diff --git a/java/com/google/gerrit/acceptance/AbstractDaemonTest.java b/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
index 7ddf2ba..f476566 100644
--- a/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
+++ b/java/com/google/gerrit/acceptance/AbstractDaemonTest.java
@@ -369,11 +369,11 @@
     if (commonServer != null) {
       try {
         commonServer.close();
-      } catch (Throwable t) {
+      } catch (Exception e) {
         throw new AssertionError(
             "Error stopping common server in "
                 + (firstTest != null ? firstTest.getTestClass().getName() : "unknown test class"),
-            t);
+            e);
       } finally {
         commonServer = null;
       }
diff --git a/java/com/google/gerrit/entities/Change.java b/java/com/google/gerrit/entities/Change.java
index ca13db9..d1826bc 100644
--- a/java/com/google/gerrit/entities/Change.java
+++ b/java/com/google/gerrit/entities/Change.java
@@ -443,9 +443,6 @@
   /** Globally assigned unique identifier of the change */
   protected Key changeKey;
 
-  /** optimistic locking */
-  protected int rowVersion;
-
   /** When this change was first introduced into the database. */
   protected Timestamp createdOn;
 
@@ -526,7 +523,6 @@
     assignee = other.assignee;
     changeId = other.changeId;
     changeKey = other.changeKey;
-    rowVersion = other.rowVersion;
     createdOn = other.createdOn;
     lastUpdatedOn = other.lastUpdatedOn;
     owner = other.owner;
@@ -587,10 +583,6 @@
     lastUpdatedOn = now;
   }
 
-  public int getRowVersion() {
-    return rowVersion;
-  }
-
   public Account.Id getOwner() {
     return owner;
   }
diff --git a/java/com/google/gerrit/entities/converter/ChangeProtoConverter.java b/java/com/google/gerrit/entities/converter/ChangeProtoConverter.java
index 25e68f9..689b4aa 100644
--- a/java/com/google/gerrit/entities/converter/ChangeProtoConverter.java
+++ b/java/com/google/gerrit/entities/converter/ChangeProtoConverter.java
@@ -43,7 +43,6 @@
     Entities.Change.Builder builder =
         Entities.Change.newBuilder()
             .setChangeId(changeIdConverter.toProto(change.getId()))
-            .setRowVersion(change.getRowVersion())
             .setChangeKey(changeKeyConverter.toProto(change.getKey()))
             .setCreatedOn(change.getCreatedOn().getTime())
             .setLastUpdatedOn(change.getLastUpdatedOn().getTime())
diff --git a/java/com/google/gerrit/httpd/BUILD b/java/com/google/gerrit/httpd/BUILD
index cd3ebb9..ea7c609 100644
--- a/java/com/google/gerrit/httpd/BUILD
+++ b/java/com/google/gerrit/httpd/BUILD
@@ -20,6 +20,7 @@
         "//java/com/google/gerrit/metrics",
         "//java/com/google/gerrit/server",
         "//java/com/google/gerrit/server/audit",
+        "//java/com/google/gerrit/server/cancellation",
         "//java/com/google/gerrit/server/git/receive",
         "//java/com/google/gerrit/server/ioutil",
         "//java/com/google/gerrit/server/logging",
diff --git a/java/com/google/gerrit/httpd/restapi/RestApiServlet.java b/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
index 7e6ab58..375aa54 100644
--- a/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
+++ b/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
@@ -114,6 +114,7 @@
 import com.google.gerrit.server.audit.ExtendedHttpAuditEvent;
 import com.google.gerrit.server.cache.PerThreadCache;
 import com.google.gerrit.server.cancellation.RequestCancelledException;
+import com.google.gerrit.server.cancellation.RequestStateProvider;
 import com.google.gerrit.server.change.ChangeFinder;
 import com.google.gerrit.server.change.RevisionResource;
 import com.google.gerrit.server.config.GerritServerConfig;
@@ -712,50 +713,45 @@
                 messageOr(e, "Quota limit reached"),
                 e.caching(),
                 e);
-      } catch (RequestCancelledException e) {
-        cause = Optional.of(e);
-        switch (e.getCancellationReason()) {
-          case CLIENT_CLOSED_REQUEST:
-            statusCode = SC_CLIENT_CLOSED_REQUEST;
-            break;
-          case CLIENT_PROVIDED_DEADLINE_EXCEEDED:
-          case SERVER_DEADLINE_EXCEEDED:
-            statusCode = SC_REQUEST_TIMEOUT;
-            break;
-        }
-
-        StringBuilder msg = new StringBuilder(e.formatCancellationReason());
-        if (e.getCancellationMessage().isPresent()) {
-          msg.append("\n\n");
-          msg.append(e.getCancellationMessage().get());
-        }
-
-        responseBytes = replyError(req, res, statusCode, msg.toString(), e);
       } catch (Exception e) {
         cause = Optional.of(e);
-        statusCode = SC_INTERNAL_SERVER_ERROR;
 
-        Optional<ExceptionHook.Status> status = getStatus(e);
-        statusCode = status.map(ExceptionHook.Status::statusCode).orElse(SC_INTERNAL_SERVER_ERROR);
-
-        if (res.isCommitted()) {
-          responseBytes = 0;
-          if (statusCode == SC_INTERNAL_SERVER_ERROR) {
-            logger.atSevere().withCause(e).log(
-                "Error in %s %s, response already committed", req.getMethod(), uriForLogging(req));
-          } else {
-            logger.atWarning().log(
-                "Response for %s %s already committed, wanted to set status %d",
-                req.getMethod(), uriForLogging(req), statusCode);
-          }
+        Optional<RequestCancelledException> requestCancelledException =
+            RequestCancelledException.getFromCausalChain(e);
+        if (requestCancelledException.isPresent()) {
+          statusCode =
+              getCancellationStatusCode(requestCancelledException.get().getCancellationReason());
+          responseBytes =
+              replyError(
+                  req, res, statusCode, getCancellationMessage(requestCancelledException.get()), e);
         } else {
-          res.reset();
-          traceContext.getTraceId().ifPresent(traceId -> res.addHeader(X_GERRIT_TRACE, traceId));
+          statusCode = SC_INTERNAL_SERVER_ERROR;
 
-          if (status.isPresent()) {
-            responseBytes = reply(req, res, e, status.get(), getUserMessages(traceContext, e));
+          Optional<ExceptionHook.Status> status = getStatus(e);
+          statusCode =
+              status.map(ExceptionHook.Status::statusCode).orElse(SC_INTERNAL_SERVER_ERROR);
+
+          if (res.isCommitted()) {
+            responseBytes = 0;
+            if (statusCode == SC_INTERNAL_SERVER_ERROR) {
+              logger.atSevere().withCause(e).log(
+                  "Error in %s %s, response already committed",
+                  req.getMethod(), uriForLogging(req));
+            } else {
+              logger.atWarning().log(
+                  "Response for %s %s already committed, wanted to set status %d",
+                  req.getMethod(), uriForLogging(req), statusCode);
+            }
           } else {
-            responseBytes = replyInternalServerError(req, res, e, getUserMessages(traceContext, e));
+            res.reset();
+            traceContext.getTraceId().ifPresent(traceId -> res.addHeader(X_GERRIT_TRACE, traceId));
+
+            if (status.isPresent()) {
+              responseBytes = reply(req, res, e, status.get(), getUserMessages(traceContext, e));
+            } else {
+              responseBytes =
+                  replyInternalServerError(req, res, e, getUserMessages(traceContext, e));
+            }
           }
         }
       } finally {
@@ -1961,6 +1957,28 @@
     return replyBinaryResult(req, res, BinaryResult.create(text).setContentType(PLAIN_TEXT));
   }
 
+  private static int getCancellationStatusCode(RequestStateProvider.Reason cancellationReason) {
+    switch (cancellationReason) {
+      case CLIENT_CLOSED_REQUEST:
+        return SC_CLIENT_CLOSED_REQUEST;
+      case CLIENT_PROVIDED_DEADLINE_EXCEEDED:
+      case SERVER_DEADLINE_EXCEEDED:
+        return SC_REQUEST_TIMEOUT;
+    }
+    logger.atSevere().log("Unexpected cancellation reason: %s", cancellationReason);
+    return SC_INTERNAL_SERVER_ERROR;
+  }
+
+  private static String getCancellationMessage(
+      RequestCancelledException requestCancelledException) {
+    StringBuilder msg = new StringBuilder(requestCancelledException.formatCancellationReason());
+    if (requestCancelledException.getCancellationMessage().isPresent()) {
+      msg.append("\n\n");
+      msg.append(requestCancelledException.getCancellationMessage().get());
+    }
+    return msg.toString();
+  }
+
   private static boolean acceptsGzip(HttpServletRequest req) {
     if (req != null) {
       String accepts = req.getHeader(HttpHeaders.ACCEPT_ENCODING);
diff --git a/java/com/google/gerrit/index/testing/AbstractFakeIndex.java b/java/com/google/gerrit/index/testing/AbstractFakeIndex.java
index 5cc8e3c..b727e96 100644
--- a/java/com/google/gerrit/index/testing/AbstractFakeIndex.java
+++ b/java/com/google/gerrit/index/testing/AbstractFakeIndex.java
@@ -36,6 +36,8 @@
 import com.google.gerrit.index.query.Predicate;
 import com.google.gerrit.index.query.ResultSet;
 import com.google.gerrit.server.account.AccountState;
+import com.google.gerrit.server.change.MergeabilityComputationBehavior;
+import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.config.SitePaths;
 import com.google.gerrit.server.index.IndexUtils;
 import com.google.gerrit.server.index.account.AccountIndex;
@@ -50,6 +52,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import org.eclipse.jgit.lib.Config;
 
 /**
  * Fake secondary index implementation for usage in tests. All values are kept in-memory.
@@ -179,14 +182,17 @@
   public static class FakeChangeIndex
       extends AbstractFakeIndex<Change.Id, ChangeData, Map<String, Object>> implements ChangeIndex {
     private final ChangeData.Factory changeDataFactory;
+    private final boolean skipMergable;
 
     @Inject
     FakeChangeIndex(
         SitePaths sitePaths,
         ChangeData.Factory changeDataFactory,
-        @Assisted Schema<ChangeData> schema) {
+        @Assisted Schema<ChangeData> schema,
+        @GerritServerConfig Config cfg) {
       super(schema, sitePaths, "changes");
       this.changeDataFactory = changeDataFactory;
+      this.skipMergable = !MergeabilityComputationBehavior.fromConfig(cfg).includeInIndex();
     }
 
     @Override
@@ -208,6 +214,9 @@
     protected Map<String, Object> docFor(ChangeData value) {
       ImmutableMap.Builder<String, Object> doc = ImmutableMap.builder();
       for (FieldDef<ChangeData, ?> field : getSchema().getFields().values()) {
+        if (ChangeField.MERGEABLE.getName().equals(field.getName()) && skipMergable) {
+          continue;
+        }
         Object docifiedValue = field.get(value);
         if (docifiedValue != null) {
           doc.put(field.getName(), field.get(value));
diff --git a/java/com/google/gerrit/lifecycle/LifecycleManager.java b/java/com/google/gerrit/lifecycle/LifecycleManager.java
index 4f09a09..42123d7 100644
--- a/java/com/google/gerrit/lifecycle/LifecycleManager.java
+++ b/java/com/google/gerrit/lifecycle/LifecycleManager.java
@@ -107,7 +107,7 @@
       LifecycleListener obj = listeners.get(i).get();
       try {
         obj.stop();
-      } catch (Throwable err) {
+      } catch (RuntimeException err) {
         logger.atWarning().withCause(err).log("Failed to stop %s", obj.getClass());
       }
       startedIndex = i - 1;
diff --git a/java/com/google/gerrit/pgm/Daemon.java b/java/com/google/gerrit/pgm/Daemon.java
index 2b4cfef..a3605f7 100644
--- a/java/com/google/gerrit/pgm/Daemon.java
+++ b/java/com/google/gerrit/pgm/Daemon.java
@@ -310,7 +310,7 @@
         RuntimeShutdown.waitFor();
       }
       return 0;
-    } catch (Throwable err) {
+    } catch (RuntimeException err) {
       logger.atSevere().withCause(err).log("Unable to start daemon");
       return 1;
     }
diff --git a/java/com/google/gerrit/pgm/http/jetty/JettyServer.java b/java/com/google/gerrit/pgm/http/jetty/JettyServer.java
index 89b4228..6f3514f 100644
--- a/java/com/google/gerrit/pgm/http/jetty/JettyServer.java
+++ b/java/com/google/gerrit/pgm/http/jetty/JettyServer.java
@@ -547,7 +547,7 @@
           filterHolder.setInitParameters(initParams);
         }
         app.addFilter(filterHolder, "/*", EnumSet.of(DispatcherType.REQUEST, DispatcherType.ASYNC));
-      } catch (Throwable e) {
+      } catch (Exception e) {
         throw new IllegalArgumentException(
             "Unable to instantiate front-end HTTP Filter " + filterClassName, e);
       }
diff --git a/java/com/google/gerrit/server/RequestCleanup.java b/java/com/google/gerrit/server/RequestCleanup.java
index f405c57..e07d148 100644
--- a/java/com/google/gerrit/server/RequestCleanup.java
+++ b/java/com/google/gerrit/server/RequestCleanup.java
@@ -44,7 +44,7 @@
       for (Iterator<Runnable> i = cleanup.iterator(); i.hasNext(); ) {
         try {
           i.next().run();
-        } catch (Throwable err) {
+        } catch (Exception err) {
           logger.atSevere().withCause(err).log("Failed to execute per-request cleanup");
         }
         i.remove();
diff --git a/java/com/google/gerrit/server/account/externalids/ExternalIdNotes.java b/java/com/google/gerrit/server/account/externalids/ExternalIdNotes.java
index 50a2f69..435a524 100644
--- a/java/com/google/gerrit/server/account/externalids/ExternalIdNotes.java
+++ b/java/com/google/gerrit/server/account/externalids/ExternalIdNotes.java
@@ -29,6 +29,7 @@
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.entities.RefNames;
+import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.git.ObjectIds;
 import com.google.gerrit.metrics.Counter0;
 import com.google.gerrit.metrics.Description;
@@ -97,12 +98,17 @@
     protected final ExternalIdCache externalIdCache;
     protected final MetricMaker metricMaker;
     protected final AllUsersName allUsersName;
+    protected final DynamicMap<ExternalIdUpsertPreprocessor> upsertPreprocessors;
 
     protected ExternalIdNotesLoader(
-        ExternalIdCache externalIdCache, MetricMaker metricMaker, AllUsersName allUsersName) {
+        ExternalIdCache externalIdCache,
+        MetricMaker metricMaker,
+        AllUsersName allUsersName,
+        DynamicMap<ExternalIdUpsertPreprocessor> upsertPreprocessors) {
       this.externalIdCache = externalIdCache;
       this.metricMaker = metricMaker;
       this.allUsersName = allUsersName;
+      this.upsertPreprocessors = upsertPreprocessors;
     }
 
     /**
@@ -192,21 +198,24 @@
         ExternalIdCache externalIdCache,
         Provider<AccountIndexer> accountIndexer,
         MetricMaker metricMaker,
-        AllUsersName allUsersName) {
-      super(externalIdCache, metricMaker, allUsersName);
+        AllUsersName allUsersName,
+        DynamicMap<ExternalIdUpsertPreprocessor> upsertPreprocessors) {
+      super(externalIdCache, metricMaker, allUsersName, upsertPreprocessors);
       this.accountIndexer = accountIndexer;
     }
 
     @Override
     public ExternalIdNotes load(Repository allUsersRepo)
         throws IOException, ConfigInvalidException {
-      return new ExternalIdNotes(metricMaker, allUsersName, allUsersRepo).load();
+      return new ExternalIdNotes(metricMaker, allUsersName, allUsersRepo, upsertPreprocessors)
+          .load();
     }
 
     @Override
     public ExternalIdNotes load(Repository allUsersRepo, @Nullable ObjectId rev)
         throws IOException, ConfigInvalidException {
-      return new ExternalIdNotes(metricMaker, allUsersName, allUsersRepo).load(rev);
+      return new ExternalIdNotes(metricMaker, allUsersName, allUsersRepo, upsertPreprocessors)
+          .load(rev);
     }
 
     @Override
@@ -220,20 +229,27 @@
 
     @Inject
     FactoryNoReindex(
-        ExternalIdCache externalIdCache, MetricMaker metricMaker, AllUsersName allUsersName) {
-      super(externalIdCache, metricMaker, allUsersName);
+        ExternalIdCache externalIdCache,
+        MetricMaker metricMaker,
+        AllUsersName allUsersName,
+        DynamicMap<ExternalIdUpsertPreprocessor> upsertPreprocessors) {
+      super(externalIdCache, metricMaker, allUsersName, upsertPreprocessors);
     }
 
     @Override
     public ExternalIdNotes load(Repository allUsersRepo)
         throws IOException, ConfigInvalidException {
-      return new ExternalIdNotes(metricMaker, allUsersName, allUsersRepo).setNoReindex().load();
+      return new ExternalIdNotes(metricMaker, allUsersName, allUsersRepo, upsertPreprocessors)
+          .setNoReindex()
+          .load();
     }
 
     @Override
     public ExternalIdNotes load(Repository allUsersRepo, @Nullable ObjectId rev)
         throws IOException, ConfigInvalidException {
-      return new ExternalIdNotes(metricMaker, allUsersName, allUsersRepo).setNoReindex().load(rev);
+      return new ExternalIdNotes(metricMaker, allUsersName, allUsersRepo, upsertPreprocessors)
+          .setNoReindex()
+          .load(rev);
     }
 
     @Override
@@ -255,7 +271,8 @@
   public static ExternalIdNotes loadReadOnly(
       AllUsersName allUsersName, Repository allUsersRepo, @Nullable ObjectId rev)
       throws IOException, ConfigInvalidException {
-    return new ExternalIdNotes(new DisabledMetricMaker(), allUsersName, allUsersRepo)
+    return new ExternalIdNotes(
+            new DisabledMetricMaker(), allUsersName, allUsersRepo, DynamicMap.emptyMap())
         .setReadOnly()
         .setNoCacheUpdate()
         .setNoReindex()
@@ -275,7 +292,8 @@
   public static ExternalIdNotes loadNoCacheUpdate(
       AllUsersName allUsersName, Repository allUsersRepo)
       throws IOException, ConfigInvalidException {
-    return new ExternalIdNotes(new DisabledMetricMaker(), allUsersName, allUsersRepo)
+    return new ExternalIdNotes(
+            new DisabledMetricMaker(), allUsersName, allUsersRepo, DynamicMap.emptyMap())
         .setNoCacheUpdate()
         .setNoReindex()
         .load();
@@ -284,6 +302,7 @@
   private final AllUsersName allUsersName;
   private final Counter0 updateCount;
   private final Repository repo;
+  private final DynamicMap<ExternalIdUpsertPreprocessor> upsertPreprocessors;
   private final CallerFinder callerFinder;
 
   private NoteMap noteMap;
@@ -312,13 +331,17 @@
   private boolean noReindex = false;
 
   private ExternalIdNotes(
-      MetricMaker metricMaker, AllUsersName allUsersName, Repository allUsersRepo) {
+      MetricMaker metricMaker,
+      AllUsersName allUsersName,
+      Repository allUsersRepo,
+      DynamicMap<ExternalIdUpsertPreprocessor> upsertPreprocessors) {
     this.updateCount =
         metricMaker.newCounter(
             "notedb/external_id_update_count",
             new Description("Total number of external ID updates.").setRate().setUnit("updates"));
     this.allUsersName = requireNonNull(allUsersName, "allUsersRepo");
     this.repo = requireNonNull(allUsersRepo, "allUsersRepo");
+    this.upsertPreprocessors = upsertPreprocessors;
     this.callerFinder =
         CallerFinder.builder()
             // 1. callers that come through ExternalIds
@@ -490,6 +513,7 @@
         (rw, n) -> {
           for (ExternalId extId : extIds) {
             ExternalId insertedExtId = upsert(rw, inserter, noteMap, extId);
+            preprocessUpsert(insertedExtId);
             newExtIds.add(insertedExtId);
           }
         });
@@ -519,6 +543,7 @@
         (rw, n) -> {
           for (ExternalId extId : extIds) {
             ExternalId updatedExtId = upsert(rw, inserter, noteMap, extId);
+            preprocessUpsert(updatedExtId);
             updatedExtIds.add(updatedExtId);
           }
         });
@@ -634,6 +659,7 @@
 
           for (ExternalId extId : toAdd) {
             ExternalId insertedExtId = upsert(rw, inserter, noteMap, extId);
+            preprocessUpsert(insertedExtId);
             updatedExtIds.add(insertedExtId);
           }
         });
@@ -667,6 +693,7 @@
 
           for (ExternalId extId : toAdd) {
             ExternalId insertedExtId = upsert(rw, inserter, noteMap, extId);
+            preprocessUpsert(insertedExtId);
             updatedExtIds.add(insertedExtId);
           }
         });
@@ -809,9 +836,9 @@
   }
 
   /**
-   * Insert or updates an new external ID and sets it in the note map.
+   * Inserts or updates a new external ID and sets it in the note map.
    *
-   * <p>If the external ID already exists it is overwritten.
+   * <p>If the external ID already exists, it is overwritten.
    */
   private static ExternalId upsert(
       RevWalk rw, ObjectInserter ins, NoteMap noteMap, ExternalId extId)
@@ -867,6 +894,7 @@
    * @return the external ID that was removed, {@code null} if no external ID with the specified key
    *     exists
    */
+  @Nullable
   private static ExternalId remove(
       RevWalk rw, NoteMap noteMap, ExternalId.Key extIdKey, Account.Id expectedAccountId)
       throws IOException, ConfigInvalidException {
@@ -917,6 +945,10 @@
     checkState(noteMap != null, "External IDs not loaded yet");
   }
 
+  private void preprocessUpsert(ExternalId extId) {
+    upsertPreprocessors.forEach(p -> p.get().upsert(extId));
+  }
+
   @FunctionalInterface
   private interface NoteMapUpdate {
     void execute(RevWalk rw, NoteMap noteMap)
diff --git a/java/com/google/gerrit/server/account/externalids/ExternalIdUpsertPreprocessor.java b/java/com/google/gerrit/server/account/externalids/ExternalIdUpsertPreprocessor.java
new file mode 100644
index 0000000..c0697db
--- /dev/null
+++ b/java/com/google/gerrit/server/account/externalids/ExternalIdUpsertPreprocessor.java
@@ -0,0 +1,30 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.account.externalids;
+
+import com.google.gerrit.extensions.annotations.ExtensionPoint;
+
+/**
+ * This optional preprocessor is called in {@link ExternalIdNotes} before an update is committed.
+ */
+@ExtensionPoint
+public interface ExternalIdUpsertPreprocessor {
+  /**
+   * Called when inserting or updating an external ID. {@link ExternalId#blobId()} is set. The
+   * upsert can be blocked by throwing {@link com.google.gerrit.exceptions.StorageException}, e.g.
+   * when a precondition or preparatory work fails.
+   */
+  void upsert(ExternalId extId);
+}
diff --git a/java/com/google/gerrit/server/cancellation/BUILD b/java/com/google/gerrit/server/cancellation/BUILD
new file mode 100644
index 0000000..05530a5
--- /dev/null
+++ b/java/com/google/gerrit/server/cancellation/BUILD
@@ -0,0 +1,14 @@
+load("@rules_java//java:defs.bzl", "java_library")
+
+java_library(
+    name = "cancellation",
+    srcs = glob(
+        ["*.java"],
+    ),
+    visibility = ["//visibility:public"],
+    deps = [
+        "//java/com/google/gerrit/common:annotations",
+        "//lib:guava",
+        "//lib/commons:lang",
+    ],
+)
diff --git a/java/com/google/gerrit/server/cancellation/RequestCancelledException.java b/java/com/google/gerrit/server/cancellation/RequestCancelledException.java
index 3c668fb..d89701f 100644
--- a/java/com/google/gerrit/server/cancellation/RequestCancelledException.java
+++ b/java/com/google/gerrit/server/cancellation/RequestCancelledException.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.cancellation;
 
+import com.google.common.base.Throwables;
 import com.google.gerrit.common.Nullable;
 import java.util.Optional;
 import org.apache.commons.lang.WordUtils;
@@ -22,6 +23,17 @@
 public class RequestCancelledException extends RuntimeException {
   private static final long serialVersionUID = 1L;
 
+  /**
+   * Checks whether the given exception was caused by {@link RequestCancelledException}. If yes, the
+   * {@link RequestCancelledException} is returned. If not, {@link Optional#empty()} is returned.
+   */
+  public static Optional<RequestCancelledException> getFromCausalChain(Throwable e) {
+    return Throwables.getCausalChain(e).stream()
+        .filter(RequestCancelledException.class::isInstance)
+        .map(RequestCancelledException.class::cast)
+        .findFirst();
+  }
+
   private final RequestStateProvider.Reason cancellationReason;
   private final Optional<String> cancellationMessage;
 
diff --git a/java/com/google/gerrit/server/cancellation/RequestStateContext.java b/java/com/google/gerrit/server/cancellation/RequestStateContext.java
new file mode 100644
index 0000000..183d779
--- /dev/null
+++ b/java/com/google/gerrit/server/cancellation/RequestStateContext.java
@@ -0,0 +1,136 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.cancellation;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.collect.ImmutableSet;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * Context that allows to register {@link RequestStateProvider}s.
+ *
+ * <p>The registered {@link RequestStateProvider}s are stored in {@link ThreadLocal} so that they
+ * can be accessed during the request execution (via {@link #getRequestStateProviders()}.
+ *
+ * <p>On {@link #close()} the {@link RequestStateProvider}s that have been registered by this {@code
+ * RequestStateContext} instance are removed from {@link ThreadLocal}.
+ *
+ * <p>Nesting {@code RequestStateContext}s is possible.
+ *
+ * <p>Currently there is no logic to automatically copy the {@link RequestStateContext} to
+ * background threads, but implementing this may be considered in the future. This means that by
+ * default we only support cancellation of the main thread, but not of background threads. That's
+ * fine as all significant work is being done in the main thread.
+ *
+ * <p>{@link com.google.gerrit.server.util.RequestContext} is also a context that is available for
+ * the time of the request, but it is not suitable to manage registrations of {@link
+ * RequestStateProvider}s. Hence {@link RequestStateProvider} registrations are managed by a
+ * separate context, which is this class, {@link RequestStateContext}:
+ *
+ * <ul>
+ *   <li>{@link com.google.gerrit.server.util.RequestContext} is an interface that has many
+ *       implementations and hence cannot manage a {@link ThreadLocal} state.
+ *   <li>{@link com.google.gerrit.server.util.RequestContext} is not an {@link AutoCloseable} and
+ *       hence cannot cleanup any {@link ThreadLocal} state on close (turning it into an {@link
+ *       AutoCloseable} would require a large refactoring).
+ *   <li>Despite the name {@link com.google.gerrit.server.util.RequestContext} is not only used for
+ *       requests scopes but also for other scopes that are not a request (e.g. plugin invocations,
+ *       email sending, manual scopes).
+ *   <li>{@link com.google.gerrit.server.util.RequestContext} is not copied to background and should
+ *       not be, but for {@link RequestStateContext} we may consider doing this in the future.
+ * </ul>
+ */
+public class RequestStateContext implements AutoCloseable {
+  /** The {@link RequestStateProvider}s that have been registered for the thread. */
+  private static final ThreadLocal<Set<RequestStateProvider>> threadLocalRequestStateProviders =
+      new ThreadLocal<>();
+
+  /**
+   * Aborts the current request by throwing a {@link RequestCancelledException} if any of the
+   * registered {@link RequestStateProvider}s reports the request as cancelled.
+   *
+   * @throws RequestCancelledException thrown if the current request is cancelled and should be
+   *     aborted
+   */
+  public static void abortIfCancelled() throws RequestCancelledException {
+    getRequestStateProviders()
+        .forEach(
+            requestStateProvider ->
+                requestStateProvider.checkIfCancelled(
+                    (reason, message) -> {
+                      throw new RequestCancelledException(reason, message);
+                    }));
+  }
+
+  /** Returns the {@link RequestStateProvider}s that have been registered for the thread. */
+  @VisibleForTesting
+  static ImmutableSet<RequestStateProvider> getRequestStateProviders() {
+    if (threadLocalRequestStateProviders.get() == null) {
+      return ImmutableSet.of();
+    }
+    return ImmutableSet.copyOf(threadLocalRequestStateProviders.get());
+  }
+
+  /** Opens a {@code RequestStateContext}. */
+  public static RequestStateContext open() {
+    return new RequestStateContext();
+  }
+
+  /**
+   * The {@link RequestStateProvider}s that have been registered by this {@code
+   * RequestStateContext}.
+   */
+  private Set<RequestStateProvider> requestStateProviders = new HashSet<>();
+
+  private RequestStateContext() {}
+
+  /**
+   * Registers a {@link RequestStateProvider}.
+   *
+   * @param requestStateProvider the {@link RequestStateProvider} that should be registered
+   * @return the {@code RequestStateContext} instance for chaining calls
+   */
+  public RequestStateContext addRequestStateProvider(RequestStateProvider requestStateProvider) {
+    if (threadLocalRequestStateProviders.get() == null) {
+      threadLocalRequestStateProviders.set(new HashSet<>());
+    }
+    if (threadLocalRequestStateProviders.get().add(requestStateProvider)) {
+      requestStateProviders.add(requestStateProvider);
+    }
+    return this;
+  }
+
+  /**
+   * Closes this {@code RequestStateContext}.
+   *
+   * <p>Ensures that all {@link RequestStateProvider}s that have been registered by this {@code
+   * RequestStateContext} instance are removed from {@link #threadLocalRequestStateProviders}.
+   *
+   * <p>If no {@link RequestStateProvider}s remain in {@link #threadLocalRequestStateProviders},
+   * {@link #threadLocalRequestStateProviders} is unset.
+   */
+  @Override
+  public void close() {
+    if (threadLocalRequestStateProviders.get() != null) {
+      requestStateProviders.forEach(
+          requestStateProvider ->
+              threadLocalRequestStateProviders.get().remove(requestStateProvider));
+      if (threadLocalRequestStateProviders.get().isEmpty()) {
+        threadLocalRequestStateProviders.remove();
+      }
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/cancellation/RequestStateProvider.java b/java/com/google/gerrit/server/cancellation/RequestStateProvider.java
index e1716eb..683ca1d 100644
--- a/java/com/google/gerrit/server/cancellation/RequestStateProvider.java
+++ b/java/com/google/gerrit/server/cancellation/RequestStateProvider.java
@@ -31,6 +31,7 @@
   void checkIfCancelled(OnCancelled onCancelled);
 
   /** Callback interface to be invoked if a request is cancelled. */
+  @FunctionalInterface
   interface OnCancelled {
     /**
      * Callback that is invoked if the request is cancelled.
diff --git a/java/com/google/gerrit/server/change/AbandonUtil.java b/java/com/google/gerrit/server/change/AbandonUtil.java
index 1bc1fad..d030ec1 100644
--- a/java/com/google/gerrit/server/change/AbandonUtil.java
+++ b/java/com/google/gerrit/server/change/AbandonUtil.java
@@ -93,7 +93,7 @@
         try {
           batchAbandon.batchAbandon(updateFactory, project, internalUser, changes, message);
           count += changes.size();
-        } catch (Throwable e) {
+        } catch (Exception e) {
           StringBuilder msg = new StringBuilder("Failed to auto-abandon inactive change(s):");
           for (ChangeData change : changes) {
             msg.append(" ").append(change.getId().get());
diff --git a/java/com/google/gerrit/server/change/ChangeResource.java b/java/com/google/gerrit/server/change/ChangeResource.java
index 27b71d6..0d0df0d 100644
--- a/java/com/google/gerrit/server/change/ChangeResource.java
+++ b/java/com/google/gerrit/server/change/ChangeResource.java
@@ -167,7 +167,6 @@
   public void prepareETag(Hasher h, CurrentUser user) {
     h.putInt(JSON_FORMAT_VERSION)
         .putLong(getChange().getLastUpdatedOn().getTime())
-        .putInt(getChange().getRowVersion())
         .putInt(user.isIdentifiedUser() ? user.getAccountId().get() : 0);
 
     if (user.isIdentifiedUser()) {
diff --git a/java/com/google/gerrit/server/config/GerritGlobalModule.java b/java/com/google/gerrit/server/config/GerritGlobalModule.java
index 076ba46..201f122 100644
--- a/java/com/google/gerrit/server/config/GerritGlobalModule.java
+++ b/java/com/google/gerrit/server/config/GerritGlobalModule.java
@@ -100,6 +100,7 @@
 import com.google.gerrit.server.account.ServiceUserClassifierImpl;
 import com.google.gerrit.server.account.VersionedAuthorizedKeys;
 import com.google.gerrit.server.account.externalids.ExternalIdModule;
+import com.google.gerrit.server.account.externalids.ExternalIdUpsertPreprocessor;
 import com.google.gerrit.server.approval.ApprovalCacheImpl;
 import com.google.gerrit.server.approval.ApprovalsUtil;
 import com.google.gerrit.server.auth.AuthBackend;
@@ -166,6 +167,7 @@
 import com.google.gerrit.server.mime.FileTypeRegistry;
 import com.google.gerrit.server.mime.MimeUtilFileTypeRegistry;
 import com.google.gerrit.server.notedb.NoteDbModule;
+import com.google.gerrit.server.notedb.StoreSubmitRequirementsOp;
 import com.google.gerrit.server.patch.DiffOperationsImpl;
 import com.google.gerrit.server.patch.PatchListCacheImpl;
 import com.google.gerrit.server.patch.PatchScriptFactory;
@@ -466,6 +468,7 @@
     factory(MergedByPushOp.Factory.class);
     factory(GitModules.Factory.class);
     factory(VersionedAuthorizedKeys.Factory.class);
+    factory(StoreSubmitRequirementsOp.Factory.class);
 
     bind(AccountManager.class);
     bind(SubscriptionGraph.Factory.class).to(ConfiguredSubscriptionGraphFactory.class);
@@ -476,5 +479,6 @@
     bind(ReloadPluginListener.class)
         .annotatedWith(UniqueAnnotations.create())
         .to(PluginConfigFactory.class);
+    DynamicMap.mapOf(binder(), ExternalIdUpsertPreprocessor.class);
   }
 }
diff --git a/java/com/google/gerrit/server/git/MultiProgressMonitor.java b/java/com/google/gerrit/server/git/MultiProgressMonitor.java
index 2d854a5..1122551 100644
--- a/java/com/google/gerrit/server/git/MultiProgressMonitor.java
+++ b/java/com/google/gerrit/server/git/MultiProgressMonitor.java
@@ -131,7 +131,7 @@
   private int spinnerIndex;
   private char spinnerState = NO_SPINNER;
   private boolean done;
-  private boolean write = true;
+  private boolean clientDisconnected;
 
   private final long maxIntervalNanos;
 
@@ -343,14 +343,14 @@
   }
 
   private void send(StringBuilder s) {
-    if (write) {
+    if (!clientDisconnected) {
       try {
         out.write(Constants.encode(s.toString()));
         out.flush();
       } catch (IOException e) {
         logger.atWarning().withCause(e).log(
             "Sending progress to client failed. Stop sending updates for task %s", taskName);
-        write = false;
+        clientDisconnected = true;
       }
     }
   }
diff --git a/java/com/google/gerrit/server/git/receive/BUILD b/java/com/google/gerrit/server/git/receive/BUILD
index b59d431..5c1cf52 100644
--- a/java/com/google/gerrit/server/git/receive/BUILD
+++ b/java/com/google/gerrit/server/git/receive/BUILD
@@ -18,6 +18,7 @@
         "//java/com/google/gerrit/index",
         "//java/com/google/gerrit/metrics",
         "//java/com/google/gerrit/server",
+        "//java/com/google/gerrit/server/cancellation",
         "//java/com/google/gerrit/server/logging",
         "//java/com/google/gerrit/server/restapi",
         "//java/com/google/gerrit/server/util/time",
diff --git a/java/com/google/gerrit/server/git/receive/ReceiveCommits.java b/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
index d074f1e..29c2698 100644
--- a/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
+++ b/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
@@ -46,6 +46,7 @@
 import com.google.common.base.Joiner;
 import com.google.common.base.Splitter;
 import com.google.common.base.Strings;
+import com.google.common.base.Throwables;
 import com.google.common.collect.BiMap;
 import com.google.common.collect.HashBiMap;
 import com.google.common.collect.ImmutableList;
@@ -645,10 +646,18 @@
       try {
         processCommandsUnsafe(commands, progress);
         rejectRemaining(commands, INTERNAL_SERVER_ERROR);
-      } catch (RequestCancelledException e) {
-        StringBuilder msg = new StringBuilder(e.formatCancellationReason());
-        if (e.getCancellationMessage().isPresent()) {
-          msg.append(String.format(" (%s)", e.getCancellationMessage().get()));
+      } catch (RuntimeException e) {
+        Optional<RequestCancelledException> requestCancelledException =
+            RequestCancelledException.getFromCausalChain(e);
+        if (!requestCancelledException.isPresent()) {
+          Throwables.throwIfUnchecked(e);
+        }
+        StringBuilder msg =
+            new StringBuilder(requestCancelledException.get().formatCancellationReason());
+        if (requestCancelledException.get().getCancellationMessage().isPresent()) {
+          msg.append(
+              String.format(
+                  " (%s)", requestCancelledException.get().getCancellationMessage().get()));
         }
         rejectRemaining(commands, msg.toString());
       }
diff --git a/java/com/google/gerrit/server/group/PeriodicGroupIndexer.java b/java/com/google/gerrit/server/group/PeriodicGroupIndexer.java
index cae213f..2823548 100644
--- a/java/com/google/gerrit/server/group/PeriodicGroupIndexer.java
+++ b/java/com/google/gerrit/server/group/PeriodicGroupIndexer.java
@@ -145,7 +145,7 @@
       }
       groupUuids = newGroupUuids;
       logger.atInfo().log("Run group indexer, %s groups reindexed", reindexCounter);
-    } catch (Throwable t) {
+    } catch (Exception t) {
       logger.atSevere().withCause(t).log("Failed to reindex groups");
     }
   }
diff --git a/java/com/google/gerrit/server/index/change/ChangeField.java b/java/com/google/gerrit/server/index/change/ChangeField.java
index 1ee12fe..5caceef 100644
--- a/java/com/google/gerrit/server/index/change/ChangeField.java
+++ b/java/com/google/gerrit/server/index/change/ChangeField.java
@@ -70,6 +70,7 @@
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.index.change.StalenessChecker.RefStatePattern;
 import com.google.gerrit.server.notedb.ReviewerStateInternal;
+import com.google.gerrit.server.notedb.SubmitRequirementProtoConverter;
 import com.google.gerrit.server.project.SubmitRuleOptions;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.query.change.ChangeQueryBuilder;
@@ -1078,6 +1079,27 @@
     return result;
   }
 
+  /** Serialized submit requirements, used for pre-populating results. */
+  public static final FieldDef<ChangeData, Iterable<byte[]>> STORED_SUBMIT_REQUIREMENTS =
+      storedOnly("full_submit_requirements")
+          .buildRepeatable(
+              cd ->
+                  toProtos(
+                      SubmitRequirementProtoConverter.INSTANCE, cd.submitRequirements().values()),
+              (cd, field) -> parseSubmitRequirements(field, cd));
+
+  private static void parseSubmitRequirements(Iterable<byte[]> values, ChangeData out) {
+    out.setSubmitRequirements(
+        StreamSupport.stream(values.spliterator(), false)
+            .map(
+                f ->
+                    SubmitRequirementProtoConverter.INSTANCE.fromProto(
+                        Protos.parseUnchecked(
+                            SubmitRequirementProtoConverter.INSTANCE.getParser(), f)))
+            .collect(
+                ImmutableMap.toImmutableMap(sr -> sr.submitRequirement(), Function.identity())));
+  }
+
   /**
    * All values of all refs that were used in the course of indexing this document.
    *
diff --git a/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java b/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java
index 879da4f..bee0c35 100644
--- a/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java
+++ b/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java
@@ -148,10 +148,14 @@
    * The computation of the {@link ChangeField#DIRECTORY} field is changed, hence reindexing is
    * required.
    */
-  static final Schema<ChangeData> V63 = schema(V62, false);
+  @Deprecated static final Schema<ChangeData> V63 = schema(V62, false);
 
   /** Added support for MIN/MAX/ANY for {@link ChangeField#LABEL} */
-  static final Schema<ChangeData> V64 = schema(V63, false);
+  @Deprecated static final Schema<ChangeData> V64 = schema(V63, false);
+
+  /** Added new field for submit requirements. */
+  static final Schema<ChangeData> V65 =
+      new Schema.Builder<ChangeData>().add(V64).add(ChangeField.STORED_SUBMIT_REQUIREMENTS).build();
 
   /**
    * Name of the change index to be used when contacting index backends or loading configurations.
diff --git a/java/com/google/gerrit/server/logging/BUILD b/java/com/google/gerrit/server/logging/BUILD
index c60af0d..ee0168c 100644
--- a/java/com/google/gerrit/server/logging/BUILD
+++ b/java/com/google/gerrit/server/logging/BUILD
@@ -9,6 +9,7 @@
     deps = [
         "//java/com/google/gerrit/common:annotations",
         "//java/com/google/gerrit/extensions:api",
+        "//java/com/google/gerrit/server/cancellation",
         "//java/com/google/gerrit/server/util/time",
         "//lib:gson",
         "//lib:guava",
diff --git a/java/com/google/gerrit/server/logging/PerformanceLogContext.java b/java/com/google/gerrit/server/logging/PerformanceLogContext.java
index b6dafdc..65e033b15 100644
--- a/java/com/google/gerrit/server/logging/PerformanceLogContext.java
+++ b/java/com/google/gerrit/server/logging/PerformanceLogContext.java
@@ -92,7 +92,7 @@
             p -> {
               try (TraceContext traceContext = newPluginTrace(p)) {
                 performanceLogRecords.forEach(r -> r.writeTo(p.get()));
-              } catch (Throwable e) {
+              } catch (RuntimeException e) {
                 logger.atWarning().withCause(e).log(
                     "Failure in %s of plugin %s", p.get().getClass(), p.getPluginName());
               }
diff --git a/java/com/google/gerrit/server/logging/TraceContext.java b/java/com/google/gerrit/server/logging/TraceContext.java
index 2fc19b5..681dfbc 100644
--- a/java/com/google/gerrit/server/logging/TraceContext.java
+++ b/java/com/google/gerrit/server/logging/TraceContext.java
@@ -24,6 +24,7 @@
 import com.google.common.collect.Table;
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.common.Nullable;
+import com.google.gerrit.server.cancellation.RequestStateContext;
 import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Consumer;
@@ -208,6 +209,7 @@
     }
 
     private TraceTimer(Runnable startLogFn, Consumer<Long> doneLogFn) {
+      RequestStateContext.abortIfCancelled();
       startLogFn.run();
       this.doneLogFn = doneLogFn;
       this.stopwatch = Stopwatch.createStarted();
@@ -217,6 +219,7 @@
     public void close() {
       stopwatch.stop();
       doneLogFn.accept(stopwatch.elapsed(TimeUnit.MILLISECONDS));
+      RequestStateContext.abortIfCancelled();
     }
   }
 
diff --git a/java/com/google/gerrit/server/notedb/ChangeNotesState.java b/java/com/google/gerrit/server/notedb/ChangeNotesState.java
index e7da025..4d6b9cf 100644
--- a/java/com/google/gerrit/server/notedb/ChangeNotesState.java
+++ b/java/com/google/gerrit/server/notedb/ChangeNotesState.java
@@ -61,14 +61,10 @@
 import com.google.gerrit.server.cache.proto.Cache.ChangeNotesStateProto.ReviewerByEmailSetEntryProto;
 import com.google.gerrit.server.cache.proto.Cache.ChangeNotesStateProto.ReviewerSetEntryProto;
 import com.google.gerrit.server.cache.proto.Cache.ChangeNotesStateProto.ReviewerStatusUpdateProto;
-import com.google.gerrit.server.cache.proto.Cache.SubmitRequirementResultProto;
 import com.google.gerrit.server.cache.serialize.CacheSerializer;
 import com.google.gerrit.server.cache.serialize.ObjectIdConverter;
-import com.google.gerrit.server.cache.serialize.entities.SubmitRequirementExpressionResultSerializer;
-import com.google.gerrit.server.cache.serialize.entities.SubmitRequirementSerializer;
 import com.google.gerrit.server.index.change.ChangeField.StoredSubmitRecord;
 import com.google.gson.Gson;
-import com.google.protobuf.Descriptors.FieldDescriptor;
 import java.sql.Timestamp;
 import java.time.Instant;
 import java.util.List;
@@ -478,11 +474,6 @@
     private static final Converter<String, ReviewerStateInternal> REVIEWER_STATE_CONVERTER =
         Enums.stringConverter(ReviewerStateInternal.class);
 
-    private static final FieldDescriptor SR_APPLICABILITY_EXPR_RESULT_FIELD =
-        SubmitRequirementResultProto.getDescriptor().findFieldByNumber(2);
-    private static final FieldDescriptor SR_OVERRIDE_EXPR_RESULT_FIELD =
-        SubmitRequirementResultProto.getDescriptor().findFieldByNumber(4);
-
     @Override
     public byte[] serialize(ChangeNotesState object) {
       checkArgument(object.metaId() != null, "meta ID is required in: %s", object);
@@ -539,7 +530,10 @@
       object.publishedComments().values().forEach(c -> b.addPublishedComment(GSON.toJson(c)));
       object
           .submitRequirementsResult()
-          .forEach(sr -> b.addSubmitRequirementResult(toSubmitRequirementResultProto(sr)));
+          .forEach(
+              sr ->
+                  b.addSubmitRequirementResult(
+                      SubmitRequirementProtoConverter.INSTANCE.toProto(sr)));
       b.setUpdateCount(object.updateCount());
       if (object.mergedOn() != null) {
         b.setMergedOnMillis(object.mergedOn().getTime());
@@ -634,53 +628,6 @@
       return builder.build();
     }
 
-    private static SubmitRequirementResultProto toSubmitRequirementResultProto(
-        SubmitRequirementResult r) {
-      SubmitRequirementResultProto.Builder builder = SubmitRequirementResultProto.newBuilder();
-      builder
-          .setSubmitRequirement(SubmitRequirementSerializer.serialize(r.submitRequirement()))
-          .setCommit(ObjectIdConverter.create().toByteString(r.patchSetCommitId()));
-      if (r.applicabilityExpressionResult().isPresent()) {
-        builder.setApplicabilityExpressionResult(
-            SubmitRequirementExpressionResultSerializer.serialize(
-                r.applicabilityExpressionResult().get()));
-      }
-      builder.setSubmittabilityExpressionResult(
-          SubmitRequirementExpressionResultSerializer.serialize(
-              r.submittabilityExpressionResult()));
-      if (r.overrideExpressionResult().isPresent()) {
-        builder.setOverrideExpressionResult(
-            SubmitRequirementExpressionResultSerializer.serialize(
-                r.overrideExpressionResult().get()));
-      }
-      return builder.build();
-    }
-
-    private static SubmitRequirementResult toSubmitRequirementResult(
-        SubmitRequirementResultProto proto) {
-      SubmitRequirementResult.Builder builder =
-          SubmitRequirementResult.builder()
-              .patchSetCommitId(ObjectIdConverter.create().fromByteString(proto.getCommit()))
-              .submitRequirement(
-                  SubmitRequirementSerializer.deserialize(proto.getSubmitRequirement()));
-      if (proto.hasField(SR_APPLICABILITY_EXPR_RESULT_FIELD)) {
-        builder.applicabilityExpressionResult(
-            Optional.of(
-                SubmitRequirementExpressionResultSerializer.deserialize(
-                    proto.getApplicabilityExpressionResult())));
-      }
-      builder.submittabilityExpressionResult(
-          SubmitRequirementExpressionResultSerializer.deserialize(
-              proto.getSubmittabilityExpressionResult()));
-      if (proto.hasField(SR_OVERRIDE_EXPR_RESULT_FIELD)) {
-        builder.overrideExpressionResult(
-            Optional.of(
-                SubmitRequirementExpressionResultSerializer.deserialize(
-                    proto.getOverrideExpressionResult())));
-      }
-      return builder.build();
-    }
-
     @Override
     public ChangeNotesState deserialize(byte[] in) {
       ChangeNotesStateProto proto = Protos.parseUnchecked(ChangeNotesStateProto.parser(), in);
@@ -728,7 +675,7 @@
                       .collect(toImmutableListMultimap(HumanComment::getCommitId, c -> c)))
               .submitRequirementsResult(
                   proto.getSubmitRequirementResultList().stream()
-                      .map(sr -> toSubmitRequirementResult(sr))
+                      .map(sr -> SubmitRequirementProtoConverter.INSTANCE.fromProto(sr))
                       .collect(toImmutableList()))
               .updateCount(proto.getUpdateCount())
               .mergedOn(proto.getHasMergedOn() ? new Timestamp(proto.getMergedOnMillis()) : null);
diff --git a/java/com/google/gerrit/server/notedb/StoreSubmitRequirementsOp.java b/java/com/google/gerrit/server/notedb/StoreSubmitRequirementsOp.java
index 47948d7..4d99f93 100644
--- a/java/com/google/gerrit/server/notedb/StoreSubmitRequirementsOp.java
+++ b/java/com/google/gerrit/server/notedb/StoreSubmitRequirementsOp.java
@@ -15,16 +15,26 @@
 package com.google.gerrit.server.notedb;
 
 import com.google.gerrit.entities.Change;
+import com.google.gerrit.server.project.SubmitRequirementsEvaluator;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.update.BatchUpdateOp;
 import com.google.gerrit.server.update.ChangeContext;
+import com.google.inject.Inject;
 
 /** A {@link BatchUpdateOp} that stores the evaluated submit requirements of a change in NoteDb. */
 public class StoreSubmitRequirementsOp implements BatchUpdateOp {
   private final ChangeData.Factory changeDataFactory;
+  private final SubmitRequirementsEvaluator evaluator;
 
-  public StoreSubmitRequirementsOp(ChangeData.Factory changeDataFactory) {
+  public interface Factory {
+    StoreSubmitRequirementsOp create();
+  }
+
+  @Inject
+  public StoreSubmitRequirementsOp(
+      ChangeData.Factory changeDataFactory, SubmitRequirementsEvaluator evaluator) {
     this.changeDataFactory = changeDataFactory;
+    this.evaluator = evaluator;
   }
 
   @Override
@@ -32,7 +42,7 @@
     Change change = ctx.getChange();
     ChangeData changeData = changeDataFactory.create(change);
     ChangeUpdate update = ctx.getUpdate(change.currentPatchSetId());
-    update.putSubmitRequirementResults(changeData.submitRequirements().values());
+    update.putSubmitRequirementResults(evaluator.getResults(changeData).values());
     return !changeData.submitRequirements().isEmpty();
   }
 }
diff --git a/java/com/google/gerrit/server/notedb/SubmitRequirementProtoConverter.java b/java/com/google/gerrit/server/notedb/SubmitRequirementProtoConverter.java
new file mode 100644
index 0000000..416b850
--- /dev/null
+++ b/java/com/google/gerrit/server/notedb/SubmitRequirementProtoConverter.java
@@ -0,0 +1,88 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.notedb;
+
+import com.google.errorprone.annotations.Immutable;
+import com.google.gerrit.entities.SubmitRequirementResult;
+import com.google.gerrit.entities.converter.ProtoConverter;
+import com.google.gerrit.server.cache.proto.Cache.SubmitRequirementResultProto;
+import com.google.gerrit.server.cache.serialize.ObjectIdConverter;
+import com.google.gerrit.server.cache.serialize.entities.SubmitRequirementExpressionResultSerializer;
+import com.google.gerrit.server.cache.serialize.entities.SubmitRequirementSerializer;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.Parser;
+import java.util.Optional;
+
+@Immutable
+public enum SubmitRequirementProtoConverter
+    implements ProtoConverter<SubmitRequirementResultProto, SubmitRequirementResult> {
+  INSTANCE;
+
+  private static final FieldDescriptor SR_APPLICABILITY_EXPR_RESULT_FIELD =
+      SubmitRequirementResultProto.getDescriptor().findFieldByNumber(2);
+  private static final FieldDescriptor SR_OVERRIDE_EXPR_RESULT_FIELD =
+      SubmitRequirementResultProto.getDescriptor().findFieldByNumber(4);
+
+  @Override
+  public SubmitRequirementResultProto toProto(SubmitRequirementResult r) {
+    SubmitRequirementResultProto.Builder builder = SubmitRequirementResultProto.newBuilder();
+    builder
+        .setSubmitRequirement(SubmitRequirementSerializer.serialize(r.submitRequirement()))
+        .setCommit(ObjectIdConverter.create().toByteString(r.patchSetCommitId()));
+    if (r.applicabilityExpressionResult().isPresent()) {
+      builder.setApplicabilityExpressionResult(
+          SubmitRequirementExpressionResultSerializer.serialize(
+              r.applicabilityExpressionResult().get()));
+    }
+    builder.setSubmittabilityExpressionResult(
+        SubmitRequirementExpressionResultSerializer.serialize(r.submittabilityExpressionResult()));
+    if (r.overrideExpressionResult().isPresent()) {
+      builder.setOverrideExpressionResult(
+          SubmitRequirementExpressionResultSerializer.serialize(
+              r.overrideExpressionResult().get()));
+    }
+    return builder.build();
+  }
+
+  @Override
+  public SubmitRequirementResult fromProto(SubmitRequirementResultProto proto) {
+    SubmitRequirementResult.Builder builder =
+        SubmitRequirementResult.builder()
+            .patchSetCommitId(ObjectIdConverter.create().fromByteString(proto.getCommit()))
+            .submitRequirement(
+                SubmitRequirementSerializer.deserialize(proto.getSubmitRequirement()));
+    if (proto.hasField(SR_APPLICABILITY_EXPR_RESULT_FIELD)) {
+      builder.applicabilityExpressionResult(
+          Optional.of(
+              SubmitRequirementExpressionResultSerializer.deserialize(
+                  proto.getApplicabilityExpressionResult())));
+    }
+    builder.submittabilityExpressionResult(
+        SubmitRequirementExpressionResultSerializer.deserialize(
+            proto.getSubmittabilityExpressionResult()));
+    if (proto.hasField(SR_OVERRIDE_EXPR_RESULT_FIELD)) {
+      builder.overrideExpressionResult(
+          Optional.of(
+              SubmitRequirementExpressionResultSerializer.deserialize(
+                  proto.getOverrideExpressionResult())));
+    }
+    return builder.build();
+  }
+
+  @Override
+  public Parser<SubmitRequirementResultProto> getParser() {
+    return SubmitRequirementResultProto.parser();
+  }
+}
diff --git a/java/com/google/gerrit/server/plugincontext/PluginContext.java b/java/com/google/gerrit/server/plugincontext/PluginContext.java
index 90d56c8..1cfee65 100644
--- a/java/com/google/gerrit/server/plugincontext/PluginContext.java
+++ b/java/com/google/gerrit/server/plugincontext/PluginContext.java
@@ -204,7 +204,7 @@
     try (TraceContext traceContext = newTrace(extension);
         Timer3.Context<String, String, String> ctx = pluginMetrics.startLatency(extension)) {
       extensionImplConsumer.run(extensionImpl);
-    } catch (Throwable e) {
+    } catch (Exception e) {
       pluginMetrics.incrementErrorCount(extension);
       logger.atWarning().withCause(e).log(
           "Failure in %s of plugin %s", extensionImpl.getClass(), extension.getPluginName());
@@ -233,7 +233,7 @@
     try (TraceContext traceContext = newTrace(extension);
         Timer3.Context<String, String, String> ctx = pluginMetrics.startLatency(extension)) {
       extensionConsumer.run(extension);
-    } catch (Throwable e) {
+    } catch (Exception e) {
       pluginMetrics.incrementErrorCount(extension);
       logger.atWarning().withCause(e).log(
           "Failure in %s of plugin %s", extensionImpl.getClass(), extension.getPluginName());
@@ -267,7 +267,7 @@
     try (TraceContext traceContext = newTrace(extension);
         Timer3.Context<String, String, String> ctx = pluginMetrics.startLatency(extension)) {
       extensionImplConsumer.run(extensionImpl);
-    } catch (Throwable e) {
+    } catch (Exception e) {
       Throwables.throwIfInstanceOf(e, exceptionClass);
       Throwables.throwIfUnchecked(e);
       pluginMetrics.incrementErrorCount(extension);
@@ -304,7 +304,7 @@
     try (TraceContext traceContext = newTrace(extension);
         Timer3.Context<String, String, String> ctx = pluginMetrics.startLatency(extension)) {
       extensionConsumer.run(extension);
-    } catch (Throwable e) {
+    } catch (Exception e) {
       Throwables.throwIfInstanceOf(e, exceptionClass);
       Throwables.throwIfUnchecked(e);
       pluginMetrics.incrementErrorCount(extension);
diff --git a/java/com/google/gerrit/server/plugins/PluginLoader.java b/java/com/google/gerrit/server/plugins/PluginLoader.java
index 0a06081..8d17d85 100644
--- a/java/com/google/gerrit/server/plugins/PluginLoader.java
+++ b/java/com/google/gerrit/server/plugins/PluginLoader.java
@@ -253,7 +253,7 @@
           FileSnapshot snapshot = FileSnapshot.save(off.toFile());
           Plugin offPlugin = loadPlugin(name, off, snapshot);
           disabled.put(name, offPlugin);
-        } catch (Throwable e) {
+        } catch (Exception e) {
           // This shouldn't happen, as the plugin was loaded earlier.
           logger.atWarning().withCause(e.getCause()).log(
               "Cannot load disabled plugin %s", active.getName());
@@ -510,7 +510,7 @@
       if (!newPlugin.isDisabled()) {
         try {
           newPlugin.start(env);
-        } catch (Throwable e) {
+        } catch (Exception e) {
           newPlugin.stop(env);
           throw e;
         }
@@ -528,7 +528,7 @@
       }
       broken.remove(name);
       return newPlugin;
-    } catch (Throwable err) {
+    } catch (Exception err) {
       broken.put(name, snapshot);
       throw new PluginInstallException(err);
     }
diff --git a/java/com/google/gerrit/server/project/SubmitRequirementsEvaluator.java b/java/com/google/gerrit/server/project/SubmitRequirementsEvaluator.java
index 65d9d9e..e66b974 100644
--- a/java/com/google/gerrit/server/project/SubmitRequirementsEvaluator.java
+++ b/java/com/google/gerrit/server/project/SubmitRequirementsEvaluator.java
@@ -14,6 +14,9 @@
 
 package com.google.gerrit.server.project;
 
+import static com.google.gerrit.server.project.ProjectCache.illegalState;
+
+import com.google.common.collect.ImmutableMap;
 import com.google.gerrit.entities.SubmitRequirement;
 import com.google.gerrit.entities.SubmitRequirementExpression;
 import com.google.gerrit.entities.SubmitRequirementExpressionResult;
@@ -26,16 +29,20 @@
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
+import java.util.Map;
 import java.util.Optional;
 
 /** Evaluates submit requirements for different change data. */
 @Singleton
 public class SubmitRequirementsEvaluator {
   private final Provider<ChangeQueryBuilder> changeQueryBuilderProvider;
+  private final ProjectCache projectCache;
 
   @Inject
-  private SubmitRequirementsEvaluator(Provider<ChangeQueryBuilder> changeQueryBuilderProvider) {
+  private SubmitRequirementsEvaluator(
+      Provider<ChangeQueryBuilder> changeQueryBuilderProvider, ProjectCache projectCache) {
     this.changeQueryBuilderProvider = changeQueryBuilderProvider;
+    this.projectCache = projectCache;
   }
 
   /**
@@ -50,6 +57,21 @@
     changeQueryBuilderProvider.get().parse(expression.expressionString());
   }
 
+  /**
+   * Evaluate and return all submit requirements for a change. Submit requirements are retrieved for
+   * the project containing the change and parent projects as well.
+   */
+  public Map<SubmitRequirement, SubmitRequirementResult> getResults(ChangeData cd) {
+    ProjectState state = projectCache.get(cd.project()).orElseThrow(illegalState(cd.project()));
+    Map<String, SubmitRequirement> requirements = state.getSubmitRequirements();
+    ImmutableMap.Builder<SubmitRequirement, SubmitRequirementResult> result =
+        ImmutableMap.builderWithExpectedSize(requirements.size());
+    for (SubmitRequirement requirement : requirements.values()) {
+      result.put(requirement, evaluate(requirement, cd));
+    }
+    return result.build();
+  }
+
   /** Evaluate a {@link SubmitRequirement} on a given {@link ChangeData}. */
   public SubmitRequirementResult evaluate(SubmitRequirement sr, ChangeData cd) {
     SubmitRequirementExpressionResult blockingResult =
diff --git a/java/com/google/gerrit/server/query/change/ChangeData.java b/java/com/google/gerrit/server/query/change/ChangeData.java
index f912250..8b4e4c7 100644
--- a/java/com/google/gerrit/server/query/change/ChangeData.java
+++ b/java/com/google/gerrit/server/query/change/ChangeData.java
@@ -38,7 +38,6 @@
 import com.google.common.flogger.FluentLogger;
 import com.google.common.primitives.Ints;
 import com.google.gerrit.common.Nullable;
-import com.google.gerrit.common.UsedAt;
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.entities.AttentionSetUpdate;
 import com.google.gerrit.entities.Change;
@@ -106,6 +105,7 @@
 import java.util.Optional;
 import java.util.Set;
 import java.util.function.Function;
+import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.PersonIdent;
@@ -932,21 +932,36 @@
     return messages;
   }
 
-  /** Get all submit requirements for this change, including those from parent projects. */
+  /**
+   * Get all evaluated submit requirements for this change, including those from parent projects.
+   * For closed changes, submit requirements are read from the change notes. For active changes,
+   * submit requirements are evaluated online.
+   *
+   * <p>For changes loaded from the index, the value will be set from index field {@link
+   * com.google.gerrit.server.index.change.ChangeField#STORED_SUBMIT_REQUIREMENTS}.
+   */
   public Map<SubmitRequirement, SubmitRequirementResult> submitRequirements() {
     if (submitRequirements == null) {
-      ProjectState state = projectCache.get(project()).orElseThrow(illegalState(project()));
-      Map<String, SubmitRequirement> requirements = state.getSubmitRequirements();
-      ImmutableMap.Builder<SubmitRequirement, SubmitRequirementResult> result =
-          ImmutableMap.builderWithExpectedSize(requirements.size());
-      for (SubmitRequirement requirement : requirements.values()) {
-        result.put(requirement, submitRequirementsEvaluator.evaluate(requirement, this));
+      if (!lazyload()) {
+        return Collections.emptyMap();
       }
-      submitRequirements = result.build();
+      Change c = change();
+      if (c != null && c.isClosed()) {
+        submitRequirements =
+            notes().getSubmitRequirementsResult().stream()
+                .collect(Collectors.toMap(r -> r.submitRequirement(), Function.identity()));
+      } else {
+        submitRequirements = submitRequirementsEvaluator.getResults(this);
+      }
     }
     return submitRequirements;
   }
 
+  public void setSubmitRequirements(
+      Map<SubmitRequirement, SubmitRequirementResult> submitRequirements) {
+    this.submitRequirements = submitRequirements;
+  }
+
   public List<SubmitRecord> submitRecords(SubmitRuleOptions options) {
     // If the change is not submitted yet, 'strict' and 'lenient' both have the same result. If the
     // change is submitted, SubmitRecord requested with 'strict' will contain just a single entry
@@ -1271,12 +1286,6 @@
     return refStates;
   }
 
-  @UsedAt(UsedAt.Project.GOOGLE)
-  public void setRefStates(Iterable<byte[]> refStates) {
-    // TODO(hanwen): remove Google use, and drop this method.
-    setRefStates(RefState.parseStates(refStates));
-  }
-
   public void setRefStates(ImmutableSetMultimap<Project.NameKey, RefState> refStates) {
     this.refStates = refStates;
     if (draftsByUser == null) {
diff --git a/java/com/google/gerrit/server/rules/PrologEnvironment.java b/java/com/google/gerrit/server/rules/PrologEnvironment.java
index 1a563ad..7d626da 100644
--- a/java/com/google/gerrit/server/rules/PrologEnvironment.java
+++ b/java/com/google/gerrit/server/rules/PrologEnvironment.java
@@ -143,7 +143,7 @@
     for (Iterator<Runnable> i = cleanup.iterator(); i.hasNext(); ) {
       try {
         i.next().run();
-      } catch (Throwable err) {
+      } catch (Exception err) {
         logger.atSevere().withCause(err).log("Failed to execute cleanup for PrologEnvironment");
       }
       i.remove();
diff --git a/java/com/google/gerrit/server/submit/MergeOp.java b/java/com/google/gerrit/server/submit/MergeOp.java
index 363cdca..942f024 100644
--- a/java/com/google/gerrit/server/submit/MergeOp.java
+++ b/java/com/google/gerrit/server/submit/MergeOp.java
@@ -241,6 +241,7 @@
   private final NotifyResolver notifyResolver;
   private final RetryHelper retryHelper;
   private final ChangeData.Factory changeDataFactory;
+  private final StoreSubmitRequirementsOp.Factory storeSubmitRequirementsOpFactory;
 
   // Changes that were updated by this MergeOp.
   private final Map<Change.Id, Change> updatedChanges;
@@ -274,7 +275,8 @@
       NotifyResolver notifyResolver,
       TopicMetrics topicMetrics,
       RetryHelper retryHelper,
-      ChangeData.Factory changeDataFactory) {
+      ChangeData.Factory changeDataFactory,
+      StoreSubmitRequirementsOp.Factory storeSubmitRequirementsOpFactory) {
     this.cmUtil = cmUtil;
     this.batchUpdateFactory = batchUpdateFactory;
     this.internalUserFactory = internalUserFactory;
@@ -291,6 +293,7 @@
     this.topicMetrics = topicMetrics;
     this.changeDataFactory = changeDataFactory;
     this.updatedChanges = new HashMap<>();
+    this.storeSubmitRequirementsOpFactory = storeSubmitRequirementsOpFactory;
   }
 
   @Override
@@ -665,7 +668,7 @@
         Change.Id changeId = entry.getKey();
         batchUpdatesByProject
             .get(project)
-            .addOp(changeId, new StoreSubmitRequirementsOp(changeDataFactory));
+            .addOp(changeId, storeSubmitRequirementsOpFactory.create());
       }
       try {
         submissionExecutor.setAdditionalBatchUpdateListeners(
diff --git a/java/com/google/gerrit/server/update/RetryableChangeAction.java b/java/com/google/gerrit/server/update/RetryableChangeAction.java
index 152db2c..84ec2bb 100644
--- a/java/com/google/gerrit/server/update/RetryableChangeAction.java
+++ b/java/com/google/gerrit/server/update/RetryableChangeAction.java
@@ -82,11 +82,11 @@
   public T call() throws UpdateException, RestApiException {
     try {
       return super.call();
-    } catch (Throwable t) {
-      Throwables.throwIfUnchecked(t);
-      Throwables.throwIfInstanceOf(t, UpdateException.class);
-      Throwables.throwIfInstanceOf(t, RestApiException.class);
-      throw new UpdateException(t);
+    } catch (Exception e) {
+      Throwables.throwIfUnchecked(e);
+      Throwables.throwIfInstanceOf(e, UpdateException.class);
+      Throwables.throwIfInstanceOf(e, RestApiException.class);
+      throw new UpdateException(e);
     }
   }
 }
diff --git a/java/com/google/gerrit/server/update/RetryableIndexQueryAction.java b/java/com/google/gerrit/server/update/RetryableIndexQueryAction.java
index cf733a6..d66edcf 100644
--- a/java/com/google/gerrit/server/update/RetryableIndexQueryAction.java
+++ b/java/com/google/gerrit/server/update/RetryableIndexQueryAction.java
@@ -87,9 +87,9 @@
   public T call() {
     try {
       return super.call();
-    } catch (Throwable t) {
-      Throwables.throwIfUnchecked(t);
-      throw new StorageException(t);
+    } catch (Exception e) {
+      Throwables.throwIfUnchecked(e);
+      throw new StorageException(e);
     }
   }
 }
diff --git a/java/com/google/gerrit/sshd/BUILD b/java/com/google/gerrit/sshd/BUILD
index 0668c1e..f3bd5e1 100644
--- a/java/com/google/gerrit/sshd/BUILD
+++ b/java/com/google/gerrit/sshd/BUILD
@@ -17,6 +17,7 @@
         "//java/com/google/gerrit/metrics",
         "//java/com/google/gerrit/server",
         "//java/com/google/gerrit/server/audit",
+        "//java/com/google/gerrit/server/cancellation",
         "//java/com/google/gerrit/server/git/receive",
         "//java/com/google/gerrit/server/ioutil",
         "//java/com/google/gerrit/server/logging",
diff --git a/java/com/google/gerrit/sshd/BaseCommand.java b/java/com/google/gerrit/sshd/BaseCommand.java
index 48a5512..42aabfb 100644
--- a/java/com/google/gerrit/sshd/BaseCommand.java
+++ b/java/com/google/gerrit/sshd/BaseCommand.java
@@ -370,7 +370,7 @@
         err.flush();
       } catch (IOException e2) {
         // Ignored
-      } catch (Throwable e2) {
+      } catch (RuntimeException e2) {
         logger.atWarning().withCause(e2).log("Cannot send failure message to client");
       }
       return f.exitCode;
@@ -381,7 +381,7 @@
       err.flush();
     } catch (IOException e2) {
       // Ignored
-    } catch (Throwable e2) {
+    } catch (RuntimeException e2) {
       logger.atWarning().withCause(e2).log("Cannot send internal server error message to client");
     }
     return 128;
@@ -500,15 +500,15 @@
 
           out.flush();
           err.flush();
-        } catch (Throwable e) {
+        } catch (Exception e) {
           try {
             out.flush();
-          } catch (Throwable e2) {
+          } catch (Exception e2) {
             // Ignored
           }
           try {
             err.flush();
-          } catch (Throwable e2) {
+          } catch (Exception e2) {
             // Ignored
           }
           rc = handleError(e);
diff --git a/java/com/google/gerrit/sshd/SshCommand.java b/java/com/google/gerrit/sshd/SshCommand.java
index 93c6c2c..e58040f 100644
--- a/java/com/google/gerrit/sshd/SshCommand.java
+++ b/java/com/google/gerrit/sshd/SshCommand.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.sshd;
 
+import com.google.common.base.Throwables;
 import com.google.gerrit.extensions.registration.DynamicSet;
 import com.google.gerrit.server.AccessPath;
 import com.google.gerrit.server.DynamicOptions;
@@ -28,6 +29,7 @@
 import com.google.inject.Inject;
 import java.io.IOException;
 import java.io.PrintWriter;
+import java.util.Optional;
 import org.apache.sshd.server.Environment;
 import org.apache.sshd.server.channel.ChannelSession;
 import org.eclipse.jgit.lib.Config;
@@ -62,10 +64,18 @@
                   RequestInfo.builder(RequestInfo.RequestType.SSH, user, traceContext).build();
               requestListeners.runEach(l -> l.onRequest(requestInfo));
               SshCommand.this.run();
-            } catch (RequestCancelledException e) {
-              StringBuilder msg = new StringBuilder(e.formatCancellationReason());
-              if (e.getCancellationMessage().isPresent()) {
-                msg.append(String.format(" (%s)", e.getCancellationMessage().get()));
+            } catch (RuntimeException e) {
+              Optional<RequestCancelledException> requestCancelledException =
+                  RequestCancelledException.getFromCausalChain(e);
+              if (!requestCancelledException.isPresent()) {
+                Throwables.throwIfUnchecked(e);
+              }
+              StringBuilder msg =
+                  new StringBuilder(requestCancelledException.get().formatCancellationReason());
+              if (requestCancelledException.get().getCancellationMessage().isPresent()) {
+                msg.append(
+                    String.format(
+                        " (%s)", requestCancelledException.get().getCancellationMessage().get()));
               }
               stderr.println(msg.toString());
             } finally {
diff --git a/java/com/google/gerrit/sshd/SshKeyCacheImpl.java b/java/com/google/gerrit/sshd/SshKeyCacheImpl.java
index 773c25b..d5f0ee8 100644
--- a/java/com/google/gerrit/sshd/SshKeyCacheImpl.java
+++ b/java/com/google/gerrit/sshd/SshKeyCacheImpl.java
@@ -138,7 +138,7 @@
         // to do with the key object, and instead we must abort this load.
         //
         throw e;
-      } catch (Throwable e) {
+      } catch (Exception e) {
         markInvalid(k);
       }
     }
diff --git a/java/com/google/gerrit/sshd/commands/UploadArchive.java b/java/com/google/gerrit/sshd/commands/UploadArchive.java
index 0eda433..c1f4a7b 100644
--- a/java/com/google/gerrit/sshd/commands/UploadArchive.java
+++ b/java/com/google/gerrit/sshd/commands/UploadArchive.java
@@ -214,16 +214,16 @@
       } catch (GitAPIException e) {
         throw new Failure(7, "fatal: git api exception, " + e);
       }
-    } catch (Throwable t) {
+    } catch (Exception e) {
       // Report the error in ERROR sideband channel. Catch Throwable too so we can also catch
       // NoClassDefFound.
       try (SideBandOutputStream sidebandError =
           new SideBandOutputStream(
               SideBandOutputStream.CH_ERROR, SideBandOutputStream.MAX_BUF, out)) {
-        sidebandError.write(t.getMessage().getBytes(UTF_8));
+        sidebandError.write(e.getMessage().getBytes(UTF_8));
         sidebandError.flush();
       }
-      throw t;
+      throw e;
     } finally {
       // In any case, cleanly close the packetOut channel
       packetOut.end();
diff --git a/java/com/google/gerrit/testing/InMemoryModule.java b/java/com/google/gerrit/testing/InMemoryModule.java
index 06d9453..12da2c1 100644
--- a/java/com/google/gerrit/testing/InMemoryModule.java
+++ b/java/com/google/gerrit/testing/InMemoryModule.java
@@ -134,7 +134,6 @@
     cfg.setString("user", null, "name", "Gerrit Code Review");
     cfg.setString("user", null, "email", "gerrit@localhost");
     cfg.unset("cache", null, "directory");
-    cfg.setString("index", null, "type", "lucene");
     cfg.setBoolean("index", "lucene", "testInmemory", true);
     cfg.setInt("sendemail", null, "threadPoolSize", 0);
     cfg.setBoolean("receive", null, "enableSignedPush", false);
@@ -240,7 +239,8 @@
     bind(AllChangesIndexer.class).toProvider(Providers.of(null));
     bind(AllGroupsIndexer.class).toProvider(Providers.of(null));
 
-    IndexType indexType = new IndexType(cfg.getString("index", null, "type"));
+    String indexTypeCfg = cfg.getString("index", null, "type");
+    IndexType indexType = new IndexType(indexTypeCfg != null ? indexTypeCfg : "fake");
     // For custom index types, callers must provide their own module.
     if (indexType.isLucene()) {
       install(luceneIndexModule());
diff --git a/java/com/google/gerrit/testing/IndexConfig.java b/java/com/google/gerrit/testing/IndexConfig.java
index daef2b3..d68dcad 100644
--- a/java/com/google/gerrit/testing/IndexConfig.java
+++ b/java/com/google/gerrit/testing/IndexConfig.java
@@ -38,7 +38,9 @@
   }
 
   public static Config createForLucene() {
-    return create();
+    Config cfg = create();
+    cfg.setString("index", null, "type", "lucene");
+    return cfg;
   }
 
   public static Config createForElasticsearch() {
diff --git a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
index c08aa7f..7785776 100644
--- a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
@@ -4325,6 +4325,101 @@
   }
 
   @Test
+  public void submitRequirement_retrievedFromNoteDbForClosedChanges() throws Exception {
+    configSubmitRequirement(
+        project,
+        SubmitRequirement.builder()
+            .setName("code-review")
+            .setSubmittabilityExpression(SubmitRequirementExpression.create("label:code-review=+2"))
+            .setAllowOverrideInChildProjects(false)
+            .build());
+
+    PushOneCommit.Result r = createChange();
+    String changeId = r.getChangeId();
+
+    ChangeInfo change = gApi.changes().id(changeId).get();
+    assertThat(change.submitRequirements).hasSize(1);
+    assertSubmitRequirementStatus(change.submitRequirements, "code-review", Status.UNSATISFIED);
+
+    voteLabel(changeId, "code-review", 2);
+
+    change = gApi.changes().id(changeId).get();
+    assertThat(change.submitRequirements).hasSize(1);
+    assertSubmitRequirementStatus(change.submitRequirements, "code-review", Status.SATISFIED);
+
+    gApi.changes().id(changeId).current().submit();
+
+    // Add new submit requirement
+    configSubmitRequirement(
+        project,
+        SubmitRequirement.builder()
+            .setName("verified")
+            .setSubmittabilityExpression(SubmitRequirementExpression.create("label:verified=+1"))
+            .setAllowOverrideInChildProjects(false)
+            .build());
+
+    // The new "verified" submit requirement is not returned, since this change is closed
+    change = gApi.changes().id(changeId).get();
+    assertThat(change.submitRequirements).hasSize(1);
+    assertSubmitRequirementStatus(change.submitRequirements, "code-review", Status.SATISFIED);
+  }
+
+  @Test
+  public void submitRequirement_backFilledFromIndexForActiveChanges() throws Exception {
+    configSubmitRequirement(
+        project,
+        SubmitRequirement.builder()
+            .setName("code-review")
+            .setSubmittabilityExpression(SubmitRequirementExpression.create("label:code-review=+2"))
+            .setAllowOverrideInChildProjects(false)
+            .build());
+
+    PushOneCommit.Result r = createChange();
+    String changeId = r.getChangeId();
+
+    voteLabel(changeId, "code-review", 2);
+
+    // Query the change. ChangeInfo is back-filled from the change index.
+    List<ChangeInfo> changeInfos =
+        gApi.changes()
+            .query()
+            .withQuery("project:{" + project.get() + "} (status:open OR status:closed)")
+            .withOptions(ImmutableSet.of(ListChangesOption.SUBMIT_REQUIREMENTS))
+            .get();
+    assertThat(changeInfos).hasSize(1);
+    assertSubmitRequirementStatus(
+        changeInfos.get(0).submitRequirements, "code-review", Status.SATISFIED);
+  }
+
+  @Test
+  public void submitRequirement_backFilledFromIndexForClosedChanges() throws Exception {
+    configSubmitRequirement(
+        project,
+        SubmitRequirement.builder()
+            .setName("code-review")
+            .setSubmittabilityExpression(SubmitRequirementExpression.create("label:code-review=+2"))
+            .setAllowOverrideInChildProjects(false)
+            .build());
+
+    PushOneCommit.Result r = createChange();
+    String changeId = r.getChangeId();
+
+    voteLabel(changeId, "code-review", 2);
+    gApi.changes().id(changeId).current().submit();
+
+    // Query the change. ChangeInfo is back-filled from the change index.
+    List<ChangeInfo> changeInfos =
+        gApi.changes()
+            .query()
+            .withQuery("project:{" + project.get() + "} (status:open OR status:closed)")
+            .withOptions(ImmutableSet.of(ListChangesOption.SUBMIT_REQUIREMENTS))
+            .get();
+    assertThat(changeInfos).hasSize(1);
+    assertSubmitRequirementStatus(
+        changeInfos.get(0).submitRequirements, "code-review", Status.SATISFIED);
+  }
+
+  @Test
   public void fourByteEmoji() throws Exception {
     // U+1F601 GRINNING FACE WITH SMILING EYES
     String smile = new String(Character.toChars(0x1f601));
diff --git a/javatests/com/google/gerrit/acceptance/rest/BUILD b/javatests/com/google/gerrit/acceptance/rest/BUILD
index 84887da..a62d551 100644
--- a/javatests/com/google/gerrit/acceptance/rest/BUILD
+++ b/javatests/com/google/gerrit/acceptance/rest/BUILD
@@ -5,6 +5,7 @@
     group = "rest_bindings_collection",
     labels = ["rest"],
     deps = [
+        "//java/com/google/gerrit/server/cancellation",
         "//java/com/google/gerrit/server/logging",
     ],
 )
diff --git a/javatests/com/google/gerrit/acceptance/rest/CancellationIT.java b/javatests/com/google/gerrit/acceptance/rest/CancellationIT.java
index 29d54cc..0713fe6 100644
--- a/javatests/com/google/gerrit/acceptance/rest/CancellationIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/CancellationIT.java
@@ -121,6 +121,27 @@
   }
 
   @Test
+  public void handleWrappedRequestCancelledException() throws Exception {
+    ProjectCreationValidationListener projectCreationListener =
+        new ProjectCreationValidationListener() {
+          @Override
+          public void validateNewProject(CreateProjectArgs args) throws ValidationException {
+            // Simulate an exceeded deadline by throwing RequestCancelledException.
+            throw new RuntimeException(
+                new RequestCancelledException(
+                    RequestStateProvider.Reason.SERVER_DEADLINE_EXCEEDED, "deadline = 10m"));
+          }
+        };
+    try (Registration registration =
+        extensionRegistry.newRegistration().add(projectCreationListener)) {
+      RestResponse response = adminRestSession.put("/projects/" + name("new"));
+      assertThat(response.getStatusCode()).isEqualTo(SC_REQUEST_TIMEOUT);
+      assertThat(response.getEntityContent())
+          .isEqualTo("Server Deadline Exceeded\n\ndeadline = 10m");
+    }
+  }
+
+  @Test
   public void handleClientDisconnectedForPush() throws Exception {
     CommitValidationListener commitValidationListener =
         new CommitValidationListener() {
@@ -185,6 +206,27 @@
   }
 
   @Test
+  public void handleWrappedRequestCancelledExceptionForPush() throws Exception {
+    CommitValidationListener commitValidationListener =
+        new CommitValidationListener() {
+          @Override
+          public List<CommitValidationMessage> onCommitReceived(CommitReceivedEvent receiveEvent)
+              throws CommitValidationException {
+            // Simulate an exceeded deadline by throwing RequestCancelledException.
+            throw new RuntimeException(
+                new RequestCancelledException(
+                    RequestStateProvider.Reason.SERVER_DEADLINE_EXCEEDED, "deadline = 10m"));
+          }
+        };
+    try (Registration registration =
+        extensionRegistry.newRegistration().add(commitValidationListener)) {
+      PushOneCommit push = pushFactory.create(admin.newIdent(), testRepo);
+      PushOneCommit.Result r = push.to("refs/heads/master");
+      r.assertErrorStatus("Server Deadline Exceeded (deadline = 10m)");
+    }
+  }
+
+  @Test
   public void handleRequestCancellationWithMessageForPush() throws Exception {
     CommitValidationListener commitValidationListener =
         new CommitValidationListener() {
diff --git a/javatests/com/google/gerrit/acceptance/server/notedb/ExternalIdNotesUpsertPreprocessorIT.java b/javatests/com/google/gerrit/acceptance/server/notedb/ExternalIdNotesUpsertPreprocessorIT.java
new file mode 100644
index 0000000..64ad900
--- /dev/null
+++ b/javatests/com/google/gerrit/acceptance/server/notedb/ExternalIdNotesUpsertPreprocessorIT.java
@@ -0,0 +1,209 @@
+// Copyright (C) 2021 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.acceptance.server.notedb;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.gerrit.testing.GerritJUnit.assertThrows;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.gerrit.acceptance.LightweightPluginDaemonTest;
+import com.google.gerrit.acceptance.TestPlugin;
+import com.google.gerrit.entities.Account;
+import com.google.gerrit.exceptions.StorageException;
+import com.google.gerrit.extensions.annotations.Exports;
+import com.google.gerrit.server.ServerInitiated;
+import com.google.gerrit.server.account.Accounts;
+import com.google.gerrit.server.account.AccountsUpdate;
+import com.google.gerrit.server.account.externalids.ExternalId;
+import com.google.gerrit.server.account.externalids.ExternalIdNotes;
+import com.google.gerrit.server.account.externalids.ExternalIdUpsertPreprocessor;
+import com.google.gerrit.server.git.meta.MetaDataUpdate;
+import com.google.gerrit.server.notedb.Sequences;
+import com.google.inject.AbstractModule;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+import com.google.inject.Singleton;
+import java.util.ArrayList;
+import java.util.List;
+import org.eclipse.jgit.lib.Repository;
+import org.junit.Before;
+import org.junit.Test;
+
+/** Tests {@link ExternalIdUpsertPreprocessor}. */
+@TestPlugin(
+    name = "external-id-update-preprocessor",
+    sysModule =
+        "com.google.gerrit.acceptance.server.notedb.ExternalIdNotesUpsertPreprocessorIT$Module")
+public class ExternalIdNotesUpsertPreprocessorIT extends LightweightPluginDaemonTest {
+  @Inject private Sequences sequences;
+  @Inject private @ServerInitiated Provider<AccountsUpdate> accountsUpdateProvider;
+  @Inject private ExternalIdNotes.Factory extIdNotesFactory;
+  @Inject private Accounts accounts;
+
+  public static class Module extends AbstractModule {
+    @Override
+    protected void configure() {
+      bind(ExternalIdUpsertPreprocessor.class)
+          .annotatedWith(Exports.named("TestPreprocessor"))
+          .to(TestPreprocessor.class);
+    }
+  }
+
+  private TestPreprocessor testPreprocessor;
+
+  @Before
+  public void setUp() {
+    testPreprocessor = plugin.getSysInjector().getInstance(TestPreprocessor.class);
+    testPreprocessor.reset();
+  }
+
+  @Test
+  public void insertAccount() throws Exception {
+    Account.Id id = Account.id(sequences.nextAccountId());
+    ExternalId extId = ExternalId.create("foo", "bar", id);
+    accountsUpdateProvider.get().insert("test", id, u -> u.addExternalId(extId));
+    assertThat(testPreprocessor.upserted).containsExactly(extId);
+  }
+
+  @Test
+  public void replaceByKeys() throws Exception {
+    Account.Id id = Account.id(sequences.nextAccountId());
+    ExternalId extId1 = ExternalId.create("foo", "bar1", id);
+    ExternalId extId2 = ExternalId.create("foo", "bar2", id);
+    accountsUpdateProvider.get().insert("test", id, u -> u.addExternalId(extId1));
+
+    testPreprocessor.reset();
+    try (Repository allUsersRepo = repoManager.openRepository(allUsers);
+        MetaDataUpdate md = metaDataUpdateFactory.create(allUsers)) {
+      ExternalIdNotes extIdNotes = extIdNotesFactory.load(allUsersRepo);
+      extIdNotes.replaceByKeys(ImmutableSet.of(extId1.key()), ImmutableSet.of(extId2));
+      extIdNotes.commit(md);
+    }
+    assertThat(testPreprocessor.upserted).containsExactly(extId2);
+  }
+
+  @Test
+  public void insert() throws Exception {
+    Account.Id id = Account.id(sequences.nextAccountId());
+    ExternalId extId = ExternalId.create("foo", "bar", id);
+
+    try (Repository allUsersRepo = repoManager.openRepository(allUsers);
+        MetaDataUpdate md = metaDataUpdateFactory.create(allUsers)) {
+      ExternalIdNotes extIdNotes = extIdNotesFactory.load(allUsersRepo);
+      extIdNotes.insert(extId);
+      extIdNotes.commit(md);
+    }
+    assertThat(testPreprocessor.upserted).containsExactly(extId);
+  }
+
+  @Test
+  public void upsert() throws Exception {
+    Account.Id id = Account.id(sequences.nextAccountId());
+    ExternalId extId = ExternalId.create("foo", "bar", id);
+
+    try (Repository allUsersRepo = repoManager.openRepository(allUsers);
+        MetaDataUpdate md = metaDataUpdateFactory.create(allUsers)) {
+      ExternalIdNotes extIdNotes = extIdNotesFactory.load(allUsersRepo);
+      extIdNotes.upsert(extId);
+      extIdNotes.commit(md);
+    }
+    assertThat(testPreprocessor.upserted).containsExactly(extId);
+  }
+
+  @Test
+  public void replace() throws Exception {
+    Account.Id id = Account.id(sequences.nextAccountId());
+    ExternalId extId1 = ExternalId.create("foo", "bar1", id);
+    ExternalId extId2 = ExternalId.create("foo", "bar2", id);
+    accountsUpdateProvider.get().insert("test", id, u -> u.addExternalId(extId1));
+
+    testPreprocessor.reset();
+    try (Repository allUsersRepo = repoManager.openRepository(allUsers);
+        MetaDataUpdate md = metaDataUpdateFactory.create(allUsers)) {
+      ExternalIdNotes extIdNotes = extIdNotesFactory.load(allUsersRepo);
+      extIdNotes.replace(ImmutableSet.of(extId1), ImmutableSet.of(extId2));
+      extIdNotes.commit(md);
+    }
+    assertThat(testPreprocessor.upserted).containsExactly(extId2);
+  }
+
+  @Test
+  public void replace_viaAccountsUpdate() throws Exception {
+    Account.Id id = Account.id(sequences.nextAccountId());
+    ExternalId extId1 = ExternalId.create("foo", "bar", id, "email1@foo", "hash");
+    ExternalId extId2 = ExternalId.create("foo", "bar", id, "email2@foo", "hash");
+    accountsUpdateProvider.get().insert("test", id, u -> u.addExternalId(extId1));
+
+    testPreprocessor.reset();
+    accountsUpdateProvider.get().update("test", id, u -> u.updateExternalId(extId2));
+    assertThat(testPreprocessor.upserted).containsExactly(extId2);
+  }
+
+  @Test
+  public void blockUpsert() throws Exception {
+    Account.Id id = Account.id(sequences.nextAccountId());
+    ExternalId extId = ExternalId.create("foo", "bar", id);
+    testPreprocessor.throwException = true;
+    StorageException e =
+        assertThrows(
+            StorageException.class,
+            () -> accountsUpdateProvider.get().insert("test", id, u -> u.addExternalId(extId)));
+    assertThat(e).hasMessageThat().contains("upsert not good");
+    assertThat(testPreprocessor.upserted).isEmpty();
+  }
+
+  @Test
+  public void blockUpsert_replace() throws Exception {
+    Account.Id id = Account.id(sequences.nextAccountId());
+    ExternalId extId1 = ExternalId.create("foo", "bar", id, "email1@foo", "hash");
+    ExternalId extId2 = ExternalId.create("foo", "bar", id, "email2@foo", "hash");
+    accountsUpdateProvider.get().insert("test", id, u -> u.addExternalId(extId1));
+
+    assertThat(accounts.get(id).get().externalIds()).containsExactly(extId1);
+
+    testPreprocessor.reset();
+    testPreprocessor.throwException = true;
+    try (Repository allUsersRepo = repoManager.openRepository(allUsers);
+        MetaDataUpdate md = metaDataUpdateFactory.create(allUsers)) {
+      ExternalIdNotes extIdNotes = extIdNotesFactory.load(allUsersRepo);
+      extIdNotes.replace(ImmutableSet.of(extId1), ImmutableSet.of(extId2));
+      StorageException e = assertThrows(StorageException.class, () -> extIdNotes.commit(md));
+      assertThat(e).hasMessageThat().contains("upsert not good");
+    }
+    assertThat(testPreprocessor.upserted).isEmpty();
+    assertThat(accounts.get(id).get().externalIds()).containsExactly(extId1);
+  }
+
+  @Singleton
+  public static class TestPreprocessor implements ExternalIdUpsertPreprocessor {
+    List<ExternalId> upserted = new ArrayList<>();
+
+    boolean throwException = false;
+
+    @Override
+    public void upsert(ExternalId extId) {
+      assertThat(extId.blobId()).isNotNull();
+      if (throwException) {
+        throw new StorageException("upsert not good");
+      }
+      upserted.add(extId);
+    }
+
+    void reset() {
+      upserted.clear();
+      throwException = false;
+    }
+  }
+}
diff --git a/javatests/com/google/gerrit/acceptance/ssh/BUILD b/javatests/com/google/gerrit/acceptance/ssh/BUILD
index 5634322..ee1b221 100644
--- a/javatests/com/google/gerrit/acceptance/ssh/BUILD
+++ b/javatests/com/google/gerrit/acceptance/ssh/BUILD
@@ -18,6 +18,7 @@
     vm_args = ["-Xmx512m"],
     deps = [
         ":util",
+        "//java/com/google/gerrit/server/cancellation",
         "//java/com/google/gerrit/server/logging",
         "//lib/commons:compress",
     ],
diff --git a/javatests/com/google/gerrit/acceptance/ssh/SshCancellationIT.java b/javatests/com/google/gerrit/acceptance/ssh/SshCancellationIT.java
index 2cb9637..3e31c16 100644
--- a/javatests/com/google/gerrit/acceptance/ssh/SshCancellationIT.java
+++ b/javatests/com/google/gerrit/acceptance/ssh/SshCancellationIT.java
@@ -99,4 +99,22 @@
       adminSshSession.assertFailure("Server Deadline Exceeded (deadline = 10m)");
     }
   }
+
+  @Test
+  public void handleWrappedRequestCancelledException() throws Exception {
+    ProjectCreationValidationListener projectCreationListener =
+        new ProjectCreationValidationListener() {
+          @Override
+          public void validateNewProject(CreateProjectArgs args) throws ValidationException {
+            throw new RuntimeException(
+                new RequestCancelledException(
+                    RequestStateProvider.Reason.SERVER_DEADLINE_EXCEEDED, "deadline = 10m"));
+          }
+        };
+    try (Registration registration =
+        extensionRegistry.newRegistration().add(projectCreationListener)) {
+      adminSshSession.exec("gerrit create-project " + name("new"));
+      adminSshSession.assertFailure("Server Deadline Exceeded (deadline = 10m)");
+    }
+  }
 }
diff --git a/javatests/com/google/gerrit/entities/converter/ChangeProtoConverterTest.java b/javatests/com/google/gerrit/entities/converter/ChangeProtoConverterTest.java
index ae8e06d..8c5e449 100644
--- a/javatests/com/google/gerrit/entities/converter/ChangeProtoConverterTest.java
+++ b/javatests/com/google/gerrit/entities/converter/ChangeProtoConverterTest.java
@@ -60,7 +60,6 @@
         Entities.Change.newBuilder()
             .setChangeId(Entities.Change_Id.newBuilder().setId(14))
             .setChangeKey(Entities.Change_Key.newBuilder().setId("change 1"))
-            .setRowVersion(0)
             .setCreatedOn(987654L)
             .setLastUpdatedOn(1234567L)
             .setOwnerAccountId(Entities.Account_Id.newBuilder().setId(35))
@@ -109,7 +108,6 @@
                     .setBranch("refs/heads/branch-74"))
             // Default values which can't be unset.
             .setCurrentPatchSetId(0)
-            .setRowVersion(0)
             .setStatus(Change.STATUS_NEW)
             .setIsPrivate(false)
             .setWorkInProgress(false)
@@ -147,7 +145,6 @@
                     .setBranch("refs/heads/branch-74"))
             .setCurrentPatchSetId(0)
             // Default values which can't be unset.
-            .setRowVersion(0)
             .setStatus(Change.STATUS_NEW)
             .setIsPrivate(false)
             .setWorkInProgress(false)
@@ -185,7 +182,6 @@
             .setCurrentPatchSetId(23)
             .setSubject("subject ABC")
             // Default values which can't be unset.
-            .setRowVersion(0)
             .setStatus(Change.STATUS_NEW)
             .setIsPrivate(false)
             .setWorkInProgress(false)
@@ -251,7 +247,6 @@
     assertThat(change.getSubject()).isNull();
     assertThat(change.currentPatchSetId()).isNull();
     // Default values for unset protobuf fields which can't be unset in the entity object.
-    assertThat(change.getRowVersion()).isEqualTo(0);
     assertThat(change.isNew()).isTrue();
     assertThat(change.isPrivate()).isFalse();
     assertThat(change.isWorkInProgress()).isFalse();
@@ -284,7 +279,6 @@
             ImmutableMap.<String, Type>builder()
                 .put("changeId", Change.Id.class)
                 .put("changeKey", Change.Key.class)
-                .put("rowVersion", int.class)
                 .put("createdOn", Timestamp.class)
                 .put("lastUpdatedOn", Timestamp.class)
                 .put("owner", Account.Id.class)
@@ -309,7 +303,6 @@
   private static void assertEqualChange(Change change, Change expectedChange) {
     assertThat(change.getChangeId()).isEqualTo(expectedChange.getChangeId());
     assertThat(change.getKey()).isEqualTo(expectedChange.getKey());
-    assertThat(change.getRowVersion()).isEqualTo(expectedChange.getRowVersion());
     assertThat(change.getCreatedOn()).isEqualTo(expectedChange.getCreatedOn());
     assertThat(change.getLastUpdatedOn()).isEqualTo(expectedChange.getLastUpdatedOn());
     assertThat(change.getOwner()).isEqualTo(expectedChange.getOwner());
diff --git a/javatests/com/google/gerrit/server/BUILD b/javatests/com/google/gerrit/server/BUILD
index 7ab7ae9..a2825322 100644
--- a/javatests/com/google/gerrit/server/BUILD
+++ b/javatests/com/google/gerrit/server/BUILD
@@ -55,6 +55,7 @@
         "//java/com/google/gerrit/server/account/externalids/testing",
         "//java/com/google/gerrit/server/cache/serialize",
         "//java/com/google/gerrit/server/cache/testing",
+        "//java/com/google/gerrit/server/cancellation",
         "//java/com/google/gerrit/server/fixes/testing",
         "//java/com/google/gerrit/server/git/receive:ref_cache",
         "//java/com/google/gerrit/server/ioutil",
diff --git a/javatests/com/google/gerrit/server/cancellation/RequestStateContextTest.java b/javatests/com/google/gerrit/server/cancellation/RequestStateContextTest.java
new file mode 100644
index 0000000..e2c43eb
--- /dev/null
+++ b/javatests/com/google/gerrit/server/cancellation/RequestStateContextTest.java
@@ -0,0 +1,178 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.cancellation;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.common.truth.Truth8.assertThat;
+import static com.google.gerrit.testing.GerritJUnit.assertThrows;
+
+import com.google.common.collect.ImmutableSet;
+import org.junit.Test;
+
+public class RequestStateContextTest {
+  @Test
+  public void openContext() {
+    assertNoRequestStateProviders();
+
+    RequestStateProvider requestStateProvider1 = new TestRequestStateProvider();
+    try (RequestStateContext requestStateContext =
+        RequestStateContext.open().addRequestStateProvider(requestStateProvider1)) {
+      RequestStateProvider requestStateProvider2 = new TestRequestStateProvider();
+      requestStateContext.addRequestStateProvider(requestStateProvider2);
+      assertRequestStateProviders(ImmutableSet.of(requestStateProvider1, requestStateProvider2));
+    }
+
+    assertNoRequestStateProviders();
+  }
+
+  @Test
+  public void openNestedContexts() {
+    assertNoRequestStateProviders();
+
+    RequestStateProvider requestStateProvider1 = new TestRequestStateProvider();
+    try (RequestStateContext requestStateContext =
+        RequestStateContext.open().addRequestStateProvider(requestStateProvider1)) {
+      RequestStateProvider requestStateProvider2 = new TestRequestStateProvider();
+      requestStateContext.addRequestStateProvider(requestStateProvider2);
+      assertRequestStateProviders(ImmutableSet.of(requestStateProvider1, requestStateProvider2));
+
+      RequestStateProvider requestStateProvider3 = new TestRequestStateProvider();
+      try (RequestStateContext requestStateContext2 =
+          RequestStateContext.open().addRequestStateProvider(requestStateProvider3)) {
+        RequestStateProvider requestStateProvider4 = new TestRequestStateProvider();
+        requestStateContext2.addRequestStateProvider(requestStateProvider4);
+        assertRequestStateProviders(
+            ImmutableSet.of(
+                requestStateProvider1,
+                requestStateProvider2,
+                requestStateProvider3,
+                requestStateProvider4));
+      }
+
+      assertRequestStateProviders(ImmutableSet.of(requestStateProvider1, requestStateProvider2));
+    }
+
+    assertNoRequestStateProviders();
+  }
+
+  @Test
+  public void openNestedContextsWithSameRequestStateProviders() {
+    assertNoRequestStateProviders();
+
+    RequestStateProvider requestStateProvider1 = new TestRequestStateProvider();
+    try (RequestStateContext requestStateContext =
+        RequestStateContext.open().addRequestStateProvider(requestStateProvider1)) {
+      RequestStateProvider requestStateProvider2 = new TestRequestStateProvider();
+      requestStateContext.addRequestStateProvider(requestStateProvider2);
+      assertRequestStateProviders(ImmutableSet.of(requestStateProvider1, requestStateProvider2));
+
+      try (RequestStateContext requestStateContext2 =
+          RequestStateContext.open().addRequestStateProvider(requestStateProvider1)) {
+        requestStateContext2.addRequestStateProvider(requestStateProvider2);
+
+        assertRequestStateProviders(ImmutableSet.of(requestStateProvider1, requestStateProvider2));
+      }
+
+      assertRequestStateProviders(ImmutableSet.of(requestStateProvider1, requestStateProvider2));
+    }
+
+    assertNoRequestStateProviders();
+  }
+
+  @Test
+  public void abortIfCancelled_noRequestStateProvider() {
+    assertNoRequestStateProviders();
+
+    // Calling abortIfCancelled() shouldn't throw an exception.
+    RequestStateContext.abortIfCancelled();
+  }
+
+  @Test
+  public void abortIfCancelled_requestNotCancelled() {
+    try (RequestStateContext requestStateContext =
+        RequestStateContext.open()
+            .addRequestStateProvider(
+                new RequestStateProvider() {
+                  @Override
+                  public void checkIfCancelled(OnCancelled onCancelled) {}
+                })) {
+      // Calling abortIfCancelled() shouldn't throw an exception.
+      RequestStateContext.abortIfCancelled();
+    }
+  }
+
+  @Test
+  public void abortIfCancelled_requestCancelled() {
+    try (RequestStateContext requestStateContext =
+        RequestStateContext.open()
+            .addRequestStateProvider(
+                new RequestStateProvider() {
+                  @Override
+                  public void checkIfCancelled(OnCancelled onCancelled) {
+                    onCancelled.onCancel(
+                        RequestStateProvider.Reason.CLIENT_CLOSED_REQUEST, /* message= */ null);
+                  }
+                })) {
+      RequestCancelledException requestCancelledException =
+          assertThrows(
+              RequestCancelledException.class, () -> RequestStateContext.abortIfCancelled());
+      assertThat(requestCancelledException)
+          .hasMessageThat()
+          .isEqualTo("Request cancelled: CLIENT_CLOSED_REQUEST");
+      assertThat(requestCancelledException.getCancellationReason())
+          .isEqualTo(RequestStateProvider.Reason.CLIENT_CLOSED_REQUEST);
+      assertThat(requestCancelledException.getCancellationMessage()).isEmpty();
+    }
+  }
+
+  @Test
+  public void abortIfCancelled_requestCancelled_withMessage() {
+    try (RequestStateContext requestStateContext =
+        RequestStateContext.open()
+            .addRequestStateProvider(
+                new RequestStateProvider() {
+                  @Override
+                  public void checkIfCancelled(OnCancelled onCancelled) {
+                    onCancelled.onCancel(
+                        RequestStateProvider.Reason.SERVER_DEADLINE_EXCEEDED, "deadline = 10m");
+                  }
+                })) {
+      RequestCancelledException requestCancelledException =
+          assertThrows(
+              RequestCancelledException.class, () -> RequestStateContext.abortIfCancelled());
+      assertThat(requestCancelledException)
+          .hasMessageThat()
+          .isEqualTo("Request cancelled: SERVER_DEADLINE_EXCEEDED (deadline = 10m)");
+      assertThat(requestCancelledException.getCancellationReason())
+          .isEqualTo(RequestStateProvider.Reason.SERVER_DEADLINE_EXCEEDED);
+      assertThat(requestCancelledException.getCancellationMessage()).hasValue("deadline = 10m");
+    }
+  }
+
+  private void assertNoRequestStateProviders() {
+    assertRequestStateProviders(ImmutableSet.of());
+  }
+
+  private void assertRequestStateProviders(
+      ImmutableSet<RequestStateProvider> expectedRequestStateProviders) {
+    assertThat(RequestStateContext.getRequestStateProviders())
+        .containsExactlyElementsIn(expectedRequestStateProviders);
+  }
+
+  private static class TestRequestStateProvider implements RequestStateProvider {
+    @Override
+    public void checkIfCancelled(OnCancelled onCancelled) {}
+  }
+}
diff --git a/javatests/com/google/gerrit/server/update/BatchUpdateTest.java b/javatests/com/google/gerrit/server/update/BatchUpdateTest.java
index 287a7fe..10599c6 100644
--- a/javatests/com/google/gerrit/server/update/BatchUpdateTest.java
+++ b/javatests/com/google/gerrit/server/update/BatchUpdateTest.java
@@ -64,6 +64,7 @@
             cfg.setInt("change", null, "maxFiles", 2);
             cfg.setInt("change", null, "maxPatchSets", MAX_PATCH_SETS);
             cfg.setInt("change", null, "maxUpdates", MAX_UPDATES);
+            cfg.setString("index", null, "type", "fake");
             return cfg;
           });
 
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.ts b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.ts
index af565cb..a090aee 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.ts
@@ -150,18 +150,25 @@
     this._query = (text: string) => this._getProjectBranchesSuggestions(text);
   }
 
+  containsDuplicateProject(changes: ChangeInfo[]) {
+    const projects: {[projectName: string]: boolean} = {};
+    for (let i = 0; i < changes.length; i++) {
+      const change = changes[i];
+      if (projects[change.project]) {
+        return true;
+      }
+      projects[change.project] = true;
+    }
+    return false;
+  }
+
   updateChanges(changes: ChangeInfo[]) {
     this.changes = changes;
     this._statuses = {};
-    const projects: {[projectName: string]: boolean} = {};
-    this._duplicateProjectChanges = false;
     changes.forEach(change => {
       this.selectedChangeIds.add(change.id);
-      if (projects[change.project]) {
-        this._duplicateProjectChanges = true;
-      }
-      projects[change.project] = true;
     });
+    this._duplicateProjectChanges = this.containsDuplicateProject(changes);
     this._changesCount = changes.length;
     this._showCherryPickTopic = changes.length > 1;
   }
@@ -185,6 +192,10 @@
     if (this.selectedChangeIds.has(changeId))
       this.selectedChangeIds.delete(changeId);
     else this.selectedChangeIds.add(changeId);
+    const changes = this.changes.filter(change =>
+      this.selectedChangeIds.has(change.id)
+    );
+    this._duplicateProjectChanges = this.containsDuplicateProject(changes);
   }
 
   _computeTopicErrorMessage(duplicateProjectChanges: boolean) {
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_test.js b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_test.js
index 536a4ab..1034674 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_test.js
+++ b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_test.js
@@ -130,6 +130,8 @@
     });
 
     test('deselecting a change removes it from being cherry picked', () => {
+      const duplicateChangesStub = sinon.stub(element,
+          'containsDuplicateProject');
       element.branch = 'master';
       const executeChangeActionStub = stubRestApi(
           'executeChangeAction').returns(Promise.resolve([]));
@@ -142,6 +144,7 @@
           querySelector('gr-dialog').$.confirm);
       flush();
       assert.equal(executeChangeActionStub.callCount, 1);
+      assert.isTrue(duplicateChangesStub.called);
     });
 
     test('deselecting all change shows error message', () => {
diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts
index 5206fdb..f4f37c1 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts
@@ -82,13 +82,9 @@
 import {Timing} from '../../../constants/reporting';
 import {RevisionInfo} from '../../shared/revision-info/revision-info';
 import {preferences$} from '../../../services/user/user-model';
-import {
-  changeComments$,
-  drafts$,
-} from '../../../services/comments/comments-model';
+import {changeComments$} from '../../../services/comments/comments-model';
 import {Subject} from 'rxjs';
 import {takeUntil} from 'rxjs/operators';
-import {UIDraft} from '../../../utils/comment-util';
 
 export const DEFAULT_NUM_FILES_SHOWN = 200;
 
@@ -316,9 +312,6 @@
   @property({type: Array})
   _dynamicPrependedContentEndpoints?: string[];
 
-  @property({type: Object})
-  diffDrafts?: {[path: string]: UIDraft[]} = {};
-
   private readonly reporting = appContext.reportingService;
 
   private readonly restApiService = appContext.restApiService;
@@ -373,9 +366,6 @@
   /** @override */
   connectedCallback() {
     super.connectedCallback();
-    drafts$.pipe(takeUntil(this.disconnected$)).subscribe(drafts => {
-      this.diffDrafts = drafts;
-    });
     changeComments$
       .pipe(takeUntil(this.disconnected$))
       .subscribe(changeComments => {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_html.ts b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_html.ts
index 5b248da..98956c9 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_html.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_html.ts
@@ -63,6 +63,7 @@
     table {
       border-collapse: collapse;
       table-layout: fixed;
+      background-color: var(--diff-blank-background-color);
     }
 
     /*
diff --git a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts
index 2ad3be6..afff6f3 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts
@@ -225,18 +225,6 @@
     this.addEventListener('comment-update', e =>
       this._handleCommentUpdate(e as CustomEvent)
     );
-    // Wait for comment to be rendered before scrolling to it
-    if (this.shouldScrollIntoView) {
-      const resizeObserver = new ResizeObserver(
-        (_entries: ResizeObserverEntry[], observer: ResizeObserver) => {
-          if (this.offsetHeight > 0) {
-            this.scrollIntoView();
-            observer.unobserve(this);
-          }
-        }
-      );
-      resizeObserver.observe(this);
-    }
   }
 
   /** @override */
diff --git a/polygerrit-ui/app/services/comments/comments-model.ts b/polygerrit-ui/app/services/comments/comments-model.ts
index b26ec9b..bbc7b1a 100644
--- a/polygerrit-ui/app/services/comments/comments-model.ts
+++ b/polygerrit-ui/app/services/comments/comments-model.ts
@@ -111,7 +111,7 @@
   if (!drafts[draft.path]) drafts[draft.path] = [] as DraftInfo[];
   else drafts[draft.path] = [...drafts[draft.path]];
   const index = drafts[draft.path].findIndex(
-    d => d.__draftID === draft.__draftID || d.id === draft.id
+    d => (d.__draftID && d.__draftID === draft.__draftID) || d.id === draft.id
   );
   if (index !== -1) {
     drafts[draft.path][index] = draft;
@@ -127,7 +127,7 @@
   nextState.drafts = {...nextState.drafts};
   const drafts = nextState.drafts;
   const index = (drafts[draft.path] || []).findIndex(
-    d => d.__draftID === draft.__draftID || d.id === draft.id
+    d => (d.__draftID && d.__draftID === draft.__draftID) || d.id === draft.id
   );
   if (index === -1) return;
   drafts[draft.path] = [...drafts[draft.path]];
diff --git a/polygerrit-ui/app/styles/themes/app-theme.ts b/polygerrit-ui/app/styles/themes/app-theme.ts
index 134003b..1996800 100644
--- a/polygerrit-ui/app/styles/themes/app-theme.ts
+++ b/polygerrit-ui/app/styles/themes/app-theme.ts
@@ -128,20 +128,20 @@
 
     --error-foreground: var(--red-700);
     --error-background: var(--red-50);
-    --error-background-hover: linear-gradient(var(--red-700-04), var(--red-700-04), var(--red-50));
-    --error-background-focus: linear-gradient(var(--red-700-12), var(--red-700-12), var(--red-50));
+    --error-background-hover: linear-gradient(var(--red-700-04), var(--red-700-04)), var(--red-50);
+    --error-background-focus: linear-gradient(var(--red-700-12), var(--red-700-12)), var(--red-50);
     --error-ripple: var(--red-700-10);
 
     --warning-foreground: var(--orange-700);
     --warning-background: var(--orange-50);
-    --warning-background-hover: linear-gradient(var(--orange-700-04), var(--orange-700-04), var(--orange-50));
-    --warning-background-focus: linear-gradient(var(--orange-700-12), var(--orange-700-12), var(--orange-50));
+    --warning-background-hover: linear-gradient(var(--orange-700-04), var(--orange-700-04)), var(--orange-50);
+    --warning-background-focus: linear-gradient(var(--orange-700-12), var(--orange-700-12)), var(--orange-50);
     --warning-ripple: var(--orange-700-10);
 
     --info-foreground: var(--blue-700);
     --info-background: var(--blue-50);
-    --info-background-hover: linear-gradient(var(--blue-700-04), var(--blue-700-04), var(--blue-50));
-    --info-background-focus: linear-gradient(var(--blue-700-12), var(--blue-700-12), var(--blue-50));
+    --info-background-hover: linear-gradient(var(--blue-700-04), var(--blue-700-04)), var(--blue-50);
+    --info-background-focus: linear-gradient(var(--blue-700-12), var(--blue-700-12)), var(--blue-50);
     --info-ripple: var(--blue-700-10);
 
     --primary-button-text-color: white;
@@ -154,14 +154,14 @@
 
     --success-foreground: var(--green-700);
     --success-background: var(--green-50);
-    --success-background-hover: linear-gradient(var(--green-700-04), var(--green-700-04), var(--green-50));
-    --success-background-focus: linear-gradient(var(--green-700-12), var(--green-700-12), var(--green-50));
+    --success-background-hover: linear-gradient(var(--green-700-04), var(--green-700-04)), var(--green-50);
+    --success-background-focus: linear-gradient(var(--green-700-12), var(--green-700-12)), var(--green-50);
     --success-ripple: var(--green-700-10);
 
     --gray-foreground: var(--gray-700);
     --gray-background: var(--gray-100);
-    --gray-background-hover: linear-gradient(var(--gray-700-04), var(--gray-700-04), var(--gray-100));
-    --gray-background-focus: linear-gradient(var(--gray-700-12), var(--gray-700-12), var(--gray-100));
+    --gray-background-hover: linear-gradient(var(--gray-700-04), var(--gray-700-04)), var(--gray-100);
+    --gray-background-focus: linear-gradient(var(--gray-700-12), var(--gray-700-12)), var(--gray-100);
     --gray-ripple: var(--gray-700-10);
 
     --disabled-foreground: var(--gray-800-38);
diff --git a/polygerrit-ui/app/styles/themes/dark-theme.ts b/polygerrit-ui/app/styles/themes/dark-theme.ts
index 69256b2..926b02d 100644
--- a/polygerrit-ui/app/styles/themes/dark-theme.ts
+++ b/polygerrit-ui/app/styles/themes/dark-theme.ts
@@ -38,20 +38,20 @@
 
       --error-foreground: var(--red-200);
       --error-background: var(--red-tonal);
-      --error-background-hover: linear-gradient(var(--white-04), var(--white-04), var(--red-tonal));
-      --error-background-focus: linear-gradient(var(--white-12), var(--white-12), var(--red-tonal));
+      --error-background-hover: linear-gradient(var(--white-04), var(--white-04)), var(--red-tonal);
+      --error-background-focus: linear-gradient(var(--white-12), var(--white-12)), var(--red-tonal);
       --error-ripple: var(--white-10);
 
       --warning-foreground: var(--orange-200);
       --warning-background: var(--orange-tonal);
-      --warning-background-hover: linear-gradient(var(--white-04), var(--white-04), var(--orange-tonal));
-      --warning-background-focus: linear-gradient(var(--white-12), var(--white-12), var(--orange-tonal));
+      --warning-background-hover: linear-gradient(var(--white-04), var(--white-04)), var(--orange-tonal);
+      --warning-background-focus: linear-gradient(var(--white-12), var(--white-12)), var(--orange-tonal);
       --warning-ripple: var(--white-10);
 
       --info-foreground: var(--blue-200);
       --info-background: var(--blue-tonal);
-      --info-background-hover: linear-gradient(var(--white-04), var(--white-04), var(--blue-tonal));
-      --info-background-focus: linear-gradient(var(--white-12), var(--white-12), var(--blue-tonal));
+      --info-background-hover: linear-gradient(var(--white-04), var(--white-04)), var(--blue-tonal);
+      --info-background-focus: linear-gradient(var(--white-12), var(--white-12)), var(--blue-tonal);
       --info-ripple: var(--white-10);
 
       --primary-button-text-color: black;
@@ -64,14 +64,14 @@
 
       --success-foreground: var(--green-200);
       --success-background: var(--green-tonal);
-      --success-background-hover: linear-gradient(var(--white-04), var(--white-04), var(--green-tonal));
-      --success-background-focus: linear-gradient(var(--white-12), var(--white-12), var(--green-tonal));
+      --success-background-hover: linear-gradient(var(--white-04), var(--white-04)), var(--green-tonal);
+      --success-background-focus: linear-gradient(var(--white-12), var(--white-12)), var(--green-tonal);
       --success-ripple: var(--white-10);
 
       --gray-foreground: var(--gray-300);
       --gray-background: var(--gray-tonal);
-      --gray-background-hover: linear-gradient(var(--white-04), var(--white-04), var(--gray-tonal));
-      --gray-background-focus: linear-gradient(var(--white-12), var(--white-12), var(--gray-tonal));
+      --gray-background-hover: linear-gradient(var(--white-04), var(--white-04)), var(--gray-tonal);
+      --gray-background-focus: linear-gradient(var(--white-12), var(--white-12)), var(--gray-tonal);
       --gray-ripple: var(--white-10);
 
       --disabled-foreground: var(--gray-200-38);
diff --git a/proto/entities.proto b/proto/entities.proto
index 84c7fbd..d4ff736 100644
--- a/proto/entities.proto
+++ b/proto/entities.proto
@@ -35,7 +35,6 @@
 message Change {
   required Change_Id change_id = 1;
   optional Change_Key change_key = 2;
-  optional int32 row_version = 3;
   optional fixed64 created_on = 4;
   optional fixed64 last_updated_on = 5;
   optional Account_Id owner_account_id = 7;
@@ -54,6 +53,7 @@
   optional PatchSet_Id cherry_pick_of = 24;
 
   // Deleted fields, should not be reused:
+  reserved 3;    // row_version
   reserved 6;    // sortkey
   reserved 9;    // open
   reserved 11;   // nbrPatchSets