFIX.length));
       }
     },
 
@@ -969,6 +986,8 @@
       if (this.shouldSuppressKeyboardShortcut(e) ||
           this.modifierPressed(e)) { return; }
 
+      if (this._diffPrefsDisabled) { return; }
+
       e.preventDefault();
       this.$.fileList.openDiffPrefs();
     },
@@ -1655,5 +1674,9 @@
     _computeCurrentRevision(currentRevision, revisions) {
       return revisions && revisions[currentRevision];
     },
+
+    _computeDiffPrefsDisabled(disableDiffPrefs, loggedIn) {
+      return disableDiffPrefs || !loggedIn;
+    },
   });
 })();
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
index ef0a376..df06e55 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
@@ -94,6 +94,20 @@
       return element.getComputedStyleValue(cssParam);
     };
 
+    test('_handleMessageAnchorTap', () => {
+      element._changeNum = '1';
+      element._patchRange = {
+        basePatchNum: 'PARENT',
+        patchNum: 1,
+      };
+      const getUrlStub = sandbox.stub(Gerrit.Nav, 'getUrlForChange');
+      const replaceStateStub = sandbox.stub(history, 'replaceState');
+      element._handleMessageAnchorTap({detail: {id: 'a12345'}});
+
+      assert.equal(getUrlStub.lastCall.args[4], '#message-a12345');
+      assert.isTrue(replaceStateStub.called);
+    });
+
     suite('keyboard shortcuts', () => {
       test('S should toggle the CL star', () => {
         const starStub = sandbox.stub(element.$.changeStar, 'toggleStar');
@@ -277,6 +291,16 @@
 
       test(', should open diff preferences', () => {
         const stub = sandbox.stub(element.$.fileList.$.diffPreferences, 'open');
+        element._loggedIn = false;
+        element.disableDiffPrefs = true;
+        MockInteractions.pressAndReleaseKeyOn(element, 188, null, ',');
+        assert.isFalse(stub.called);
+
+        element._loggedIn = true;
+        MockInteractions.pressAndReleaseKeyOn(element, 188, null, ',');
+        assert.isFalse(stub.called);
+
+        element.disableDiffPrefs = false;
         MockInteractions.pressAndReleaseKeyOn(element, 188, null, ',');
         assert.isTrue(stub.called);
       });
diff --git a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.html b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.html
index 142e706..924ddab 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.html
+++ b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.html
@@ -249,10 +249,10 @@
           <gr-diff-mode-selector
               id="modeSelect"
               mode="{{diffViewMode}}"
-              save-on-change="[[loggedIn]]"></gr-diff-mode-selector>
+              save-on-change="[[!diffPrefsDisabled]]"></gr-diff-mode-selector>
           <span id="diffPrefsContainer"
               class="hideOnEdit"
-              hidden$="[[_computePrefsButtonHidden(diffPrefs, loggedIn)]]"
+              hidden$="[[_computePrefsButtonHidden(diffPrefs, diffPrefsDisabled)]]"
               hidden>
             <gr-button
                 link
diff --git a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.js b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.js
index 665472b..b9e6288 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.js
+++ b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.js
@@ -62,6 +62,7 @@
       serverConfig: Object,
       shownFileCount: Number,
       diffPrefs: Object,
+      diffPrefsDisabled: Boolean,
       diffViewMode: {
         type: String,
         notify: true,
@@ -186,11 +187,10 @@
           });
     },
 
-    _computePrefsButtonHidden(prefs, loggedIn) {
-      return !loggedIn || !prefs;
+    _computePrefsButtonHidden(prefs, diffPrefsDisabled) {
+      return diffPrefsDisabled || !prefs;
     },
 
-
     _fileListActionsVisible(shownFileCount, maxFilesForBulkActions) {
       return shownFileCount <= maxFilesForBulkActions;
     },
diff --git a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.html b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.html
index e2685e1..adfeeb4 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.html
+++ b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.html
@@ -62,21 +62,21 @@
       });
     });
 
-    test('Diff preferences hidden when no prefs or logged out', () => {
-      element.loggedIn = false;
+    test('Diff preferences hidden when no prefs or diffPrefsDisabled', () => {
+      element.diffPrefsDisabled = true;
       flushAsynchronousOperations();
       assert.isTrue(element.$.diffPrefsContainer.hidden);
 
-      element.loggedIn = true;
+      element.diffPrefsDisabled = false;
       flushAsynchronousOperations();
       assert.isTrue(element.$.diffPrefsContainer.hidden);
 
-      element.loggedIn = false;
+      element.diffPrefsDisabled = true;
       element.diffPrefs = {font_size: '12'};
       flushAsynchronousOperations();
       assert.isTrue(element.$.diffPrefsContainer.hidden);
 
-      element.loggedIn = true;
+      element.diffPrefsDisabled = false;
       flushAsynchronousOperations();
       assert.isFalse(element.$.diffPrefsContainer.hidden);
     });
@@ -265,7 +265,7 @@
 
     suite('editMode behavior', () => {
       setup(() => {
-        element.loggedIn = true;
+        element.diffPrefsDisabled = false;
         element.diffPrefs = {};
       });
 
diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.html b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.html
index 358e994..fa9ec7f 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.html
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.html
@@ -400,7 +400,6 @@
                 path="[[file.__path]]"
                 prefs="[[diffPrefs]]"
                 project-name="[[change.project]]"
-                project-config="[[projectConfig]]"
                 on-line-selected="_onLineSelected"
                 no-render-on-prefs-change
                 view-mode="[[diffViewMode]]"></gr-diff-host>
diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.html b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.html
index df92b1e..51f0e5f 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.html
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.html
@@ -1358,7 +1358,7 @@
         id: '503008e2_0ab203ee',
         line: 10,
         updated: '2018-02-14 22:07:43.000000000',
-        message: 'response',
+        message: 'a comment',
         unresolved: true,
       },
       {
@@ -1367,7 +1367,7 @@
         line: 20,
         in_reply_to: 'ecf0b9fa_fe1a5f62',
         updated: '2018-02-13 22:07:43.000000000',
-        message: 'a comments',
+        message: 'response',
         unresolved: true,
       },
     ];
@@ -1704,11 +1704,43 @@
     });
 
     test('reloadCommentsForThreadWithRootId', () => {
+      // Expand the commit message diff
+      MockInteractions.keyUpOn(element, 73, 'shift', 'i');
+      const diffs = renderAndGetNewDiffs(0);
+      flushAsynchronousOperations();
+
+      // Two comment threads should be generated by renderAndGetNewDiffs
+      const threadEls = diffs[0].getThreadEls();
+      assert.equal(threadEls.length, 2);
+      const threadElsByRootId = new Map(
+          threadEls.map(threadEl => [threadEl.rootId, threadEl]));
+
+      const thread1 = threadElsByRootId.get('503008e2_0ab203ee');
+      assert.equal(thread1.comments.length, 1);
+      assert.equal(thread1.comments[0].message, 'a comment');
+      assert.equal(thread1.comments[0].line, 10);
+
+      const thread2 = threadElsByRootId.get('ecf0b9fa_fe1a5f62');
+      assert.equal(thread2.comments.length, 2);
+      assert.isTrue(thread2.comments[0].unresolved);
+      assert.equal(thread2.comments[0].message, 'another comment');
+      assert.equal(thread2.comments[0].line, 20);
+
       const commentStub =
           sandbox.stub(element.changeComments, 'getCommentsForThread');
       const commentStubRes1 = [
         {
           patch_set: 2,
+          id: '503008e2_0ab203ee',
+          line: 20,
+          updated: '2018-02-08 18:49:18.000000000',
+          message: 'edited text',
+          unresolved: false,
+        },
+      ];
+      const commentStubRes2 = [
+        {
+          patch_set: 2,
           id: 'ecf0b9fa_fe1a5f62',
           line: 20,
           updated: '2018-02-08 18:49:18.000000000',
@@ -1719,6 +1751,7 @@
           patch_set: 2,
           id: '503008e2_0ab203ee',
           line: 10,
+          in_reply_to: 'ecf0b9fa_fe1a5f62',
           updated: '2018-02-14 22:07:43.000000000',
           message: 'response',
           unresolved: true,
@@ -1727,57 +1760,35 @@
           patch_set: 2,
           id: '503008e2_0ab203ef',
           line: 20,
-          in_reply_to: 'ecf0b9fa_fe1a5f62',
+          in_reply_to: '503008e2_0ab203ee',
           updated: '2018-02-15 22:07:43.000000000',
           message: 'a third comment in the thread',
           unresolved: true,
         },
       ];
-      const commentStubRes2 = [
-        {
-          patch_set: 2,
-          id: 'ecf0b9fa_fe1a5f62',
-          line: 20,
-          updated: '2018-02-08 18:49:18.000000000',
-          message: 'edited text',
-          unresolved: false,
-        },
-      ];
-      commentStub.withArgs('cc788d2c_cb1d728c').returns(
+      commentStub.withArgs('503008e2_0ab203ee').returns(
           commentStubRes1);
       commentStub.withArgs('ecf0b9fa_fe1a5f62').returns(
           commentStubRes2);
-      // Expand the commit message diff
-      MockInteractions.keyUpOn(element, 73, 'shift', 'i');
-      const diffs = renderAndGetNewDiffs(0);
-      flushAsynchronousOperations();
-
-      // Two comment threads sould be generated
-      const commentThreadEls = diffs[0].getThreadEls();
-      assert(commentThreadEls[0].comments.length, 2);
-      assert(commentThreadEls[1].comments.length, 1);
-      assert.isTrue(commentThreadEls[1].comments[0].unresolved);
-      assert.equal(commentThreadEls[1].comments[0].message, 'another comment');
-
-      // Reload comments from the first comment thread, which should have a new
-      // reply.
-      element.reloadCommentsForThreadWithRootId('cc788d2c_cb1d728c',
-          '/COMMIT_MSG');
-      assert(commentThreadEls[0].comments.length, 3);
-
 
       // Reload comments from the first comment thread, which should have a
       // an updated message and a toggled resolve state.
+      element.reloadCommentsForThreadWithRootId('503008e2_0ab203ee',
+          '/COMMIT_MSG');
+      assert.equal(thread1.comments.length, 1);
+      assert.isFalse(thread1.comments[0].unresolved);
+      assert.equal(thread1.comments[0].message, 'edited text');
+
+      // Reload comments from the second comment thread, which should have a new
+      // reply.
       element.reloadCommentsForThreadWithRootId('ecf0b9fa_fe1a5f62',
           '/COMMIT_MSG');
-      assert(commentThreadEls[1].comments.length, 1);
-      assert.isFalse(commentThreadEls[1].comments[0].unresolved);
-      assert.equal(commentThreadEls[1].comments[0].message, 'edited text');
+      assert.equal(thread2.comments.length, 3);
 
       const commentStubCount = commentStub.callCount;
       const getThreadsSpy = sandbox.spy(diffs[0], 'getThreadEls');
 
-      // Should not be getting threadss when the file is not expanded.
+      // Should not be getting threads when the file is not expanded.
       element.reloadCommentsForThreadWithRootId('ecf0b9fa_fe1a5f62',
           'other/file');
       assert.isFalse(getThreadsSpy.called);
diff --git a/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row.js b/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row.js
index 0682ab2..f472331 100644
--- a/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row.js
+++ b/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row.js
@@ -69,7 +69,8 @@
     },
 
     _computeBlankItems(permittedLabels, label, side) {
-      if (!permittedLabels || !permittedLabels[label] || !this.labelValues ||
+      if (!permittedLabels || !permittedLabels[label] ||
+          !permittedLabels[label].length || !this.labelValues ||
           !Object.keys(this.labelValues).length) {
         return [];
       }
@@ -135,7 +136,8 @@
     },
 
     _computeAnyPermittedLabelValues(permittedLabels, label) {
-      return permittedLabels.hasOwnProperty(label);
+      return permittedLabels.hasOwnProperty(label) &&
+        permittedLabels[label].length;
     },
 
     _computeHiddenClass(permittedLabels, label) {
diff --git a/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row_test.html b/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row_test.html
index e5431f6..1e4d471 100644
--- a/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row_test.html
+++ b/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row_test.html
@@ -258,6 +258,11 @@
       flushAsynchronousOperations();
       assert.isOk(element.$$('iron-selector'));
       assert.isTrue(element.$$('iron-selector').hidden);
+
+      element.permittedLabels = {Verified: []};
+      flushAsynchronousOperations();
+      assert.isOk(element.$$('iron-selector'));
+      assert.isTrue(element.$$('iron-selector').hidden);
     });
 
     test('asymetrical labels', () => {
diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message.html b/polygerrit-ui/app/elements/change/gr-message/gr-message.html
index 19b0716b..32c4c1f 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message.html
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message.html
@@ -132,9 +132,12 @@
         right: var(--default-horizontal-margin);
         top: 10px;
       }
-      .date {
+      span.date {
         color: var(--deemphasized-text-color);
       }
+      span.date:hover {
+        text-decoration: underline;
+      }
       .dateContainer iron-icon {
         cursor: pointer;
       }
@@ -227,12 +230,12 @@
             </span>
           </template>
           <template is="dom-if" if="[[message.id]]">
-            <a class="date" href$="[[_computeMessageHash(message)]]" on-tap="_handleLinkTap">
+            <span class="date" on-tap="_handleAnchorTap">
               <gr-date-formatter
                   has-tooltip
                   show-date-and-time
                   date-str="[[message.date]]"></gr-date-formatter>
-            </a>
+            </span>
           </template>
           <iron-icon
               id="expandToggle"
diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message.js b/polygerrit-ui/app/elements/change/gr-message/gr-message.js
index 0590c73..8ecd6b0 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message.js
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message.js
@@ -24,17 +24,17 @@
     is: 'gr-message',
 
     /**
-     * Fired when this message's permalink is tapped.
-     *
-     * @event scroll-to
-     */
-
-    /**
      * Fired when this message's reply link is tapped.
      *
      * @event reply
      */
 
+    /**
+     * Fired when the message's timestamp is tapped.
+     *
+     * @event message-anchor-tap
+     */
+
     listeners: {
       tap: '_handleTap',
     },
@@ -223,22 +223,12 @@
       return classes.join(' ');
     },
 
-    _computeMessageHash(message) {
-      return '#message-' + message.id;
-    },
-
-    _handleLinkTap(e) {
+    _handleAnchorTap(e) {
       e.preventDefault();
-
-      this.fire('scroll-to', {message: this.message}, {bubbles: false});
-
-      const hash = this._computeMessageHash(this.message);
-      // Don't add the hash to the window history if it's already there.
-      // Otherwise you mess up expected back button behavior.
-      if (window.location.hash == hash) { return; }
-      // Change the URL but don’t trigger a nav event. Otherwise it will
-      // reload the page.
-      page.show(window.location.pathname + hash, null, false);
+      this.dispatchEvent(new CustomEvent('message-anchor-tap', {
+        bubbles: true,
+        detail: {id: this.message.id},
+      }));
     },
 
     _handleReplyTap(e) {
diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message_test.html b/polygerrit-ui/app/elements/change/gr-message/gr-message_test.html
index 870f366..64a5b26 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message_test.html
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message_test.html
@@ -164,6 +164,24 @@
       });
     });
 
+    test('clicking on date link fires event', () => {
+      element.message = {
+        type: 'REVIEWER_UPDATE',
+        updated: '2016-01-12 20:24:49.448000000',
+        reviewer: {},
+        id: '47c43261_55aa2c41',
+      };
+      flushAsynchronousOperations();
+      const stub = sinon.stub();
+      element.addEventListener('message-anchor-tap', stub);
+      const dateEl = element.$$('.date');
+      assert.ok(dateEl);
+      MockInteractions.tap(dateEl);
+
+      assert.isTrue(stub.called);
+      assert.deepEqual(stub.lastCall.args[0].detail, {id: element.message.id});
+    });
+
     test('votes', () => {
       element.message = {
         author: {},
diff --git a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.html b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.html
index 0a7dacc..80708a1 100644
--- a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.html
+++ b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.html
@@ -109,7 +109,7 @@
           hide-automated="[[_hideAutomated]]"
           project-name="[[projectName]]"
           show-reply-button="[[showReplyButtons]]"
-          on-scroll-to="_handleScrollTo"
+          on-message-anchor-tap="_handleAnchorTap"
           label-extremes="[[_labelExtremes]]"
           data-message-id$="[[message.id]]"></gr-message>
     </template>
diff --git a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.js b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.js
index 89a3523..023431c 100644
--- a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.js
+++ b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.js
@@ -184,8 +184,8 @@
       this.handleExpandCollapse(!this._expanded);
     },
 
-    _handleScrollTo(e) {
-      this.scrollToMessage(e.detail.message.id);
+    _handleAnchorTap(e) {
+      this.scrollToMessage(e.detail.id);
     },
 
     _hasAutomatedMessages(messages) {
diff --git a/polygerrit-ui/app/elements/core/gr-navigation/gr-navigation.html b/polygerrit-ui/app/elements/core/gr-navigation/gr-navigation.html
index bc31b60..7278c5a 100644
--- a/polygerrit-ui/app/elements/core/gr-navigation/gr-navigation.html
+++ b/polygerrit-ui/app/elements/core/gr-navigation/gr-navigation.html
@@ -33,6 +33,8 @@
     //        also be provided.
     //    - `edit`, optional, Boolean: whether or not to load the file list with
     //        edit controls.
+    //    - `messageHash`, optional, String: the hash of the change message to
+    //        scroll to.
     //
     // - Gerrit.Nav.View.SEARCH:
     //    - `query`, optional, String: the literal search query. If provided,
@@ -164,6 +166,7 @@
         CHANGE: 'change',
         DASHBOARD: 'dashboard',
         DIFF: 'diff',
+        DOCUMENTATION_SEARCH: 'documentation-search',
         EDIT: 'edit',
         GROUP: 'group',
         PLUGIN_SCREEN: 'plugin-screen',
@@ -352,9 +355,11 @@
        * @param {number|string=} opt_basePatchNum The string 'PARENT' can be
        *     used for none.
        * @param {boolean=} opt_isEdit
+       * @param {string=} opt_messageHash
        * @return {string}
        */
-      getUrlForChange(change, opt_patchNum, opt_basePatchNum, opt_isEdit) {
+      getUrlForChange(change, opt_patchNum, opt_basePatchNum, opt_isEdit,
+          opt_messageHash) {
         if (opt_basePatchNum === PARENT_PATCHNUM) {
           opt_basePatchNum = undefined;
         }
@@ -368,6 +373,7 @@
           basePatchNum: opt_basePatchNum,
           edit: opt_isEdit,
           host: change.internalHost || undefined,
+          messageHash: opt_messageHash,
         });
       },
 
diff --git a/polygerrit-ui/app/elements/core/gr-router/gr-router.js b/polygerrit-ui/app/elements/core/gr-router/gr-router.js
index bdd0942..0f2bbff 100644
--- a/polygerrit-ui/app/elements/core/gr-router/gr-router.js
+++ b/polygerrit-ui/app/elements/core/gr-router/gr-router.js
@@ -148,6 +148,10 @@
     IMPROPERLY_ENCODED_PLUS: /^\/c\/(.+)\/\ \/(.+)$/,
 
     PLUGIN_SCREEN: /^\/x\/([\w-]+)\/([\w-]+)\/?/,
+
+    DOCUMENTATION_SEARCH_FILTER: '/Documentation/q/filter::filter',
+    DOCUMENTATION_SEARCH: /^\/Documentation\/q\/(.*)$/,
+    DOCUMENTATION: /^\/Documentation(\/)?(.+)?/,
   };
 
   /**
@@ -395,6 +399,9 @@
       } else if (params.edit) {
         suffix += ',edit';
       }
+      if (params.messageHash) {
+        suffix += params.messageHash;
+      }
       if (params.project) {
         const encodedProject = this.encodeURL(params.project, true);
         return `/c/${encodedProject}/+/${params.changeNum}${suffix}`;
@@ -845,6 +852,17 @@
 
       this._mapRoute(RoutePattern.PLUGIN_SCREEN, '_handlePluginScreen');
 
+      this._mapRoute(RoutePattern.DOCUMENTATION_SEARCH_FILTER,
+          '_handleDocumentationSearchRoute');
+
+      // redirects /Documentation/q/* to /Documentation/q/filter:*
+      this._mapRoute(RoutePattern.DOCUMENTATION_SEARCH,
+          '_handleDocumentationSearchRedirectRoute');
+
+      // Makes sure /Documentation/* links work (doin't return 404)
+      this._mapRoute(RoutePattern.DOCUMENTATION,
+          '_handleDocumentationRedirectRoute');
+
       // Note: this route should appear last so it only catches URLs unmatched
       // by other patterns.
       this._mapRoute(RoutePattern.DEFAULT, '_handleDefaultRoute');
@@ -1422,6 +1440,27 @@
       this._setParams({view, plugin, screen});
     },
 
+    _handleDocumentationSearchRoute(data) {
+      this._setParams({
+        view: Gerrit.Nav.View.DOCUMENTATION_SEARCH,
+        filter: data.params.filter || null,
+      });
+    },
+
+    _handleDocumentationSearchRedirectRoute(data) {
+      this._redirect('/Documentation/q/filter:' +
+          encodeURIComponent(data.params[0]));
+    },
+
+    _handleDocumentationRedirectRoute(data) {
+      if (data.params[1]) {
+        location.reload();
+      } else {
+        // Redirect /Documentation to /Documentation/index.html
+        this._redirect('/Documentation/index.html');
+      }
+    },
+
     /**
      * Catchall route for when no other route is matched.
      */
diff --git a/polygerrit-ui/app/elements/core/gr-router/gr-router_test.html b/polygerrit-ui/app/elements/core/gr-router/gr-router_test.html
index 781e25b..b9eaa18 100644
--- a/polygerrit-ui/app/elements/core/gr-router/gr-router_test.html
+++ b/polygerrit-ui/app/elements/core/gr-router/gr-router_test.html
@@ -157,6 +157,9 @@
         '_handleDefaultRoute',
         '_handleChangeLegacyRoute',
         '_handleDiffLegacyRoute',
+        '_handleDocumentationRedirectRoute',
+        '_handleDocumentationSearchRoute',
+        '_handleDocumentationSearchRedirectRoute',
         '_handleLegacyLinenum',
         '_handleImproperlyEncodedPlusRoute',
         '_handlePassThroughRoute',
@@ -281,6 +284,9 @@
         paramsWithQuery.basePatchNum = 5;
         assert.equal(element._generateUrl(paramsWithQuery),
             '/c/test/+/1234/5..10?revert&foo=bar');
+
+        params.messageHash = '#123';
+        assert.equal(element._generateUrl(params), '/c/test/+/1234/5..10#123');
       });
 
       test('change with repo name encoding', () => {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-binary.js b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-binary.js
index b2fc64c..a9242be 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-binary.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-binary.js
@@ -14,14 +14,16 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-(function(window, GrDiffBuilderSideBySide) {
+(function(window, GrDiffBuilder) {
   'use strict';
 
   // Prevent redefinition.
   if (window.GrDiffBuilderBinary) { return; }
 
-  function GrDiffBuilderBinary(diff, comments, prefs, outputEl) {
-    GrDiffBuilder.call(this, diff, comments, null, prefs, outputEl);
+  function GrDiffBuilderBinary(diff, patchRange, commentThreadEls, prefs,
+      outputEl) {
+    GrDiffBuilder.call(this, diff, patchRange, commentThreadEls, prefs,
+        outputEl);
   }
 
   GrDiffBuilderBinary.prototype = Object.create(GrDiffBuilder.prototype);
@@ -43,4 +45,4 @@
   };
 
   window.GrDiffBuilderBinary = GrDiffBuilderBinary;
-})(window, GrDiffBuilderSideBySide);
+})(window, GrDiffBuilder);
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-image.js b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-image.js
index 88ff79b..c52a504 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-image.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-image.js
@@ -22,9 +22,9 @@
 
   const IMAGE_MIME_PATTERN = /^image\/(bmp|gif|jpeg|jpg|png|tiff|webp)$/;
 
-  function GrDiffBuilderImage(diff, comments, createThreadGroupFn, prefs,
+  function GrDiffBuilderImage(diff, patchRange, commentThreadEls, prefs,
       outputEl, baseImage, revisionImage) {
-    GrDiffBuilderSideBySide.call(this, diff, comments, createThreadGroupFn,
+    GrDiffBuilderSideBySide.call(this, diff, patchRange, commentThreadEls,
         prefs, outputEl, []);
     this._baseImage = baseImage;
     this._revisionImage = revisionImage;
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-side-by-side.js b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-side-by-side.js
index fafae63..da085c2 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-side-by-side.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-side-by-side.js
@@ -20,9 +20,9 @@
   // Prevent redefinition.
   if (window.GrDiffBuilderSideBySide) { return; }
 
-  function GrDiffBuilderSideBySide(diff, comments, createThreadGroupFn, prefs,
-      outputEl, layers) {
-    GrDiffBuilder.call(this, diff, comments, createThreadGroupFn, prefs,
+  function GrDiffBuilderSideBySide(diff, patchRange, commentThreadEls,
+      prefs, outputEl, layers) {
+    GrDiffBuilder.call(this, diff, patchRange, commentThreadEls, prefs,
         outputEl, layers);
   }
   GrDiffBuilderSideBySide.prototype = Object.create(GrDiffBuilder.prototype);
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified.js b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified.js
index 9a04b1f..0657ee4 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder-unified.js
@@ -20,9 +20,9 @@
   // Prevent redefinition.
   if (window.GrDiffBuilderUnified) { return; }
 
-  function GrDiffBuilderUnified(diff, comments, createThreadGroupFn, prefs,
+  function GrDiffBuilderUnified(diff, patchRange, commentThreadEls, prefs,
       outputEl, layers) {
-    GrDiffBuilder.call(this, diff, comments, createThreadGroupFn, prefs,
+    GrDiffBuilder.call(this, diff, patchRange, commentThreadEls, prefs,
         outputEl, layers);
   }
   GrDiffBuilderUnified.prototype = Object.create(GrDiffBuilder.prototype);
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.html b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.html
index cc66e3b..e26201a 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.html
@@ -16,9 +16,9 @@
 -->
 <link rel="import" href="../../../bower_components/polymer/polymer.html">
 <link rel="import" href="../../core/gr-reporting/gr-reporting.html">
-<link rel="import" href="../gr-diff-comment-thread/gr-diff-comment-thread.html">
-<link rel="import" href="../gr-diff-comment-thread-group/gr-diff-comment-thread-group.html">
+<link rel="import" href="../../shared/gr-js-api-interface/gr-js-api-interface.html">
 <link rel="import" href="../gr-diff-processor/gr-diff-processor.html">
+<link rel="import" href="../gr-diff-comment-thread/gr-diff-comment-thread.html">
 <link rel="import" href="../gr-ranged-comment-layer/gr-ranged-comment-layer.html">
 <link rel="import" href="../gr-syntax-layer/gr-syntax-layer.html">
 
@@ -113,18 +113,14 @@
           isImageDiff: Boolean,
           baseImage: Object,
           revisionImage: Object,
-          projectName: String,
           parentIndex: Number,
+          path: String,
+          projectName: String,
           /**
            * @type {Defs.LineOfInterest|null}
            */
           lineOfInterest: Object,
 
-          /**
-           * @type {function(number, booleam, !string)}
-           */
-          createCommentFn: Function,
-
           _builder: Object,
           _groups: Array,
           _layers: Array,
@@ -135,6 +131,10 @@
           return this.queryEffectiveChildren('#diffTable');
         },
 
+        get _commentThreadElements() {
+          return this.queryAllEffectiveChildren('.comment-thread');
+        },
+
         observers: [
           '_groupsChanged(_groups.splices)',
         ],
@@ -156,10 +156,6 @@
           }
 
           this._layers = layers;
-
-          this.async(() => {
-            this._preRenderThread();
-          });
         },
 
         render(comments, prefs) {
@@ -170,7 +166,8 @@
           // Stop the processor and syntax layer (if they're running).
           this.cancel();
 
-          this._builder = this._getDiffBuilder(this.diff, comments, prefs);
+          this._builder = this._getDiffBuilder(
+              this.diff, comments.meta.patchRange, prefs);
 
           this.$.processor.context = prefs.context;
           this.$.processor.keyLocations = this._getKeyLocations(comments,
@@ -294,7 +291,7 @@
           throw Error(`Invalid preference value: ${pref}`);
         },
 
-        _getDiffBuilder(diff, comments, prefs) {
+        _getDiffBuilder(diff, patchRange, prefs) {
           if (isNaN(prefs.tab_size) || prefs.tab_size <= 0) {
             this._handlePreferenceError('tab size');
             return;
@@ -306,20 +303,22 @@
           }
 
           let builder = null;
-          const createFn = this.createCommentFn;
           if (this.isImageDiff) {
-            builder = new GrDiffBuilderImage(diff, comments, createFn, prefs,
-              this.diffElement, this.baseImage, this.revisionImage);
+            builder = new GrDiffBuilderImage(diff, patchRange,
+              this._commentThreadElements, prefs, this.diffElement,
+              this.baseImage, this.revisionImage);
           } else if (diff.binary) {
             // If the diff is binary, but not an image.
-            return new GrDiffBuilderBinary(diff, comments, prefs,
-                this.diffElement);
+            return new GrDiffBuilderBinary(diff, patchRange,
+                this._commentThreadElements, prefs, this.diffElement);
           } else if (this.viewMode === DiffViewMode.SIDE_BY_SIDE) {
-            builder = new GrDiffBuilderSideBySide(diff, comments, createFn,
-                prefs, this.diffElement, this._layers);
+            builder = new GrDiffBuilderSideBySide(diff, patchRange,
+                this._commentThreadElements, prefs, this.diffElement,
+                this._layers);
           } else if (this.viewMode === DiffViewMode.UNIFIED) {
-            builder = new GrDiffBuilderUnified(diff, comments, createFn, prefs,
-                this.diffElement, this._layers);
+            builder = new GrDiffBuilderUnified(diff, patchRange,
+                this._commentThreadElements, prefs, this.diffElement,
+                this._layers);
           }
           if (!builder) {
             throw Error('Unsupported diff view mode: ' + this.viewMode);
@@ -446,25 +445,6 @@
         },
 
         /**
-         * In pages with large diffs, creating the first comment thread can be
-         * slow because nested Polymer elements (particularly
-         * iron-autogrow-textarea) add style elements to the document head,
-         * which, in turn, triggers a reflow on the page. Create a hidden
-         * thread, attach it to the page, and remove it so the stylesheet will
-         * already exist and the user's comment will be quick to load.
-         * @see https://gerrit-review.googlesource.com/c/82213/
-         */
-        _preRenderThread() {
-          const thread = document.createElement('gr-diff-comment-thread');
-          thread.setAttribute('hidden', true);
-          thread.addDraft();
-          const parent = Polymer.dom(this.root);
-          parent.appendChild(thread);
-          Polymer.dom.flush();
-          parent.removeChild(thread);
-        },
-
-        /**
          * @return {boolean} whether any of the lines in _groups are longer
          * than SYNTAX_MAX_LINE_LENGTH.
          */
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.js b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.js
index 4b85c22..6ea48ac 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.js
@@ -20,6 +20,60 @@
   // Prevent redefinition.
   if (window.GrDiffBuilder) { return; }
 
+  /** @enum {string} */
+  Gerrit.DiffSide = {
+    LEFT: 'left',
+    RIGHT: 'right',
+    BOTH: 'both',
+  };
+
+  /**
+   * @param {!Array<!HTMLElement>} threadEls
+   * @param {!{beforeNumber: (number|string|undefined),
+   *           afterNumber: (number|string|undefined)}}
+   *     lineInfo
+   * @param {!Gerrit.DiffSide=} side The side (LEFT, RIGHT, BOTH) for
+   *     which to return the threads (default: BOTH).
+   * @return {!Array<!HTMLElement>} The thread elements matching the given
+   *     location.
+   */
+  Gerrit.filterThreadElsForLocation = function(
+      threadEls, lineInfo, side = Gerrit.DiffSide.BOTH) {
+    function matchesLeftLine(threadEl) {
+      return threadEl.getAttribute('comment-side') ==
+          Gerrit.DiffSide.LEFT &&
+          threadEl.getAttribute('line-num') == lineInfo.beforeNumber;
+    }
+    function matchesRightLine(threadEl) {
+      return threadEl.getAttribute('comment-side') ==
+          Gerrit.DiffSide.RIGHT &&
+          threadEl.getAttribute('line-num') == lineInfo.afterNumber;
+    }
+    function matchesFileComment(threadEl) {
+      return (side === Gerrit.DiffSide.BOTH ||
+              threadEl.getAttribute('comment-side') == side) &&
+            // line/range comments have 1-based line set, if line is falsy it's
+            // a file comment
+            !threadEl.getAttribute('line-num');
+    }
+
+    // Select the appropriate matchers for the desired side and line
+    // If side is BOTH, we want both the left and right matcher.
+    const matchers = [];
+    if (side !== Gerrit.DiffSide.RIGHT) {
+      matchers.push(matchesLeftLine);
+    }
+    if (side !== Gerrit.DiffSide.LEFT) {
+      matchers.push(matchesRightLine);
+    }
+    if (lineInfo.afterNumber === 'FILE' ||
+        lineInfo.beforeNumber === 'FILE') {
+      matchers.push(matchesFileComment);
+    }
+    return threadEls.filter(threadEl =>
+        matchers.some(matcher => matcher(threadEl)));
+  };
+
   /**
    * In JS, unicode code points above 0xFFFF occupy two elements of a string.
    * For example '𐀏'.length is 2. An occurence of such a code point is called a
@@ -42,11 +96,10 @@
    */
   const REGEX_TAB_OR_SURROGATE_PAIR = /\t|[\uD800-\uDBFF][\uDC00-\uDFFF]/;
 
-  function GrDiffBuilder(diff, comments, createThreadGroupFn, prefs, outputEl,
-      layers) {
+  function GrDiffBuilder(diff, patchRange, commentThreadEls, prefs,
+      outputEl, layers) {
     this._diff = diff;
-    this._comments = comments;
-    this._createThreadGroupFn = createThreadGroupFn;
+    this._patchRange = patchRange;
     this._prefs = prefs;
     this._outputEl = outputEl;
     this.groups = [];
@@ -67,6 +120,8 @@
         layer.addListener(this._handleLayerUpdate.bind(this));
       }
     }
+
+    this._threadEls = commentThreadEls;
   }
 
   GrDiffBuilder.GroupType = {
@@ -319,148 +374,27 @@
     return button;
   };
 
-  GrDiffBuilder.prototype._getCommentsForLine = function(comments, line,
-      opt_side) {
-    function byLineNum(lineNum) {
-      return function(c) {
-        return (c.line === lineNum) ||
-               (c.line === undefined && lineNum === GrDiffLine.FILE);
-      };
-    }
-    const leftComments =
-        comments[GrDiffBuilder.Side.LEFT].filter(byLineNum(line.beforeNumber));
-    const rightComments =
-        comments[GrDiffBuilder.Side.RIGHT].filter(byLineNum(line.afterNumber));
-
-    leftComments.forEach(c => { c.__commentSide = 'left'; });
-    rightComments.forEach(c => { c.__commentSide = 'right'; });
-
-    let result;
-
-    switch (opt_side) {
-      case GrDiffBuilder.Side.LEFT:
-        result = leftComments;
-        break;
-      case GrDiffBuilder.Side.RIGHT:
-        result = rightComments;
-        break;
-      default:
-        result = leftComments.concat(rightComments);
-        break;
-    }
-
-    return result;
-  };
-
   /**
-   * @param {Array<Object>} comments
-   * @param {string} patchForNewThreads
-   */
-  GrDiffBuilder.prototype._getThreads = function(comments, patchForNewThreads) {
-    const sortedComments = comments.slice(0).sort((a, b) => {
-      if (b.__draft && !a.__draft ) { return 0; }
-      if (a.__draft && !b.__draft ) { return 1; }
-      return util.parseDate(a.updated) - util.parseDate(b.updated);
-    });
-
-    const threads = [];
-    for (const comment of sortedComments) {
-      // If the comment is in reply to another comment, find that comment's
-      // thread and append to it.
-      if (comment.in_reply_to) {
-        const thread = threads.find(thread =>
-            thread.comments.some(c => c.id === comment.in_reply_to));
-        if (thread) {
-          thread.comments.push(comment);
-          continue;
-        }
-      }
-
-      // Otherwise, this comment starts its own thread.
-      const newThread = {
-        start_datetime: comment.updated,
-        comments: [comment],
-        commentSide: comment.__commentSide,
-        /**
-         * Determines what the patchNum of a thread should be. Use patchNum from
-         * comment if it exists, otherwise the property of the thread group.
-         * This is needed for switching between side-by-side and unified views
-         * when there are unsaved drafts.
-         */
-        patchNum: comment.patch_set || patchForNewThreads,
-        rootId: comment.id || comment.__draftID,
-      };
-      if (comment.range) {
-        newThread.range = Object.assign({}, comment.range);
-      }
-      threads.push(newThread);
-    }
-    return threads;
-  };
-
-  /**
-   * Returns the patch number that new comment threads should be attached to.
-   *
-   * @param {GrDiffLine} line The line new thread will be attached to.
-   * @param {string=} opt_side Set to LEFT to force adding it to the LEFT side -
-   *     will be ignored if the left is a parent or a merge parent
-   * @return {number} Patch set to attach the new thread to
-   */
-  GrDiffBuilder.prototype._determinePatchNumForNewThreads = function(
-      patchRange, line, opt_side) {
-    if ((line.type === GrDiffLine.Type.REMOVE ||
-         opt_side === GrDiffBuilder.Side.LEFT) &&
-        patchRange.basePatchNum !== 'PARENT' &&
-        !Gerrit.PatchSetBehavior.isMergeParent(patchRange.basePatchNum)) {
-      return patchRange.basePatchNum;
-    } else {
-      return patchRange.patchNum;
-    }
-  };
-
-  /**
-   * Returns whether the comments on the given line are on a (merge) parent.
-   *
-   * @param {string} firstCommentSide
-   * @param {{basePatchNum: number, patchNum: number}} patchRange
-   * @param {GrDiffLine} line The line the comments are on.
-   * @param {string=} opt_side
-   * @return {boolean} True iff the comments on the given line are on a (merge)
-   *    parent.
-   */
-  GrDiffBuilder.prototype._determineIsOnParent = function(
-      firstCommentSide, patchRange, line, opt_side) {
-    return ((line.type === GrDiffLine.Type.REMOVE ||
-             opt_side === GrDiffBuilder.Side.LEFT) &&
-            (patchRange.basePatchNum === 'PARENT' ||
-             Gerrit.PatchSetBehavior.isMergeParent(
-                 patchRange.basePatchNum))) ||
-          firstCommentSide === 'PARENT';
-  };
-
-  /**
-   * @param {GrDiffLine} line
-   * @param {string=} opt_side
+   * @param {!GrDiffLine} line
+   * @param {!GrDiffBuilder.Side=} side The side (LEFT, RIGHT, BOTH) for which
+   *     to return the thread group (default: BOTH).
    * @return {!Object}
    */
   GrDiffBuilder.prototype._commentThreadGroupForLine = function(
-      line, opt_side) {
-    const comments =
-    this._getCommentsForLine(this._comments, line, opt_side);
-    if (!comments || comments.length === 0) {
+      line, commentSide = GrDiffBuilder.Side.BOTH) {
+    const threadElsForGroup =
+        Gerrit.filterThreadElsForLocation(this._threadEls, line, commentSide);
+    if (!threadElsForGroup || threadElsForGroup.length === 0) {
       return null;
     }
 
-    const patchNum = this._determinePatchNumForNewThreads(
-        this._comments.meta.patchRange, line, opt_side);
-    const isOnParent = this._determineIsOnParent(
-        comments[0].side, this._comments.meta.patchRange, line, opt_side);
-
-    const threadGroupEl = this._createThreadGroupFn(patchNum, isOnParent,
-        opt_side);
-    threadGroupEl.threads = this._getThreads(comments, patchNum);
-    if (opt_side) {
-      threadGroupEl.setAttribute('data-side', opt_side);
+    const threadGroupEl = document.createElement('div');
+    threadGroupEl.className = 'thread-group';
+    for (const threadEl of threadElsForGroup) {
+      Polymer.dom(threadGroupEl).appendChild(threadEl);
+    }
+    if (commentSide) {
+      threadGroupEl.setAttribute('data-side', commentSide);
     }
     return threadGroupEl;
   };
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder_test.html b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder_test.html
index 3238cbc..a855833 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder_test.html
@@ -57,9 +57,9 @@
 
 <script>
   suite('gr-diff-builder tests', () => {
+    let prefs;
     let element;
     let builder;
-    let createThreadGroupFn;
     let sandbox;
     const LINE_FEED_HTML = '<span class="style-scope gr-diff br"></span>';
 
@@ -70,178 +70,74 @@
         getLoggedIn() { return Promise.resolve(false); },
         getProjectConfig() { return Promise.resolve({}); },
       });
-      const prefs = {
+      prefs = {
         line_length: 10,
         show_tabs: true,
         tab_size: 4,
       };
-      createThreadGroupFn = sinon.spy(() => ({
-        setAttribute: sinon.spy(),
-      }));
       builder = new GrDiffBuilder(
-          {content: []}, {left: [], right: []}, createThreadGroupFn, prefs);
+          {content: []}, {left: [], right: []}, [], prefs);
     });
 
     teardown(() => { sandbox.restore(); });
 
-    test('_getThreads', () => {
-      const patchForNewThreads = 3;
-      const comments = [
-        {
-          id: 'sallys_confession',
-          message: 'i like you, jack',
-          updated: '2015-12-23 15:00:20.396000000',
-          __commentSide: 'left',
-        }, {
-          id: 'jacks_reply',
-          message: 'i like you, too',
-          updated: '2015-12-24 15:01:20.396000000',
-          __commentSide: 'left',
-          in_reply_to: 'sallys_confession',
-        },
-        {
-          id: 'new_draft',
-          message: 'i do not like either of you',
-          __commentSide: 'left',
-          __draft: true,
-          updated: '2015-12-20 15:01:20.396000000',
-        },
-      ];
+    test('filterThreadElsForLocation with no threads', () => {
+      const line = {beforeNumber: 3, afterNumber: 5};
 
-      let expectedThreadGroups = [
-        {
-          start_datetime: '2015-12-23 15:00:20.396000000',
-          commentSide: 'left',
-          comments: [{
-            id: 'sallys_confession',
-            message: 'i like you, jack',
-            updated: '2015-12-23 15:00:20.396000000',
-            __commentSide: 'left',
-          }, {
-            id: 'jacks_reply',
-            message: 'i like you, too',
-            updated: '2015-12-24 15:01:20.396000000',
-            __commentSide: 'left',
-            in_reply_to: 'sallys_confession',
-          }],
-          rootId: 'sallys_confession',
-          patchNum: 3,
-        },
-        {
-          start_datetime: '2015-12-20 15:01:20.396000000',
-          commentSide: 'left',
-          comments: [
-            {
-              id: 'new_draft',
-              message: 'i do not like either of you',
-              __commentSide: 'left',
-              __draft: true,
-              updated: '2015-12-20 15:01:20.396000000',
-            },
-          ],
-          rootId: 'new_draft',
-          patchNum: 3,
-        },
-      ];
-
-      assert.deepEqual(
-          builder._getThreads(comments, patchForNewThreads),
-          expectedThreadGroups);
-
-      // Patch num should get inherited from comment rather
-      comments.push({
-        id: 'betsys_confession',
-        message: 'i like you, jack',
-        updated: '2015-12-24 15:00:10.396000000',
-        range: {
-          start_line: 1,
-          start_character: 1,
-          end_line: 1,
-          end_character: 2,
-        },
-        __commentSide: 'left',
-      });
-
-      expectedThreadGroups = [
-        {
-          start_datetime: '2015-12-23 15:00:20.396000000',
-          commentSide: 'left',
-          comments: [{
-            id: 'sallys_confession',
-            message: 'i like you, jack',
-            updated: '2015-12-23 15:00:20.396000000',
-            __commentSide: 'left',
-          }, {
-            id: 'jacks_reply',
-            in_reply_to: 'sallys_confession',
-            message: 'i like you, too',
-            updated: '2015-12-24 15:01:20.396000000',
-            __commentSide: 'left',
-          }],
-          patchNum: 3,
-          rootId: 'sallys_confession',
-        },
-        {
-          start_datetime: '2015-12-24 15:00:10.396000000',
-          commentSide: 'left',
-          comments: [{
-            id: 'betsys_confession',
-            message: 'i like you, jack',
-            updated: '2015-12-24 15:00:10.396000000',
-            range: {
-              start_line: 1,
-              start_character: 1,
-              end_line: 1,
-              end_character: 2,
-            },
-            __commentSide: 'left',
-          }],
-          patchNum: 3,
-          rootId: 'betsys_confession',
-          range: {
-            start_line: 1,
-            start_character: 1,
-            end_line: 1,
-            end_character: 2,
-          },
-        },
-        {
-          start_datetime: '2015-12-20 15:01:20.396000000',
-          commentSide: 'left',
-          comments: [
-            {
-              id: 'new_draft',
-              message: 'i do not like either of you',
-              __commentSide: 'left',
-              __draft: true,
-              updated: '2015-12-20 15:01:20.396000000',
-            },
-          ],
-          rootId: 'new_draft',
-          patchNum: 3,
-        },
-      ];
-
-      assert.deepEqual(
-          builder._getThreads(comments, patchForNewThreads),
-          expectedThreadGroups);
+      const threads = [];
+      assert.deepEqual(Gerrit.filterThreadElsForLocation(threads, line), []);
+      assert.deepEqual(Gerrit.filterThreadElsForLocation(threads, line,
+          Gerrit.DiffSide.LEFT), []);
+      assert.deepEqual(Gerrit.filterThreadElsForLocation(threads, line,
+          Gerrit.DiffSide.RIGHT), []);
     });
 
-    test('multiple comments at same location but not threaded', () => {
-      const comments = [
-        {
-          id: 'sallys_confession',
-          message: 'i like you, jack',
-          updated: '2015-12-23 15:00:20.396000000',
-          __commentSide: 'left',
-        }, {
-          id: 'jacks_reply',
-          message: 'i like you, too',
-          updated: '2015-12-24 15:01:20.396000000',
-          __commentSide: 'left',
-        },
-      ];
-      assert.equal(builder._getThreads(comments, '3').length, 2);
+    test('filterThreadElsForLocation for line comments', () => {
+      const line = {beforeNumber: 3, afterNumber: 5};
+
+      const l3 = document.createElement('div');
+      l3.setAttribute('line-num', 3);
+      l3.setAttribute('comment-side', 'left');
+
+      const l5 = document.createElement('div');
+      l5.setAttribute('line-num', 5);
+      l5.setAttribute('comment-side', 'left');
+
+      const r3 = document.createElement('div');
+      r3.setAttribute('line-num', 3);
+      r3.setAttribute('comment-side', 'right');
+
+      const r5 = document.createElement('div');
+      r5.setAttribute('line-num', 5);
+      r5.setAttribute('comment-side', 'right');
+
+      const threadEls = [l3, l5, r3, r5];
+      assert.deepEqual(Gerrit.filterThreadElsForLocation(threadEls, line),
+          [l3, r5]);
+      assert.deepEqual(Gerrit.filterThreadElsForLocation(threadEls, line,
+          Gerrit.DiffSide.LEFT), [l3]);
+      assert.deepEqual(Gerrit.filterThreadElsForLocation(threadEls, line,
+          Gerrit.DiffSide.RIGHT), [r5]);
+    });
+
+    test('filterThreadElsForLocation for file comments', () => {
+      const line = {beforeNumber: 'FILE', afterNumber: 'FILE'};
+
+      const l = document.createElement('div');
+      l.setAttribute('comment-side', 'left');
+
+      const r = document.createElement('div');
+      r.setAttribute('comment-side', 'right');
+
+      const threadEls = [l, r];
+      assert.deepEqual(Gerrit.filterThreadElsForLocation(threadEls, line),
+          [l, r]);
+      assert.deepEqual(Gerrit.filterThreadElsForLocation(threadEls, line,
+          Gerrit.DiffSide.BOTH), [l, r]);
+      assert.deepEqual(Gerrit.filterThreadElsForLocation(threadEls, line,
+          Gerrit.DiffSide.LEFT), [l]);
+      assert.deepEqual(Gerrit.filterThreadElsForLocation(threadEls, line,
+          Gerrit.DiffSide.RIGHT), [r]);
     });
 
     test('_createElement classStr applies all classes', () => {
@@ -417,128 +313,76 @@
       }
     });
 
-    test('comments', () => {
-      const line = new GrDiffLine(GrDiffLine.Type.BOTH);
-      line.beforeNumber = 3;
-      line.afterNumber = 5;
-
-      let comments = {left: [], right: []};
-      assert.deepEqual(builder._getCommentsForLine(comments, line), []);
-      assert.deepEqual(builder._getCommentsForLine(comments, line,
-          GrDiffBuilder.Side.LEFT), []);
-      assert.deepEqual(builder._getCommentsForLine(comments, line,
-          GrDiffBuilder.Side.RIGHT), []);
-
-      comments = {
-        left: [
-          {id: 'l3', line: 3},
-          {id: 'l5', line: 5},
-        ],
-        right: [
-          {id: 'r3', line: 3},
-          {id: 'r5', line: 5},
-        ],
-      };
-      assert.deepEqual(builder._getCommentsForLine(comments, line),
-          [{id: 'l3', line: 3, __commentSide: 'left'},
-          {id: 'r5', line: 5, __commentSide: 'right'}]);
-      assert.deepEqual(builder._getCommentsForLine(comments, line,
-          GrDiffBuilder.Side.LEFT), [{id: 'l3', line: 3,
-            __commentSide: 'left'}]);
-      assert.deepEqual(builder._getCommentsForLine(comments, line,
-          GrDiffBuilder.Side.RIGHT), [{id: 'r5', line: 5,
-            __commentSide: 'right'}]);
-    });
-
     test('comment thread group creation', () => {
-      const l3 = {id: 'l3', line: 3, updated: '2016-08-09 00:42:32.000000000',
-        __commentSide: 'left'};
-      const l5 = {id: 'l5', line: 5, updated: '2016-08-09 00:42:32.000000000',
-        __commentSide: 'left'};
-      const r5 = {id: 'r5', line: 5, updated: '2016-08-09 00:42:32.000000000',
-        __commentSide: 'right'};
+      const l3 = document.createElement('div');
+      l3.className = 'comment-thread';
+      l3.setAttribute('comment-side', 'left');
+      l3.setAttribute('line-num', 3);
 
-      builder._comments = {
-        meta: {
-          changeNum: '42',
-          patchRange: {
-            basePatchNum: 'PARENT',
-            patchNum: '3',
-          },
-          path: '/path/to/foo',
-          projectConfig: {foo: 'bar'},
-        },
-        left: [l3, l5],
-        right: [r5],
-      };
+      const l5 = document.createElement('div');
+      l5.className = 'comment-thread';
+      l5.setAttribute('comment-side', 'left');
+      l5.setAttribute('line-num', 5);
 
-      function threadForComment(c, patchNum) {
-        return {
-          commentSide: c.__commentSide,
-          comments: [c],
-          patchNum,
-          rootId: c.id,
-          start_datetime: c.updated,
-        };
-      }
+      const r5 = document.createElement('div');
+      r5.className = 'comment-thread';
+      r5.setAttribute('comment-side', 'right');
+      r5.setAttribute('line-num', 5);
 
-      function checkThreadGroupProps(threadGroupEl, patchNum, isOnParent,
-          comments) {
-        assert.equal(createThreadGroupFn.lastCall.args[0], patchNum);
-        assert.equal(createThreadGroupFn.lastCall.args[1], isOnParent);
-        assert.deepEqual(
-            threadGroupEl.threads,
-            comments.map(c => threadForComment(c, patchNum)));
+      builder = new GrDiffBuilder(
+          {content: []}, {basePatchNum: 'PARENT', patchNum: '3'}, [l3, l5, r5],
+          prefs);
+
+      function checkThreadGroupProps(threadGroupEl,
+          expectedThreadEls) {
+        const threadEls = Polymer.dom(threadGroupEl).queryDistributedElements(
+            '.comment-thread');
+        assert.equal(threadEls.length, expectedThreadEls.length);
+        for (let i=0; i<expectedThreadEls.length; i++) {
+          assert.equal(threadEls[i], expectedThreadEls[i]);
+        }
       }
 
       let line = new GrDiffLine(GrDiffLine.Type.BOTH);
       line.beforeNumber = 5;
       line.afterNumber = 5;
       let threadGroupEl = builder._commentThreadGroupForLine(line);
-      assert.isTrue(createThreadGroupFn.calledOnce);
-      checkThreadGroupProps(threadGroupEl, '3', false, [l5, r5]);
+      checkThreadGroupProps(threadGroupEl, [l5, r5]);
 
       threadGroupEl =
           builder._commentThreadGroupForLine(line, GrDiffBuilder.Side.RIGHT);
-      assert.isTrue(createThreadGroupFn.calledTwice);
-      checkThreadGroupProps(threadGroupEl, '3', false, [r5]);
+      checkThreadGroupProps(threadGroupEl, [r5]);
 
       threadGroupEl =
           builder._commentThreadGroupForLine(line, GrDiffBuilder.Side.LEFT);
-      assert.isTrue(createThreadGroupFn.calledThrice);
-      checkThreadGroupProps(threadGroupEl, '3', true, [l5]);
+      checkThreadGroupProps(threadGroupEl, [l5]);
 
-      builder._comments.meta.patchRange.basePatchNum = '1';
+      builder._patchRange.basePatchNum = '1';
 
       threadGroupEl = builder._commentThreadGroupForLine(line);
-      assert.equal(createThreadGroupFn.callCount, 4);
-      checkThreadGroupProps(threadGroupEl, '3', false, [l5, r5]);
+      checkThreadGroupProps(threadGroupEl, [l5, r5]);
 
       threadEl =
           builder._commentThreadGroupForLine(line, GrDiffBuilder.Side.LEFT);
-      assert.equal(createThreadGroupFn.callCount, 5);
-      checkThreadGroupProps(threadEl, '1', false, [l5]);
+      checkThreadGroupProps(threadEl, [l5]);
 
       threadGroupEl =
           builder._commentThreadGroupForLine(line, GrDiffBuilder.Side.RIGHT);
-      assert.equal(createThreadGroupFn.callCount, 6);
-      checkThreadGroupProps(threadGroupEl, '3', false, [r5]);
+      checkThreadGroupProps(threadGroupEl, [r5]);
 
-      builder._comments.meta.patchRange.basePatchNum = 'PARENT';
+      builder._patchRange.basePatchNum = 'PARENT';
 
       line = new GrDiffLine(GrDiffLine.Type.REMOVE);
       line.beforeNumber = 5;
       line.afterNumber = 5;
       threadGroupEl = builder._commentThreadGroupForLine(line);
-      assert.equal(createThreadGroupFn.callCount, 7);
-      checkThreadGroupProps(threadGroupEl, '3', true, [l5, r5]);
+      checkThreadGroupProps(threadGroupEl, [l5, r5]);
 
       line = new GrDiffLine(GrDiffLine.Type.ADD);
       line.beforeNumber = 3;
       line.afterNumber = 5;
       threadGroupEl = builder._commentThreadGroupForLine(line);
-      assert.equal(createThreadGroupFn.callCount, 8);
-      checkThreadGroupProps(threadGroupEl, '3', false, [l3, r5]);
+      checkThreadGroupProps(threadGroupEl, [l3, r5]);
     });
 
 
@@ -572,16 +416,18 @@
       });
 
       const lineOfInterest = {number: 789, leftSide: true};
-      assert.deepEqual(element._getKeyLocations(comments, lineOfInterest), {
-        left: {FILE: true, 123: true, 789: true},
-        right: {456: true},
-      });
+      assert.deepEqual(
+          element._getKeyLocations(comments, lineOfInterest), {
+            left: {FILE: true, 123: true, 789: true},
+            right: {456: true},
+          });
 
       delete lineOfInterest.leftSide;
-      assert.deepEqual(element._getKeyLocations(comments, lineOfInterest), {
-        left: {FILE: true, 123: true},
-        right: {456: true, 789: true},
-      });
+      assert.deepEqual(
+          element._getKeyLocations(comments, lineOfInterest), {
+            left: {FILE: true, 123: true},
+            right: {456: true, 789: true},
+          });
     });
 
     suite('_isTotal', () => {
@@ -1023,7 +869,7 @@
         processStub = sandbox.stub(element.$.processor, 'process')
             .returns(Promise.resolve());
         sandbox.stub(element, '_anyLineTooLong').returns(true);
-        comments = {left: [], right: []};
+        comments = {left: [], right: [], meta: {patchRange: undefined}};
         prefs = {
           line_length: 10,
           show_tabs: true,
@@ -1071,6 +917,7 @@
     suite('rendering', () => {
       let content;
       let outputEl;
+      let comments;
 
       setup(done => {
         const prefs = {
@@ -1098,9 +945,10 @@
         });
         element = fixture('basic');
         outputEl = element.queryEffectiveChildren('#diffTable');
+        comments = {left: [], right: [], meta: {patchRange: undefined}};
         sandbox.stub(element, '_getDiffBuilder', () => {
           const builder = new GrDiffBuilder(
-              {content}, {left: [], right: []}, null, prefs, outputEl);
+              {content}, undefined, [], prefs, outputEl);
           sandbox.stub(builder, 'addColumns');
           builder.buildSectionElement = function(group) {
             const section = document.createElement('stub');
@@ -1112,7 +960,7 @@
           return builder;
         });
         element.diff = {content};
-        element.render({left: [], right: []}, prefs).then(done);
+        element.render(comments, prefs).then(done);
       });
 
       test('reporting', done => {
@@ -1137,7 +985,7 @@
       });
 
       test('addColumns is called', done => {
-        element.render({left: [], right: []}, {}).then(done);
+        element.render(comments, {}).then(done);
         assert.isTrue(element._builder.addColumns.called);
       });
 
@@ -1161,7 +1009,7 @@
 
       test('render-start and render are fired', done => {
         const dispatchEventStub = sandbox.stub(element, 'dispatchEvent');
-        element.render({left: [], right: []}, {}).then(() => {
+        element.render(comments, {}).then(() => {
           const firedEventTypes = dispatchEventStub.getCalls()
               .map(c => { return c.args[0].type; });
           assert.include(firedEventTypes, 'render-start');
@@ -1189,7 +1037,7 @@
           context: -1,
           syntax_highlighting: true,
         };
-        element.render({left: [], right: []}, prefs);
+        element.render(comments, prefs);
       });
 
       test('cancel', () => {
@@ -1206,6 +1054,7 @@
       let builder;
       let diff;
       let prefs;
+      let comments;
 
       setup(done => {
         element = fixture('mock-diff');
@@ -1217,8 +1066,9 @@
           show_tabs: true,
           tab_size: 4,
         };
+        comments = {left: [], right: [], meta: {patchRange: undefined}};
 
-        element.render({left: [], right: []}, prefs).then(() => {
+        element.render(comments, prefs).then(() => {
           builder = element._builder;
           done();
         });
@@ -1328,7 +1178,7 @@
       test('_getNextContentOnSide unified left', done => {
         // Re-render as unified:
         element.viewMode = 'UNIFIED_DIFF';
-        element.render({left: [], right: []}, prefs).then(() => {
+        element.render(comments, prefs).then(() => {
           builder = element._builder;
 
           const startElem = builder.getContentByLine(5, 'left',
@@ -1348,7 +1198,7 @@
       test('_getNextContentOnSide unified right', done => {
         // Re-render as unified:
         element.viewMode = 'UNIFIED_DIFF';
-        element.render({left: [], right: []}, prefs).then(() => {
+        element.render(comments, prefs).then(() => {
           builder = element._builder;
 
           const startElem = builder.getContentByLine(5, 'right',
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-comment-thread-group/gr-diff-comment-thread-group.html b/polygerrit-ui/app/elements/diff/gr-diff-comment-thread-group/gr-diff-comment-thread-group.html
deleted file mode 100644
index 58b7c32..0000000
--- a/polygerrit-ui/app/elements/diff/gr-diff-comment-thread-group/gr-diff-comment-thread-group.html
+++ /dev/null
@@ -1,50 +0,0 @@
-<!--
-@license
-Copyright (C) 2017 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.
--->
-
-<link rel="import" href="../../../bower_components/polymer/polymer.html">
-<link rel="import" href="../gr-diff-comment-thread/gr-diff-comment-thread.html">
-<link rel="import" href="../../../styles/shared-styles.html">
-
-<dom-module id="gr-diff-comment-thread-group">
-  <template>
-    <style include="shared-styles">
-      :host {
-        display: block;
-        max-width: var(--content-width, 80ch);
-        white-space: normal;
-      }
-      gr-diff-comment-thread + gr-diff-comment-thread {
-        margin-top: .2em;
-      }
-    </style>
-    <template is="dom-repeat" items="[[threads]]" as="thread">
-      <gr-diff-comment-thread
-          comments="[[thread.comments]]"
-          comment-side="[[thread.commentSide]]"
-          is-on-parent="[[isOnParent]]"
-          parent-index="[[parentIndex]]"
-          change-num="[[changeNum]]"
-          patch-num="[[thread.patchNum]]"
-          root-id="{{thread.rootId}}"
-          path="[[path]]"
-          project-name="[[projectName]]"
-          range="[[thread.range]]"
-          on-thread-discard="_handleThreadDiscard"></gr-diff-comment-thread>
-    </template>
-  </template>
-  <script src="gr-diff-comment-thread-group.js"></script>
-</dom-module>
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-comment-thread-group/gr-diff-comment-thread-group.js b/polygerrit-ui/app/elements/diff/gr-diff-comment-thread-group/gr-diff-comment-thread-group.js
deleted file mode 100644
index ae45c93..0000000
--- a/polygerrit-ui/app/elements/diff/gr-diff-comment-thread-group/gr-diff-comment-thread-group.js
+++ /dev/null
@@ -1,133 +0,0 @@
-/**
- * @license
- * Copyright (C) 2017 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.
- */
-(function() {
-  'use strict';
-
-  Polymer({
-    is: 'gr-diff-comment-thread-group',
-
-    properties: {
-      changeNum: String,
-      projectName: String,
-      patchForNewThreads: String,
-      range: Object,
-      isOnParent: {
-        type: Boolean,
-        value: false,
-      },
-      parentIndex: {
-        type: Number,
-        value: null,
-      },
-      threads: {
-        type: Array,
-        value() { return []; },
-      },
-    },
-
-    get threadEls() {
-      return Polymer.dom(this.root).querySelectorAll('gr-diff-comment-thread');
-    },
-
-    /**
-     * Adds a new thread. Range is optional because a comment can be
-     * added to a line without a range selected.
-     *
-     * @param {!Object} opt_range
-     */
-    addNewThread(commentSide, opt_range) {
-      this.push('threads', {
-        comments: [],
-        commentSide,
-        patchNum: this.patchForNewThreads,
-        range: opt_range,
-      });
-    },
-
-    removeThread(rootId) {
-      for (let i = 0; i < this.threads.length; i++) {
-        if (this.threads[i].rootId === rootId) {
-          this.splice('threads', i, 1);
-          return;
-        }
-      }
-    },
-
-    /**
-     * Fetch the thread group at the given range, or the range-less thread
-     * on the line if no range is provided, lineNum, and side.
-     *
-     * @param {string} side
-     * @param {!Object=} opt_range
-     * @return {!Object|undefined}
-     */
-    getThread(side, opt_range) {
-      const threads = [].filter.call(this.threadEls,
-          thread => this._rangesEqual(thread.range, opt_range))
-          .filter(thread => thread.commentSide === side);
-      if (threads.length === 1) {
-        return threads[0];
-      }
-    },
-
-    _handleThreadDiscard(e) {
-      this.removeThread(e.detail.rootId);
-    },
-
-    /**
-     * Compare two ranges. Either argument may be falsy, but will only return
-     * true if both are falsy or if neither are falsy and have the same position
-     * values.
-     *
-     * @param {Object=} a range 1
-     * @param {Object=} b range 2
-     * @return {boolean}
-     */
-    _rangesEqual(a, b) {
-      if (!a && !b) { return true; }
-      if (!a || !b) { return false; }
-      return a.startLine === b.startLine &&
-          a.startChar === b.startChar &&
-          a.endLine === b.endLine &&
-          a.endChar === b.endChar;
-    },
-
-    _sortByDate(threadGroups) {
-      if (!threadGroups.length) { return; }
-      return threadGroups.sort((a, b) => {
-        // If a comment is a draft, it doesn't have a start_datetime yet.
-        // Assume it is newer than the comment it is being compared to.
-        if (!a.start_datetime) {
-          return 1;
-        }
-        if (!b.start_datetime) {
-          return -1;
-        }
-        return util.parseDate(a.start_datetime) -
-            util.parseDate(b.start_datetime);
-      });
-    },
-
-    _calculateLocationRange(range, comment) {
-      return 'range-' + range.start_line + '-' +
-          range.start_character + '-' +
-          range.end_line + '-' +
-          range.end_character + '-' +
-          comment.__commentSide;
-    },
-  });
-})();
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-comment-thread-group/gr-diff-comment-thread-group_test.html b/polygerrit-ui/app/elements/diff/gr-diff-comment-thread-group/gr-diff-comment-thread-group_test.html
deleted file mode 100644
index 1fb8136..0000000
--- a/polygerrit-ui/app/elements/diff/gr-diff-comment-thread-group/gr-diff-comment-thread-group_test.html
+++ /dev/null
@@ -1,232 +0,0 @@
-<!DOCTYPE html>
-<!--
-@license
-Copyright (C) 2017 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.
--->
-
-<meta name="viewport" content="width=device-width, minimum-scale=1.0, initial-scale=1.0, user-scalable=yes">
-<title>gr-diff-comment-thread-group</title>
-
-<script src="../../../bower_components/webcomponentsjs/webcomponents-lite.min.js"></script>
-<script src="../../../bower_components/web-component-tester/browser.js"></script>
-<link rel="import" href="../../../test/common-test-setup.html"/>
-<script src="../../../scripts/util.js"></script>
-
-<link rel="import" href="gr-diff-comment-thread-group.html">
-
-<script>void(0);</script>
-
-<test-fixture id="basic">
-  <template>
-    <gr-diff-comment-thread-group></gr-diff-comment-thread-group>
-  </template>
-</test-fixture>
-
-<script>
-  suite('gr-diff-comment-thread-group tests', () => {
-    let element;
-    let sandbox;
-
-    setup(() => {
-      sandbox = sinon.sandbox.create();
-      stub('gr-rest-api-interface', {
-        getLoggedIn() { return Promise.resolve(false); },
-      });
-      element = fixture('basic');
-    });
-
-    teardown(() => {
-      sandbox.restore();
-    });
-
-    test('getThread', () => {
-      const range = {
-        start_line: 1,
-        start_character: 1,
-        end_line: 1,
-        end_character: 2,
-      };
-      element.threads = [
-        {
-          rootId: 'sallys_confession',
-          commentSide: 'left',
-          comments: [
-            {
-              id: 'sallys_confession',
-              message: 'i like you, jack',
-              updated: '2015-12-23 15:00:20.396000000',
-              __commentSide: 'left',
-            }, {
-              id: 'jacks_reply',
-              message: 'i like you, too',
-              updated: '2015-12-24 15:01:20.396000000',
-              __commentSide: 'left',
-              in_reply_to: 'sallys_confession',
-            }, {
-              id: 'new_draft',
-              message: 'i do not like either of you',
-              __commentSide: 'left',
-              __draft: true,
-              in_reply_to: 'sallys_confession',
-              updated: '2015-12-20 15:01:20.396000000',
-            },
-          ],
-        },
-        {
-          rootId: 'right_side_comment',
-          commentSide: 'right',
-          comments: [
-            {
-              id: 'right_side_comment',
-              message: 'right side comment',
-              __commentSide: 'right',
-              __draft: true,
-              updated: '2015-12-20 15:01:20.396000000',
-            },
-          ],
-        }, {
-          rootId: 'betsys_confession',
-          commentSide: 'left',
-          range,
-          comments: [
-            {
-              id: 'betsys_confession',
-              message: 'i like you more, jack',
-              updated: '2015-12-24 15:00:10.396000000',
-              range,
-              __commentSide: 'left',
-            },
-          ],
-        },
-      ];
-
-      flushAsynchronousOperations();
-      assert.deepEqual(element.getThread('right').rootId, 'right_side_comment');
-      assert.deepEqual(element.getThread('right').comments.length, 1);
-      assert.deepEqual(element.getThread('left').rootId, 'sallys_confession');
-      assert.deepEqual(element.getThread('left').comments.length, 3);
-      assert.deepEqual(element.getThread('left', range).rootId,
-          'betsys_confession');
-      assert.deepEqual(element.getThread('left', range).comments.length, 1);
-    });
-
-    test('_sortByDate', () => {
-      let threadGroups = [
-        {
-          start_datetime: '2015-12-23 15:00:20.396000000',
-          comments: [],
-          locationRange: 'line',
-        },
-        {
-          start_datetime: '2015-12-22 15:00:10.396000000',
-          comments: [],
-          locationRange: 'range-1-1-1-2',
-        },
-      ];
-
-      let expectedResult = [
-        {
-          start_datetime: '2015-12-22 15:00:10.396000000',
-          comments: [],
-          locationRange: 'range-1-1-1-2',
-        }, {
-          start_datetime: '2015-12-23 15:00:20.396000000',
-          comments: [],
-          locationRange: 'line',
-        },
-      ];
-
-      assert.deepEqual(element._sortByDate(threadGroups), expectedResult);
-
-      // When a comment doesn't have a date, the one without the date should be
-      // last.
-      threadGroups = [
-        {
-          start_datetime: '2015-12-23 15:00:20.396000000',
-          comments: [],
-          locationRange: 'line',
-        },
-        {
-          comments: [],
-          locationRange: 'range-1-1-1-2',
-        },
-      ];
-
-      expectedResult = [
-        {
-          start_datetime: '2015-12-23 15:00:20.396000000',
-          comments: [],
-          locationRange: 'line',
-        },
-        {
-          comments: [],
-          locationRange: 'range-1-1-1-2',
-        },
-      ];
-
-      assert.deepEqual(element._sortByDate(threadGroups), expectedResult);
-    });
-
-    test('_calculateLocationRange', () => {
-      const comment = {__commentSide: 'left'};
-      const range = {
-        start_line: 1,
-        start_character: 2,
-        end_line: 3,
-        end_character: 4,
-      };
-      assert.equal(
-          element._calculateLocationRange(range, comment),
-          'range-1-2-3-4-left');
-    });
-
-    test('addNewThread', () => {
-      const locationRange = 'range-1-2-3-4';
-      element._threads = [{locationRange: 'line'}];
-      element.addNewThread(locationRange);
-      assert(element._threads.length, 2);
-    });
-
-    test('removeThread', () => {
-      const locationRange = 'range-1-2-3-4';
-      element._threads = [
-        {locationRange: 'range-1-2-3-4', comments: []},
-        {locationRange: 'line', comments: []},
-      ];
-      flushAsynchronousOperations();
-      element.removeThread(locationRange);
-      flushAsynchronousOperations();
-      assert(element._threads.length, 1);
-    });
-
-    test('_rangesEqual', () => {
-      const range1 =
-          {startLine: 123, startChar: 345, endLine: 234, endChar: 456};
-      const range2 =
-          {startLine: 1, startChar: 2, endLine: 3, endChar: 4};
-
-      assert.isTrue(element._rangesEqual(null, null));
-      assert.isTrue(element._rangesEqual(null, undefined));
-      assert.isTrue(element._rangesEqual(undefined, null));
-      assert.isTrue(element._rangesEqual(undefined, undefined));
-
-      assert.isFalse(element._rangesEqual(range1, null));
-      assert.isFalse(element._rangesEqual(null, range1));
-      assert.isFalse(element._rangesEqual(range1, range2));
-
-      assert.isTrue(element._rangesEqual(range1, Object.assign({}, range1)));
-    });
-  });
-</script>
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-comment-thread/gr-diff-comment-thread.js b/polygerrit-ui/app/elements/diff/gr-diff-comment-thread/gr-diff-comment-thread.js
index d5e6855..f3e3249 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-comment-thread/gr-diff-comment-thread.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-comment-thread/gr-diff-comment-thread.js
@@ -35,18 +35,47 @@
      * @event thread-changed
      */
 
+     /**
+      * gr-diff-comment-thread exposes the following attributes that allow a
+      * diff widget like gr-diff to show the thread in the right location:
+      *
+      * line-num:
+      *     1-based line number or undefined if it refers to the entire file.
+      *
+      * comment-side:
+      *     "left" or "right". These indicate which of the two diffed versions
+      *     the comment relates to. In the case of unified diff, the left
+      *     version is the one whose line number column is further to the left.
+      *
+      * range:
+      *     The range of text that the comment refers to (startLine, startChar,
+      *     endLine, endChar), serialized as JSON. If set, range's startLine
+      *     will have the same value as line-num. Line numbers are 1-based,
+      *     char numbers are 0-based. The start position (startLine, startChar)
+      *     is inclusive, and the end position (endLine, endChar) is exclusive.
+      */
     properties: {
       changeNum: String,
       comments: {
         type: Array,
         value() { return []; },
       },
-      range: Object,
+      /**
+       * @type {?{startLine: number, startChar: number, endLine: number,
+       *          endChar: number}}
+       */
+      range: {
+        type: Object,
+        reflectToAttribute: true,
+      },
       keyEventTarget: {
         type: Object,
         value() { return document.body; },
       },
-      commentSide: String,
+      commentSide: {
+        type: String,
+        reflectToAttribute: true,
+      },
       patchNum: String,
       path: String,
       projectName: {
@@ -79,8 +108,11 @@
         type: Boolean,
         value: false,
       },
-      /** Necessary only if showFilePath is true */
-      lineNum: Number,
+      /** Necessary only if showFilePath is true or when used with gr-diff */
+      lineNum: {
+        type: Number,
+        reflectToAttribute: true,
+      },
       unresolved: {
         type: Boolean,
         notify: true,
@@ -231,7 +263,7 @@
         // Ensure drafts are at the end. There should only be one but in edge
         // cases could be more. In the unlikely event two drafts are being
         // compared, use the typical date compare.
-        if (c2.__draft && !c1.__draft ) { return 0; }
+        if (c2.__draft && !c1.__draft ) { return -1; }
         if (c1.__draft && !c2.__draft ) { return 1; }
         if (dateCompare === 0 && (!c1.id || !c1.id.localeCompare)) { return 0; }
         // If same date, fall back to sorting by id.
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-comment-thread/gr-diff-comment-thread_test.html b/polygerrit-ui/app/elements/diff/gr-diff-comment-thread/gr-diff-comment-thread_test.html
index b525a60..58648bf 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-comment-thread/gr-diff-comment-thread_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-comment-thread/gr-diff-comment-thread_test.html
@@ -714,5 +714,28 @@
       assert.equal(element._orderedComments[1].id, '2');
       assert.equal(element._orderedComments[2].id, '3');
     });
+
+    test('reflects lineNum and commentSide to attributes', () => {
+      element.lineNum = 7;
+      element.commentSide = 'left';
+
+      assert.equal(element.getAttribute('line-num'), '7');
+      assert.equal(element.getAttribute('comment-side'), 'left');
+    });
+
+    test('reflects range to JSON serialized attribute if set', () => {
+      element.range = {startLine: 4, endLine: 5, startChar: 6, endChar: 7};
+
+      assert.deepEqual(
+          JSON.parse(element.getAttribute('range')),
+          {startLine: 4, endLine: 5, startChar: 6, endChar: 7});
+    });
+
+    test('removes range attribute if range is unset', () => {
+      element.range = {startLine: 4, endLine: 5, startChar: 6, endChar: 7};
+      element.range = undefined;
+
+      assert.notOk(element.hasAttribute('range'));
+    });
   });
 </script>
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.html b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.html
index 6ea0330..72c7285 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.html
@@ -91,10 +91,12 @@
         text-align: right;
         white-space: nowrap;
       }
-      a.date:link,
-      a.date:visited {
+      span.date {
         color: var(--deemphasized-text-color);
       }
+      span.date:hover {
+        text-decoration: underline;
+      }
       .actions {
         display: flex;
         justify-content: flex-end;
@@ -255,11 +257,11 @@
             on-tap="_handleCommentDelete">
           (Delete)
         </gr-button>
-        <a class="date" href$="[[_computeLinkToComment(comment)]]" on-tap="_handleLinkTap">
+        <span class="date" on-tap="_handleAnchorTap">
           <gr-date-formatter
               has-tooltip
               date-str="[[comment.updated]]"></gr-date-formatter>
-        </a>
+        </span>
         <div class="show-hide">
           <label class="show-hide">
             <input type="checkbox" class="show-hide"
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.js b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.js
index 90d465f..5165db0 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment.js
@@ -29,6 +29,8 @@
   const REPORT_UPDATE_DRAFT = 'UpdateDraftComment';
   const REPORT_DISCARD_DRAFT = 'DiscardDraftComment';
 
+  const FILE = 'FILE';
+
   Polymer({
     is: 'gr-diff-comment',
 
@@ -64,6 +66,12 @@
      * @event comment-mouse-out
      */
 
+    /**
+     * Fired when the comment's timestamp is tapped.
+     *
+     * @event comment-anchor-tap
+     */
+
     properties: {
       changeNum: String,
       /** @type {?} */
@@ -333,10 +341,6 @@
       }
     },
 
-    _computeLinkToComment(comment) {
-      return '#' + comment.line;
-    },
-
     _computeDeleteButtonClass(isAdmin, draft) {
       return isAdmin && !draft ? 'showDeleteButtons' : '';
     },
@@ -401,15 +405,16 @@
       }, STORAGE_DEBOUNCE_INTERVAL);
     },
 
-    _handleLinkTap(e) {
+    _handleAnchorTap(e) {
       e.preventDefault();
-      const hash = this._computeLinkToComment(this.comment);
-      // Don't add the hash to the window history if it's already there.
-      // Otherwise you mess up expected back button behavior.
-      if (window.location.hash == hash) { return; }
-      // Change the URL but don’t trigger a nav event. Otherwise it will
-      // reload the page.
-      page.show(window.location.pathname + hash, null, false);
+      if (!this.comment.line) { return; }
+      this.dispatchEvent(new CustomEvent('comment-anchor-tap', {
+        bubbles: true,
+        detail: {
+          number: this.comment.line || FILE,
+          side: this.side,
+        },
+      }));
     },
 
     _handleEdit(e) {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment_test.html b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment_test.html
index ca85892..912e615 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-comment/gr-diff-comment_test.html
@@ -99,15 +99,17 @@
           'header middle content is not visible');
     });
 
-    test('clicking on date link does not trigger nav', () => {
-      const showStub = sinon.stub(page, 'show');
+    test('clicking on date link fires event', () => {
+      element.side = 'PARENT';
+      const stub = sinon.stub();
+      element.addEventListener('comment-anchor-tap', stub);
       const dateEl = element.$$('.date');
       assert.ok(dateEl);
       MockInteractions.tap(dateEl);
-      const dest = window.location.pathname + '#5';
-      assert(showStub.lastCall.calledWithExactly(dest, null, false),
-          'Should navigate to ' + dest + ' without triggering nav');
-      showStub.restore();
+
+      assert.isTrue(stub.called);
+      assert.deepEqual(stub.lastCall.args[0].detail,
+          {side: element.side, number: element.comment.line});
     });
 
     test('message is not retrieved from storage when other edits', done => {
@@ -733,17 +735,6 @@
       assert.isTrue(saveStub.calledOnce);
     });
 
-    test('clicking on date link does not trigger nav', () => {
-      const showStub = sinon.stub(page, 'show');
-      const dateEl = element.$$('.date');
-      assert.ok(dateEl);
-      MockInteractions.tap(dateEl);
-      const dest = window.location.pathname + '#5';
-      assert(showStub.lastCall.calledWithExactly(dest, null, false),
-          'Should navigate to ' + dest + ' without triggering nav');
-      showStub.restore();
-    });
-
     test('proper event fires on resolve, comment is not saved', done => {
       const save = sandbox.stub(element, 'save');
       element.addEventListener('comment-update', e => {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.html b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.html
index 9668a54..f111378 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.html
@@ -60,7 +60,11 @@
 
       diffElement.loggedIn = false;
       diffElement.patchRange = {basePatchNum: 1, patchNum: 2};
-      diffElement.comments = {left: [], right: []};
+      diffElement.comments = {
+        left: [],
+        right: [],
+        meta: {patchRange: undefined},
+      };
       const setupDone = () => {
         cursorElement._updateStops();
         cursorElement.moveToFirstChunk();
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.js b/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.js
index af8725e..577eec6 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.js
@@ -35,7 +35,7 @@
     listeners: {
       'comment-mouse-out': '_handleCommentMouseOut',
       'comment-mouse-over': '_handleCommentMouseOver',
-      'create-comment': '_createComment',
+      'create-range-comment': '_createRangeComment',
     },
 
     observers: [
@@ -317,7 +317,7 @@
       }
     },
 
-    _createComment(e) {
+    _createRangeComment(e) {
       this._removeActionBox();
     },
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight_test.html b/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight_test.html
index b10e3cc..98d55c0 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight_test.html
@@ -215,9 +215,9 @@
         assert.isFalse(builder.getContentsByLineRange.called);
       });
 
-      test('on create-comment action box is removed', () => {
+      test('on create-range-comment action box is removed', () => {
         sandbox.stub(element, '_removeActionBox');
-        element.fire('create-comment', {
+        element.fire('create-range-comment', {
           comment: {
             range: {},
           },
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.html b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.html
index e3bf866..d335e7a 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.html
@@ -16,9 +16,10 @@
 -->
 
 <link rel="import" href="../../../bower_components/polymer/polymer.html">
+<link rel="import" href="../../../behaviors/gr-patch-set-behavior/gr-patch-set-behavior.html">
 <link rel="import" href="../../core/gr-reporting/gr-reporting.html">
 <link rel="import" href="../../shared/gr-rest-api-interface/gr-rest-api-interface.html">
-
+<link rel="import" href="../gr-diff-comment-thread/gr-diff-comment-thread.html">
 <link rel="import" href="../gr-diff/gr-diff.html">
 
 <dom-module id="gr-diff-host">
@@ -30,7 +31,6 @@
         patch-range="[[patchRange]]"
         path="[[path]]"
         prefs="[[prefs]]"
-        project-config="[[projectConfig]]"
         project-name="[[projectName]]"
         display-line="[[displayLine]]"
         is-image-diff="[[isImageDiff]]"
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js
index 6f61fb9..5e4a3fd 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js
@@ -45,13 +45,35 @@
     return !!(diff.binary && (isA || isB));
   }
 
+  /** @typedef {{startLine: number, startChar: number,
+   *             endLine: number, endChar: number}} */
+  Gerrit.Range;
+
+
+  /**
+   * Compare two ranges. Either argument may be falsy, but will only return
+   * true if both are falsy or if neither are falsy and have the same position
+   * values.
+   *
+   * @param {Gerrit.Range=} a range 1
+   * @param {Gerrit.Range=} b range 2
+   * @return {boolean}
+   */
+  function rangesEqual(a, b) {
+    if (!a && !b) { return true; }
+    if (!a || !b) { return false; }
+    return a.startLine === b.startLine &&
+        a.startChar === b.startChar &&
+        a.endLine === b.endLine &&
+        a.endChar === b.endChar;
+  }
+
   /**
    * Wrapper around gr-diff.
    *
    * Webcomponent fetching diffs and related data from restAPI and passing them
    * to the presentational gr-diff for rendering.
    */
-  // TODO(oler): Move all calls to restAPI from gr-diff here.
   Polymer({
     is: 'gr-diff-host',
 
@@ -84,9 +106,6 @@
       prefs: {
         type: Object,
       },
-      projectConfig: {
-        type: Object,
-      },
       projectName: String,
       displayLine: {
         type: Boolean,
@@ -111,7 +130,10 @@
         type: Boolean,
         value: false,
       },
-      comments: Object,
+      comments: {
+        type: Object,
+        observer: '_commentsChanged',
+      },
       lineWrapping: {
         type: Boolean,
         value: false,
@@ -174,10 +196,24 @@
       },
 
       _loadedWhitespaceLevel: String,
+
+      _parentIndex: {
+        type: Number,
+        computed: '_computeParentIndex(patchRange.*)',
+      },
+
+      _threadEls: {
+        type: Array,
+        value: [],
+      },
     },
 
+    behaviors: [
+      Gerrit.PatchSetBehavior,
+    ],
+
     listeners: {
-      'draft-interaction': '_handleDraftInteraction',
+      'create-comment': '_handleCreateComment',
     },
 
     observers: [
@@ -299,9 +335,12 @@
       this._blame = null;
     },
 
-    /** @return {!Array<!HTMLElement>} */
+    /**
+     * The thread elements in this diff, in no particular order.
+     * @return {!Array<!HTMLElement>}
+     */
     getThreadEls() {
-      return this.$.diff.getThreadEls();
+      return this._threadEls;
     },
 
     /** @param {HTMLElement} el */
@@ -428,6 +467,70 @@
       return isImageDiff(diff);
     },
 
+
+    _commentsChanged(newComments) {
+      const allComments = [];
+      for (const side of [GrDiffBuilder.Side.LEFT, GrDiffBuilder.Side.RIGHT]) {
+        // This is needed by the threading.
+        for (const comment of newComments[side]) {
+          comment.__commentSide = side;
+        }
+        allComments.push(...newComments[side]);
+      }
+      // Currently, the only way this is ever changed here is when the initial
+      // comments are loaded, so it's okay performance wise to clear the threads
+      // and recreate them. If this changes in future, we might want to reuse
+      // some DOM nodes here.
+      this._clearThreads();
+      const threads = this._createThreads(allComments);
+      for (const thread of threads) {
+        const threadEl = this._createThreadElement(thread);
+        this._attachThreadElement(threadEl);
+      }
+    },
+
+    /**
+     * @param {!Array<!Object>} comments
+     * @return {!Array<!Object>} Threads for the given comments.
+     */
+    _createThreads(comments) {
+      const sortedComments = comments.slice(0).sort((a, b) => {
+        if (b.__draft && !a.__draft ) { return 0; }
+        if (a.__draft && !b.__draft ) { return 1; }
+        return util.parseDate(a.updated) - util.parseDate(b.updated);
+      });
+
+      const threads = [];
+      for (const comment of sortedComments) {
+        // If the comment is in reply to another comment, find that comment's
+        // thread and append to it.
+        if (comment.in_reply_to) {
+          const thread = threads.find(thread =>
+              thread.comments.some(c => c.id === comment.in_reply_to));
+          if (thread) {
+            thread.comments.push(comment);
+            continue;
+          }
+        }
+
+        // Otherwise, this comment starts its own thread.
+        const newThread = {
+          start_datetime: comment.updated,
+          comments: [comment],
+          commentSide: comment.__commentSide,
+          patchNum: comment.patch_set,
+          rootId: comment.id || comment.__draftID,
+          lineNum: comment.line,
+          isOnParent: comment.side === 'PARENT',
+        };
+        if (comment.range) {
+          newThread.range = Object.assign({}, comment.range);
+        }
+        threads.push(newThread);
+      }
+      return threads;
+    },
+
     /**
      * @param {Object} blame
      * @return {boolean}
@@ -445,11 +548,120 @@
           this.patchRange);
     },
 
-    _handleDraftInteraction() {
+    /** @param {CustomEvent} e */
+    _handleCreateComment(e) {
+      const {lineNum, side, patchNum, isOnParent, range} = e.detail;
+      const threadEl = this._getOrCreateThread(patchNum, lineNum, side, range,
+          isOnParent);
+      threadEl.addOrEditDraft(lineNum, range);
+
       this.$.reporting.recordDraftInteraction();
     },
 
     /**
+     * Gets or creates a comment thread at a given location.
+     * May provide a range, to get/create a range comment.
+     *
+     * @param {string} patchNum
+     * @param {?number} lineNum
+     * @param {string} commentSide
+     * @param {Gerrit.Range|undefined} range
+     * @param {boolean} isOnParent
+     * @return {!Object}
+     */
+    _getOrCreateThread(patchNum, lineNum, commentSide, range, isOnParent) {
+      let threadEl = this._getThreadEl(lineNum, commentSide, range);
+      if (!threadEl) {
+        threadEl = this._createThreadElement({
+          comments: [],
+          commentSide,
+          patchNum,
+          lineNum,
+          range,
+          isOnParent,
+        });
+        this._attachThreadElement(threadEl);
+      }
+      return threadEl;
+    },
+
+    _attachThreadElement(threadEl) {
+      this._threadEls.push(threadEl);
+      Polymer.dom(this.$.diff).appendChild(threadEl);
+    },
+
+    _clearThreads() {
+      for (const threadEl of this._threadEls) {
+        const parent = Polymer.dom(threadEl).parentNode;
+        Polymer.dom(parent).removeChild(threadEl);
+      }
+      this._threadEls = [];
+    },
+
+    _createThreadElement(thread) {
+      const threadEl = document.createElement('gr-diff-comment-thread');
+      threadEl.className = 'comment-thread';
+      threadEl.comments = thread.comments;
+      threadEl.commentSide = thread.commentSide;
+      threadEl.isOnParent = !!thread.isOnParent;
+      threadEl.parentIndex = this._parentIndex;
+      threadEl.changeNum = this.changeNum;
+      threadEl.patchNum = thread.patchNum;
+      threadEl.lineNum = thread.lineNum;
+      const rootIdChangedListener = changeEvent => {
+        thread.rootId = changeEvent.detail.value;
+      };
+      threadEl.addEventListener('root-id-changed', rootIdChangedListener);
+      threadEl.path = this.path;
+      threadEl.projectName = this.projectName;
+      threadEl.range = thread.range;
+      const threadDiscardListener = e => {
+        const threadEl = /** @type {!Node} */ (e.currentTarget);
+
+        const parent = Polymer.dom(threadEl).parentNode;
+        Polymer.dom(parent).removeChild(threadEl);
+
+        const i = this._threadEls.findIndex(
+            threadEl => threadEl.rootId == e.detail.rootId);
+        this._threadEls.splice(i, 1);
+
+        threadEl.removeEventListener('root-id-changed', rootIdChangedListener);
+        threadEl.removeEventListener('thread-discard', threadDiscardListener);
+      };
+      threadEl.addEventListener('thread-discard', threadDiscardListener);
+      return threadEl;
+    },
+
+    /**
+     * Gets a comment thread element at a given location.
+     * May provide a range, to get a range comment.
+     *
+     * @param {?number} lineNum
+     * @param {string} commentSide
+     * @param {!Gerrit.Range=} range
+     * @return {?Node}
+     */
+    _getThreadEl(lineNum, commentSide, range=undefined) {
+      let line;
+      if (commentSide === GrDiffBuilder.Side.LEFT) {
+        line = {beforeNumber: lineNum};
+      } else if (commentSide === GrDiffBuilder.Side.RIGHT) {
+        line = {afterNumber: lineNum};
+      } else {
+        throw new Error(`Unknown side: ${commentSide}`);
+      }
+      function matchesRange(threadEl) {
+        const threadRange = /** @type {!Gerrit.Range} */(
+            JSON.parse(threadEl.getAttribute('range')));
+        return rangesEqual(threadRange, range);
+      }
+
+      const filteredThreadEls = Gerrit.filterThreadElsForLocation(
+          this._threadEls, line, commentSide).filter(matchesRange);
+      return filteredThreadEls.length ? filteredThreadEls[0] : null;
+    },
+
+    /**
      * Take a diff that was loaded with a ignore-whitespace other than
      * IGNORE_NONE, and convert delta chunks labeled as common into shared
      * chunks.
@@ -506,5 +718,15 @@
         this.reload();
       }
     },
+
+    /**
+     * @param {Object} patchRangeRecord
+     * @return {number|null}
+     */
+    _computeParentIndex(patchRangeRecord) {
+      return this.isMergeParent(patchRangeRecord.base.basePatchNum) ?
+          this.getParentIndex(patchRangeRecord.base.basePatchNum) : null;
+    },
+
   });
 })();
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html
index f83253e..c7ee1c2 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html
@@ -37,16 +37,50 @@
   suite('gr-diff-host tests', () => {
     let element;
     let sandbox;
+    let getLoggedIn;
 
     setup(() => {
       sandbox = sinon.sandbox.create();
+      getLoggedIn = false;
+      stub('gr-rest-api-interface', {
+        async getLoggedIn() { return getLoggedIn; },
+      });
       element = fixture('basic');
+      // For reasons beyond me, fixture reuses elements, cleans out some
+      // stuff but not that list.
+      element._threadEls = [];
     });
 
     teardown(() => {
       sandbox.restore();
     });
 
+    test('thread-discard handling', () => {
+      const threads = [
+        {comments: [{id: 4711}]},
+        {comments: [{id: 42}]},
+      ];
+      element._parentIndex = 1;
+      element.changeNum = '2';
+      element.path = 'some/path';
+      element.projectName = 'Some project';
+      const threadEls = threads.map(
+          thread => element._createThreadElement(thread));
+      assert.equal(threadEls.length, 2);
+      assert.equal(threadEls[0].rootId, 4711);
+      assert.equal(threadEls[1].rootId, 42);
+      for (const threadEl of threadEls) {
+        Polymer.dom(element).appendChild(threadEl);
+      }
+
+      threadEls[0].dispatchEvent(
+          new CustomEvent('thread-discard', {detail: {rootId: 4711}}));
+      const attachedThreads = element.queryAllEffectiveChildren(
+          'gr-diff-comment-thread');
+      assert.equal(attachedThreads.length, 1);
+      assert.equal(attachedThreads[0].rootId, 42);
+    });
+
     test('reload() cancels before network resolves', () => {
       const cancelStub = sandbox.stub(element.$.diff, 'cancel');
 
@@ -59,12 +93,8 @@
 
     suite('not logged in', () => {
       setup(() => {
-        const getLoggedInPromise = Promise.resolve(false);
-        stub('gr-rest-api-interface', {
-          getLoggedIn() { return getLoggedInPromise; },
-        });
+        getLoggedIn = false;
         element = fixture('basic');
-        return getLoggedInPromise;
       });
 
       test('reload() loads files weblinks', () => {
@@ -181,7 +211,11 @@
               });
 
           element.patchRange = {basePatchNum: 'PARENT', patchNum: 1};
-          element.comments = {left: [], right: []};
+          element.comments = {
+            left: [],
+            right: [],
+            meta: {patchRange: element.patchRange},
+          };
         });
 
         test('renders image diffs with same file name', done => {
@@ -555,13 +589,10 @@
       });
     });
 
-    test('delegates getThreadEls()', () => {
+    test('getThreadEls() returns _threadEls', () => {
       const returnValue = [document.createElement('b')];
-      const stub = sandbox.stub(element.$.diff, 'getThreadEls')
-          .returns(returnValue);
+      element._threadEls = returnValue;
       assert.equal(element.getThreadEls(), returnValue);
-      assert.isTrue(stub.calledOnce);
-      assert.equal(stub.lastCall.args.length, 0);
     });
 
     test('delegates addDraftAtLine(el)', () => {
@@ -617,12 +648,6 @@
       assert.equal(element.$.diff.prefs, value);
     });
 
-    test('passes in projectConfig', () => {
-      const value = {};
-      element.projectConfig = value;
-      assert.equal(element.$.diff.projectConfig, value);
-    });
-
     test('passes in changeNum', () => {
       const value = '12345';
       element.changeNum = value;
@@ -776,6 +801,190 @@
       });
     });
 
+    test('_createThreads', () => {
+      const comments = [
+        {
+          id: 'sallys_confession',
+          message: 'i like you, jack',
+          updated: '2015-12-23 15:00:20.396000000',
+          line: 1,
+          __commentSide: 'left',
+        }, {
+          id: 'jacks_reply',
+          message: 'i like you, too',
+          updated: '2015-12-24 15:01:20.396000000',
+          __commentSide: 'left',
+          line: 1,
+          in_reply_to: 'sallys_confession',
+        },
+        {
+          id: 'new_draft',
+          message: 'i do not like either of you',
+          __commentSide: 'left',
+          __draft: true,
+          updated: '2015-12-20 15:01:20.396000000',
+        },
+      ];
+
+      const actualThreads = element._createThreads(comments);
+
+      assert.equal(actualThreads.length, 2);
+
+      assert.equal(
+          actualThreads[0].start_datetime, '2015-12-23 15:00:20.396000000');
+      assert.equal(actualThreads[0].commentSide, 'left');
+      assert.equal(actualThreads[0].comments.length, 2);
+      assert.deepEqual(actualThreads[0].comments[0], comments[0]);
+      assert.deepEqual(actualThreads[0].comments[1], comments[1]);
+      assert.equal(actualThreads[0].patchNum, undefined);
+      assert.equal(actualThreads[0].rootId, 'sallys_confession');
+      assert.equal(actualThreads[0].lineNum, 1);
+
+      assert.equal(
+          actualThreads[1].start_datetime, '2015-12-20 15:01:20.396000000');
+      assert.equal(actualThreads[1].commentSide, 'left');
+      assert.equal(actualThreads[1].comments.length, 1);
+      assert.deepEqual(actualThreads[1].comments[0], comments[2]);
+      assert.equal(actualThreads[1].patchNum, undefined);
+      assert.equal(actualThreads[1].rootId, 'new_draft');
+      assert.equal(actualThreads[1].lineNum, undefined);
+    });
+
+    test('_createThreads inherits patchNum and range', () => {
+      const comments = [{
+        id: 'betsys_confession',
+        message: 'i like you, jack',
+        updated: '2015-12-24 15:00:10.396000000',
+        range: {
+          start_line: 1,
+          start_character: 1,
+          end_line: 1,
+          end_character: 2,
+        },
+        patch_set: 5,
+        __commentSide: 'left',
+        line: 1,
+      }];
+
+      expectedThreads = [
+        {
+          start_datetime: '2015-12-24 15:00:10.396000000',
+          commentSide: 'left',
+          comments: [{
+            id: 'betsys_confession',
+            message: 'i like you, jack',
+            updated: '2015-12-24 15:00:10.396000000',
+            range: {
+              start_line: 1,
+              start_character: 1,
+              end_line: 1,
+              end_character: 2,
+            },
+            patch_set: 5,
+            __commentSide: 'left',
+            line: 1,
+          }],
+          patchNum: 5,
+          rootId: 'betsys_confession',
+          range: {
+            start_line: 1,
+            start_character: 1,
+            end_line: 1,
+            end_character: 2,
+          },
+          lineNum: 1,
+          isOnParent: false,
+        },
+      ];
+
+      assert.deepEqual(
+          element._createThreads(comments),
+          expectedThreads);
+    });
+
+    test('_createThreads does not thread unrelated comments at same location',
+        () => {
+          const comments = [
+            {
+              id: 'sallys_confession',
+              message: 'i like you, jack',
+              updated: '2015-12-23 15:00:20.396000000',
+              __commentSide: 'left',
+            }, {
+              id: 'jacks_reply',
+              message: 'i like you, too',
+              updated: '2015-12-24 15:01:20.396000000',
+              __commentSide: 'left',
+            },
+          ];
+          assert.equal(element._createThreads(comments).length, 2);
+        });
+
+    test('_createThreads derives isOnParent using  side from first comment',
+        () => {
+          const comments = [
+            {
+              id: 'sallys_confession',
+              message: 'i like you, jack',
+              updated: '2015-12-23 15:00:20.396000000',
+              // line: 1,
+              // __commentSide: 'left',
+            }, {
+              id: 'jacks_reply',
+              message: 'i like you, too',
+              updated: '2015-12-24 15:01:20.396000000',
+              // __commentSide: 'left',
+              // line: 1,
+              in_reply_to: 'sallys_confession',
+            },
+          ];
+
+          assert.equal(element._createThreads(comments)[0].isOnParent, false);
+
+          comments[0].side = 'REVISION';
+          assert.equal(element._createThreads(comments)[0].isOnParent, false);
+
+          comments[0].side = 'PARENT';
+          assert.equal(element._createThreads(comments)[0].isOnParent, true);
+        });
+
+    test('_getOrCreateThread', () => {
+      const commentSide = 'left';
+
+      assert.isOk(element._getOrCreateThread('2', 3,
+          commentSide, undefined, false));
+
+      let threads = Polymer.dom(element.$.diff)
+          .queryDistributedElements('gr-diff-comment-thread');
+
+      assert.equal(threads.length, 1);
+      assert.equal(threads[0].commentSide, commentSide);
+      assert.equal(threads[0].range, undefined);
+      assert.equal(threads[0].isOnParent, false);
+      assert.equal(threads[0].patchNum, 2);
+
+
+      // Try to fetch a thread with a different range.
+      range = {
+        startLine: 1,
+        startChar: 1,
+        endLine: 1,
+        endChar: 3,
+      };
+
+      assert.isOk(element._getOrCreateThread(
+          '3', 1, commentSide, range, true));
+
+      threads = Polymer.dom(element.$.diff)
+          .queryDistributedElements('gr-diff-comment-thread');
+
+      assert.equal(threads.length, 2);
+      assert.equal(threads[1].commentSide, commentSide);
+      assert.equal(threads[1].range, range);
+      assert.equal(threads[1].isOnParent, true);
+      assert.equal(threads[1].patchNum, 3);
+    });
+
     suite('_translateChunksToIgnore', () => {
       let content;
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html
index 0866849..b3210cc 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html
@@ -286,11 +286,11 @@
             <span>Diff view:</span>
             <gr-diff-mode-selector
                 id="modeSelect"
-                save-on-change="[[_loggedIn]]"
+                save-on-change="[[!_diffPrefsDisabled]]"
                 mode="{{changeViewState.diffMode}}"></gr-diff-mode-selector>
           </div>
           <span id="diffPrefsContainer"
-              hidden$="[[_computePrefsButtonHidden(_prefs, _loggedIn)]]" hidden>
+              hidden$="[[_computePrefsButtonHidden(_prefs, _diffPrefsDisabled)]]" hidden>
             <span class="preferences desktop">
               <gr-button
                   link
@@ -332,10 +332,10 @@
         patch-range="[[_patchRange]]"
         path="[[_path]]"
         prefs="[[_prefs]]"
-        project-config="[[_projectConfig]]"
         project-name="[[_change.project]]"
         view-mode="[[_diffMode]]"
         is-blame-loaded="{{_isBlameLoaded}}"
+        on-comment-anchor-tap="_onLineSelected"
         on-line-selected="_onLineSelected">
     </gr-diff-host>
     <gr-diff-preferences
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js
index 6f361d8..59c5b1f 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js
@@ -69,6 +69,14 @@
         value() { return {}; },
         observer: '_changeViewStateChanged',
       },
+      disableDiffPrefs: {
+        type: Boolean,
+        value: false,
+      },
+      _diffPrefsDisabled: {
+        type: Boolean,
+        computed: '_computeDiffPrefsDisabled(disableDiffPrefs, _loggedIn)',
+      },
       /** @type {?} */
       _patchRange: Object,
       /** @type {?} */
@@ -450,6 +458,7 @@
     _handleCommaKey(e) {
       if (this.shouldSuppressKeyboardShortcut(e) ||
           this.modifierPressed(e)) { return; }
+      if (this._diffPrefsDisabled) { return; }
 
       e.preventDefault();
       this.$.diffPreferences.open();
@@ -791,8 +800,8 @@
           (unresolvedString ? `${unresolvedString}` : '');
     },
 
-    _computePrefsButtonHidden(prefs, loggedIn) {
-      return !loggedIn || !prefs;
+    _computePrefsButtonHidden(prefs, prefsDisabled) {
+      return prefsDisabled || !prefs;
     },
 
     _handleFileChange(e) {
@@ -1012,5 +1021,9 @@
       if (this.shouldSuppressKeyboardShortcut(e)) { return; }
       this.$.diffHost.expandAllContext();
     },
+
+    _computeDiffPrefsDisabled(disableDiffPrefs, loggedIn) {
+      return disableDiffPrefs || !loggedIn;
+    },
   });
 })();
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.html b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.html
index 431578b..3a5ca51 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.html
@@ -135,6 +135,7 @@
       element._fileList = ['chell.go', 'glados.txt', 'wheatley.md'];
       element._path = 'glados.txt';
       element.changeViewState.selectedFileIndex = 1;
+      element._loggedIn = true;
 
       const diffNavStub = sandbox.stub(Gerrit.Nav, 'navigateToDiff');
       const changeNavStub = sandbox.stub(Gerrit.Nav, 'navigateToChange');
@@ -177,6 +178,10 @@
       MockInteractions.pressAndReleaseKeyOn(element, 188, null, ',');
       assert(showPrefsStub.calledOnce);
 
+      element.disableDiffPrefs = true;
+      MockInteractions.pressAndReleaseKeyOn(element, 188, null, ',');
+      assert(showPrefsStub.calledOnce);
+
       let scrollStub = sandbox.stub(element.$.cursor, 'moveToNextChunk');
       MockInteractions.pressAndReleaseKeyOn(element, 78, null, 'n');
       assert(scrollStub.calledOnce);
@@ -343,23 +348,39 @@
           PARENT), 'Should navigate to /c/42/1');
     });
 
-    test('Diff preferences hidden when no prefs or logged out', () => {
-      element._loggedIn = false;
-      flushAsynchronousOperations();
-      assert.isTrue(element.$.diffPrefsContainer.hidden);
+    suite('diff prefs hidden', () => {
+      test('when no prefs or logged out', () => {
+        element.disableDiffPrefs = false;
+        element._loggedIn = false;
+        flushAsynchronousOperations();
+        assert.isTrue(element.$.diffPrefsContainer.hidden);
 
-      element._loggedIn = true;
-      flushAsynchronousOperations();
-      assert.isTrue(element.$.diffPrefsContainer.hidden);
+        element._loggedIn = true;
+        flushAsynchronousOperations();
+        assert.isTrue(element.$.diffPrefsContainer.hidden);
 
-      element._loggedIn = false;
-      element._prefs = {font_size: '12'};
-      flushAsynchronousOperations();
-      assert.isTrue(element.$.diffPrefsContainer.hidden);
+        element._loggedIn = false;
+        element._prefs = {font_size: '12'};
+        flushAsynchronousOperations();
+        assert.isTrue(element.$.diffPrefsContainer.hidden);
 
-      element._loggedIn = true;
-      flushAsynchronousOperations();
-      assert.isFalse(element.$.diffPrefsContainer.hidden);
+        element._loggedIn = true;
+        flushAsynchronousOperations();
+        assert.isFalse(element.$.diffPrefsContainer.hidden);
+      });
+
+      test('when disableDiffPrefs is set', () => {
+        element._loggedIn = true;
+        element._prefs = {font_size: '12'};
+        element.disableDiffPrefs = false;
+        flushAsynchronousOperations();
+
+        assert.isFalse(element.$.diffPrefsContainer.hidden);
+        element.disableDiffPrefs = true;
+        flushAsynchronousOperations();
+
+        assert.isTrue(element.$.diffPrefsContainer.hidden);
+      });
     });
 
     test('prefsButton opens gr-diff-preferences', () => {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html
index bddfc6d..7f7ec72 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html
@@ -20,7 +20,6 @@
 <link rel="import" href="../../../styles/shared-styles.html">
 <link rel="import" href="../../shared/gr-button/gr-button.html">
 <link rel="import" href="../gr-diff-builder/gr-diff-builder.html">
-<link rel="import" href="../gr-diff-comment-thread/gr-diff-comment-thread.html">
 <link rel="import" href="../gr-diff-highlight/gr-diff-highlight.html">
 <link rel="import" href="../gr-diff-selection/gr-diff-selection.html">
 <link rel="import" href="../gr-syntax-themes/gr-syntax-theme.html">
@@ -36,6 +35,11 @@
       :host(.no-left) .sideBySide ::content .right:not([data-value]) + td {
         display: none;
       }
+      .thread-group, ::slotted(*) .thread-group {
+        display: block;
+        max-width: var(--content-width, 80ch);
+        white-space: normal;
+      }
       .diffContainer {
         display: flex;
         font-family: var(--monospace-font-family);
@@ -290,9 +294,8 @@
               is-image-diff="[[isImageDiff]]"
               base-image="[[baseImage]]"
               revision-image="[[revisionImage]]"
-              parent-index="[[_parentIndex]]"
-              create-comment-fn="[[_createThreadGroupFn]]"
               line-of-interest="[[lineOfInterest]]">
+            <slot></slot>
             <table
                 id="diffTable"
                 class$="[[_diffTableClass]]"
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
index 3ae8806..76a62b8 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.js
@@ -60,9 +60,9 @@
      */
 
      /**
-      * Fired when a draft is added or edited.
+      * Fired when a comment is created
       *
-      * @event draft-interaction
+      * @event create-comment
       */
 
     properties: {
@@ -78,10 +78,6 @@
         type: Object,
         observer: '_prefsObserver',
       },
-      projectConfig: {
-        type: Object,
-        observer: '_projectConfigChanged',
-      },
       projectName: String,
       displayLine: {
         type: Boolean,
@@ -176,27 +172,17 @@
         observer: '_blameChanged',
       },
 
-      _parentIndex: {
-        type: Number,
-        computed: '_computeParentIndex(patchRange.*)',
-      },
+      parentIndex: Number,
 
       _newlineWarning: {
         type: String,
         computed: '_computeNewlineWarning(diff)',
       },
 
-      /**
-       * @type {function(number, boolean, !string)}
-       */
-      _createThreadGroupFn: {
-        type: Function,
-        value() {
-          return this._createCommentThreadGroup.bind(this);
-        },
-      },
-
       _diffLength: Number,
+
+      /** @type {?PolymerDomApi.ObserveHandle} */
+      _nodeObserver: Object,
     },
 
     behaviors: [
@@ -207,7 +193,12 @@
       'comment-discard': '_handleCommentDiscard',
       'comment-update': '_handleCommentUpdate',
       'comment-save': '_handleCommentSave',
-      'create-comment': '_handleCreateComment',
+      'create-range-comment': '_handleCreateRangeComment',
+      'render-content': '_handleRenderContent',
+    },
+
+    detached() {
+      this._unobserveNodes();
     },
 
     /** Cancel any remaining diff builder rendering work. */
@@ -247,17 +238,6 @@
           {bubbles: true}));
     },
 
-    /** @return {!Array<!HTMLElement>} */
-    getThreadEls() {
-      let threads = [];
-      const threadGroupEls = Polymer.dom(this.root)
-          .querySelectorAll('gr-diff-comment-thread-group');
-      for (const threadGroupEl of threadGroupEls) {
-        threads = threads.concat(threadGroupEl.threadEls);
-      }
-      return threads;
-    },
-
     /** @return {string} */
     _computeContainerClass(loggedIn, viewMode, displayLine) {
       const classes = ['diffContainer'];
@@ -322,7 +302,7 @@
       this._createComment(el, lineNum);
     },
 
-    _handleCreateComment(e) {
+    _handleCreateRangeComment(e) {
       const range = e.detail.range;
       const side = e.detail.side;
       const lineNum = range.endLine;
@@ -359,88 +339,49 @@
 
     /**
      * @param {!Object} lineEl
-     * @param {number=} opt_lineNum
-     * @param {string=} opt_side
-     * @param {!Object=} opt_range
+     * @param {number=} lineNum
+     * @param {string=} side
+     * @param {!Object=} range
      */
-    _createComment(lineEl, opt_lineNum, opt_side, opt_range) {
-      this.dispatchEvent(new CustomEvent('draft-interaction', {bubbles: true}));
+    _createComment(lineEl, lineNum=undefined, side=undefined, range=undefined) {
       const contentText = this.$.diffBuilder.getContentByLineEl(lineEl);
       const contentEl = contentText.parentElement;
-      const side = opt_side ||
+      side = side ||
           this._getCommentSideByLineAndContent(lineEl, contentEl);
-      const patchNum = this._getPatchNumByLineAndContent(lineEl, contentEl);
+      const patchForNewThreads = this._getPatchNumByLineAndContent(
+          lineEl, contentEl);
       const isOnParent =
-        this._getIsParentCommentByLineAndContent(lineEl, contentEl);
-      const threadEl = this._getOrCreateThread(contentEl, patchNum,
-          side, isOnParent, opt_range);
-      threadEl.addOrEditDraft(opt_lineNum, opt_range);
-    },
-
-    /**
-     * Fetch the thread group at the given range, or the range-less thread
-     * on the line if no range is provided.
-     *
-     * @param {!Object} threadGroupEl
-     * @param {string} commentSide
-     * @param {!Object=} opt_range
-     * @return {!Object}
-     */
-    _getThread(threadGroupEl, commentSide, opt_range) {
-      return threadGroupEl.getThread(commentSide, opt_range);
+          this._getIsParentCommentByLineAndContent(lineEl, contentEl);
+      this.dispatchEvent(new CustomEvent('create-comment', {
+        bubbles: true,
+        detail: {
+          lineNum,
+          side,
+          patchNum: patchForNewThreads,
+          isOnParent,
+          range,
+        },
+      }));
     },
 
     _getThreadGroupForLine(contentEl) {
-      return contentEl.querySelector('gr-diff-comment-thread-group');
+      return contentEl.querySelector('.thread-group');
     },
 
     /**
-     * Gets or creates a comment thread for a specific spot on a diff.
-     * May include a range, if the comment is a range comment.
-     *
+     * Gets or creates a comment thread group for a specific line and side on a
+     * diff.
      * @param {!Object} contentEl
-     * @param {number} patchNum
-     * @param {string} commentSide
-     * @param {boolean} isOnParent
-     * @param {!Object=} opt_range
-     * @return {!Object}
+     * @return {!Node}
      */
-    _getOrCreateThread(contentEl, patchNum, commentSide,
-        isOnParent, opt_range) {
+    _getOrCreateThreadGroup(contentEl) {
       // Check if thread group exists.
       let threadGroupEl = this._getThreadGroupForLine(contentEl);
       if (!threadGroupEl) {
-        threadGroupEl = this._createCommentThreadGroup(patchNum, isOnParent,
-            commentSide);
+        threadGroupEl = document.createElement('div');
+        threadGroupEl.className = 'thread-group';
         contentEl.appendChild(threadGroupEl);
       }
-
-      let threadEl = this._getThread(threadGroupEl, commentSide, opt_range);
-
-      if (!threadEl) {
-        threadGroupEl.addNewThread(commentSide, opt_range);
-        Polymer.dom.flush();
-        threadEl = this._getThread(threadGroupEl, commentSide, opt_range);
-      }
-      return threadEl;
-    },
-
-    /**
-     * @param {number} patchNum
-     * @param {boolean} isOnParent
-     * @param {!string} commentSide
-     * @return {!Object}
-     */
-    _createCommentThreadGroup(patchNum, isOnParent, commentSide) {
-      const threadGroupEl =
-          document.createElement('gr-diff-comment-thread-group');
-      threadGroupEl.changeNum = this.changeNum;
-      threadGroupEl.commentSide = commentSide;
-      threadGroupEl.patchForNewThreads = patchNum;
-      threadGroupEl.path = this.path;
-      threadGroupEl.isOnParent = isOnParent;
-      threadGroupEl.projectName = this.projectName;
-      threadGroupEl.parentIndex = this._parentIndex;
       return threadGroupEl;
     },
 
@@ -632,6 +573,7 @@
     },
 
     _renderDiffTable() {
+      this._unobserveNodes();
       if (!this.prefs) {
         this.dispatchEvent(new CustomEvent('render', {bubbles: true}));
         return;
@@ -648,6 +590,34 @@
       this.$.diffBuilder.render(this.comments, this._getBypassPrefs());
     },
 
+    _handleRenderContent() {
+      this._nodeObserver = Polymer.dom(this).observeNodes(info => {
+        const addedThreadEls = info.addedNodes.filter(
+            node => node.nodeType === Node.ELEMENT_NODE);
+        // In principal we should also handle removed nodes, but I have not
+        // figured out how to do that yet without also catching all the removals
+        // caused by further redistribution. Right now, comments are never
+        // removed by no longer slotting them in, so I decided to not handle
+        // this situation until it occurs.
+        for (const threadEl of addedThreadEls) {
+          const lineNum = Number(threadEl.getAttribute('line-num'));
+          const commentSide = threadEl.getAttribute('comment-side');
+          const lineEl = this.$.diffBuilder.getLineElByNumber(
+              lineNum, commentSide);
+          const contentText = this.$.diffBuilder.getContentByLineEl(lineEl);
+          const contentEl = contentText.parentElement;
+          const threadGroupEl = this._getOrCreateThreadGroup(contentEl);
+          Polymer.dom(threadGroupEl).appendChild(threadEl);
+        }
+      });
+    },
+
+    _unobserveNodes() {
+      if (this._nodeObserver) {
+        Polymer.dom(this).unobserveNodes(this._nodeObserver);
+      }
+    },
+
     /**
      * Get the preferences object including the safety bypass context (if any).
      */
@@ -659,16 +629,10 @@
     },
 
     clearDiffContent() {
+      this._unobserveNodes();
       this.$.diffTable.innerHTML = null;
     },
 
-    _projectConfigChanged(projectConfig) {
-      const threadEls = this.getThreadEls();
-      for (let i = 0; i < threadEls.length; i++) {
-        threadEls[i].projectConfig = projectConfig;
-      }
-    },
-
     /** @return {!Array} */
     _computeDiffHeaderItems(diffInfoRecord) {
       const diffInfo = diffInfoRecord.base;
@@ -710,16 +674,6 @@
       return errorMessage ? 'showError' : '';
     },
 
-    /**
-     * @return {number|null}
-     */
-    _computeParentIndex(patchRangeRecord) {
-      if (!this.isMergeParent(patchRangeRecord.base.basePatchNum)) {
-        return null;
-      }
-      return this.getParentIndex(patchRangeRecord.base.basePatchNum);
-    },
-
     expandAllContext() {
       this._handleFullBypass();
     },
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html
index faf529b..4befd2f 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.html
@@ -295,15 +295,6 @@
 
       test('thread groups', () => {
         const contentEl = document.createElement('div');
-        const commentSide = 'left';
-        const patchNum = 1;
-        const side = 'PARENT';
-        let range = {
-          startLine: 1,
-          startChar: 1,
-          endLine: 1,
-          endChar: 2,
-        };
 
         element.changeNum = 123;
         element.patchRange = {basePatchNum: 1, patchNum: 2};
@@ -311,36 +302,20 @@
 
         const mock = document.createElement('mock-diff-response');
         element.$.diffBuilder._builder = element.$.diffBuilder._getDiffBuilder(
-            mock.diffResponse, {}, {tab_size: 2, line_length: 80});
+            mock.diffResponse, {left: [], right: []},
+            {tab_size: 2, line_length: 80});
 
         // No thread groups.
         assert.isNotOk(element._getThreadGroupForLine(contentEl));
 
         // A thread group gets created.
-        assert.isOk(element._getOrCreateThread(contentEl,
-            patchNum, commentSide, side));
+        const threadGroupEl = element._getOrCreateThreadGroup(contentEl);
+        assert.isOk(threadGroupEl);
 
-        // Try to fetch a thread with a different range.
-        range = {
-          startLine: 1,
-          startChar: 1,
-          endLine: 1,
-          endChar: 3,
-        };
-
-        assert.isOk(element._getOrCreateThread(
-            contentEl, patchNum, commentSide, side, range));
         // The new thread group can be fetched.
         assert.isOk(element._getThreadGroupForLine(contentEl));
 
-        assert.equal(contentEl.querySelectorAll(
-            'gr-diff-comment-thread-group').length, 1);
-
-        const threadGroup = contentEl.querySelector(
-            'gr-diff-comment-thread-group');
-        const threadLength = Polymer.dom(threadGroup.root).
-              querySelectorAll('gr-diff-comment-thread').length;
-        assert.equal(threadLength, 2);
+        assert.equal(contentEl.querySelectorAll('.thread-group').length, 1);
       });
 
       suite('image diffs', () => {
@@ -359,7 +334,11 @@
           };
 
           element.patchRange = {basePatchNum: 'PARENT', patchNum: 1};
-          element.comments = {left: [], right: []};
+          element.comments = {
+            left: [],
+            right: [],
+            meta: {patchRange: undefined},
+          };
           element.isImageDiff = true;
           element.prefs = {
             auto_hide_diff_table_header: true,
@@ -688,6 +667,7 @@
           element.comments = {
             left: [],
             right: [],
+            meta: {patchRange: undefined},
           };
           element.prefs = {
             context: 10,
diff --git a/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box.js b/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box.js
index 6349ab6..0f84877 100644
--- a/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box.js
+++ b/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box.js
@@ -23,7 +23,7 @@
     /**
      * Fired when the comment creation action was taken (hotkey, click).
      *
-     * @event create-comment
+     * @event create-range-comment
      */
 
     properties: {
@@ -110,7 +110,7 @@
     },
 
     _fireCreateComment() {
-      this.fire('create-comment', {side: this.side, range: this.range});
+      this.fire('create-range-comment', {side: this.side, range: this.range});
     },
   });
 })();
diff --git a/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box_test.html b/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box_test.html
index 19155e4..4f1065a 100644
--- a/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box_test.html
@@ -98,7 +98,7 @@
       element.range = range;
       MockInteractions.pressAndReleaseKeyOn(document.body, 67, null, 'c');
       assert(element.fire.calledWithExactly(
-          'create-comment',
+          'create-range-comment',
           {
             side,
             range,
diff --git a/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.html b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.html
new file mode 100644
index 0000000..720f353
--- /dev/null
+++ b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.html
@@ -0,0 +1,62 @@
+<!--
+@license
+Copyright (C) 2018 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.
+-->
+<link rel="import" href="../../../bower_components/polymer/polymer.html">
+
+<link rel="import" href="../../../behaviors/base-url-behavior/base-url-behavior.html">
+<link rel="import" href="../../../behaviors/gr-list-view-behavior/gr-list-view-behavior.html">
+<link rel="import" href="../../../bower_components/iron-input/iron-input.html">
+<link rel="import" href="../../../styles/gr-table-styles.html">
+<link rel="import" href="../../../styles/shared-styles.html">
+<link rel="import" href="../../shared/gr-list-view/gr-list-view.html">
+<link rel="import" href="../../shared/gr-rest-api-interface/gr-rest-api-interface.html">
+
+<dom-module id="gr-documentation-search">
+  <template>
+    <style include="shared-styles"></style>
+    <style include="gr-table-styles"></style>
+    <gr-list-view
+        filter="[[_filter]]"
+        items=false
+        offset=0
+        loading="[[_loading]]"
+        path="[[_path]]">
+      <table id="list" class="genericList">
+        <tr class="headerRow">
+          <th class="name topHeader">Name</th>
+          <th class="name topHeader"></th>
+          <th class="name topHeader"></th>
+        </tr>
+        <tr id="loading" class$="loadingMsg [[computeLoadingClass(_loading)]]">
+          <td>Loading...</td>
+        </tr>
+        <tbody class$="[[computeLoadingClass(_loading)]]">
+          <template is="dom-repeat" items="[[_documentationSearches]]">
+            <tr class="table">
+              <td class="name">
+                <a href$="[[_computeSearchUrl(item.url)]]">[[item.title]]</a>
+              </td>
+              <td></td>
+              <td></td>
+            </tr>
+          </template>
+        </tbody>
+      </table>
+    </gr-list-view>
+    <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
+  </template>
+  <script src="gr-documentation-search.js"></script>
+</dom-module>
diff --git a/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.js b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.js
new file mode 100644
index 0000000..f850b9d
--- /dev/null
+++ b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.js
@@ -0,0 +1,81 @@
+/**
+ * @license
+ * Copyright (C) 2018 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.
+ */
+(function() {
+  'use strict';
+
+  Polymer({
+    is: 'gr-documentation-search',
+
+    properties: {
+      /**
+       * URL params passed from the router.
+       */
+      params: {
+        type: Object,
+        observer: '_paramsChanged',
+      },
+
+      _path: {
+        type: String,
+        readOnly: true,
+        value: '/Documentation',
+      },
+      _documentationSearches: Array,
+
+      _loading: {
+        type: Boolean,
+        value: true,
+      },
+      _filter: {
+        type: String,
+        value: '',
+      },
+    },
+
+    behaviors: [
+      Gerrit.ListViewBehavior,
+    ],
+
+    attached() {
+      this.dispatchEvent(
+          new CustomEvent('title-change', {title: 'Documentation Search'}));
+    },
+
+    _paramsChanged(params) {
+      this._loading = true;
+      this._filter = this.getFilterValue(params);
+
+      return this._getDocumentationSearches(this._filter);
+    },
+
+    _getDocumentationSearches(filter) {
+      this._documentationSearches = [];
+      return this.$.restAPI.getDocumentationSearches(filter)
+          .then(searches => {
+            // Late response.
+            if (filter !== this._filter || !searches) { return; }
+            this._documentationSearches = searches;
+            this._loading = false;
+          });
+    },
+
+    _computeSearchUrl(url) {
+      if (!url) { return ''; }
+      return this.getBaseUrl() + '/' + url;
+    },
+  });
+})();
diff --git a/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search_test.html b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search_test.html
new file mode 100644
index 0000000..84addb0
--- /dev/null
+++ b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search_test.html
@@ -0,0 +1,120 @@
+<!DOCTYPE html>
+<!--
+@license
+Copyright (C) 2018 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.
+-->
+
+<meta name="viewport" content="width=device-width, minimum-scale=1.0, initial-scale=1.0, user-scalable=yes">
+<title>gr-documentation-search</title>
+
+<script src="../../../bower_components/page/page.js"></script>
+<script src="../../../bower_components/webcomponentsjs/webcomponents-lite.min.js"></script>
+<script src="../../../bower_components/web-component-tester/browser.js"></script>
+<link rel="import" href="../../../test/common-test-setup.html"/>
+<link rel="import" href="gr-documentation-search.html">
+
+<script>void(0);</script>
+
+<test-fixture id="basic">
+  <template>
+    <gr-documentation-search></gr-documentation-search>
+  </template>
+</test-fixture>
+
+<script>
+  let counter;
+  const documentationGenerator = () => {
+    return {
+      title: `Gerrit Code Review - REST API Developers Notes${++counter}`,
+      url: 'Documentation/dev-rest-api.html',
+    };
+  };
+
+  suite('gr-documentation-search tests', () => {
+    let element;
+    let documentationSearches;
+    let sandbox;
+    let value;
+
+    setup(() => {
+      sandbox = sinon.sandbox.create();
+      sandbox.stub(page, 'show');
+      element = fixture('basic');
+      counter = 0;
+    });
+
+    teardown(() => {
+      sandbox.restore();
+    });
+
+    suite('list with searches for documentation', () => {
+      setup(done => {
+        documentationSearches = _.times(26, documentationGenerator);
+        stub('gr-rest-api-interface', {
+          getDocumentationSearches() {
+            return Promise.resolve(documentationSearches);
+          },
+        });
+        element._paramsChanged(value).then(() => { flush(done); });
+      });
+
+      test('test for test repo in the list', done => {
+        flush(() => {
+          assert.equal(element._documentationSearches[0].title,
+              'Gerrit Code Review - REST API Developers Notes1');
+          assert.equal(element._documentationSearches[0].url,
+              'Documentation/dev-rest-api.html');
+          done();
+        });
+      });
+    });
+
+    suite('filter', () => {
+      setup(() => {
+        documentationSearches = _.times(25, documentationGenerator);
+        documentationSearchesFiltered = _.times(1, documentationSearches);
+      });
+
+      test('_paramsChanged', done => {
+        sandbox.stub(element.$.restAPI, 'getDocumentationSearches', () => {
+          return Promise.resolve(documentationSearches);
+        });
+        const value = {
+          filter: 'test',
+        };
+        element._paramsChanged(value).then(() => {
+          assert.isTrue(element.$.restAPI.getDocumentationSearches.lastCall
+              .calledWithExactly('test'));
+          done();
+        });
+      });
+    });
+
+    suite('loading', () => {
+      test('correct contents are displayed', () => {
+        assert.isTrue(element._loading);
+        assert.equal(element.computeLoadingClass(element._loading), 'loading');
+        assert.equal(getComputedStyle(element.$.loading).display, 'block');
+
+        element._loading = false;
+        element._repos = _.times(25, documentationGenerator);
+
+        flushAsynchronousOperations();
+        assert.equal(element.computeLoadingClass(element._loading), '');
+        assert.equal(getComputedStyle(element.$.loading).display, 'none');
+      });
+    });
+  });
+</script>
diff --git a/polygerrit-ui/app/elements/gr-app.html b/polygerrit-ui/app/elements/gr-app.html
index 787a1c6..b34cd0a 100644
--- a/polygerrit-ui/app/elements/gr-app.html
+++ b/polygerrit-ui/app/elements/gr-app.html
@@ -48,6 +48,7 @@
 <link rel="import" href="../styles/shared-styles.html">
 <link rel="import" href="../styles/themes/app-theme.html">
 <link rel="import" href="./admin/gr-admin-view/gr-admin-view.html">
+<link rel="import" href="./documentation/gr-documentation-search/gr-documentation-search.html">
 <link rel="import" href="./change-list/gr-change-list-view/gr-change-list-view.html">
 <link rel="import" href="./change-list/gr-dashboard-view/gr-dashboard-view.html">
 <link rel="import" href="./change/gr-change-view/gr-change-view.html">
@@ -198,6 +199,11 @@
       <template is="dom-if" if="[[_showCLAView]]" restamp="true">
         <gr-cla-view></gr-cla-view>
       </template>
+      <template is="dom-if" if="[[_showDocumentationSearch]]" restamp="true">
+        <gr-documentation-search
+            params="[[params]]">
+        </gr-documentation-search>
+      </template>
       <div id="errorView" class="errorView">
         <div class="errorEmoji">[[_lastError.emoji]]</div>
         <div class="errorText">[[_lastError.text]]</div>
diff --git a/polygerrit-ui/app/elements/gr-app.js b/polygerrit-ui/app/elements/gr-app.js
index b0cc514..9c465f0 100644
--- a/polygerrit-ui/app/elements/gr-app.js
+++ b/polygerrit-ui/app/elements/gr-app.js
@@ -72,6 +72,7 @@
       _showCLAView: Boolean,
       _showEditorView: Boolean,
       _showPluginScreen: Boolean,
+      _showDocumentationSearch: Boolean,
       /** @type {?} */
       _viewState: Object,
       /** @type {?} */
@@ -315,6 +316,8 @@
       if (isPluginScreen) {
         this.async(() => this.set('_showPluginScreen', true), 1);
       }
+      this.set('_showDocumentationSearch',
+          view === Gerrit.Nav.View.DOCUMENTATION_SEARCH);
       if (this.params.justRegistered) {
         this.$.registrationOverlay.open();
         this.$.registrationDialog.loadData().then(() => {
diff --git a/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown.js b/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown.js
index dcb428f..3d9d36b 100644
--- a/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown.js
+++ b/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown.js
@@ -229,7 +229,7 @@
       if (typeof link.url === 'undefined') {
         return '';
       }
-      if (link.target) {
+      if (link.target || !link.url.startsWith('/')) {
         return link.url;
       }
       return this._computeRelativeURL(link.url);
diff --git a/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown_test.html b/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown_test.html
index 456f235..7bb4dce 100644
--- a/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown_test.html
+++ b/polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown_test.html
@@ -73,6 +73,12 @@
 
     test('link URLs', () => {
       assert.equal(
+          element._computeLinkURL({url: 'http://example.com/test'}),
+          'http://example.com/test');
+      assert.equal(
+          element._computeLinkURL({url: 'https://example.com/test'}),
+          'https://example.com/test');
+      assert.equal(
           element._computeLinkURL({url: '/test'}),
           '//' + window.location.host + '/test');
       assert.equal(
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js
index c0078e9..2a1ad9e 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js
@@ -2981,6 +2981,22 @@
       });
     },
 
+    /**
+     * @param {string} filter
+     * @return {!Promise<?Object>}
+     */
+    getDocumentationSearches(filter) {
+      filter = filter.trim();
+      const encodedFilter = encodeURIComponent(filter);
+
+      // TODO(kaspern): Rename rest api from /projects/ to /repos/ once backend
+      // supports it.
+      return this._fetchSharedCacheURL({
+        url: `/Documentation/?q=${encodedFilter}`,
+        anonymizedUrl: '/Documentation/?*',
+      });
+    },
+
     getMergeable(changeNum) {
       return this._getChangeURLAndFetch({
         changeNum,
diff --git a/polygerrit-ui/app/embed/embed.html b/polygerrit-ui/app/embed/embed.html
index 948916f..1b2f20f 100644
--- a/polygerrit-ui/app/embed/embed.html
+++ b/polygerrit-ui/app/embed/embed.html
@@ -25,7 +25,6 @@
 <link rel="import" href="../elements/core/gr-search-bar/gr-search-bar.html">
 <link rel="import" href="../elements/diff/gr-diff-view/gr-diff-view.html">
 <link rel="import" href="../elements/change-list/gr-change-list-view/gr-change-list-view.html">
-<link rel="import" href="../elements/change-list/gr-change-list/gr-change-list.html">
-<link rel="import" href="../elements/change-list/gr-create-change-help/gr-create-change-help.html">
 <link rel="import" href="../elements/change-list/gr-dashboard-view/gr-dashboard-view.html">
+<link rel="import" href="../elements/change-list/gr-embed-dashboard/gr-embed-dashboard.html">
 <link rel="import" href="../styles/themes/app-theme.html">
diff --git a/polygerrit-ui/app/test/index.html b/polygerrit-ui/app/test/index.html
index 5b9ae15..20a4a1e 100644
--- a/polygerrit-ui/app/test/index.html
+++ b/polygerrit-ui/app/test/index.html
@@ -103,7 +103,6 @@
     'core/gr-smart-search/gr-smart-search_test.html',
     'diff/gr-comment-api/gr-comment-api_test.html',
     'diff/gr-diff-builder/gr-diff-builder_test.html',
-    'diff/gr-diff-comment-thread-group/gr-diff-comment-thread-group_test.html',
     'diff/gr-diff-comment-thread/gr-diff-comment-thread_test.html',
     'diff/gr-diff-comment/gr-diff-comment_test.html',
     'diff/gr-diff-cursor/gr-diff-cursor_test.html',
@@ -120,6 +119,7 @@
     'diff/gr-ranged-comment-layer/gr-ranged-comment-layer_test.html',
     'diff/gr-selection-action-box/gr-selection-action-box_test.html',
     'diff/gr-syntax-layer/gr-syntax-layer_test.html',
+    'documentation/gr-documentation-search/gr-documentation-search_test.html',
     'edit/gr-default-editor/gr-default-editor_test.html',
     'edit/gr-edit-controls/gr-edit-controls_test.html',
     'edit/gr-edit-file-controls/gr-edit-file-controls_test.html',
diff --git a/tools/maven/gerrit-acceptance-framework_pom.xml b/tools/maven/gerrit-acceptance-framework_pom.xml
index e66a938..c5faa49 100644
--- a/tools/maven/gerrit-acceptance-framework_pom.xml
+++ b/tools/maven/gerrit-acceptance-framework_pom.xml
@@ -2,7 +2,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.gerrit</groupId>
   <artifactId>gerrit-acceptance-framework</artifactId>
-  <version>2.16-rc3</version>
+  <version>3.0-SNAPSHOT</version>
   <packaging>jar</packaging>
   <name>Gerrit Code Review - Acceptance Test Framework</name>
   <description>Framework for Gerrit's acceptance tests</description>
diff --git a/tools/maven/gerrit-extension-api_pom.xml b/tools/maven/gerrit-extension-api_pom.xml
index 623964c..52b11c1 100644
--- a/tools/maven/gerrit-extension-api_pom.xml
+++ b/tools/maven/gerrit-extension-api_pom.xml
@@ -2,7 +2,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.gerrit</groupId>
   <artifactId>gerrit-extension-api</artifactId>
-  <version>2.16-rc3</version>
+  <version>3.0-SNAPSHOT</version>
   <packaging>jar</packaging>
   <name>Gerrit Code Review - Extension API</name>
   <description>API for Gerrit Extensions</description>
diff --git a/tools/maven/gerrit-plugin-api_pom.xml b/tools/maven/gerrit-plugin-api_pom.xml
index 212e739..d22c3ee 100644
--- a/tools/maven/gerrit-plugin-api_pom.xml
+++ b/tools/maven/gerrit-plugin-api_pom.xml
@@ -2,7 +2,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.gerrit</groupId>
   <artifactId>gerrit-plugin-api</artifactId>
-  <version>2.16-rc3</version>
+  <version>3.0-SNAPSHOT</version>
   <packaging>jar</packaging>
   <name>Gerrit Code Review - Plugin API</name>
   <description>API for Gerrit Plugins</description>
diff --git a/tools/maven/gerrit-plugin-gwtui_pom.xml b/tools/maven/gerrit-plugin-gwtui_pom.xml
index 1fe482c..e756352 100644
--- a/tools/maven/gerrit-plugin-gwtui_pom.xml
+++ b/tools/maven/gerrit-plugin-gwtui_pom.xml
@@ -2,7 +2,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.gerrit</groupId>
   <artifactId>gerrit-plugin-gwtui</artifactId>
-  <version>2.16-rc3</version>
+  <version>3.0-SNAPSHOT</version>
   <packaging>jar</packaging>
   <name>Gerrit Code Review - Plugin GWT UI</name>
   <description>Common Classes for Gerrit GWT UI Plugins</description>
diff --git a/tools/maven/gerrit-war_pom.xml b/tools/maven/gerrit-war_pom.xml
index 4a84174..e6c04e2 100644
--- a/tools/maven/gerrit-war_pom.xml
+++ b/tools/maven/gerrit-war_pom.xml
@@ -2,7 +2,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.gerrit</groupId>
   <artifactId>gerrit-war</artifactId>
-  <version>2.16-rc3</version>
+  <version>3.0-SNAPSHOT</version>
   <packaging>war</packaging>
   <name>Gerrit Code Review - WAR</name>
   <description>Gerrit WAR</description>
diff --git a/version.bzl b/version.bzl
index 04b03a7..20fd8a7 100644
--- a/version.bzl
+++ b/version.bzl
@@ -2,4 +2,4 @@
 # Used by :api_install and :api_deploy targets
 # when talking to the destination repository.
 #
-GERRIT_VERSION = "2.16-rc3"
+GERRIT_VERSION = "3.0-SNAPSHOT"