diff --git a/.bazelversion b/.bazelversion
index b2525e3..1b58cc1 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-0.27.0rc3
\ No newline at end of file
+0.27.0
diff --git a/Documentation/dev-crafting-changes.txt b/Documentation/dev-crafting-changes.txt
index 3440e85..a22bea9 100644
--- a/Documentation/dev-crafting-changes.txt
+++ b/Documentation/dev-crafting-changes.txt
@@ -110,7 +110,7 @@
 link:https://github.com/google/google-java-format[`google-java-format`]
 tool (version 1.7), and to format Bazel BUILD, WORKSPACE and .bzl files the
 link:https://github.com/bazelbuild/buildtools/tree/master/buildifier[`buildifier`]
-tool (version 0.22.0).
+tool (version 0.26.0).
 These tools automatically apply format according to the style guides; this
 streamlines code review by reducing the need for time-consuming, tedious,
 and contentious discussions about trivial issues like whitespace.
diff --git a/WORKSPACE b/WORKSPACE
index f160f64..855309f 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -66,7 +66,7 @@
 
 load("@bazel_skylib//lib:versions.bzl", "versions")
 
-versions.check(minimum_bazel_version = "0.25.0")
+versions.check(minimum_bazel_version = "0.26.1")
 
 load("@io_bazel_rules_closure//closure:defs.bzl", "closure_repositories")
 
@@ -83,8 +83,11 @@
 # Golang support for PolyGerrit local dev server.
 http_archive(
     name = "io_bazel_rules_go",
-    sha256 = "6776d68ebb897625dead17ae510eac3d5f6342367327875210df44dbe2aeeb19",
-    url = "https://github.com/bazelbuild/rules_go/releases/download/0.17.1/rules_go-0.17.1.tar.gz",
+    sha256 = "f04d2373bcaf8aa09bccb08a98a57e721306c8f6043a2a0ee610fd6853dcde3d",
+    urls = [
+        "https://storage.googleapis.com/bazel-mirror/github.com/bazelbuild/rules_go/releases/download/0.18.6/rules_go-0.18.6.tar.gz",
+        "https://github.com/bazelbuild/rules_go/releases/download/0.18.6/rules_go-0.18.6.tar.gz",
+    ],
 )
 
 load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_dependencies")
@@ -772,24 +775,24 @@
 )
 
 # When updating Bouncy Castle, also update it in bazlets.
-BC_VERS = "1.60"
+BC_VERS = "1.61"
 
 maven_jar(
     name = "bcprov",
     artifact = "org.bouncycastle:bcprov-jdk15on:" + BC_VERS,
-    sha1 = "bd47ad3bd14b8e82595c7adaa143501e60842a84",
+    sha1 = "00df4b474e71be02c1349c3292d98886f888d1f7",
 )
 
 maven_jar(
     name = "bcpg",
     artifact = "org.bouncycastle:bcpg-jdk15on:" + BC_VERS,
-    sha1 = "13c7a199c484127daad298996e95818478431a2c",
+    sha1 = "422656435514ab8a28752b117d5d2646660a0ace",
 )
 
 maven_jar(
     name = "bcpkix",
     artifact = "org.bouncycastle:bcpkix-jdk15on:" + BC_VERS,
-    sha1 = "d0c46320fbc07be3a24eb13a56cee4e3d38e0c75",
+    sha1 = "89bb3aa5b98b48e584eee2a7401b7682a46779b4",
 )
 
 maven_jar(
diff --git a/java/com/google/gerrit/acceptance/ChangeIndexedCounter.java b/java/com/google/gerrit/acceptance/ChangeIndexedCounter.java
index 286b045..e04a643 100644
--- a/java/com/google/gerrit/acceptance/ChangeIndexedCounter.java
+++ b/java/com/google/gerrit/acceptance/ChangeIndexedCounter.java
@@ -37,17 +37,12 @@
     countsByChange.clear();
   }
 
-  long getCount(ChangeInfo info) {
-    return countsByChange.get(info._number);
-  }
-
   public void assertReindexOf(ChangeInfo info) {
     assertReindexOf(info, 1);
   }
 
-  public void assertReindexOf(ChangeInfo info, int expectedCount) {
-    assertThat(getCount(info)).isEqualTo(expectedCount);
-    assertThat(countsByChange).hasSize(1);
+  public void assertReindexOf(ChangeInfo info, long expectedCount) {
+    assertThat(countsByChange.asMap()).containsExactly(info._number, expectedCount);
     clear();
   }
 }
diff --git a/java/com/google/gerrit/extensions/validators/CommentForValidation.java b/java/com/google/gerrit/extensions/validators/CommentForValidation.java
new file mode 100644
index 0000000..51ae5ae
--- /dev/null
+++ b/java/com/google/gerrit/extensions/validators/CommentForValidation.java
@@ -0,0 +1,48 @@
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.extensions.validators;
+
+import com.google.auto.value.AutoValue;
+
+/**
+ * Holds a comment's text and {@link CommentType} in order to pass it to a validation plugin.
+ *
+ * @see CommentValidator
+ */
+@AutoValue
+public abstract class CommentForValidation {
+
+  /** The type of comment. */
+  public enum CommentType {
+    /** A regular (inline) comment. */
+    INLINE_COMMENT,
+    /** A file comment. */
+    FILE_COMMENT,
+    /** A change message. */
+    CHANGE_MESSAGE
+  }
+
+  public static CommentForValidation create(CommentType type, String text) {
+    return new AutoValue_CommentForValidation(type, text);
+  }
+
+  public abstract CommentType getType();
+
+  public abstract String getText();
+
+  public CommentValidationFailure failValidation(String message) {
+    return CommentValidationFailure.create(this, message);
+  }
+}
diff --git a/java/com/google/gerrit/extensions/validators/CommentValidationFailure.java b/java/com/google/gerrit/extensions/validators/CommentValidationFailure.java
new file mode 100644
index 0000000..1a832760
--- /dev/null
+++ b/java/com/google/gerrit/extensions/validators/CommentValidationFailure.java
@@ -0,0 +1,32 @@
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.extensions.validators;
+
+import com.google.auto.value.AutoValue;
+
+/** A comment or review message was rejected by a {@link CommentValidator}. */
+@AutoValue
+public abstract class CommentValidationFailure {
+  static CommentValidationFailure create(
+      CommentForValidation commentForValidation, String message) {
+    return new AutoValue_CommentValidationFailure(commentForValidation, message);
+  }
+
+  /** Returns the offending comment. */
+  public abstract CommentForValidation getComment();
+
+  /** A friendly message set by the {@link CommentValidator}. */
+  public abstract String getMessage();
+}
diff --git a/java/com/google/gerrit/extensions/validators/CommentValidator.java b/java/com/google/gerrit/extensions/validators/CommentValidator.java
new file mode 100644
index 0000000..cfefdef
--- /dev/null
+++ b/java/com/google/gerrit/extensions/validators/CommentValidator.java
@@ -0,0 +1,34 @@
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.extensions.validators;
+
+import com.google.common.collect.ImmutableList;
+import com.google.gerrit.extensions.annotations.ExtensionPoint;
+
+/**
+ * Validates review comments and messages. Rejecting any comment/message will prevent all comments
+ * from being published.
+ */
+@ExtensionPoint
+public interface CommentValidator {
+
+  /**
+   * Validate the specified comments.
+   *
+   * @return An empty list if all comments are valid, or else a list of validation failures.
+   */
+  ImmutableList<CommentValidationFailure> validateComments(
+      ImmutableList<CommentForValidation> comments);
+}
diff --git a/java/com/google/gerrit/httpd/raw/IndexServlet.java b/java/com/google/gerrit/httpd/raw/IndexServlet.java
index 978f3eb..4c9fc3b 100644
--- a/java/com/google/gerrit/httpd/raw/IndexServlet.java
+++ b/java/com/google/gerrit/httpd/raw/IndexServlet.java
@@ -25,7 +25,7 @@
 import com.google.template.soy.SoyFileSet;
 import com.google.template.soy.data.SanitizedContent;
 import com.google.template.soy.data.UnsafeSanitizedContentOrdainer;
-import com.google.template.soy.tofu.SoyTofu;
+import com.google.template.soy.jbcsrc.api.SoySauce;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.net.URISyntaxException;
@@ -42,7 +42,7 @@
   @Nullable private final String cdnPath;
   @Nullable private final String faviconPath;
   private final GerritApi gerritApi;
-  private final SoyTofu soyTofu;
+  private final SoySauce soySauce;
   private final Function<String, SanitizedContent> urlOrdainer;
 
   IndexServlet(
@@ -54,11 +54,11 @@
     this.cdnPath = cdnPath;
     this.faviconPath = faviconPath;
     this.gerritApi = gerritApi;
-    this.soyTofu =
+    this.soySauce =
         SoyFileSet.builder()
             .add(Resources.getResource("com/google/gerrit/httpd/raw/PolyGerritIndexHtml.soy"))
             .build()
-            .compileToTofu();
+            .compileTemplates();
     this.urlOrdainer =
         (s) ->
             UnsafeSanitizedContentOrdainer.ordainAsSafe(
@@ -67,7 +67,7 @@
 
   @Override
   protected void doGet(HttpServletRequest req, HttpServletResponse rsp) throws IOException {
-    SoyTofu.Renderer renderer;
+    SoySauce.Renderer renderer;
     try {
       Map<String, String[]> parameterMap = req.getParameterMap();
       // TODO(hiesel): Remove URL ordainer as parameter once Soy is consistent
@@ -75,9 +75,9 @@
           IndexHtmlUtil.templateData(
               gerritApi, canonicalUrl, cdnPath, faviconPath, parameterMap, urlOrdainer);
       renderer =
-          soyTofu
-              .newRenderer("com.google.gerrit.httpd.raw.Index")
-              .setContentKind(SanitizedContent.ContentKind.HTML)
+          soySauce
+              .renderTemplate("com.google.gerrit.httpd.raw.Index")
+              .setExpectedContentKind(SanitizedContent.ContentKind.HTML)
               .setData(templateData);
     } catch (URISyntaxException | RestApiException e) {
       throw new IOException(e);
@@ -87,7 +87,7 @@
     rsp.setContentType("text/html");
     rsp.setStatus(SC_OK);
     try (OutputStream w = rsp.getOutputStream()) {
-      w.write(renderer.render().getBytes(UTF_8));
+      w.write(renderer.render().get().getBytes(UTF_8));
     }
   }
 }
diff --git a/java/com/google/gerrit/httpd/restapi/RestApiServlet.java b/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
index efdf5ba..45e4749 100644
--- a/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
+++ b/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
@@ -310,7 +310,10 @@
           logger.atFinest().log(
               "Received REST request: %s %s (parameters: %s)",
               req.getMethod(), req.getRequestURI(), getParameterNames(req));
-          logger.atFinest().log("Calling user: %s", globals.currentUser.get().getLoggableName());
+          logger.atFinest().log(
+              "Calling user: %s (groups = %s)",
+              globals.currentUser.get().getLoggableName(),
+              globals.currentUser.get().getEffectiveGroups().getKnownGroups());
 
           if (isCorsPreflight(req)) {
             doCorsPreflight(req, res);
diff --git a/java/com/google/gerrit/pgm/http/jetty/JettyServer.java b/java/com/google/gerrit/pgm/http/jetty/JettyServer.java
index 7745ad4..22bc21d 100644
--- a/java/com/google/gerrit/pgm/http/jetty/JettyServer.java
+++ b/java/com/google/gerrit/pgm/http/jetty/JettyServer.java
@@ -196,7 +196,7 @@
         c = newServerConnector(server, acceptors, config);
 
       } else if ("https".equals(u.getScheme())) {
-        SslContextFactory ssl = new SslContextFactory();
+        SslContextFactory.Server ssl = new SslContextFactory.Server();
         final Path keystore = getFile(cfg, "sslkeystore", "etc/keystore");
         String password = cfg.getString("httpd", null, "sslkeypassword");
         if (password == null) {
diff --git a/java/com/google/gerrit/server/PublishCommentUtil.java b/java/com/google/gerrit/server/PublishCommentUtil.java
index 8ae5bcd..6a1c859 100644
--- a/java/com/google/gerrit/server/PublishCommentUtil.java
+++ b/java/com/google/gerrit/server/PublishCommentUtil.java
@@ -18,13 +18,18 @@
 import static com.google.gerrit.reviewdb.client.PatchLineComment.Status.PUBLISHED;
 import static java.util.stream.Collectors.toSet;
 
+import com.google.common.collect.ImmutableList;
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.exceptions.StorageException;
+import com.google.gerrit.extensions.validators.CommentForValidation;
+import com.google.gerrit.extensions.validators.CommentValidationFailure;
+import com.google.gerrit.extensions.validators.CommentValidator;
 import com.google.gerrit.reviewdb.client.Comment;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.patch.PatchListCache;
 import com.google.gerrit.server.patch.PatchListNotAvailableException;
+import com.google.gerrit.server.plugincontext.PluginSetContext;
 import com.google.gerrit.server.update.ChangeContext;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
@@ -77,4 +82,20 @@
   private static PatchSet.Id psId(ChangeNotes notes, Comment c) {
     return PatchSet.id(notes.getChangeId(), c.key.patchSetId);
   }
+
+  /**
+   * Helper to run the specified set of {@link CommentValidator}-s on the specified comments.
+   *
+   * @return See {@link CommentValidator#validateComments(ImmutableList)}.
+   */
+  public static ImmutableList<CommentValidationFailure> findInvalidComments(
+      PluginSetContext<CommentValidator> commentValidators,
+      ImmutableList<CommentForValidation> commentsForValidation) {
+    ImmutableList.Builder<CommentValidationFailure> commentValidationFailures =
+        new ImmutableList.Builder<>();
+    commentValidators.runEach(
+        listener ->
+            commentValidationFailures.addAll(listener.validateComments(commentsForValidation)));
+    return commentValidationFailures.build();
+  }
 }
diff --git a/java/com/google/gerrit/server/config/GerritGlobalModule.java b/java/com/google/gerrit/server/config/GerritGlobalModule.java
index 14747e5..afe4e52 100644
--- a/java/com/google/gerrit/server/config/GerritGlobalModule.java
+++ b/java/com/google/gerrit/server/config/GerritGlobalModule.java
@@ -62,6 +62,7 @@
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.registration.DynamicSet;
 import com.google.gerrit.extensions.systemstatus.MessageOfTheDay;
+import com.google.gerrit.extensions.validators.CommentValidator;
 import com.google.gerrit.extensions.webui.BranchWebLink;
 import com.google.gerrit.extensions.webui.DiffWebLink;
 import com.google.gerrit.extensions.webui.FileHistoryWebLink;
@@ -144,7 +145,7 @@
 import com.google.gerrit.server.mail.send.FromAddressGenerator;
 import com.google.gerrit.server.mail.send.FromAddressGeneratorProvider;
 import com.google.gerrit.server.mail.send.InboundEmailRejectionSender;
-import com.google.gerrit.server.mail.send.MailSoyTofuProvider;
+import com.google.gerrit.server.mail.send.MailSoySauceProvider;
 import com.google.gerrit.server.mail.send.MailTemplates;
 import com.google.gerrit.server.mime.FileTypeRegistry;
 import com.google.gerrit.server.mime.MimeUtilFileTypeRegistry;
@@ -191,7 +192,7 @@
 import com.google.inject.Inject;
 import com.google.inject.TypeLiteral;
 import com.google.inject.internal.UniqueAnnotations;
-import com.google.template.soy.tofu.SoyTofu;
+import com.google.template.soy.jbcsrc.api.SoySauce;
 import java.util.List;
 import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.transport.PostReceiveHook;
@@ -281,7 +282,7 @@
 
     bind(ApprovalsUtil.class);
 
-    bind(SoyTofu.class).annotatedWith(MailTemplates.class).toProvider(MailSoyTofuProvider.class);
+    bind(SoySauce.class).annotatedWith(MailTemplates.class).toProvider(MailSoySauceProvider.class);
     bind(FromAddressGenerator.class).toProvider(FromAddressGeneratorProvider.class).in(SINGLETON);
     bind(Boolean.class)
         .annotatedWith(EnableReverseDnsLookup.class)
@@ -341,6 +342,7 @@
     DynamicSet.bind(binder(), EventListener.class).to(EventsMetrics.class);
     DynamicSet.setOf(binder(), UserScopedEventListener.class);
     DynamicSet.setOf(binder(), CommitValidationListener.class);
+    DynamicSet.setOf(binder(), CommentValidator.class);
     DynamicSet.setOf(binder(), ChangeMessageModifier.class);
     DynamicSet.setOf(binder(), RefOperationValidationListener.class);
     DynamicSet.setOf(binder(), OnSubmitValidationListener.class);
diff --git a/java/com/google/gerrit/server/git/receive/ReceiveCommits.java b/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
index 98ed97a..77d9049 100644
--- a/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
+++ b/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
@@ -17,9 +17,9 @@
 import static com.google.common.base.MoreObjects.firstNonNull;
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkState;
+import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.common.flogger.LazyArgs.lazy;
-import static com.google.gerrit.common.FooterConstants.CHANGE_ID;
 import static com.google.gerrit.git.ObjectIds.abbreviateName;
 import static com.google.gerrit.reviewdb.client.RefNames.REFS_CHANGES;
 import static com.google.gerrit.reviewdb.client.RefNames.isConfigRef;
@@ -81,19 +81,26 @@
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.UnprocessableEntityException;
+import com.google.gerrit.extensions.validators.CommentForValidation;
+import com.google.gerrit.extensions.validators.CommentForValidation.CommentType;
+import com.google.gerrit.extensions.validators.CommentValidationFailure;
+import com.google.gerrit.extensions.validators.CommentValidator;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.BooleanProjectConfig;
 import com.google.gerrit.reviewdb.client.BranchNameKey;
 import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.client.Comment;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.client.PatchSetInfo;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.reviewdb.client.RefNames;
 import com.google.gerrit.server.ApprovalsUtil;
 import com.google.gerrit.server.ChangeUtil;
+import com.google.gerrit.server.CommentsUtil;
 import com.google.gerrit.server.CreateGroupPermissionSyncer;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.PatchSetUtil;
+import com.google.gerrit.server.PublishCommentUtil;
 import com.google.gerrit.server.account.AccountResolver;
 import com.google.gerrit.server.change.ChangeInserter;
 import com.google.gerrit.server.change.NotifyResolver;
@@ -301,6 +308,8 @@
   private final ChangeNotes.Factory notesFactory;
   private final ChangeReportFormatter changeFormatter;
   private final CmdLineParser.Factory optionParserFactory;
+  private final CommentsUtil commentsUtil;
+  private final PluginSetContext<CommentValidator> commentValidators;
   private final BranchCommitValidator.Factory commitValidatorFactory;
   private final CreateGroupPermissionSyncer createGroupPermissionSyncer;
   private final CreateRefControl createRefControl;
@@ -378,11 +387,13 @@
       ChangeNotes.Factory notesFactory,
       DynamicItem<ChangeReportFormatter> changeFormatterProvider,
       CmdLineParser.Factory optionParserFactory,
+      CommentsUtil commentsUtil,
       BranchCommitValidator.Factory commitValidatorFactory,
       CreateGroupPermissionSyncer createGroupPermissionSyncer,
       CreateRefControl createRefControl,
       DynamicMap<ProjectConfigEntry> pluginConfigEntries,
       PluginSetContext<ReceivePackInitializer> initializers,
+      PluginSetContext<CommentValidator> commentValidators,
       MergedByPushOp.Factory mergedByPushOpFactory,
       PatchSetInfoFactory patchSetInfoFactory,
       PatchSetUtil psUtil,
@@ -415,6 +426,8 @@
     this.batchUpdateFactory = batchUpdateFactory;
     this.changeFormatter = changeFormatterProvider.get();
     this.changeInserterFactory = changeInserterFactory;
+    this.commentsUtil = commentsUtil;
+    this.commentValidators = commentValidators;
     this.commitValidatorFactory = commitValidatorFactory;
     this.createRefControl = createRefControl;
     this.createGroupPermissionSyncer = createGroupPermissionSyncer;
@@ -545,7 +558,9 @@
   // Process as many commands as possible, but may leave some commands in state NOT_ATTEMPTED.
   private void processCommandsUnsafe(
       Collection<ReceiveCommand> commands, MultiProgressMonitor progress) {
-    logger.atFinest().log("Calling user: %s", user.getLoggableName());
+    logger.atFine().log(
+        "Calling user: %s (groups = %s)",
+        user.getLoggableName(), user.getEffectiveGroups().getKnownGroups());
 
     if (!projectState.getProject().getState().permitsWrite()) {
       for (ReceiveCommand cmd : commands) {
@@ -1299,7 +1314,6 @@
     Optional<AuthException> err = checkRefPermission(cmd, RefPermission.DELETE);
     if (!err.isPresent()) {
       validRefOperation(cmd);
-
     } else {
       rejectProhibited(cmd, err.get());
     }
@@ -1375,6 +1389,13 @@
     final ReceiveCommand cmd;
     final LabelTypes labelTypes;
     private final boolean defaultPublishComments;
+    /**
+     * Result of running {@link CommentValidator}-s on drafts that are published with the commit
+     * (which happens iff {@code --publish-comments} is set). Remains {@code true} if none are
+     * installed.
+     */
+    private boolean commentsValid = true;
+
     BranchNameKey dest;
     PermissionBackend.ForRef perm;
     Set<String> reviewer = Sets.newLinkedHashSet();
@@ -1577,7 +1598,15 @@
           .collect(toImmutableSet());
     }
 
+    void setCommentsValid(boolean commentsValid) {
+      this.commentsValid = commentsValid;
+    }
+
     boolean shouldPublishComments() {
+      if (!commentsValid) {
+        // Validation messages of type WARNING have already been added, now withhold the comments.
+        return false;
+      }
       if (publishComments) {
         return true;
       } else if (noPublishComments) {
@@ -1974,7 +2003,7 @@
       messages.addAll(validationResult.messages());
       if (validationResult.isValid()) {
         logger.atFine().log("Replacing change %s", changeEnt.getId());
-        requestReplace(cmd, true, changeEnt, newCommit);
+        requestReplaceAndValidateComments(cmd, true, changeEnt, newCommit);
       }
     } catch (IOException e) {
       reject(cmd, "I/O exception validating commit");
@@ -1982,10 +2011,12 @@
   }
 
   /**
-   * Add an update for an existing change. Returns true if it succeeded; rejects the command if it
-   * failed.
+   * Update an existing change. If draft comments are to be published, these are validated and may
+   * be withheld.
+   *
+   * @return True if the command succeeded, false if it was rejected.
    */
-  private boolean requestReplace(
+  private boolean requestReplaceAndValidateComments(
       ReceiveCommand cmd, boolean checkMergedInto, Change change, RevCommit newCommit) {
     if (change.isClosed()) {
       reject(
@@ -2000,6 +2031,30 @@
       reject(cmd, "duplicate request");
       return false;
     }
+
+    if (magicBranch != null && magicBranch.shouldPublishComments()) {
+      List<Comment> drafts =
+          commentsUtil.draftByChangeAuthor(notesFactory.createChecked(change), user.getAccountId());
+      ImmutableList<CommentForValidation> draftsForValidation =
+          drafts.stream()
+              .map(
+                  comment ->
+                      CommentForValidation.create(
+                          comment.lineNbr > 0
+                              ? CommentType.INLINE_COMMENT
+                              : CommentType.FILE_COMMENT,
+                          comment.message))
+              .collect(toImmutableList());
+      ImmutableList<CommentValidationFailure> commentValidationFailures =
+          PublishCommentUtil.findInvalidComments(commentValidators, draftsForValidation);
+      magicBranch.setCommentsValid(commentValidationFailures.isEmpty());
+      commentValidationFailures.forEach(
+          failure ->
+              addMessage(
+                  "Comment validation failure: " + failure.getMessage(),
+                  ValidationMessage.Type.WARNING));
+    }
+
     replaceByChange.put(req.ontoChange, req);
     return true;
   }
@@ -2099,7 +2154,7 @@
           }
         }
 
-        List<String> idList = c.getFooterLines(CHANGE_ID);
+        List<String> idList = c.getFooterLines(FooterConstants.CHANGE_ID);
         if (!idList.isEmpty()) {
           pending.put(c, lookupByChangeKey(c, Change.key(idList.get(idList.size() - 1).trim())));
         } else {
@@ -2216,7 +2271,8 @@
               continue;
             }
           }
-          if (requestReplace(magicBranch.cmd, false, changes.get(0).change(), p.commit)) {
+          if (requestReplaceAndValidateComments(
+              magicBranch.cmd, false, changes.get(0).change(), p.commit)) {
             continue;
           }
           return Collections.emptyList();
@@ -3195,7 +3251,7 @@
                   }
                 }
 
-                for (String changeId : c.getFooterLines(CHANGE_ID)) {
+                for (String changeId : c.getFooterLines(FooterConstants.CHANGE_ID)) {
                   if (byKey == null) {
                     byKey = executeIndexQuery(() -> openChangesByKeyByBranch(branch));
                   }
diff --git a/java/com/google/gerrit/server/mail/receive/MailProcessor.java b/java/com/google/gerrit/server/mail/receive/MailProcessor.java
index 3655369..034bcc9 100644
--- a/java/com/google/gerrit/server/mail/receive/MailProcessor.java
+++ b/java/com/google/gerrit/server/mail/receive/MailProcessor.java
@@ -18,6 +18,7 @@
 
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.exceptions.StorageException;
 import com.google.gerrit.extensions.client.Side;
@@ -26,6 +27,9 @@
 import com.google.gerrit.extensions.registration.Extension;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.UnprocessableEntityException;
+import com.google.gerrit.extensions.validators.CommentForValidation;
+import com.google.gerrit.extensions.validators.CommentValidationFailure;
+import com.google.gerrit.extensions.validators.CommentValidator;
 import com.google.gerrit.mail.HtmlParser;
 import com.google.gerrit.mail.MailComment;
 import com.google.gerrit.mail.MailHeaderParser;
@@ -43,6 +47,7 @@
 import com.google.gerrit.server.ChangeMessagesUtil;
 import com.google.gerrit.server.CommentsUtil;
 import com.google.gerrit.server.PatchSetUtil;
+import com.google.gerrit.server.PublishCommentUtil;
 import com.google.gerrit.server.account.AccountCache;
 import com.google.gerrit.server.account.AccountState;
 import com.google.gerrit.server.account.Emails;
@@ -54,6 +59,7 @@
 import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.patch.PatchListCache;
 import com.google.gerrit.server.patch.PatchListNotAvailableException;
+import com.google.gerrit.server.plugincontext.PluginSetContext;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.query.change.InternalChangeQuery;
 import com.google.gerrit.server.update.BatchUpdate;
@@ -83,6 +89,15 @@
 public class MailProcessor {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
+  private static final ImmutableMap<MailComment.CommentType, CommentForValidation.CommentType>
+      MAIL_COMMENT_TYPE_TO_VALIDATION_TYPE =
+          ImmutableMap.of(
+              MailComment.CommentType.CHANGE_MESSAGE,
+                  CommentForValidation.CommentType.CHANGE_MESSAGE,
+              MailComment.CommentType.FILE_COMMENT, CommentForValidation.CommentType.FILE_COMMENT,
+              MailComment.CommentType.INLINE_COMMENT,
+                  CommentForValidation.CommentType.INLINE_COMMENT);
+
   private final Emails emails;
   private final InboundEmailRejectionSender.Factory emailRejectionSender;
   private final RetryHelper retryHelper;
@@ -98,6 +113,7 @@
   private final ApprovalsUtil approvalsUtil;
   private final AccountCache accountCache;
   private final DynamicItem<UrlFormatter> urlFormatter;
+  private final PluginSetContext<CommentValidator> commentValidators;
 
   @Inject
   public MailProcessor(
@@ -115,7 +131,8 @@
       ApprovalsUtil approvalsUtil,
       CommentAdded commentAdded,
       AccountCache accountCache,
-      DynamicItem<UrlFormatter> urlFormatter) {
+      DynamicItem<UrlFormatter> urlFormatter,
+      PluginSetContext<CommentValidator> commentValidators) {
     this.emails = emails;
     this.emailRejectionSender = emailRejectionSender;
     this.retryHelper = retryHelper;
@@ -131,6 +148,7 @@
     this.approvalsUtil = approvalsUtil;
     this.accountCache = accountCache;
     this.urlFormatter = urlFormatter;
+    this.commentValidators = commentValidators;
   }
 
   /**
@@ -259,6 +277,21 @@
         return;
       }
 
+      ImmutableList<CommentForValidation> parsedCommentsForValidation =
+          parsedComments.stream()
+              .map(
+                  comment ->
+                      CommentForValidation.create(
+                          MAIL_COMMENT_TYPE_TO_VALIDATION_TYPE.get(comment.getType()),
+                          comment.getMessage()))
+              .collect(ImmutableList.toImmutableList());
+      ImmutableList<CommentValidationFailure> commentValidationFailures =
+          PublishCommentUtil.findInvalidComments(commentValidators, parsedCommentsForValidation);
+      if (!commentValidationFailures.isEmpty()) {
+        sendRejectionEmail(message, InboundEmailRejectionSender.Error.COMMENT_REJECTED);
+        return;
+      }
+
       Op o = new Op(PatchSet.id(cd.getId(), metadata.patchSet), parsedComments, message.id());
       BatchUpdate batchUpdate = buf.create(project, ctx.getUser(), TimeUtil.nowTs());
       batchUpdate.addOp(cd.getId(), o);
diff --git a/java/com/google/gerrit/server/mail/send/EmailArguments.java b/java/com/google/gerrit/server/mail/send/EmailArguments.java
index fe2f74b..ede5765 100644
--- a/java/com/google/gerrit/server/mail/send/EmailArguments.java
+++ b/java/com/google/gerrit/server/mail/send/EmailArguments.java
@@ -45,7 +45,7 @@
 import com.google.gerrit.server.validators.OutgoingEmailValidationListener;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
-import com.google.template.soy.tofu.SoyTofu;
+import com.google.template.soy.jbcsrc.api.SoySauce;
 import java.util.List;
 import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.PersonIdent;
@@ -75,7 +75,7 @@
 
   final ChangeQueryBuilder queryBuilder;
   final ChangeData.Factory changeDataFactory;
-  final SoyTofu soyTofu;
+  final SoySauce soySauce;
   final EmailSettings settings;
   final DynamicSet<OutgoingEmailValidationListener> outgoingEmailValidationListeners;
   final Provider<InternalAccountQuery> accountQueryProvider;
@@ -105,7 +105,7 @@
       AllProjectsName allProjectsName,
       ChangeQueryBuilder queryBuilder,
       ChangeData.Factory changeDataFactory,
-      @MailTemplates SoyTofu soyTofu,
+      @MailTemplates SoySauce soySauce,
       EmailSettings settings,
       @SshAdvertisedAddresses List<String> sshAddresses,
       SitePaths site,
@@ -134,7 +134,7 @@
     this.allProjectsName = allProjectsName;
     this.queryBuilder = queryBuilder;
     this.changeDataFactory = changeDataFactory;
-    this.soyTofu = soyTofu;
+    this.soySauce = soySauce;
     this.settings = settings;
     this.sshAddresses = sshAddresses;
     this.site = site;
diff --git a/java/com/google/gerrit/server/mail/send/InboundEmailRejectionSender.java b/java/com/google/gerrit/server/mail/send/InboundEmailRejectionSender.java
index b5d384d..f0b3c66 100644
--- a/java/com/google/gerrit/server/mail/send/InboundEmailRejectionSender.java
+++ b/java/com/google/gerrit/server/mail/send/InboundEmailRejectionSender.java
@@ -32,7 +32,8 @@
     PARSING_ERROR,
     INACTIVE_ACCOUNT,
     UNKNOWN_ACCOUNT,
-    INTERNAL_EXCEPTION;
+    INTERNAL_EXCEPTION,
+    COMMENT_REJECTED
   }
 
   public interface Factory {
diff --git a/java/com/google/gerrit/server/mail/send/MailSoyTofuProvider.java b/java/com/google/gerrit/server/mail/send/MailSoySauceProvider.java
similarity index 90%
rename from java/com/google/gerrit/server/mail/send/MailSoyTofuProvider.java
rename to java/com/google/gerrit/server/mail/send/MailSoySauceProvider.java
index 3bb44c7..151567e 100644
--- a/java/com/google/gerrit/server/mail/send/MailSoyTofuProvider.java
+++ b/java/com/google/gerrit/server/mail/send/MailSoySauceProvider.java
@@ -22,17 +22,17 @@
 import com.google.inject.ProvisionException;
 import com.google.inject.Singleton;
 import com.google.template.soy.SoyFileSet;
+import com.google.template.soy.jbcsrc.api.SoySauce;
 import com.google.template.soy.shared.SoyAstCache;
-import com.google.template.soy.tofu.SoyTofu;
 import java.io.IOException;
 import java.io.Reader;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 
-/** Configures Soy Tofu object for rendering email templates. */
+/** Configures Soy Sauce object for rendering email templates. */
 @Singleton
-public class MailSoyTofuProvider implements Provider<SoyTofu> {
+public class MailSoySauceProvider implements Provider<SoySauce> {
 
   // Note: will fail to construct the tofu object if this array is empty.
   private static final String[] TEMPLATES = {
@@ -82,19 +82,19 @@
   private final SoyAstCache cache;
 
   @Inject
-  MailSoyTofuProvider(SitePaths site, SoyAstCache cache) {
+  MailSoySauceProvider(SitePaths site, SoyAstCache cache) {
     this.site = site;
     this.cache = cache;
   }
 
   @Override
-  public SoyTofu get() throws ProvisionException {
+  public SoySauce get() throws ProvisionException {
     SoyFileSet.Builder builder = SoyFileSet.builder();
     builder.setSoyAstCache(cache);
     for (String name : TEMPLATES) {
       addTemplate(builder, name);
     }
-    return builder.build().compileToTofu();
+    return builder.build().compileTemplates();
   }
 
   private void addTemplate(SoyFileSet.Builder builder, String name) throws ProvisionException {
diff --git a/java/com/google/gerrit/server/mail/send/OutgoingEmail.java b/java/com/google/gerrit/server/mail/send/OutgoingEmail.java
index db97f06..ef6b21d 100644
--- a/java/com/google/gerrit/server/mail/send/OutgoingEmail.java
+++ b/java/com/google/gerrit/server/mail/send/OutgoingEmail.java
@@ -543,11 +543,12 @@
   }
 
   private String soyTemplate(String name, SanitizedContent.ContentKind kind) {
-    return args.soyTofu
-        .newRenderer("com.google.gerrit.server.mail.template." + name)
-        .setContentKind(kind)
+    return args.soySauce
+        .renderTemplate("com.google.gerrit.server.mail.template." + name)
+        .setExpectedContentKind(kind)
         .setData(soyContext)
-        .render();
+        .render()
+        .get();
   }
 
   protected String textTemplate(String name) {
diff --git a/java/com/google/gerrit/server/permissions/DefaultRefFilter.java b/java/com/google/gerrit/server/permissions/DefaultRefFilter.java
index 6f9f75a..5c17be8 100644
--- a/java/com/google/gerrit/server/permissions/DefaultRefFilter.java
+++ b/java/com/google/gerrit/server/permissions/DefaultRefFilter.java
@@ -49,6 +49,8 @@
 import com.google.gerrit.server.git.TagCache;
 import com.google.gerrit.server.git.TagMatcher;
 import com.google.gerrit.server.group.InternalGroup;
+import com.google.gerrit.server.logging.TraceContext;
+import com.google.gerrit.server.logging.TraceContext.TraceTimer;
 import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.notedb.ChangeNotes.Factory.ChangeNotesResult;
 import com.google.gerrit.server.permissions.PermissionBackend.RefFilterOptions;
@@ -129,52 +131,82 @@
   /** Filters given refs and tags by visibility. */
   Map<String, Ref> filter(Map<String, Ref> refs, Repository repo, RefFilterOptions opts)
       throws PermissionBackendException {
+    logger.atFinest().log(
+        "Filter refs for repository %s by visibility (options = %s, refs = %s)",
+        projectState.getNameKey(), opts, refs);
+    logger.atFinest().log(
+        "Calling user: %s (groups = %s)",
+        user.getLoggableName(), user.getEffectiveGroups().getKnownGroups());
+    logger.atFinest().log(
+        "auth.skipFullRefEvaluationIfAllRefsAreVisible = %s",
+        skipFullRefEvaluationIfAllRefsAreVisible);
+    logger.atFinest().log(
+        "Project state %s permits read = %s",
+        projectState.getProject().getState(), projectState.statePermitsRead());
+
     // See if we can get away with a single, cheap ref evaluation.
     if (refs.size() == 1) {
       String refName = Iterables.getOnlyElement(refs.values()).getName();
       if (opts.filterMeta() && isMetadata(refName)) {
+        logger.atFinest().log("Filter out metadata ref %s", refName);
         return ImmutableMap.of();
       }
       if (RefNames.isRefsChanges(refName)) {
-        return canSeeSingleChangeRef(refName) ? refs : ImmutableMap.of();
+        boolean isChangeRefVisisble = canSeeSingleChangeRef(refName);
+        if (isChangeRefVisisble) {
+          logger.atFinest().log("Change ref %s is visible", refName);
+          return refs;
+        }
+        logger.atFinest().log("Filter out non-visible change ref %s", refName);
+        return ImmutableMap.of();
       }
     }
 
     // Perform an initial ref filtering with all the refs the caller asked for. If we find tags that
-    // we have to investigate (deferred tags) separately then perform a reachability check starting
+    // we have to investigate separately (deferred tags) then perform a reachability check starting
     // from all visible branches (refs/heads/*).
     Result initialRefFilter = filterRefs(refs, repo, opts);
     Map<String, Ref> visibleRefs = initialRefFilter.visibleRefs();
     if (!initialRefFilter.deferredTags().isEmpty()) {
-      Result allVisibleBranches = filterRefs(getTaggableRefsMap(repo), repo, opts);
-      checkState(
-          allVisibleBranches.deferredTags().isEmpty(),
-          "unexpected tags found when filtering refs/heads/* " + allVisibleBranches.deferredTags());
+      try (TraceTimer traceTimer = TraceContext.newTimer("Check visibility of deferred tags")) {
+        Result allVisibleBranches = filterRefs(getTaggableRefsMap(repo), repo, opts);
+        checkState(
+            allVisibleBranches.deferredTags().isEmpty(),
+            "unexpected tags found when filtering refs/heads/* "
+                + allVisibleBranches.deferredTags());
 
-      TagMatcher tags =
-          tagCache
-              .get(projectState.getNameKey())
-              .matcher(tagCache, repo, allVisibleBranches.visibleRefs().values());
-      for (Ref tag : initialRefFilter.deferredTags()) {
-        try {
-          if (tags.isReachable(tag)) {
-            visibleRefs.put(tag.getName(), tag);
+        TagMatcher tags =
+            tagCache
+                .get(projectState.getNameKey())
+                .matcher(tagCache, repo, allVisibleBranches.visibleRefs().values());
+        for (Ref tag : initialRefFilter.deferredTags()) {
+          try {
+            if (tags.isReachable(tag)) {
+              logger.atFinest().log("Include reachable tag %s", tag.getName());
+              visibleRefs.put(tag.getName(), tag);
+            } else {
+              logger.atFinest().log("Filter out non-reachable tag %s", tag.getName());
+            }
+          } catch (IOException e) {
+            throw new PermissionBackendException(e);
           }
-        } catch (IOException e) {
-          throw new PermissionBackendException(e);
         }
       }
     }
+
+    logger.atFinest().log("visible refs = %s", visibleRefs);
     return visibleRefs;
   }
 
   /**
    * Filters refs by visibility. Returns tags where visibility can't be trivially computed
-   * separately for later ref-walk-based visibility computation. Tags where visibility is trivial to
+   * separately for later rev-walk-based visibility computation. Tags where visibility is trivial to
    * compute will be returned as part of {@link Result#visibleRefs()}.
    */
   Result filterRefs(Map<String, Ref> refs, Repository repo, RefFilterOptions opts)
       throws PermissionBackendException {
+    logger.atFinest().log("Filter refs (refs = %s)", refs);
+
     if (projectState.isAllUsers()) {
       refs = addUsersSelfSymref(refs);
     }
@@ -182,16 +214,22 @@
     // TODO(hiesel): Remove when optimization is done.
     boolean hasReadOnRefsStar =
         checkProjectPermission(permissionBackendForProject, ProjectPermission.READ);
+    logger.atFinest().log("User has READ on refs/* = %s", hasReadOnRefsStar);
     if (skipFullRefEvaluationIfAllRefsAreVisible && !projectState.isAllUsers()) {
       if (projectState.statePermitsRead() && hasReadOnRefsStar) {
         skipFilterCount.increment();
+        logger.atFinest().log(
+            "Fast path, all refs are visible because user has READ on refs/*: %s", refs);
         return new AutoValue_DefaultRefFilter_Result(refs, ImmutableList.of());
       } else if (projectControl.allRefsAreVisible(ImmutableSet.of(RefNames.REFS_CONFIG))) {
         skipFilterCount.increment();
-        return new AutoValue_DefaultRefFilter_Result(
-            fastHideRefsMetaConfig(refs), ImmutableList.of());
+        refs = fastHideRefsMetaConfig(refs);
+        logger.atFinest().log(
+            "Fast path, all refs except %s are visible: %s", RefNames.REFS_CONFIG, refs);
+        return new AutoValue_DefaultRefFilter_Result(refs, ImmutableList.of());
       }
     }
+    logger.atFinest().log("Doing full ref filtering");
     fullFilterCount.increment();
 
     boolean viewMetadata;
@@ -204,36 +242,53 @@
       isAdmin = withUser.testOrFalse(GlobalPermission.ADMINISTRATE_SERVER);
       identifiedUser = user.asIdentifiedUser();
       userId = identifiedUser.getAccountId();
+      logger.atFinest().log(
+          "Account = %d; can view metadata = %s; is admin = %s",
+          userId.get(), viewMetadata, isAdmin);
     } else {
+      logger.atFinest().log("User is anonymous");
       viewMetadata = false;
       isAdmin = false;
       userId = null;
       identifiedUser = null;
     }
 
-    Map<String, Ref> result = new HashMap<>();
+    Map<String, Ref> resultRefs = new HashMap<>();
     List<Ref> deferredTags = new ArrayList<>();
     for (Ref ref : refs.values()) {
       String name = ref.getName();
       Change.Id changeId;
       Account.Id accountId;
       AccountGroup.UUID accountGroupUuid;
-      if (name.startsWith(REFS_CACHE_AUTOMERGE) || (opts.filterMeta() && isMetadata(name))) {
+      if (name.startsWith(REFS_CACHE_AUTOMERGE)) {
+        logger.atFinest().log("Filter out ref %s", name);
+        continue;
+      } else if (opts.filterMeta() && isMetadata(name)) {
+        logger.atFinest().log("Filter out metadata ref %s", name);
         continue;
       } else if (RefNames.isRefsEdit(name)) {
         // Edits are visible only to the owning user, if change is visible.
         if (viewMetadata || visibleEdit(repo, name)) {
-          result.put(name, ref);
+          logger.atFinest().log("Include edit ref %s", name);
+          resultRefs.put(name, ref);
+        } else {
+          logger.atFinest().log("Filter out edit ref %s", name);
         }
       } else if ((changeId = Change.Id.fromRef(name)) != null) {
         // Change ref is visible only if the change is visible.
         if (viewMetadata || visible(repo, changeId)) {
-          result.put(name, ref);
+          logger.atFinest().log("Include change ref %s", name);
+          resultRefs.put(name, ref);
+        } else {
+          logger.atFinest().log("Filter out change ref %s", name);
         }
       } else if ((accountId = Account.Id.fromRef(name)) != null) {
         // Account ref is visible only to the corresponding account.
         if (viewMetadata || (accountId.equals(userId) && canReadRef(name))) {
-          result.put(name, ref);
+          logger.atFinest().log("Include user ref %s", name);
+          resultRefs.put(name, ref);
+        } else {
+          logger.atFinest().log("Filter out user ref %s", name);
         }
       } else if ((accountGroupUuid = AccountGroup.UUID.fromRef(name)) != null) {
         // Group ref is visible only to the corresponding owner group.
@@ -242,7 +297,10 @@
             || (group != null
                 && isGroupOwner(group, identifiedUser, isAdmin)
                 && canReadRef(name))) {
-          result.put(name, ref);
+          logger.atFinest().log("Include group ref %s", name);
+          resultRefs.put(name, ref);
+        } else {
+          logger.atFinest().log("Filter out group ref %s", name);
         }
       } else if (isTag(ref)) {
         if (hasReadOnRefsStar) {
@@ -255,39 +313,56 @@
           // (e.g. a private change ref) if a tag was attached to it. Tags are meant to be used on
           // the regular Git tree that users interact with, not on any of the Gerrit trees, so this
           // is a negligible risk.
-          result.put(name, ref);
+          logger.atFinest().log("Include tag ref %s because user has read on refs/*", name);
+          resultRefs.put(name, ref);
         } else {
           // If its a tag, consider it later.
           if (ref.getObjectId() != null) {
+            logger.atFinest().log("Defer tag ref %s", name);
             deferredTags.add(ref);
+          } else {
+            logger.atFinest().log("Filter out tag ref %s that is not a tag", name);
           }
         }
       } else if (name.startsWith(RefNames.REFS_SEQUENCES)) {
         // Sequences are internal database implementation details.
         if (viewMetadata) {
-          result.put(name, ref);
+          logger.atFinest().log("Include sequence ref %s", name);
+          resultRefs.put(name, ref);
+        } else {
+          logger.atFinest().log("Filter out sequence ref %s", name);
         }
       } else if (projectState.isAllUsers()
           && (name.equals(RefNames.REFS_EXTERNAL_IDS) || name.equals(RefNames.REFS_GROUPNAMES))) {
         // The notes branches with the external IDs / group names must not be exposed to normal
         // users.
         if (viewMetadata) {
-          result.put(name, ref);
+          logger.atFinest().log("Include external IDs branch %s", name);
+          resultRefs.put(name, ref);
+        } else {
+          logger.atFinest().log("Filter out external IDs branch %s", name);
         }
       } else if (canReadRef(ref.getLeaf().getName())) {
         // Use the leaf to lookup the control data. If the reference is
         // symbolic we want the control around the final target. If its
         // not symbolic then getLeaf() is a no-op returning ref itself.
-        result.put(name, ref);
+        logger.atFinest().log(
+            "Include ref %s because its leaf %s is readable", name, ref.getLeaf().getName());
+        resultRefs.put(name, ref);
       } else if (isRefsUsersSelf(ref)) {
         // viewMetadata allows to see all account refs, hence refs/users/self should be included as
         // well
         if (viewMetadata) {
-          result.put(name, ref);
+          logger.atFinest().log("Include ref %s", REFS_USERS_SELF);
+          resultRefs.put(name, ref);
         }
+      } else {
+        logger.atFinest().log("Filter out ref %s", name);
       }
     }
-    return new AutoValue_DefaultRefFilter_Result(result, deferredTags);
+    Result result = new AutoValue_DefaultRefFilter_Result(resultRefs, deferredTags);
+    logger.atFinest().log("Result of ref filtering = %s", result);
+    return result;
   }
 
   /**
@@ -324,12 +399,17 @@
 
   private Map<String, Ref> addUsersSelfSymref(Map<String, Ref> refs) {
     if (user.isIdentifiedUser()) {
-      Ref r = refs.get(RefNames.refsUsers(user.getAccountId()));
-      if (r != null) {
-        SymbolicRef s = new SymbolicRef(REFS_USERS_SELF, r);
-        refs = new HashMap<>(refs);
-        refs.put(s.getName(), s);
+      String refName = RefNames.refsUsers(user.getAccountId());
+      Ref r = refs.get(refName);
+      if (r == null) {
+        logger.atWarning().log("User ref %s not found", refName);
+        return refs;
       }
+
+      SymbolicRef s = new SymbolicRef(REFS_USERS_SELF, r);
+      refs = new HashMap<>(refs);
+      refs.put(s.getName(), s);
+      logger.atFinest().log("Added %s as alias for user ref %s", REFS_USERS_SELF, refName);
     }
     return refs;
   }
@@ -341,36 +421,44 @@
       } else {
         visibleChanges = visibleChangesBySearch();
       }
+      logger.atFinest().log("Visible changes: %s", visibleChanges.keySet());
     }
     return visibleChanges.containsKey(changeId);
   }
 
   private boolean visibleEdit(Repository repo, String name) throws PermissionBackendException {
     Change.Id id = Change.Id.fromEditRefPart(name);
-    // Initialize if it wasn't yet
-    if (visibleChanges == null) {
-      visible(repo, id);
-    }
     if (id == null) {
+      logger.atWarning().log("Couldn't extract change ID from edit ref %s", name);
       return false;
     }
 
     if (user.isIdentifiedUser()
         && name.startsWith(RefNames.refsEditPrefix(user.asIdentifiedUser().getAccountId()))
         && visible(repo, id)) {
+      logger.atFinest().log("Own change edit ref is visible: %s", name);
       return true;
     }
+
+    // Initialize visibleChanges if it wasn't initialized yet.
+    if (visibleChanges == null) {
+      visible(repo, id);
+    }
     if (visibleChanges.containsKey(id)) {
       try {
         // Default to READ_PRIVATE_CHANGES as there is no special permission for reading edits.
         permissionBackendForProject
             .ref(visibleChanges.get(id).branch())
             .check(RefPermission.READ_PRIVATE_CHANGES);
+        logger.atFinest().log("Foreign change edit ref is visible: %s", name);
         return true;
       } catch (AuthException e) {
+        logger.atFinest().log("Foreign change edit ref is not visible: %s", name);
         return false;
       }
     }
+
+    logger.atFinest().log("Change %d of change edit ref %s is not visible", id.get(), name);
     return false;
   }
 
@@ -442,7 +530,9 @@
   }
 
   private boolean isMetadata(String name) {
-    return RefNames.isRefsChanges(name) || RefNames.isRefsEdit(name);
+    boolean isMetaData = RefNames.isRefsChanges(name) || RefNames.isRefsEdit(name);
+    logger.atFinest().log("ref %s is " + (isMetaData ? "" : "not ") + "a metadata ref", name);
+    return isMetaData;
   }
 
   private static boolean isTag(Ref ref) {
@@ -478,8 +568,10 @@
     requireNonNull(group);
 
     // Keep this logic in sync with GroupControl#isOwner().
-    return isAdmin
-        || (user != null && user.getEffectiveGroups().contains(group.getOwnerGroupUUID()));
+    boolean isGroupOwner =
+        isAdmin || (user != null && user.getEffectiveGroups().contains(group.getOwnerGroupUUID()));
+    logger.atFinest().log("User is owner of group %s = %s", group.getGroupUUID(), isGroupOwner);
+    return isGroupOwner;
   }
 
   /**
diff --git a/java/com/google/gerrit/server/restapi/change/PostReview.java b/java/com/google/gerrit/server/restapi/change/PostReview.java
index 18d668a..b8ea310 100644
--- a/java/com/google/gerrit/server/restapi/change/PostReview.java
+++ b/java/com/google/gerrit/server/restapi/change/PostReview.java
@@ -16,6 +16,7 @@
 
 import static com.google.common.base.MoreObjects.firstNonNull;
 import static com.google.common.base.Preconditions.checkState;
+import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.gerrit.server.CommentsUtil.setCommentCommitId;
 import static com.google.gerrit.server.notedb.ReviewerStateInternal.REVIEWER;
 import static com.google.gerrit.server.permissions.LabelPermission.ForUser.ON_BEHALF_OF;
@@ -29,9 +30,11 @@
 
 import com.google.auto.value.AutoValue;
 import com.google.common.base.Strings;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Ordering;
+import com.google.common.collect.Streams;
 import com.google.common.flogger.FluentLogger;
 import com.google.common.hash.HashCode;
 import com.google.common.hash.Hashing;
@@ -61,6 +64,10 @@
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.UnprocessableEntityException;
 import com.google.gerrit.extensions.restapi.Url;
+import com.google.gerrit.extensions.validators.CommentForValidation;
+import com.google.gerrit.extensions.validators.CommentForValidation.CommentType;
+import com.google.gerrit.extensions.validators.CommentValidationFailure;
+import com.google.gerrit.extensions.validators.CommentValidator;
 import com.google.gerrit.json.OutputFormat;
 import com.google.gerrit.mail.Address;
 import com.google.gerrit.reviewdb.client.Account;
@@ -106,12 +113,14 @@
 import com.google.gerrit.server.permissions.LabelPermission;
 import com.google.gerrit.server.permissions.PermissionBackend;
 import com.google.gerrit.server.permissions.PermissionBackendException;
+import com.google.gerrit.server.plugincontext.PluginSetContext;
 import com.google.gerrit.server.project.ProjectCache;
 import com.google.gerrit.server.project.ProjectState;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.update.BatchUpdate;
 import com.google.gerrit.server.update.BatchUpdateOp;
 import com.google.gerrit.server.update.ChangeContext;
+import com.google.gerrit.server.update.CommentsRejectedException;
 import com.google.gerrit.server.update.Context;
 import com.google.gerrit.server.update.RetryHelper;
 import com.google.gerrit.server.update.RetryingRestModifyView;
@@ -136,6 +145,8 @@
 import java.util.Optional;
 import java.util.OptionalInt;
 import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.ObjectId;
@@ -145,7 +156,7 @@
     extends RetryingRestModifyView<RevisionResource, ReviewInput, Response<ReviewResult>> {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
-  public static final String ERROR_ADDING_REVIEWER = "error adding reviewer";
+  private static final String ERROR_ADDING_REVIEWER = "error adding reviewer";
   public static final String ERROR_WIP_READY_MUTUALLY_EXCLUSIVE =
       "work_in_progress and ready are mutually exclusive";
 
@@ -172,6 +183,7 @@
   private final WorkInProgressOp.Factory workInProgressOpFactory;
   private final ProjectCache projectCache;
   private final PermissionBackend permissionBackend;
+  private final PluginSetContext<CommentValidator> commentValidators;
   private final boolean strictLabels;
 
   @Inject
@@ -194,7 +206,8 @@
       @GerritServerConfig Config gerritConfig,
       WorkInProgressOp.Factory workInProgressOpFactory,
       ProjectCache projectCache,
-      PermissionBackend permissionBackend) {
+      PermissionBackend permissionBackend,
+      PluginSetContext<CommentValidator> commentValidators) {
     super(retryHelper);
     this.changeResourceFactory = changeResourceFactory;
     this.changeDataFactory = changeDataFactory;
@@ -214,6 +227,7 @@
     this.workInProgressOpFactory = workInProgressOpFactory;
     this.projectCache = projectCache;
     this.permissionBackend = permissionBackend;
+    this.commentValidators = commentValidators;
     this.strictLabels = gerritConfig.getBoolean("change", "strictLabels", false);
   }
 
@@ -290,7 +304,7 @@
       Account.Id id = revision.getUser().getAccountId();
       boolean ccOrReviewer = false;
       if (input.labels != null && !input.labels.isEmpty()) {
-        ccOrReviewer = input.labels.values().stream().filter(v -> v != 0).findFirst().isPresent();
+        ccOrReviewer = input.labels.values().stream().anyMatch(v -> v != 0);
       }
 
       if (!ccOrReviewer) {
@@ -792,7 +806,10 @@
     }
   }
 
-  /** Used to compare Comments with CommentInput comments. */
+  /**
+   * Used to compare existing {@link Comment}-s with {@link CommentInput} comments by copying only
+   * the fields to compare.
+   */
   @AutoValue
   abstract static class CommentSetEntry {
     private static CommentSetEntry create(
@@ -854,12 +871,11 @@
     @Override
     public boolean updateChange(ChangeContext ctx)
         throws ResourceConflictException, UnprocessableEntityException, IOException,
-            PatchListNotAvailableException {
+            PatchListNotAvailableException, CommentsRejectedException {
       user = ctx.getIdentifiedUser();
       notes = ctx.getNotes();
       ps = psUtil.get(ctx.getNotes(), psId);
-      boolean dirty = false;
-      dirty |= insertComments(ctx);
+      boolean dirty = insertComments(ctx);
       dirty |= insertRobotComments(ctx);
       dirty |= updateLabels(projectState, ctx);
       dirty |= insertMessage(ctx);
@@ -888,14 +904,19 @@
     }
 
     private boolean insertComments(ChangeContext ctx)
-        throws UnprocessableEntityException, PatchListNotAvailableException {
-      Map<String, List<CommentInput>> map = in.comments;
-      if (map == null) {
-        map = Collections.emptyMap();
+        throws UnprocessableEntityException, PatchListNotAvailableException,
+            CommentsRejectedException {
+      Map<String, List<CommentInput>> inputComments = in.comments;
+      if (inputComments == null) {
+        inputComments = Collections.emptyMap();
       }
 
-      Map<String, Comment> drafts = Collections.emptyMap();
-      if (!map.isEmpty() || in.drafts != DraftHandling.KEEP) {
+      // HashMap instead of Collections.emptyMap() avoids warning about remove() on immutable
+      // object.
+      Map<String, Comment> drafts = new HashMap<>();
+      // If there are inputComments we need the deduplication loop below, so we have to read (and
+      // publish) drafts here.
+      if (!inputComments.isEmpty() || in.drafts != DraftHandling.KEEP) {
         if (in.drafts == DraftHandling.PUBLISH_ALL_REVISIONS) {
           drafts = changeDrafts(ctx);
         } else {
@@ -903,51 +924,84 @@
         }
       }
 
+      // This will be populated with Comment-s created from inputComments.
       List<Comment> toPublish = new ArrayList<>();
 
-      Set<CommentSetEntry> existingIds =
+      Set<CommentSetEntry> existingComments =
           in.omitDuplicateComments ? readExistingComments(ctx) : Collections.emptySet();
 
-      for (Map.Entry<String, List<CommentInput>> ent : map.entrySet()) {
-        String path = ent.getKey();
-        for (CommentInput c : ent.getValue()) {
-          String parent = Url.decode(c.inReplyTo);
-          Comment e = drafts.remove(Url.decode(c.id));
-          if (e == null) {
-            e = commentsUtil.newComment(ctx, path, psId, c.side(), c.message, c.unresolved, parent);
+      // Deduplication:
+      // - Ignore drafts with the same ID as an inputComment here. These are deleted later.
+      // - Swallow comments that already exist.
+      for (Map.Entry<String, List<CommentInput>> entry : inputComments.entrySet()) {
+        String path = entry.getKey();
+        for (CommentInput inputComment : entry.getValue()) {
+          Comment comment = drafts.remove(Url.decode(inputComment.id));
+          if (comment == null) {
+            String parent = Url.decode(inputComment.inReplyTo);
+            comment =
+                commentsUtil.newComment(
+                    ctx,
+                    path,
+                    psId,
+                    inputComment.side(),
+                    inputComment.message,
+                    inputComment.unresolved,
+                    parent);
           } else {
-            e.writtenOn = ctx.getWhen();
-            e.side = c.side();
-            e.message = c.message;
+            // In ChangeUpdate#putComment() the draft with the same ID will be deleted.
+            comment.writtenOn = ctx.getWhen();
+            comment.side = inputComment.side();
+            comment.message = inputComment.message;
           }
 
-          setCommentCommitId(e, patchListCache, ctx.getChange(), ps);
-          e.setLineNbrAndRange(c.line, c.range);
-          e.tag = in.tag;
+          setCommentCommitId(comment, patchListCache, ctx.getChange(), ps);
+          comment.setLineNbrAndRange(inputComment.line, inputComment.range);
+          comment.tag = in.tag;
 
-          if (existingIds.contains(CommentSetEntry.create(e))) {
+          if (existingComments.contains(CommentSetEntry.create(comment))) {
             continue;
           }
-          toPublish.add(e);
+          toPublish.add(comment);
         }
       }
 
       switch (in.drafts) {
         case PUBLISH:
         case PUBLISH_ALL_REVISIONS:
+          validateComments(Streams.concat(drafts.values().stream(), toPublish.stream()));
           publishCommentUtil.publish(ctx, psId, drafts.values(), in.tag);
           comments.addAll(drafts.values());
           break;
         case KEEP:
         default:
+          validateComments(toPublish.stream());
           break;
       }
-      ChangeUpdate u = ctx.getUpdate(psId);
-      commentsUtil.putComments(u, Status.PUBLISHED, toPublish);
+      ChangeUpdate changeUpdate = ctx.getUpdate(psId);
+      commentsUtil.putComments(changeUpdate, Status.PUBLISHED, toPublish);
       comments.addAll(toPublish);
       return !toPublish.isEmpty();
     }
 
+    private void validateComments(Stream<Comment> comments) throws CommentsRejectedException {
+      ImmutableList<CommentForValidation> draftsForValidation =
+          comments
+              .map(
+                  comment ->
+                      CommentForValidation.create(
+                          comment.lineNbr > 0
+                              ? CommentForValidation.CommentType.INLINE_COMMENT
+                              : CommentType.FILE_COMMENT,
+                          comment.message))
+              .collect(toImmutableList());
+      ImmutableList<CommentValidationFailure> draftValidationFailures =
+          PublishCommentUtil.findInvalidComments(commentValidators, draftsForValidation);
+      if (!draftValidationFailures.isEmpty()) {
+        throw new CommentsRejectedException(draftValidationFailures);
+      }
+    }
+
     private boolean insertRobotComments(ChangeContext ctx) throws PatchListNotAvailableException {
       if (in.robotComments == null) {
         return false;
@@ -1042,21 +1096,19 @@
     }
 
     private Map<String, Comment> changeDrafts(ChangeContext ctx) {
-      Map<String, Comment> drafts = new HashMap<>();
-      for (Comment c : commentsUtil.draftByChangeAuthor(ctx.getNotes(), user.getAccountId())) {
-        c.tag = in.tag;
-        drafts.put(c.key.uuid, c);
-      }
-      return drafts;
+      return commentsUtil.draftByChangeAuthor(ctx.getNotes(), user.getAccountId()).stream()
+          .collect(
+              Collectors.toMap(
+                  c -> c.key.uuid,
+                  c -> {
+                    c.tag = in.tag;
+                    return c;
+                  }));
     }
 
     private Map<String, Comment> patchSetDrafts(ChangeContext ctx) {
-      Map<String, Comment> drafts = new HashMap<>();
-      for (Comment c :
-          commentsUtil.draftByPatchSetAuthor(psId, user.getAccountId(), ctx.getNotes())) {
-        drafts.put(c.key.uuid, c);
-      }
-      return drafts;
+      return commentsUtil.draftByPatchSetAuthor(psId, user.getAccountId(), ctx.getNotes()).stream()
+          .collect(Collectors.toMap(c -> c.key.uuid, c -> c));
     }
 
     private Map<String, Short> approvalsByKey(Collection<PatchSetApproval> patchsetApprovals) {
@@ -1104,10 +1156,7 @@
       }
       ChangeData cd = changeDataFactory.create(ctx.getNotes());
       ReviewerSet reviewers = cd.reviewers();
-      if (reviewers.byState(REVIEWER).contains(ctx.getAccountId())) {
-        return true;
-      }
-      return false;
+      return reviewers.byState(REVIEWER).contains(ctx.getAccountId());
     }
 
     private boolean updateLabels(ProjectState projectState, ChangeContext ctx)
@@ -1323,7 +1372,7 @@
       return current;
     }
 
-    private boolean insertMessage(ChangeContext ctx) {
+    private boolean insertMessage(ChangeContext ctx) throws CommentsRejectedException {
       String msg = Strings.nullToEmpty(in.message).trim();
 
       StringBuilder buf = new StringBuilder();
@@ -1336,6 +1385,15 @@
         buf.append(String.format("\n\n(%d comments)", comments.size()));
       }
       if (!msg.isEmpty()) {
+        ImmutableList<CommentValidationFailure> messageValidationFailure =
+            PublishCommentUtil.findInvalidComments(
+                commentValidators,
+                ImmutableList.of(
+                    CommentForValidation.create(
+                        CommentForValidation.CommentType.CHANGE_MESSAGE, msg)));
+        if (!messageValidationFailure.isEmpty()) {
+          throw new CommentsRejectedException(messageValidationFailure);
+        }
         buf.append("\n\n").append(msg);
       } else if (in.ready) {
         buf.append("\n\n" + START_REVIEW_MESSAGE);
diff --git a/java/com/google/gerrit/server/schema/MysqlAccountPatchReviewStore.java b/java/com/google/gerrit/server/schema/MysqlAccountPatchReviewStore.java
index 35bf2cb..677b2de 100644
--- a/java/com/google/gerrit/server/schema/MysqlAccountPatchReviewStore.java
+++ b/java/com/google/gerrit/server/schema/MysqlAccountPatchReviewStore.java
@@ -38,7 +38,7 @@
 
   @Override
   public StorageException convertError(String op, SQLException err) {
-    switch (getSQLStateInt(err)) {
+    switch (err.getErrorCode()) {
       case 1022: // ER_DUP_KEY
       case 1062: // ER_DUP_ENTRY
       case 1169: // ER_DUP_UNIQUE;
diff --git a/java/com/google/gerrit/server/update/BatchUpdate.java b/java/com/google/gerrit/server/update/BatchUpdate.java
index 2a958af..6dee241 100644
--- a/java/com/google/gerrit/server/update/BatchUpdate.java
+++ b/java/com/google/gerrit/server/update/BatchUpdate.java
@@ -34,6 +34,7 @@
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.extensions.api.changes.NotifyHandling;
 import com.google.gerrit.extensions.config.FactoryModule;
+import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestApiException;
@@ -187,6 +188,10 @@
         || e instanceof NoSuchRefException
         || e instanceof NoSuchProjectException) {
       throw new ResourceNotFoundException(e.getMessage(), e);
+    } else if (e instanceof CommentsRejectedException) {
+      // SC_BAD_REQUEST is not ideal because it's not a syntactic error, but there is no better
+      // status code and it's isolated in monitoring.
+      throw new BadRequestException(e.getMessage(), e);
     }
 
     Throwables.throwIfUnchecked(e);
@@ -290,7 +295,7 @@
   private enum ChangeResult {
     SKIPPED,
     UPSERTED,
-    DELETED;
+    DELETED
   }
 
   private final GitRepositoryManager repoManager;
@@ -567,9 +572,7 @@
         handle.setResult(id, ChangeResult.SKIPPED);
         continue;
       }
-      for (ChangeUpdate u : ctx.updates.values()) {
-        handle.manager.add(u);
-      }
+      ctx.updates.values().forEach(handle.manager::add);
       if (ctx.deleted) {
         logDebug("Change %s was deleted", id);
         handle.manager.deleteChange(id);
diff --git a/java/com/google/gerrit/server/update/CommentsRejectedException.java b/java/com/google/gerrit/server/update/CommentsRejectedException.java
new file mode 100644
index 0000000..6b0c04d
--- /dev/null
+++ b/java/com/google/gerrit/server/update/CommentsRejectedException.java
@@ -0,0 +1,47 @@
+// Copyright (C) 2019 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.update;
+
+import com.google.common.collect.ImmutableList;
+import com.google.gerrit.extensions.validators.CommentValidationFailure;
+import java.util.Collection;
+import java.util.stream.Collectors;
+
+/** Thrown when comment validation rejected a comment, preventing it from being published. */
+public class CommentsRejectedException extends Exception {
+  private static final long serialVersionUID = 1L;
+
+  private final ImmutableList<CommentValidationFailure> commentValidationFailures;
+
+  public CommentsRejectedException(Collection<CommentValidationFailure> commentValidationFailures) {
+    this.commentValidationFailures = ImmutableList.copyOf(commentValidationFailures);
+  }
+
+  @Override
+  public String getMessage() {
+    return "One or more comments were rejected in validation: "
+        + commentValidationFailures.stream()
+            .map(CommentValidationFailure::getMessage)
+            .collect(Collectors.joining("; "));
+  }
+
+  /**
+   * Returns the validation failures that caused this exception. By contract this list is never
+   * empty.
+   */
+  public ImmutableList<CommentValidationFailure> getCommentValidationFailures() {
+    return commentValidationFailures;
+  }
+}
diff --git a/java/com/google/gerrit/testing/TestCommentHelper.java b/java/com/google/gerrit/testing/TestCommentHelper.java
new file mode 100644
index 0000000..b72cca7
--- /dev/null
+++ b/java/com/google/gerrit/testing/TestCommentHelper.java
@@ -0,0 +1,107 @@
+// Copyright (C) 2019 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.testing;
+
+import static java.util.stream.Collectors.toList;
+
+import com.google.gerrit.extensions.api.GerritApi;
+import com.google.gerrit.extensions.api.changes.DraftInput;
+import com.google.gerrit.extensions.client.Comment;
+import com.google.gerrit.extensions.client.Comment.Range;
+import com.google.gerrit.extensions.client.Side;
+import com.google.gerrit.extensions.common.CommentInfo;
+import com.google.inject.Inject;
+import java.util.Collection;
+
+/** Test helper for dealing with comments/drafts. */
+public class TestCommentHelper {
+  private final GerritApi gApi;
+
+  @Inject
+  public TestCommentHelper(GerritApi gerritApi) {
+    gApi = gerritApi;
+  }
+
+  public DraftInput newDraft(String message) {
+    return populate(new DraftInput(), "file", message);
+  }
+
+  public DraftInput newDraft(String path, Side side, int line, String message) {
+    DraftInput d = new DraftInput();
+    return populate(d, path, side, line, message);
+  }
+
+  public void addDraft(String changeId, String revId, DraftInput in) throws Exception {
+    gApi.changes().id(changeId).revision(revId).createDraft(in).get();
+  }
+
+  public Collection<CommentInfo> getPublishedComments(String changeId) throws Exception {
+    return gApi.changes().id(changeId).comments().values().stream()
+        .flatMap(Collection::stream)
+        .collect(toList());
+  }
+
+  public static <C extends Comment> C populate(C c, String path, String message) {
+    return populate(c, path, createLineRange(), message);
+  }
+
+  private static <C extends Comment> C populate(C c, String path, Range range, String message) {
+    int line = range.startLine;
+    c.path = path;
+    c.side = Side.REVISION;
+    c.parent = null;
+    c.line = line != 0 ? line : null;
+    c.message = message;
+    c.unresolved = false;
+    if (line != 0) c.range = range;
+    return c;
+  }
+
+  private static <C extends Comment> C populate(
+      C c, String path, Side side, Range range, String message) {
+    int line = range.startLine;
+    c.path = path;
+    c.side = side;
+    c.parent = null;
+    c.line = line != 0 ? line : null;
+    c.message = message;
+    c.unresolved = false;
+    if (line != 0) c.range = range;
+    return c;
+  }
+
+  private static <C extends Comment> C populate(
+      C c, String path, Side side, int line, String message) {
+    return populate(c, path, side, createLineRange(line), message);
+  }
+
+  private static Range createLineRange() {
+    Range range = new Range();
+    range.startLine = 0;
+    range.startCharacter = 1;
+    range.endLine = 0;
+    range.endCharacter = 5;
+    return range;
+  }
+
+  private static Range createLineRange(int line) {
+    Range range = new Range();
+    range.startLine = line;
+    range.startCharacter = 1;
+    range.endLine = line;
+    range.endCharacter = 5;
+    return range;
+  }
+}
diff --git a/javatests/com/google/gerrit/acceptance/api/accounts/AccountIT.java b/javatests/com/google/gerrit/acceptance/api/accounts/AccountIT.java
index f5954d9..228f233 100644
--- a/javatests/com/google/gerrit/acceptance/api/accounts/AccountIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/accounts/AccountIT.java
@@ -3291,10 +3291,6 @@
       countsByAccount.clear();
     }
 
-    long getCount(Account.Id accountId) {
-      return countsByAccount.get(accountId.get());
-    }
-
     void assertReindexOf(TestAccount testAccount) {
       assertReindexOf(testAccount, 1);
     }
@@ -3303,19 +3299,18 @@
       assertReindexOf(Account.id(accountInfo._accountId), 1);
     }
 
-    void assertReindexOf(TestAccount testAccount, int expectedCount) {
-      assertThat(getCount(testAccount.id())).isEqualTo(expectedCount);
-      assertThat(countsByAccount).hasSize(1);
+    void assertReindexOf(TestAccount testAccount, long expectedCount) {
+      assertThat(countsByAccount.asMap()).containsExactly(testAccount.id().get(), expectedCount);
       clear();
     }
 
-    void assertReindexOf(Account.Id accountId, int expectedCount) {
-      assertThat(getCount(accountId)).isEqualTo(expectedCount);
+    void assertReindexOf(Account.Id accountId, long expectedCount) {
+      assertThat(countsByAccount.asMap()).containsEntry(accountId.get(), expectedCount);
       countsByAccount.remove(accountId.get());
     }
 
     void assertNoReindex() {
-      assertThat(countsByAccount).isEmpty();
+      assertThat(countsByAccount.asMap()).isEmpty();
     }
   }
 
@@ -3339,23 +3334,17 @@
       countsByProjectRefs.clear();
     }
 
-    long getCount(String projectRef) {
-      return countsByProjectRefs.get(projectRef);
-    }
-
     void assertRefUpdateFor(String... projectRefs) {
-      Map<String, Integer> expectedRefUpdateCounts = new HashMap<>();
+      Map<String, Long> expectedRefUpdateCounts = new HashMap<>();
       for (String projectRef : projectRefs) {
-        expectedRefUpdateCounts.put(projectRef, 1);
+        expectedRefUpdateCounts.put(projectRef, 1L);
       }
       assertRefUpdateFor(expectedRefUpdateCounts);
     }
 
-    void assertRefUpdateFor(Map<String, Integer> expectedProjectRefUpdateCounts) {
-      for (Map.Entry<String, Integer> e : expectedProjectRefUpdateCounts.entrySet()) {
-        assertThat(getCount(e.getKey())).isEqualTo(e.getValue());
-      }
-      assertThat(countsByProjectRefs).hasSize(expectedProjectRefUpdateCounts.size());
+    void assertRefUpdateFor(Map<String, Long> expectedProjectRefUpdateCounts) {
+      assertThat(countsByProjectRefs.asMap())
+          .containsExactlyEntriesIn(expectedProjectRefUpdateCounts);
       clear();
     }
   }
diff --git a/javatests/com/google/gerrit/acceptance/api/change/PostReviewIT.java b/javatests/com/google/gerrit/acceptance/api/change/PostReviewIT.java
new file mode 100644
index 0000000..ebed15c
--- /dev/null
+++ b/javatests/com/google/gerrit/acceptance/api/change/PostReviewIT.java
@@ -0,0 +1,288 @@
+// Copyright (C) 2019 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.api.change;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.gerrit.testing.GerritJUnit.assertThrows;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Iterables;
+import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.PushOneCommit;
+import com.google.gerrit.extensions.annotations.Exports;
+import com.google.gerrit.extensions.api.changes.DraftInput;
+import com.google.gerrit.extensions.api.changes.ReviewInput;
+import com.google.gerrit.extensions.api.changes.ReviewInput.CommentInput;
+import com.google.gerrit.extensions.api.changes.ReviewInput.DraftHandling;
+import com.google.gerrit.extensions.client.Side;
+import com.google.gerrit.extensions.common.ChangeMessageInfo;
+import com.google.gerrit.extensions.config.FactoryModule;
+import com.google.gerrit.extensions.restapi.BadRequestException;
+import com.google.gerrit.extensions.validators.CommentForValidation;
+import com.google.gerrit.extensions.validators.CommentForValidation.CommentType;
+import com.google.gerrit.extensions.validators.CommentValidator;
+import com.google.gerrit.server.restapi.change.PostReview;
+import com.google.gerrit.server.update.CommentsRejectedException;
+import com.google.gerrit.testing.TestCommentHelper;
+import com.google.inject.Inject;
+import com.google.inject.Module;
+import java.sql.Timestamp;
+import org.easymock.Capture;
+import org.easymock.EasyMock;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+/** Tests for comment validation in {@link PostReview}. */
+public class PostReviewIT extends AbstractDaemonTest {
+  @Inject private CommentValidator mockCommentValidator;
+  @Inject private TestCommentHelper testCommentHelper;
+
+  private static final String COMMENT_TEXT = "The comment text";
+
+  private Capture<ImmutableList<CommentForValidation>> capture = new Capture<>();
+
+  @Override
+  public Module createModule() {
+    return new FactoryModule() {
+      @Override
+      public void configure() {
+        CommentValidator mockCommentValidator = EasyMock.createMock(CommentValidator.class);
+        bind(CommentValidator.class)
+            .annotatedWith(Exports.named(mockCommentValidator.getClass()))
+            .toInstance(mockCommentValidator);
+        bind(CommentValidator.class).toInstance(mockCommentValidator);
+      }
+    };
+  }
+
+  @Before
+  public void resetMock() {
+    EasyMock.reset(mockCommentValidator);
+  }
+
+  @After
+  public void verifyMock() {
+    EasyMock.verify(mockCommentValidator);
+  }
+
+  @Test
+  public void validateCommentsInInput_commentOK() throws Exception {
+    EasyMock.expect(
+            mockCommentValidator.validateComments(
+                ImmutableList.of(
+                    CommentForValidation.create(
+                        CommentForValidation.CommentType.FILE_COMMENT, COMMENT_TEXT))))
+        .andReturn(ImmutableList.of());
+    EasyMock.replay(mockCommentValidator);
+
+    PushOneCommit.Result r = createChange();
+
+    ReviewInput input = new ReviewInput();
+    CommentInput comment = newComment(r.getChange().currentFilePaths().get(0));
+    comment.updated = new Timestamp(0);
+    input.comments = ImmutableMap.of(comment.path, ImmutableList.of(comment));
+
+    assertThat(testCommentHelper.getPublishedComments(r.getChangeId())).isEmpty();
+    gApi.changes().id(r.getChangeId()).current().review(input);
+
+    assertThat(testCommentHelper.getPublishedComments(r.getChangeId())).hasSize(1);
+  }
+
+  @Test
+  public void validateCommentsInInput_commentRejected() throws Exception {
+    CommentForValidation commentForValidation =
+        CommentForValidation.create(CommentType.FILE_COMMENT, COMMENT_TEXT);
+    EasyMock.expect(
+            mockCommentValidator.validateComments(
+                ImmutableList.of(
+                    CommentForValidation.create(CommentType.FILE_COMMENT, COMMENT_TEXT))))
+        .andReturn(ImmutableList.of(commentForValidation.failValidation("Oh no!")));
+    EasyMock.replay(mockCommentValidator);
+
+    PushOneCommit.Result r = createChange();
+
+    ReviewInput input = new ReviewInput();
+    CommentInput comment = newComment(r.getChange().currentFilePaths().get(0));
+    comment.updated = new Timestamp(0);
+    input.comments = ImmutableMap.of(comment.path, ImmutableList.of(comment));
+
+    assertThat(testCommentHelper.getPublishedComments(r.getChangeId())).isEmpty();
+    BadRequestException badRequestException =
+        assertThrows(
+            BadRequestException.class,
+            () -> gApi.changes().id(r.getChangeId()).current().review(input));
+    assertThat(badRequestException.getCause()).isInstanceOf(CommentsRejectedException.class);
+    assertThat(
+            Iterables.getOnlyElement(
+                    ((CommentsRejectedException) badRequestException.getCause())
+                        .getCommentValidationFailures())
+                .getComment()
+                .getText())
+        .isEqualTo(COMMENT_TEXT);
+    assertThat(badRequestException.getCause()).hasMessageThat().contains("Oh no!");
+    assertThat(testCommentHelper.getPublishedComments(r.getChangeId())).isEmpty();
+  }
+
+  @Test
+  public void validateDrafts_draftOK() throws Exception {
+    EasyMock.expect(
+            mockCommentValidator.validateComments(
+                ImmutableList.of(
+                    CommentForValidation.create(
+                        CommentForValidation.CommentType.INLINE_COMMENT, COMMENT_TEXT))))
+        .andReturn(ImmutableList.of());
+    EasyMock.replay(mockCommentValidator);
+
+    PushOneCommit.Result r = createChange();
+
+    DraftInput draft =
+        testCommentHelper.newDraft(
+            r.getChange().currentFilePaths().get(0), Side.REVISION, 1, COMMENT_TEXT);
+    gApi.changes().id(r.getChangeId()).revision(r.getCommit().getName()).createDraft(draft).get();
+    assertThat(testCommentHelper.getPublishedComments(r.getChangeId())).isEmpty();
+
+    ReviewInput input = new ReviewInput();
+    input.drafts = DraftHandling.PUBLISH;
+
+    gApi.changes().id(r.getChangeId()).current().review(input);
+    assertThat(testCommentHelper.getPublishedComments(r.getChangeId())).hasSize(1);
+  }
+
+  @Test
+  public void validateDrafts_draftRejected() throws Exception {
+    CommentForValidation commentForValidation =
+        CommentForValidation.create(CommentType.INLINE_COMMENT, COMMENT_TEXT);
+    EasyMock.expect(
+            mockCommentValidator.validateComments(
+                ImmutableList.of(
+                    CommentForValidation.create(
+                        CommentForValidation.CommentType.INLINE_COMMENT, COMMENT_TEXT))))
+        .andReturn(ImmutableList.of(commentForValidation.failValidation("Oh no!")));
+    EasyMock.replay(mockCommentValidator);
+    PushOneCommit.Result r = createChange();
+
+    DraftInput draft =
+        testCommentHelper.newDraft(
+            r.getChange().currentFilePaths().get(0), Side.REVISION, 1, COMMENT_TEXT);
+    testCommentHelper.addDraft(r.getChangeId(), r.getCommit().getName(), draft);
+    assertThat(testCommentHelper.getPublishedComments(r.getChangeId())).isEmpty();
+
+    ReviewInput input = new ReviewInput();
+    input.drafts = DraftHandling.PUBLISH;
+    BadRequestException badRequestException =
+        assertThrows(
+            BadRequestException.class,
+            () -> gApi.changes().id(r.getChangeId()).current().review(input));
+    assertThat(badRequestException.getCause()).isInstanceOf(CommentsRejectedException.class);
+    assertThat(
+            Iterables.getOnlyElement(
+                    ((CommentsRejectedException) badRequestException.getCause())
+                        .getCommentValidationFailures())
+                .getComment()
+                .getText())
+        .isEqualTo(draft.message);
+    assertThat(badRequestException.getCause()).hasMessageThat().contains("Oh no!");
+    assertThat(testCommentHelper.getPublishedComments(r.getChangeId())).isEmpty();
+  }
+
+  @Test
+  public void validateDrafts_inlineVsFileComments_allOK() throws Exception {
+    PushOneCommit.Result r = createChange();
+    DraftInput draftInline =
+        testCommentHelper.newDraft(
+            r.getChange().currentFilePaths().get(0), Side.REVISION, 1, COMMENT_TEXT);
+    testCommentHelper.addDraft(r.getChangeId(), r.getCommit().getName(), draftInline);
+    DraftInput draftFile = testCommentHelper.newDraft(COMMENT_TEXT);
+    testCommentHelper.addDraft(r.getChangeId(), r.getCommit().getName(), draftFile);
+    assertThat(testCommentHelper.getPublishedComments(r.getChangeId())).isEmpty();
+
+    EasyMock.expect(mockCommentValidator.validateComments(EasyMock.capture(capture)))
+        .andReturn(ImmutableList.of());
+    EasyMock.replay(mockCommentValidator);
+
+    ReviewInput input = new ReviewInput();
+    input.drafts = DraftHandling.PUBLISH;
+    gApi.changes().id(r.getChangeId()).current().review(input);
+    assertThat(testCommentHelper.getPublishedComments(r.getChangeId())).hasSize(2);
+
+    assertThat(capture.getValues()).hasSize(1);
+    assertThat(capture.getValue())
+        .containsExactly(
+            CommentForValidation.create(
+                CommentForValidation.CommentType.INLINE_COMMENT, draftInline.message),
+            CommentForValidation.create(
+                CommentForValidation.CommentType.FILE_COMMENT, draftFile.message));
+  }
+
+  @Test
+  public void validateCommentsInChangeMessage_messageOK() throws Exception {
+    EasyMock.expect(
+            mockCommentValidator.validateComments(
+                ImmutableList.of(
+                    CommentForValidation.create(CommentType.CHANGE_MESSAGE, COMMENT_TEXT))))
+        .andReturn(ImmutableList.of());
+    EasyMock.replay(mockCommentValidator);
+    PushOneCommit.Result r = createChange();
+
+    ReviewInput input = new ReviewInput().message(COMMENT_TEXT);
+    int numMessages = gApi.changes().id(r.getChangeId()).get().messages.size();
+    gApi.changes().id(r.getChangeId()).current().review(input);
+    assertThat(gApi.changes().id(r.getChangeId()).get().messages).hasSize(numMessages + 1);
+    ChangeMessageInfo message =
+        Iterables.getLast(gApi.changes().id(r.getChangeId()).get().messages);
+    assertThat(message.message).contains(COMMENT_TEXT);
+  }
+
+  @Test
+  public void validateCommentsInChangeMessage_messageRejected() throws Exception {
+    CommentForValidation commentForValidation =
+        CommentForValidation.create(CommentType.CHANGE_MESSAGE, COMMENT_TEXT);
+    EasyMock.expect(
+            mockCommentValidator.validateComments(
+                ImmutableList.of(
+                    CommentForValidation.create(CommentType.CHANGE_MESSAGE, COMMENT_TEXT))))
+        .andReturn(ImmutableList.of(commentForValidation.failValidation("Oh no!")));
+    EasyMock.replay(mockCommentValidator);
+    PushOneCommit.Result r = createChange();
+
+    ReviewInput input = new ReviewInput().message(COMMENT_TEXT);
+    assertThat(gApi.changes().id(r.getChangeId()).get().messages)
+        .hasSize(1); // From the initial commit.
+    BadRequestException badRequestException =
+        assertThrows(
+            BadRequestException.class,
+            () -> gApi.changes().id(r.getChangeId()).current().review(input));
+    assertThat(badRequestException.getCause()).isInstanceOf(CommentsRejectedException.class);
+    assertThat(
+            Iterables.getOnlyElement(
+                    ((CommentsRejectedException) badRequestException.getCause())
+                        .getCommentValidationFailures())
+                .getComment()
+                .getText())
+        .isEqualTo(COMMENT_TEXT);
+    assertThat(badRequestException.getCause()).hasMessageThat().contains("Oh no!");
+    assertThat(gApi.changes().id(r.getChangeId()).get().messages)
+        .hasSize(1); // Unchanged from before.
+    ChangeMessageInfo message =
+        Iterables.getLast(gApi.changes().id(r.getChangeId()).get().messages);
+    assertThat(message.message).doesNotContain(COMMENT_TEXT);
+  }
+
+  private static CommentInput newComment(String path) {
+    return TestCommentHelper.populate(new CommentInput(), path, PostReviewIT.COMMENT_TEXT);
+  }
+}
diff --git a/javatests/com/google/gerrit/acceptance/api/group/GroupsIT.java b/javatests/com/google/gerrit/acceptance/api/group/GroupsIT.java
index 9eb1270..d908ee5f 100644
--- a/javatests/com/google/gerrit/acceptance/api/group/GroupsIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/group/GroupsIT.java
@@ -16,7 +16,6 @@
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.truth.Truth.assertThat;
-import static com.google.common.truth.Truth.assertWithMessage;
 import static com.google.common.truth.Truth8.assertThat;
 import static com.google.gerrit.acceptance.GitUtil.deleteRef;
 import static com.google.gerrit.acceptance.GitUtil.fetch;
@@ -31,6 +30,7 @@
 import static java.lang.annotation.ElementType.METHOD;
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
 import static java.util.stream.Collectors.toList;
+import static java.util.stream.Collectors.toMap;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
@@ -1564,24 +1564,18 @@
       countsByGroup.clear();
     }
 
-    long getCount(AccountGroup.UUID groupUuid) {
-      return countsByGroup.get(groupUuid.get());
-    }
-
     void assertReindexOf(AccountGroup.UUID groupUuid) {
       assertReindexOf(ImmutableList.of(groupUuid));
     }
 
     void assertReindexOf(List<AccountGroup.UUID> groupUuids) {
-      for (AccountGroup.UUID groupUuid : groupUuids) {
-        assertWithMessage(groupUuid.get()).that(getCount(groupUuid)).isEqualTo(1);
-      }
-      assertThat(countsByGroup).hasSize(groupUuids.size());
+      Map<String, Long> expected = groupUuids.stream().collect(toMap(u -> u.get(), u -> 1L));
+      assertThat(countsByGroup.asMap()).containsExactlyEntriesIn(expected);
       clear();
     }
 
     void assertNoReindex() {
-      assertThat(countsByGroup).isEmpty();
+      assertThat(countsByGroup.asMap()).isEmpty();
     }
   }
 }
diff --git a/javatests/com/google/gerrit/acceptance/api/project/ProjectIT.java b/javatests/com/google/gerrit/acceptance/api/project/ProjectIT.java
index dce0ab2..91c8d22 100644
--- a/javatests/com/google/gerrit/acceptance/api/project/ProjectIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/project/ProjectIT.java
@@ -723,14 +723,13 @@
       assertReindexOf(projectName, 1);
     }
 
-    void assertReindexOf(String projectName, int expectedCount) {
-      assertThat(getCount(projectName)).isEqualTo(expectedCount);
-      assertThat(countsByProject).hasSize(1);
+    void assertReindexOf(String projectName, long expectedCount) {
+      assertThat(countsByProject.asMap()).containsExactly(projectName, expectedCount);
       clear();
     }
 
     void assertNoReindex() {
-      assertThat(countsByProject).isEmpty();
+      assertThat(countsByProject.asMap()).isEmpty();
     }
 
     void assertReindexExactly(ImmutableMap<String, Long> expected) {
diff --git a/javatests/com/google/gerrit/acceptance/server/git/receive/BUILD b/javatests/com/google/gerrit/acceptance/server/git/receive/BUILD
new file mode 100644
index 0000000..760e7f4
--- /dev/null
+++ b/javatests/com/google/gerrit/acceptance/server/git/receive/BUILD
@@ -0,0 +1,8 @@
+load("//javatests/com/google/gerrit/acceptance:tests.bzl", "acceptance_tests")
+
+acceptance_tests(
+    srcs = glob(["*IT.java"]),
+    group = "receive",
+    labels = ["server"],
+    deps = [],
+)
diff --git a/javatests/com/google/gerrit/acceptance/server/git/receive/ReceiveCommitsCommentValidationIT.java b/javatests/com/google/gerrit/acceptance/server/git/receive/ReceiveCommitsCommentValidationIT.java
new file mode 100644
index 0000000..cb5add3
--- /dev/null
+++ b/javatests/com/google/gerrit/acceptance/server/git/receive/ReceiveCommitsCommentValidationIT.java
@@ -0,0 +1,143 @@
+// Copyright (C) 2019 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.git.receive;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.collect.ImmutableList;
+import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.PushOneCommit;
+import com.google.gerrit.acceptance.PushOneCommit.Result;
+import com.google.gerrit.extensions.annotations.Exports;
+import com.google.gerrit.extensions.api.changes.DraftInput;
+import com.google.gerrit.extensions.client.Side;
+import com.google.gerrit.extensions.config.FactoryModule;
+import com.google.gerrit.extensions.validators.CommentForValidation;
+import com.google.gerrit.extensions.validators.CommentForValidation.CommentType;
+import com.google.gerrit.extensions.validators.CommentValidator;
+import com.google.gerrit.testing.TestCommentHelper;
+import com.google.inject.Inject;
+import com.google.inject.Module;
+import org.easymock.Capture;
+import org.easymock.EasyMock;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * Tests for comment validation when publishing drafts via the {@code --publish-comments} option.
+ */
+public class ReceiveCommitsCommentValidationIT extends AbstractDaemonTest {
+  @Inject private CommentValidator mockCommentValidator;
+  @Inject private TestCommentHelper testCommentHelper;
+
+  private static final String COMMENT_TEXT = "The comment text";
+
+  private Capture<ImmutableList<CommentForValidation>> capture = new Capture<>();
+
+  @Override
+  public Module createModule() {
+    return new FactoryModule() {
+      @Override
+      public void configure() {
+        CommentValidator mockCommentValidator = EasyMock.createMock(CommentValidator.class);
+        bind(CommentValidator.class)
+            .annotatedWith(Exports.named(mockCommentValidator.getClass()))
+            .toInstance(mockCommentValidator);
+        bind(CommentValidator.class).toInstance(mockCommentValidator);
+      }
+    };
+  }
+
+  @Before
+  public void resetMock() {
+    EasyMock.reset(mockCommentValidator);
+  }
+
+  @After
+  public void verifyMock() {
+    EasyMock.verify(mockCommentValidator);
+  }
+
+  @Test
+  public void validateComments_commentOK() throws Exception {
+    EasyMock.expect(
+            mockCommentValidator.validateComments(
+                ImmutableList.of(
+                    CommentForValidation.create(
+                        CommentForValidation.CommentType.FILE_COMMENT, COMMENT_TEXT))))
+        .andReturn(ImmutableList.of());
+    EasyMock.replay(mockCommentValidator);
+    PushOneCommit.Result result = createChange();
+    String changeId = result.getChangeId();
+    String revId = result.getCommit().getName();
+    DraftInput comment = testCommentHelper.newDraft(COMMENT_TEXT);
+    testCommentHelper.addDraft(changeId, revId, comment);
+    assertThat(testCommentHelper.getPublishedComments(result.getChangeId())).isEmpty();
+    Result amendResult = amendChange(changeId, "refs/for/master%publish-comments", admin, testRepo);
+    amendResult.assertOkStatus();
+    amendResult.assertNotMessage("Comment validation failure:");
+    assertThat(testCommentHelper.getPublishedComments(result.getChangeId())).hasSize(1);
+  }
+
+  @Test
+  public void validateComments_commentRejected() throws Exception {
+    CommentForValidation commentForValidation =
+        CommentForValidation.create(CommentType.FILE_COMMENT, COMMENT_TEXT);
+    EasyMock.expect(
+            mockCommentValidator.validateComments(
+                ImmutableList.of(
+                    CommentForValidation.create(
+                        CommentForValidation.CommentType.FILE_COMMENT, COMMENT_TEXT))))
+        .andReturn(ImmutableList.of(commentForValidation.failValidation("Oh no!")));
+    EasyMock.replay(mockCommentValidator);
+    PushOneCommit.Result result = createChange();
+    String changeId = result.getChangeId();
+    String revId = result.getCommit().getName();
+    DraftInput comment = testCommentHelper.newDraft(COMMENT_TEXT);
+    testCommentHelper.addDraft(changeId, revId, comment);
+    assertThat(testCommentHelper.getPublishedComments(result.getChangeId())).isEmpty();
+    Result amendResult = amendChange(changeId, "refs/for/master%publish-comments", admin, testRepo);
+    amendResult.assertOkStatus();
+    amendResult.assertMessage("Comment validation failure:");
+    assertThat(testCommentHelper.getPublishedComments(result.getChangeId())).isEmpty();
+  }
+
+  @Test
+  public void validateComments_inlineVsFileComments_allOK() throws Exception {
+    EasyMock.expect(mockCommentValidator.validateComments(EasyMock.capture(capture)))
+        .andReturn(ImmutableList.of());
+    EasyMock.replay(mockCommentValidator);
+    PushOneCommit.Result result = createChange();
+    String changeId = result.getChangeId();
+    String revId = result.getCommit().getName();
+    DraftInput draftFile = testCommentHelper.newDraft(COMMENT_TEXT);
+    testCommentHelper.addDraft(changeId, revId, draftFile);
+    DraftInput draftInline =
+        testCommentHelper.newDraft(
+            result.getChange().currentFilePaths().get(0), Side.REVISION, 1, COMMENT_TEXT);
+    testCommentHelper.addDraft(changeId, revId, draftInline);
+    assertThat(testCommentHelper.getPublishedComments(result.getChangeId())).isEmpty();
+    amendChange(changeId, "refs/for/master%publish-comments", admin, testRepo);
+    assertThat(testCommentHelper.getPublishedComments(result.getChangeId())).hasSize(2);
+    assertThat(capture.getValues()).hasSize(1);
+    assertThat(capture.getValue())
+        .containsExactly(
+            CommentForValidation.create(
+                CommentForValidation.CommentType.INLINE_COMMENT, draftInline.message),
+            CommentForValidation.create(
+                CommentForValidation.CommentType.FILE_COMMENT, draftFile.message));
+  }
+}
diff --git a/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java b/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java
index f917fd8..6e14635 100644
--- a/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/mail/MailProcessorIT.java
@@ -16,25 +16,61 @@
 
 import static com.google.common.truth.Truth.assertThat;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.gerrit.acceptance.testsuite.account.AccountOperations;
+import com.google.gerrit.extensions.annotations.Exports;
 import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.common.ChangeMessageInfo;
 import com.google.gerrit.extensions.common.CommentInfo;
+import com.google.gerrit.extensions.config.FactoryModule;
+import com.google.gerrit.extensions.validators.CommentForValidation;
+import com.google.gerrit.extensions.validators.CommentValidator;
 import com.google.gerrit.mail.MailMessage;
 import com.google.gerrit.mail.MailProcessingUtil;
 import com.google.gerrit.server.mail.receive.MailProcessor;
 import com.google.gerrit.testing.FakeEmailSender.Message;
+import com.google.gerrit.testing.TestCommentHelper;
 import com.google.inject.Inject;
+import com.google.inject.Module;
 import java.time.ZoneId;
 import java.time.ZonedDateTime;
 import java.util.Collection;
 import java.util.List;
+import org.easymock.EasyMock;
+import org.junit.Before;
 import org.junit.Test;
 
 public class MailProcessorIT extends AbstractMailIT {
   @Inject private MailProcessor mailProcessor;
   @Inject private AccountOperations accountOperations;
+  @Inject private CommentValidator mockCommentValidator;
+  @Inject private TestCommentHelper testCommentHelper;
+
+  private static final String COMMENT_TEXT = "The comment text";
+
+  @Override
+  public Module createModule() {
+    return new FactoryModule() {
+      @Override
+      public void configure() {
+        CommentValidator mockCommentValidator = EasyMock.createMock(CommentValidator.class);
+        bind(CommentValidator.class)
+            .annotatedWith(Exports.named(mockCommentValidator.getClass()))
+            .toInstance(mockCommentValidator);
+        bind(CommentValidator.class).toInstance(mockCommentValidator);
+      }
+    };
+  }
+
+  @Before
+  public void setUp() {
+    // Let the mock comment validator accept all comments during test setup.
+    EasyMock.reset(mockCommentValidator);
+    EasyMock.expect(mockCommentValidator.validateComments(EasyMock.anyObject()))
+        .andReturn(ImmutableList.of());
+    EasyMock.replay(mockCommentValidator);
+  }
 
   @Test
   public void parseAndPersistChangeMessage() throws Exception {
@@ -223,6 +259,108 @@
     assertThat(message.headers()).containsKey("Subject");
   }
 
+  @Test
+  public void validateChangeMessage_rejected() throws Exception {
+    String changeId = createChangeWithReview();
+    ChangeInfo changeInfo = gApi.changes().id(changeId).get();
+    List<CommentInfo> comments = gApi.changes().id(changeId).current().commentsAsList();
+    String ts =
+        MailProcessingUtil.rfcDateformatter.format(
+            ZonedDateTime.ofInstant(comments.get(0).updated.toInstant(), ZoneId.of("UTC")));
+
+    EasyMock.reset(mockCommentValidator);
+    CommentForValidation commentForValidation =
+        CommentForValidation.create(CommentForValidation.CommentType.CHANGE_MESSAGE, COMMENT_TEXT);
+    EasyMock.expect(
+            mockCommentValidator.validateComments(
+                ImmutableList.of(
+                    CommentForValidation.create(
+                        CommentForValidation.CommentType.CHANGE_MESSAGE, COMMENT_TEXT))))
+        .andReturn(ImmutableList.of(commentForValidation.failValidation("Oh no!")));
+    EasyMock.replay(mockCommentValidator);
+
+    MailMessage.Builder b = messageBuilderWithDefaultFields();
+    String txt = newPlaintextBody(getChangeUrl(changeInfo) + "/1", COMMENT_TEXT, null, null, null);
+    b.textContent(txt + textFooterForChange(changeInfo._number, ts));
+
+    Collection<CommentInfo> commentsBefore = testCommentHelper.getPublishedComments(changeId);
+    mailProcessor.process(b.build());
+    assertThat(testCommentHelper.getPublishedComments(changeId)).isEqualTo(commentsBefore);
+
+    assertNotifyTo(user);
+    Message message = sender.nextMessage();
+    assertThat(message.body()).contains("rejected one or more comments");
+    EasyMock.verify(mockCommentValidator);
+  }
+
+  @Test
+  public void validateInlineComment_rejected() throws Exception {
+    String changeId = createChangeWithReview();
+    ChangeInfo changeInfo = gApi.changes().id(changeId).get();
+    List<CommentInfo> comments = gApi.changes().id(changeId).current().commentsAsList();
+    String ts =
+        MailProcessingUtil.rfcDateformatter.format(
+            ZonedDateTime.ofInstant(comments.get(0).updated.toInstant(), ZoneId.of("UTC")));
+
+    EasyMock.reset(mockCommentValidator);
+    CommentForValidation commentForValidation =
+        CommentForValidation.create(CommentForValidation.CommentType.CHANGE_MESSAGE, COMMENT_TEXT);
+    EasyMock.expect(
+            mockCommentValidator.validateComments(
+                ImmutableList.of(
+                    CommentForValidation.create(
+                        CommentForValidation.CommentType.INLINE_COMMENT, COMMENT_TEXT))))
+        .andReturn(ImmutableList.of(commentForValidation.failValidation("Oh no!")));
+    EasyMock.replay(mockCommentValidator);
+
+    MailMessage.Builder b = messageBuilderWithDefaultFields();
+    String txt = newPlaintextBody(getChangeUrl(changeInfo) + "/1", null, COMMENT_TEXT, null, null);
+    b.textContent(txt + textFooterForChange(changeInfo._number, ts));
+
+    Collection<CommentInfo> commentsBefore = testCommentHelper.getPublishedComments(changeId);
+    mailProcessor.process(b.build());
+    assertThat(testCommentHelper.getPublishedComments(changeId)).isEqualTo(commentsBefore);
+
+    assertNotifyTo(user);
+    Message message = sender.nextMessage();
+    assertThat(message.body()).contains("rejected one or more comments");
+    EasyMock.verify(mockCommentValidator);
+  }
+
+  @Test
+  public void validateFileComment_rejected() throws Exception {
+    String changeId = createChangeWithReview();
+    ChangeInfo changeInfo = gApi.changes().id(changeId).get();
+    List<CommentInfo> comments = gApi.changes().id(changeId).current().commentsAsList();
+    String ts =
+        MailProcessingUtil.rfcDateformatter.format(
+            ZonedDateTime.ofInstant(comments.get(0).updated.toInstant(), ZoneId.of("UTC")));
+
+    EasyMock.reset(mockCommentValidator);
+    CommentForValidation commentForValidation =
+        CommentForValidation.create(CommentForValidation.CommentType.CHANGE_MESSAGE, COMMENT_TEXT);
+    EasyMock.expect(
+            mockCommentValidator.validateComments(
+                ImmutableList.of(
+                    CommentForValidation.create(
+                        CommentForValidation.CommentType.FILE_COMMENT, COMMENT_TEXT))))
+        .andReturn(ImmutableList.of(commentForValidation.failValidation("Oh no!")));
+    EasyMock.replay(mockCommentValidator);
+
+    MailMessage.Builder b = messageBuilderWithDefaultFields();
+    String txt = newPlaintextBody(getChangeUrl(changeInfo) + "/1", null, null, COMMENT_TEXT, null);
+    b.textContent(txt + textFooterForChange(changeInfo._number, ts));
+
+    Collection<CommentInfo> commentsBefore = testCommentHelper.getPublishedComments(changeId);
+    mailProcessor.process(b.build());
+    assertThat(testCommentHelper.getPublishedComments(changeId)).isEqualTo(commentsBefore);
+
+    assertNotifyTo(user);
+    Message message = sender.nextMessage();
+    assertThat(message.body()).contains("rejected one or more comments");
+    EasyMock.verify(mockCommentValidator);
+  }
+
   private String getChangeUrl(ChangeInfo changeInfo) {
     return canonicalWebUrl.get() + "c/" + changeInfo.project + "/+/" + changeInfo._number;
   }
diff --git a/lib/js/npm.bzl b/lib/js/npm.bzl
index 8a9e1ee..5a6a8c0 100644
--- a/lib/js/npm.bzl
+++ b/lib/js/npm.bzl
@@ -1,11 +1,11 @@
 NPM_VERSIONS = {
     "bower": "1.8.8",
     "crisper": "2.0.2",
-    "polymer-bundler": "4.0.2",
+    "polymer-bundler": "4.0.9",
 }
 
 NPM_SHA1S = {
     "bower": "82544be34a33aeae7efb8bdf9905247b2cffa985",
     "crisper": "7183c58cea33632fb036c91cefd1b43e390d22a2",
-    "polymer-bundler": "6b296b6099ab5a0e93ca914cbe93e753f2395910",
+    "polymer-bundler": "c80c9815690d76656d1fa6a231481850b4fa3874",
 }
diff --git a/package.json b/package.json
index 8a18318f..6b9a38d 100644
--- a/package.json
+++ b/package.json
@@ -8,6 +8,7 @@
     "eslint-config-google": "^0.13.0",
     "eslint-plugin-html": "^5.0.5",
     "fried-twinkie": "^0.2.2",
+    "polylint": "^2.10.4",
     "typescript": "^2.x.x",
     "web-component-tester": "^6.5.0"
   },
@@ -15,7 +16,8 @@
     "start": "polygerrit-ui/run-server.sh",
     "test": "WCT_HEADLESS_MODE=1 WCT_ARGS='--verbose -l chrome' ./polygerrit-ui/app/run_test.sh",
     "eslint": "./node_modules/eslint/bin/eslint.js --ignore-pattern 'bower_components/' --ignore-pattern 'gr-linked-text' --ignore-pattern 'scripts/vendor' --ext .html,.js polygerrit-ui/app || exit 0",
-    "test-template": "./polygerrit-ui/app/run_template_test.sh"
+    "test-template": "./polygerrit-ui/app/run_template_test.sh",
+    "polylint": "bazel test polygerrit-ui/app:polylint_test"
   },
   "repository": {
     "type": "git",
diff --git a/polygerrit-ui/README.md b/polygerrit-ui/README.md
index 9ceda8c..a73f243 100644
--- a/polygerrit-ui/README.md
+++ b/polygerrit-ui/README.md
@@ -32,7 +32,6 @@
 
 ```sh
 npm install
-sudo npm install -g polylint
 ```
 
 It may complain about a missing `typescript@2.3.4` peer dependency, which is
@@ -175,6 +174,13 @@
 ```sh
 bazel test //polygerrit-ui/app:polylint_test
 ```
+
+or
+
+```sh
+npm run polylint
+```
+
 ## Template Type Safety
 Polymer elements are not type checked against the element definition, making it
 trivial to break the display when refactoring or moving code. We now run
diff --git a/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section.html b/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section.html
index 398ed9c..cddbbf3 100644
--- a/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section.html
+++ b/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section.html
@@ -65,11 +65,11 @@
       #addPermission,
       #deleteBtn,
       .editingRef .name,
-      #editRefInput {
+      .editRefInput {
         display: none;
       }
       .editing #editBtn,
-      .editingRef #editRefInput {
+      .editingRef .editRefInput {
         display: flex;
       }
       .deleted #deletedContainer {
@@ -100,12 +100,18 @@
               <iron-icon id="icon" icon="gr-icons:create"></iron-icon>
             </gr-button>
           </div>
-          <input
-              id="editRefInput"
+          <iron-input
+              class="editRefInput"
               bind-value="{{section.id}}"
-              is="iron-input"
               type="text"
               on-input="_handleValueChange">
+            <input
+                class="editRefInput"
+                bind-value="{{section.id}}"
+                is="iron-input"
+                type="text"
+                on-input="_handleValueChange">
+          </iron-input>
           <gr-button
               link
               id="deleteBtn"
diff --git a/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section.js b/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section.js
index 41ce201..d771448 100644
--- a/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section.js
+++ b/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section.js
@@ -214,9 +214,15 @@
       delete this.section.value.deleted;
     },
 
+    editRefInput() {
+      return Polymer.dom(this.root).querySelector(Polymer.Element ?
+          'iron-input.editRefInput' :
+          'input[is=iron-input].editRefInput');
+    },
+
     editReference() {
       this._editingRef = true;
-      this.$.editRefInput.focus();
+      this.editRefInput().focus();
     },
 
     _isEditEnabled(canUpload, ownerOf, sectionId) {
diff --git a/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section_test.html b/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section_test.html
index 6b08ed3..5110dc1 100644
--- a/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section_test.html
+++ b/polygerrit-ui/app/elements/admin/gr-access-section/gr-access-section_test.html
@@ -457,7 +457,7 @@
               1);
         });
 
-        test('edit section reference', () => {
+        test('edit section reference', done => {
           element.canUpload = true;
           element.ownerOf = [];
           element.section = {id: 'refs/for/bar', value: {permissions: {}}};
@@ -466,14 +466,16 @@
           assert.isTrue(element.$.section.classList.contains('editing'));
           assert.isFalse(element._editingRef);
           MockInteractions.tap(element.$.editBtn);
-          element.$.editRefInput.bindValue='new/ref';
-          flushAsynchronousOperations();
-          assert.equal(element.section.id, 'new/ref');
-          assert.isTrue(element._editingRef);
-          assert.isTrue(element.$.section.classList.contains('editingRef'));
-          element.editing = false;
-          assert.isFalse(element._editingRef);
-          assert.equal(element.section.id, 'refs/for/bar');
+          element.editRefInput().bindValue='new/ref';
+          setTimeout(() => {
+            assert.equal(element.section.id, 'new/ref');
+            assert.isTrue(element._editingRef);
+            assert.isTrue(element.$.section.classList.contains('editingRef'));
+            element.editing = false;
+            assert.isFalse(element._editingRef);
+            assert.equal(element.section.id, 'refs/for/bar');
+            done();
+          });
         });
 
         test('_handleValueChange', () => {
diff --git a/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list.html b/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list.html
index c448f5b..b2a3105 100644
--- a/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list.html
+++ b/polygerrit-ui/app/elements/admin/gr-admin-group-list/gr-admin-group-list.html
@@ -18,7 +18,6 @@
 <link rel="import" href="/bower_components/polymer/polymer.html">
 
 <link rel="import" href="../../../behaviors/gr-list-view-behavior/gr-list-view-behavior.html">
-<link rel="import" href="/bower_components/iron-input/iron-input.html">
 <link rel="import" href="../../../styles/gr-table-styles.html">
 <link rel="import" href="../../../styles/shared-styles.html">
 <link rel="import" href="../../core/gr-navigation/gr-navigation.html">
diff --git a/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog.html b/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog.html
index 252dcfd..518905c 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog.html
+++ b/polygerrit-ui/app/elements/admin/gr-create-change-dialog/gr-create-change-dialog.html
@@ -69,23 +69,33 @@
       <section class$="[[_computeBranchClass(baseChange)]]">
         <span class="title">Provide base commit sha1 for change</span>
         <span class="value">
-          <input
-              is="iron-input"
-              id="baseCommitInput"
+          <iron-input
               maxlength="40"
               placeholder="(optional)"
               bind-value="{{baseCommit}}">
+            <input
+                is="iron-input"
+                id="baseCommitInput"
+                maxlength="40"
+                placeholder="(optional)"
+                bind-value="{{baseCommit}}">
+          </iron-input>
         </span>
       </section>
       <section>
         <span class="title">Enter topic for new change</span>
         <span class="value">
-          <input
-              is="iron-input"
-              id="tagNameInput"
+          <iron-input
               maxlength="1024"
               placeholder="(optional)"
               bind-value="{{topic}}">
+            <input
+                is="iron-input"
+                id="tagNameInput"
+                maxlength="1024"
+                placeholder="(optional)"
+                bind-value="{{topic}}">
+          </iron-input>
         </span>
       </section>
       <section id="description">
diff --git a/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog.html b/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog.html
index 73a3f4e..ed631de 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog.html
+++ b/polygerrit-ui/app/elements/admin/gr-create-group-dialog/gr-create-group-dialog.html
@@ -39,10 +39,13 @@
       <div id="form">
         <section>
           <span class="title">Group name</span>
-          <input
-              is="iron-input"
-              id="groupNameInput"
+          <iron-input
               bind-value="{{_name}}">
+            <input
+                is="iron-input"
+                id="groupNameInput"
+                bind-value="{{_name}}">
+          </iron-input>
         </section>
       </div>
     </div>
diff --git a/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog.html b/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog.html
index a1fbd37..8986a71 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog.html
+++ b/polygerrit-ui/app/elements/admin/gr-create-pointer-dialog/gr-create-pointer-dialog.html
@@ -44,27 +44,39 @@
       <div id="form">
         <section>
           <span class="title">[[detailType]] name</span>
-          <input
-              is="iron-input"
-              id="itemNameInput"
+          <iron-input
               placeholder="[[detailType]] Name"
               bind-value="{{_itemName}}">
+            <input
+                is="iron-input"
+                id="itemNameInput"
+                placeholder="[[detailType]] Name"
+                bind-value="{{_itemName}}">
+          </iron-input>
         </section>
         <section>
           <span class="title">Initial Revision</span>
-          <input
-              is="iron-input"
-              id="itemRevisionInput"
+          <iron-input
               placeholder="Revision (Branch or SHA-1)"
               bind-value="{{_itemRevision}}">
+            <input
+                is="iron-input"
+                id="itemRevisionInput"
+                placeholder="Revision (Branch or SHA-1)"
+                bind-value="{{_itemRevision}}">
+          </iron-input>
         </section>
         <section class$="[[_computeHideItemClass(itemDetail)]]">
           <span class="title">Annotation</span>
-          <input
-              is="iron-input"
-              id="itemAnnotationInput"
+          <iron-input
               placeholder="Annotation (Optional)"
               bind-value="{{_itemAnnotation}}">
+            <input
+                is="iron-input"
+                id="itemAnnotationInput"
+                placeholder="Annotation (Optional)"
+                bind-value="{{_itemAnnotation}}">
+          </iron-input>
         </section>
       </div>
     </div>
diff --git a/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog.html b/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog.html
index 0feeced..5c48de1 100644
--- a/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog.html
+++ b/polygerrit-ui/app/elements/admin/gr-create-repo-dialog/gr-create-repo-dialog.html
@@ -54,10 +54,13 @@
       <div id="form">
         <section>
           <span class="title">Repository name</span>
-          <input is="iron-input"
-              id="repoNameInput"
-              autocomplete="on"
-              bind-value="{{_repoConfig.name}}">
+          <iron-input autocomplete="on"
+                      bind-value="{{_repoConfig.name}}">
+            <input is="iron-input"
+                   id="repoNameInput"
+                   autocomplete="on"
+                   bind-value="{{_repoConfig.name}}">
+          </iron-input>
         </section>
         <section>
           <span class="title">Rights inherit from</span>
diff --git a/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members.html b/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members.html
index 787f2b4..52cbfb3 100644
--- a/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members.html
+++ b/polygerrit-ui/app/elements/admin/gr-group-members/gr-group-members.html
@@ -19,7 +19,6 @@
 <link rel="import" href="../../../behaviors/gr-url-encoding-behavior/gr-url-encoding-behavior.html">
 <link rel="import" href="/bower_components/polymer/polymer.html">
 <link rel="import" href="/bower_components/iron-autogrow-textarea/iron-autogrow-textarea.html">
-<link rel="import" href="/bower_components/iron-input/iron-input.html">
 <link rel="import" href="../../../styles/gr-form-styles.html">
 <link rel="import" href="../../../styles/gr-subpage-styles.html">
 <link rel="import" href="../../../styles/gr-table-styles.html">
diff --git a/polygerrit-ui/app/elements/admin/gr-group/gr-group.html b/polygerrit-ui/app/elements/admin/gr-group/gr-group.html
index 9f49e4b..a3bbddc 100644
--- a/polygerrit-ui/app/elements/admin/gr-group/gr-group.html
+++ b/polygerrit-ui/app/elements/admin/gr-group/gr-group.html
@@ -17,7 +17,6 @@
 
 <link rel="import" href="/bower_components/polymer/polymer.html">
 <link rel="import" href="/bower_components/iron-autogrow-textarea/iron-autogrow-textarea.html">
-<link rel="import" href="/bower_components/iron-input/iron-input.html">
 <link rel="import" href="../../../styles/gr-form-styles.html">
 <link rel="import" href="../../../styles/gr-subpage-styles.html">
 <link rel="import" href="../../../styles/shared-styles.html">
diff --git a/polygerrit-ui/app/elements/admin/gr-plugin-config-array-editor/gr-plugin-config-array-editor.html b/polygerrit-ui/app/elements/admin/gr-plugin-config-array-editor/gr-plugin-config-array-editor.html
index 2625d65..9ef408b 100644
--- a/polygerrit-ui/app/elements/admin/gr-plugin-config-array-editor/gr-plugin-config-array-editor.html
+++ b/polygerrit-ui/app/elements/admin/gr-plugin-config-array-editor/gr-plugin-config-array-editor.html
@@ -83,11 +83,15 @@
         <div class="row placeholder">None configured.</div>
       </template>
       <div class$="row [[_computeShowInputRow(disabled)]]">
-        <input
-            is="iron-input"
-            id="input"
+        <iron-input
             on-keydown="_handleInputKeydown"
-            bind-value="{{_newValue}}"/>
+            bind-value="{{_newValue}}">
+          <input
+              is="iron-input"
+              id="input"
+              on-keydown="_handleInputKeydown"
+              bind-value="{{_newValue}}">
+        </iron-input>
         <gr-button
             id="addButton"
             disabled$="[[!_newValue.length]]"
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands.html b/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands.html
index ea4d165..63c2a97 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands.html
+++ b/polygerrit-ui/app/elements/admin/gr-repo-commands/gr-repo-commands.html
@@ -17,7 +17,6 @@
 
 <link rel="import" href="/bower_components/polymer/polymer.html">
 <link rel="import" href="/bower_components/iron-autogrow-textarea/iron-autogrow-textarea.html">
-<link rel="import" href="/bower_components/iron-input/iron-input.html">
 <link rel="import" href="../../../styles/gr-form-styles.html">
 <link rel="import" href="../../../styles/gr-subpage-styles.html">
 <link rel="import" href="../../../styles/shared-styles.html">
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list.html b/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list.html
index 44b94e1..1c02b3c 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list.html
+++ b/polygerrit-ui/app/elements/admin/gr-repo-detail-list/gr-repo-detail-list.html
@@ -124,10 +124,14 @@
                       class="editBtn">
                     edit
                   </gr-button>
-                  <input
-                      is=iron-input
+                  <iron-input
                       bind-value="{{_revisedRef}}"
                       class="editItem">
+                    <input
+                        is=iron-input
+                        bind-value="{{_revisedRef}}"
+                        class="editItem">
+                  </iron-input>
                   <gr-button
                       link
                       on-tap="_handleCancelRevision"
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list.html b/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list.html
index 1a728ab..52db4c2 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list.html
+++ b/polygerrit-ui/app/elements/admin/gr-repo-list/gr-repo-list.html
@@ -17,7 +17,6 @@
 <link rel="import" href="/bower_components/polymer/polymer.html">
 
 <link rel="import" href="../../../behaviors/gr-list-view-behavior/gr-list-view-behavior.html">
-<link rel="import" href="/bower_components/iron-input/iron-input.html">
 <link rel="import" href="../../../styles/gr-table-styles.html">
 <link rel="import" href="../../../styles/shared-styles.html">
 <link rel="import" href="../../shared/gr-dialog/gr-dialog.html">
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-plugin-config/gr-repo-plugin-config.html b/polygerrit-ui/app/elements/admin/gr-repo-plugin-config/gr-repo-plugin-config.html
index 69c86d9..872d282 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-plugin-config/gr-repo-plugin-config.html
+++ b/polygerrit-ui/app/elements/admin/gr-repo-plugin-config/gr-repo-plugin-config.html
@@ -87,12 +87,18 @@
                 </gr-select>
               </template>
               <template is="dom-if" if="[[_isString(option.info.type)]]">
-                <input
-                    is="iron-input"
+                <iron-input
                     value="[[option.info.value]]"
                     on-input="_handleStringChange"
                     data-option-key$="[[option._key]]"
-                    disabled$="[[_computeDisabled(option.info.editable)]]"></input>
+                    disabled$="[[_computeDisabled(option.info.editable)]]">
+                  <input
+                      is="iron-input"
+                      value="[[option.info.value]]"
+                      on-input="_handleStringChange"
+                      data-option-key$="[[option._key]]"
+                      disabled$="[[_computeDisabled(option.info.editable)]]">
+                </iron-input>
               </template>
               <template is="dom-if" if="[[option.info.inherited_value]]">
                 <span class="inherited">
diff --git a/polygerrit-ui/app/elements/admin/gr-repo/gr-repo.html b/polygerrit-ui/app/elements/admin/gr-repo/gr-repo.html
index f6b6d29..29cc2bd 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo/gr-repo.html
+++ b/polygerrit-ui/app/elements/admin/gr-repo/gr-repo.html
@@ -270,12 +270,17 @@
               <section>
                 <span class="title">Maximum Git object size limit</span>
                 <span class="value">
-                  <input
-                      id="maxGitObjSizeInput"
+                  <iron-input
                       bind-value="{{_repoConfig.max_object_size_limit.configured_value}}"
-                      is="iron-input"
                       type="text"
                       disabled$="[[_readOnly]]">
+                    <input
+                        id="maxGitObjSizeInput"
+                        bind-value="{{_repoConfig.max_object_size_limit.configured_value}}"
+                        is="iron-input"
+                        type="text"
+                        disabled$="[[_readOnly]]">
+                  </iron-input>
                   <template is="dom-if" if="[[_repoConfig.max_object_size_limit.value]]">
                     effective: [[_repoConfig.max_object_size_limit.value]] bytes
                   </template>
diff --git a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.html b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.html
index bcb0df4..e69d48f 100644
--- a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.html
+++ b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.html
@@ -19,7 +19,6 @@
 
 <link rel="import" href="../../../behaviors/gr-patch-set-behavior/gr-patch-set-behavior.html">
 <link rel="import" href="../../../behaviors/rest-client-behavior/rest-client-behavior.html">
-<link rel="import" href="/bower_components/iron-input/iron-input.html">
 <link rel="import" href="../../admin/gr-create-change-dialog/gr-create-change-dialog.html">
 <link rel="import" href="../../core/gr-navigation/gr-navigation.html">
 <link rel="import" href="../../core/gr-reporting/gr-reporting.html">
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.html b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.html
index 508e881..767b62d 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.html
+++ b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.html
@@ -15,8 +15,9 @@
 limitations under the License.
 -->
 
-<link rel="import" href="/bower_components/iron-autogrow-textarea/iron-autogrow-textarea.html">
 <link rel="import" href="/bower_components/polymer/polymer.html">
+<link rel="import" href="/bower_components/iron-autogrow-textarea/iron-autogrow-textarea.html">
+<link rel="import" href="/bower_components/iron-input/iron-input.html">
 <link rel="import" href="../../../styles/shared-styles.html">
 <link rel="import" href="../../shared/gr-autocomplete/gr-autocomplete.html">
 <link rel="import" href="../../shared/gr-dialog/gr-dialog.html">
@@ -77,12 +78,17 @@
         <label for="baseInput">
           Provide base commit sha1 for cherry-pick
         </label>
-        <input
-            is="iron-input"
-            id="baseCommitInput"
+        <iron-input
             maxlength="40"
             placeholder="(optional)"
             bind-value="{{baseCommit}}">
+          <input
+              is="iron-input"
+              id="baseCommitInput"
+              maxlength="40"
+              placeholder="(optional)"
+              bind-value="{{baseCommit}}">
+        </iron-input>
         <label for="messageInput">
           Cherry Pick Commit Message
         </label>
diff --git a/polygerrit-ui/app/elements/change/gr-included-in-dialog/gr-included-in-dialog.html b/polygerrit-ui/app/elements/change/gr-included-in-dialog/gr-included-in-dialog.html
index a749431..d5d8128 100644
--- a/polygerrit-ui/app/elements/change/gr-included-in-dialog/gr-included-in-dialog.html
+++ b/polygerrit-ui/app/elements/change/gr-included-in-dialog/gr-included-in-dialog.html
@@ -16,6 +16,7 @@
 -->
 
 <link rel="import" href="/bower_components/polymer/polymer.html">
+<link rel="import" href="/bower_components/iron-input/iron-input.html">
 <link rel="import" href="../../../styles/shared-styles.html">
 <link rel="import" href="../../shared/gr-rest-api-interface/gr-rest-api-interface.html">
 
@@ -77,11 +78,15 @@
             link
             on-tap="_handleCloseTap">Close</gr-button>
       </span>
-      <input
-          id="filterInput"
-          is="iron-input"
+      <iron-input
           placeholder="Filter"
           on-bind-value-changed="_onFilterChanged">
+        <input
+            id="filterInput"
+            is="iron-input"
+            placeholder="Filter"
+            on-bind-value-changed="_onFilterChanged">
+      </iron-input>
     </header>
     <div class$="[[_computeLoadingClass(_loaded)]]">Loading...</div>
     <template
diff --git a/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.html b/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.html
index 72c5b44..46f973e 100644
--- a/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.html
+++ b/polygerrit-ui/app/elements/change/gr-reviewer-list/gr-reviewer-list.html
@@ -16,7 +16,6 @@
 -->
 
 <link rel="import" href="/bower_components/polymer/polymer.html">
-<link rel="import" href="/bower_components/iron-input/iron-input.html">
 <link rel="import" href="../../shared/gr-account-chip/gr-account-chip.html">
 <link rel="import" href="../../shared/gr-button/gr-button.html">
 <link rel="import" href="../../shared/gr-rest-api-interface/gr-rest-api-interface.html">
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html
index d9cf979..c992a51 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html
@@ -21,6 +21,7 @@
 <link rel="import" href="../../../behaviors/keyboard-shortcut-behavior/keyboard-shortcut-behavior.html">
 <link rel="import" href="../../../behaviors/rest-client-behavior/rest-client-behavior.html">
 <link rel="import" href="/bower_components/iron-dropdown/iron-dropdown.html">
+<link rel="import" href="/bower_components/iron-input/iron-input.html">
 <link rel="import" href="../../../styles/shared-styles.html">
 <link rel="import" href="../../core/gr-navigation/gr-navigation.html">
 <link rel="import" href="../../core/gr-reporting/gr-reporting.html">
@@ -303,7 +304,9 @@
           <gr-endpoint-decorator name="annotation-toggler">
             <span hidden id="annotation-span">
               <label for="annotation-checkbox" id="annotation-label"></label>
-              <input is="iron-input" type="checkbox" id="annotation-checkbox" disabled>
+              <iron-input type="checkbox" disabled>
+                <input is="iron-input" type="checkbox" id="annotation-checkbox" disabled>
+              </iron-input>
             </span>
           </gr-endpoint-decorator>
         </div>
diff --git a/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.html b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.html
index 616172b..5072b9d 100644
--- a/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.html
+++ b/polygerrit-ui/app/elements/documentation/gr-documentation-search/gr-documentation-search.html
@@ -18,7 +18,6 @@
 
 <link rel="import" href="../../../behaviors/base-url-behavior/base-url-behavior.html">
 <link rel="import" href="../../../behaviors/gr-list-view-behavior/gr-list-view-behavior.html">
-<link rel="import" href="/bower_components/iron-input/iron-input.html">
 <link rel="import" href="../../../styles/gr-table-styles.html">
 <link rel="import" href="../../../styles/shared-styles.html">
 <link rel="import" href="../../shared/gr-list-view/gr-list-view.html">
diff --git a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.html b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.html
index ea5024a..2d66bc2 100644
--- a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.html
+++ b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.html
@@ -132,11 +132,16 @@
               placeholder="Enter an existing full file path."
               query="[[_query]]"
               text="{{_path}}"></gr-autocomplete>
-          <input
-              class="newPathInput"
-              is="iron-input"
+          <iron-input
+              class="newPathIronInput"
               bind-value="{{_newPath}}"
-              placeholder="Enter the new path."/>
+              placeholder="Enter the new path.">
+            <input
+                class="newPathInput"
+                is="iron-input"
+                bind-value="{{_newPath}}"
+                placeholder="Enter the new path.">
+          </iron-input>
         </div>
       </gr-dialog>
       <gr-dialog
@@ -148,10 +153,14 @@
           on-cancel="_handleDialogCancel">
         <div class="header" slot="header">Restore this file?</div>
         <div class="main" slot="main">
-          <input
-              is="iron-input"
+          <iron-input
               disabled
-              bind-value="{{_path}}"/>
+              bind-value="{{_path}}">
+            <input
+                is="iron-input"
+                disabled
+                bind-value="{{_path}}">
+          </iron-input>
         </div>
       </gr-dialog>
     </gr-overlay>
diff --git a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.html b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.html
index 75a371f8..df029ed 100644
--- a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.html
+++ b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.html
@@ -191,6 +191,9 @@
     let navStub;
     let renameStub;
     let renameAutocomplete;
+    const inputSelector = Polymer.Element ?
+        '.newPathIronInput' :
+        '.newPathInput';
 
     setup(() => {
       navStub = sandbox.stub(Gerrit.Nav, 'navigateToChange');
@@ -210,7 +213,7 @@
         assert.isTrue(queryStub.called);
         assert.isTrue(element.$.renameDialog.disabled);
 
-        element.$.renameDialog.querySelector('.newPathInput').bindValue =
+        element.$.renameDialog.querySelector(inputSelector).bindValue =
             'src/test.newPath';
 
         assert.isFalse(element.$.renameDialog.disabled);
@@ -238,7 +241,7 @@
         assert.isTrue(queryStub.called);
         assert.isTrue(element.$.renameDialog.disabled);
 
-        element.$.renameDialog.querySelector('.newPathInput').bindValue =
+        element.$.renameDialog.querySelector(inputSelector).bindValue =
             'src/test.newPath';
 
         assert.isFalse(element.$.renameDialog.disabled);
@@ -260,7 +263,7 @@
         assert.isTrue(element.$.renameDialog.disabled);
         element.$.renameDialog.querySelector('gr-autocomplete').text =
             'src/test.cpp';
-        element.$.renameDialog.querySelector('.newPathInput').bindValue =
+        element.$.renameDialog.querySelector(inputSelector).bindValue =
             'src/test.newPath';
         assert.isFalse(element.$.renameDialog.disabled);
         MockInteractions.tap(element.$.renameDialog.$$('gr-button'));
diff --git a/polygerrit-ui/app/elements/gr-app-p2.html b/polygerrit-ui/app/elements/gr-app-p2.html
index 2ce5ed8..5742350 100644
--- a/polygerrit-ui/app/elements/gr-app-p2.html
+++ b/polygerrit-ui/app/elements/gr-app-p2.html
@@ -21,7 +21,6 @@
 <link rel="import" href="/bower_components/polymer/polymer.html">
 <link rel="import" href="/bower_components/polymer-resin/polymer-resin.html">
 <link rel="import" href="/bower_components/polymer/lib/legacy/legacy-data-mixin.html">
-<link rel="import" href="/bower_components/shadycss/apply-shim.html">
 <link rel="import" href="../behaviors/safe-types-behavior/safe-types-behavior.html">
 <script>
   security.polymer_resin.install({
diff --git a/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info.html b/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info.html
index 7d469a3..8de8db8 100644
--- a/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info.html
+++ b/polygerrit-ui/app/elements/settings/gr-account-info/gr-account-info.html
@@ -79,12 +79,17 @@
         <span
             hidden$="[[!usernameMutable]]"
             class="value">
-          <input
-              is="iron-input"
-              id="usernameInput"
+          <iron-input
               disabled="[[_saving]]"
               on-keydown="_handleKeydown"
               bind-value="{{_username}}">
+            <input
+                is="iron-input"
+                id="usernameInput"
+                disabled="[[_saving]]"
+                on-keydown="_handleKeydown"
+                bind-value="{{_username}}">
+          </iron-input>
         </span>
       </section>
       <section id="nameSection">
@@ -95,24 +100,34 @@
         <span
             hidden$="[[!nameMutable]]"
             class="value">
-          <input
-              is="iron-input"
-              id="nameInput"
+          <iron-input
               disabled="[[_saving]]"
               on-keydown="_handleKeydown"
               bind-value="{{_account.name}}">
+            <input
+                is="iron-input"
+                id="nameInput"
+                disabled="[[_saving]]"
+                on-keydown="_handleKeydown"
+                bind-value="{{_account.name}}">
+          </iron-input>
         </span>
       </section>
       <section>
         <span class="title">Status (e.g. "Vacation")</span>
         <span class="value">
-          <input
-              is="iron-input"
-              id="statusInput"
+          <iron-input
               disabled="[[_saving]]"
               on-keydown="_handleKeydown"
               bind-value="{{_account.status}}">
-          </span>
+            <input
+                is="iron-input"
+                id="statusInput"
+                disabled="[[_saving]]"
+                on-keydown="_handleKeydown"
+                bind-value="{{_account.status}}">
+          </iron-input>
+        </span>
       </section>
     </div>
     <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
diff --git a/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor.html b/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor.html
index 43bb2db..8b32be9 100644
--- a/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor.html
+++ b/polygerrit-ui/app/elements/settings/gr-change-table-editor/gr-change-table-editor.html
@@ -16,7 +16,6 @@
 -->
 <link rel="import" href="../../../behaviors/gr-change-table-behavior/gr-change-table-behavior.html">
 <link rel="import" href="/bower_components/polymer/polymer.html">
-<link rel="import" href="/bower_components/iron-input/iron-input.html">
 <link rel="import" href="../../shared/gr-button/gr-button.html">
 <link rel="import" href="../../shared/gr-date-formatter/gr-date-formatter.html">
 <link rel="import" href="../../shared/gr-rest-api-interface/gr-rest-api-interface.html">
diff --git a/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view.html b/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view.html
index bb5c069..2d5fd26 100644
--- a/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view.html
+++ b/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view.html
@@ -95,7 +95,13 @@
         </div>
         <div class$="agreementsTextBox [[_computeHideAgreementClass(_agreementName, _serverConfig.auth.contributor_agreements)]]">
           <h3 class="smallHeading">Complete the agreement:</h3>
-          <input id="input-agreements" is="iron-input" bind-value="{{_agreementsText}}" placeholder="Enter 'I agree' here" />
+          <iron-input bind-value="{{_agreementsText}}"
+                      placeholder="Enter 'I agree' here">
+            <input id="input-agreements"
+                   is="iron-input"
+                   bind-value="{{_agreementsText}}"
+                   placeholder="Enter 'I agree' here">
+          </iron-input>
           <gr-button on-tap="_handleSaveAgreements" disabled="[[_disableAgreementsText(_agreementsText)]]">
             Submit
           </gr-button>
diff --git a/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences.html b/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences.html
index 33fc879..53a30c3 100644
--- a/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences.html
+++ b/polygerrit-ui/app/elements/settings/gr-edit-preferences/gr-edit-preferences.html
@@ -16,6 +16,7 @@
 -->
 
 <link rel="import" href="/bower_components/polymer/polymer.html">
+<link rel="import" href="/bower_components/iron-input/iron-input.html">
 <link rel="import" href="../../../styles/gr-form-styles.html">
 <link rel="import" href="../../../styles/shared-styles.html">
 <link rel="import" href="../../shared/gr-rest-api-interface/gr-rest-api-interface.html">
@@ -29,40 +30,64 @@
       <section>
         <span class="title">Tab width</span>
         <span class="value">
-          <input
-              is="iron-input"
+          <iron-input
               type="number"
               prevent-invalid-input
               allowed-pattern="[0-9]"
               bind-value="{{editPrefs.tab_size}}"
               on-keypress="_handleEditPrefsChanged"
               on-change="_handleEditPrefsChanged">
+            <input
+                is="iron-input"
+                type="number"
+                prevent-invalid-input
+                allowed-pattern="[0-9]"
+                bind-value="{{editPrefs.tab_size}}"
+                on-keypress="_handleEditPrefsChanged"
+                on-change="_handleEditPrefsChanged">
+          </iron-input>
         </span>
       </section>
       <section>
         <span class="title">Columns</span>
         <span class="value">
-          <input
-              is="iron-input"
+          <iron-input
               type="number"
               prevent-invalid-input
               allowed-pattern="[0-9]"
               bind-value="{{editPrefs.line_length}}"
               on-keypress="_handleEditPrefsChanged"
               on-change="_handleEditPrefsChanged">
+            <input
+                is="iron-input"
+                type="number"
+                prevent-invalid-input
+                allowed-pattern="[0-9]"
+                bind-value="{{editPrefs.line_length}}"
+                on-keypress="_handleEditPrefsChanged"
+                on-change="_handleEditPrefsChanged">
+          </iron-input>
         </span>
       </section>
       <section>
         <span class="title">Indent unit</span>
         <span class="value">
-          <input
-              is="iron-input"
+          <iron-input
               type="number"
               prevent-invalid-input
               allowed-pattern="[0-9]"
               bind-value="{{editPrefs.indent_unit}}"
               on-keypress="_handleEditPrefsChanged"
               on-change="_handleEditPrefsChanged">
+            <input
+                is="iron-input"
+                type="number"
+                prevent-invalid-input
+                allowed-pattern="[0-9]"
+                bind-value="{{editPrefs.indent_unit}}"
+                on-keypress="_handleEditPrefsChanged"
+                on-change="_handleEditPrefsChanged">
+          </iron-input>
         </span>
       </section>
       <section>
diff --git a/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor.html b/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor.html
index 98b9b6d..f508288 100644
--- a/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor.html
+++ b/polygerrit-ui/app/elements/settings/gr-email-editor/gr-email-editor.html
@@ -63,14 +63,22 @@
             <tr>
               <td class="emailColumn">[[item.email]]</td>
               <td class="preferredControl" on-tap="_handlePreferredControlTap">
-                <input
-                    is="iron-input"
+                <iron-input
                     class="preferredRadio"
                     type="radio"
                     on-change="_handlePreferredChange"
                     name="preferred"
                     value="[[item.email]]"
                     checked$="[[item.preferred]]">
+                  <input
+                      is="iron-input"
+                      class="preferredRadio"
+                      type="radio"
+                      on-change="_handlePreferredChange"
+                      name="preferred"
+                      value="[[item.email]]"
+                      checked$="[[item.preferred]]">
+                </iron-input>
               </td>
               <td>
                 <gr-button
diff --git a/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password.js b/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password.js
index cda6da7..99f4504 100644
--- a/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password.js
+++ b/polygerrit-ui/app/elements/settings/gr-http-password/gr-http-password.js
@@ -27,6 +27,10 @@
       _passwordUrl: String,
     },
 
+    attached() {
+      this.loadData();
+    },
+
     loadData() {
       const promises = [];
 
diff --git a/polygerrit-ui/app/elements/settings/gr-menu-editor/gr-menu-editor.html b/polygerrit-ui/app/elements/settings/gr-menu-editor/gr-menu-editor.html
index 56f4cfa..703c34c 100644
--- a/polygerrit-ui/app/elements/settings/gr-menu-editor/gr-menu-editor.html
+++ b/polygerrit-ui/app/elements/settings/gr-menu-editor/gr-menu-editor.html
@@ -85,19 +85,30 @@
         <tfoot>
           <tr>
             <th>
-              <input
-                  is="iron-input"
+              <iron-input
                   placeholder="New Title"
                   on-keydown="_handleInputKeydown"
                   bind-value="{{_newName}}">
+                <input
+                    is="iron-input"
+                    placeholder="New Title"
+                    on-keydown="_handleInputKeydown"
+                    bind-value="{{_newName}}">
+              </iron-input>
             </th>
             <th>
-              <input
+              <iron-input
                   class="newUrlInput"
-                  is="iron-input"
                   placeholder="New URL"
                   on-keydown="_handleInputKeydown"
                   bind-value="{{_newUrl}}">
+                <input
+                    class="newUrlInput"
+                    is="iron-input"
+                    placeholder="New URL"
+                    on-keydown="_handleInputKeydown"
+                    bind-value="{{_newUrl}}">
+              </iron-input>
             </th>
             <th></th>
             <th></th>
diff --git a/polygerrit-ui/app/elements/settings/gr-registration-dialog/gr-registration-dialog.html b/polygerrit-ui/app/elements/settings/gr-registration-dialog/gr-registration-dialog.html
index 66b06f8..cdc0825 100644
--- a/polygerrit-ui/app/elements/settings/gr-registration-dialog/gr-registration-dialog.html
+++ b/polygerrit-ui/app/elements/settings/gr-registration-dialog/gr-registration-dialog.html
@@ -16,6 +16,7 @@
 -->
 
 <link rel="import" href="/bower_components/polymer/polymer.html">
+<link rel="import" href="/bower_components/iron-input/iron-input.html">
 <link rel="import" href="../../../styles/gr-form-styles.html">
 <link rel="import" href="../../core/gr-navigation/gr-navigation.html">
 <link rel="import" href="../../shared/gr-button/gr-button.html">
@@ -81,19 +82,27 @@
         <hr>
         <section>
           <div class="title">Full Name</div>
-          <input
-              is="iron-input"
-              id="name"
+          <iron-input
               bind-value="{{_account.name}}"
               disabled="[[_saving]]">
+            <input
+                is="iron-input"
+                id="name"
+                bind-value="{{_account.name}}"
+                disabled="[[_saving]]">
+          </iron-input>
         </section>
         <section class$="[[_computeUsernameClass(_usernameMutable)]]">
           <div class="title">Username</div>
-          <input
-              is="iron-input"
-              id="username"
+          <iron-input
               bind-value="{{_account.username}}"
               disabled="[[_saving]]">
+            <input
+                is="iron-input"
+                id="username"
+                bind-value="{{_account.username}}"
+                disabled="[[_saving]]">
+          </iron-input>
         </section>
         <section>
           <div class="title">Preferred Email</div>
diff --git a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.html b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.html
index 68518a0..d193041 100644
--- a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.html
+++ b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.html
@@ -16,6 +16,7 @@
 -->
 
 <link rel="import" href="/bower_components/polymer/polymer.html">
+<link rel="import" href="/bower_components/iron-input/iron-input.html">
 
 <link rel="import" href="../../../behaviors/docs-url-behavior/docs-url-behavior.html">
 <link rel="import" href="/bower_components/paper-toggle-button/paper-toggle-button.html">
@@ -49,7 +50,7 @@
       :host {
         color: var(--primary-text-color);
       }
-      #newEmailInput {
+      .newEmailInput {
         width: 20em;
       }
       #email {
@@ -365,14 +366,22 @@
           <section>
             <span class="title">New email address</span>
             <span class="value">
-              <input
-                  id="newEmailInput"
+              <iron-input
+                  class="newEmailInput"
                   bind-value="{{_newEmail}}"
-                  is="iron-input"
                   type="text"
                   disabled="[[_addingEmail]]"
                   on-keydown="_handleNewEmailKeydown"
                   placeholder="email@example.com">
+                <input
+                    class="newEmailInput"
+                    bind-value="{{_newEmail}}"
+                    is="iron-input"
+                    type="text"
+                    disabled="[[_addingEmail]]"
+                    on-keydown="_handleNewEmailKeydown"
+                    placeholder="email@example.com">
+              </iron-input>
             </span>
           </section>
           <section
@@ -387,12 +396,14 @@
               disabled="[[!_computeAddEmailButtonEnabled(_newEmail, _addingEmail)]]"
               on-tap="_handleAddEmailButton">Send verification</gr-button>
         </fieldset>
-        <div hidden$="[[!_showHttpAuth(_serverConfig)]]">
-          <h2 id="HTTPCredentials">HTTP Credentials</h2>
-          <fieldset>
-            <gr-http-password id="httpPass"></gr-http-password>
-          </fieldset>
-        </div>
+        <template is="dom-if" if="[[_showHttpAuth(_serverConfig)]]">
+          <div>
+            <h2 id="HTTPCredentials">HTTP Credentials</h2>
+            <fieldset>
+              <gr-http-password id="httpPass"></gr-http-password>
+            </fieldset>
+          </div>
+        </template>
         <div hidden$="[[!_serverConfig.sshd]]">
           <h2
               id="SSHKeys"
diff --git a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.js b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.js
index d776b54..041dc64 100644
--- a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.js
+++ b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.js
@@ -166,7 +166,6 @@
         this.$.accountInfo.loadData(),
         this.$.watchedProjectsEditor.loadData(),
         this.$.groupList.loadData(),
-        this.$.httpPass.loadData(),
         this.$.identities.loadData(),
         this.$.editPrefs.loadData(),
         this.$.diffPrefs.loadData(),
diff --git a/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor.html b/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor.html
index e314608..35d43c7 100644
--- a/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor.html
+++ b/polygerrit-ui/app/elements/settings/gr-watched-projects-editor/gr-watched-projects-editor.html
@@ -15,6 +15,7 @@
 limitations under the License.
 -->
 <link rel="import" href="/bower_components/polymer/polymer.html">
+<link rel="import" href="/bower_components/iron-input/iron-input.html">
 <link rel="import" href="../../shared/gr-autocomplete/gr-autocomplete.html">
 <link rel="import" href="../../shared/gr-button/gr-button.html">
 <link rel="import" href="../../shared/gr-rest-api-interface/gr-rest-api-interface.html">
@@ -103,11 +104,15 @@
                   placeholder="Repo"></gr-autocomplete>
             </th>
             <th colspan$="[[_getTypeCount()]]">
-              <input
-                  id="newFilter"
+              <iron-input
                   class="newFilterInput"
-                  is="iron-input"
                   placeholder="branch:name, or other search expression">
+                <input
+                    id="newFilter"
+                    class="newFilterInput"
+                    is="iron-input"
+                    placeholder="branch:name, or other search expression">
+              </iron-input>
             </th>
             <th>
               <gr-button link on-tap="_handleAddProject">Add</gr-button>
diff --git a/polygerrit-ui/app/elements/shared/gr-copy-clipboard/gr-copy-clipboard.html b/polygerrit-ui/app/elements/shared/gr-copy-clipboard/gr-copy-clipboard.html
index f6b4a27..8fea7e2 100644
--- a/polygerrit-ui/app/elements/shared/gr-copy-clipboard/gr-copy-clipboard.html
+++ b/polygerrit-ui/app/elements/shared/gr-copy-clipboard/gr-copy-clipboard.html
@@ -47,20 +47,29 @@
       }
     </style>
     <div class="text">
-        <input id="input" is="iron-input"
+      <iron-input
+          class$="copyText [[_computeInputClass(hideInput)]]"
+          type="text"
+          bind-value="[[text]]"
+          on-tap="_handleInputTap"
+          readonly>
+        <input
+            id="input"
+            is="iron-input"
             class$="copyText [[_computeInputClass(hideInput)]]"
             type="text"
             bind-value="[[text]]"
             on-tap="_handleInputTap"
             readonly>
-        <gr-button id="button"
-            link
-            has-tooltip="[[hasTooltip]]"
-            class="copyToClipboard"
-            title="[[buttonTitle]]"
-            on-tap="_copyToClipboard">
-          <iron-icon id="icon" icon="gr-icons:content-copy"></iron-icon>
-        </gr-button>
+      </iron-input>
+      <gr-button id="button"
+          link
+          has-tooltip="[[hasTooltip]]"
+          class="copyToClipboard"
+          title="[[buttonTitle]]"
+          on-tap="_copyToClipboard">
+        <iron-icon id="icon" icon="gr-icons:content-copy"></iron-icon>
+      </gr-button>
     </div>
   </template>
   <script src="gr-copy-clipboard.js"></script>
diff --git a/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences.html b/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences.html
index e21e5a4..9d85d44 100644
--- a/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences.html
+++ b/polygerrit-ui/app/elements/shared/gr-diff-preferences/gr-diff-preferences.html
@@ -60,43 +60,67 @@
       <section>
         <span class="title">Diff width</span>
         <span class="value">
-          <input
-              is="iron-input"
+          <iron-input
               type="number"
-              id="columnsInput"
               prevent-invalid-input
               allowed-pattern="[0-9]"
               bind-value="{{diffPrefs.line_length}}"
               on-keypress="_handleDiffPrefsChanged"
               on-change="_handleDiffPrefsChanged">
+            <input
+                is="iron-input"
+                type="number"
+                id="columnsInput"
+                prevent-invalid-input
+                allowed-pattern="[0-9]"
+                bind-value="{{diffPrefs.line_length}}"
+                on-keypress="_handleDiffPrefsChanged"
+                on-change="_handleDiffPrefsChanged">
+          </iron-input>
         </span>
       </section>
       <section>
         <span class="title">Tab width</span>
         <span class="value">
-          <input
-              is="iron-input"
+          <iron-input
               type="number"
-              id="tabSizeInput"
               prevent-invalid-input
               allowed-pattern="[0-9]"
               bind-value="{{diffPrefs.tab_size}}"
               on-keypress="_handleDiffPrefsChanged"
               on-change="_handleDiffPrefsChanged">
+            <input
+                is="iron-input"
+                type="number"
+                id="tabSizeInput"
+                prevent-invalid-input
+                allowed-pattern="[0-9]"
+                bind-value="{{diffPrefs.tab_size}}"
+                on-keypress="_handleDiffPrefsChanged"
+                on-change="_handleDiffPrefsChanged">
+          </iron-input>
         </span>
       </section>
       <section hidden$="[[!diffPrefs.font_size]]">
         <span class="title">Font size</span>
         <span class="value">
-          <input
-              is="iron-input"
+          <iron-input
               type="number"
-              id="fontSizeInput"
               prevent-invalid-input
               allowed-pattern="[0-9]"
               bind-value="{{diffPrefs.font_size}}"
               on-keypress="_handleDiffPrefsChanged"
               on-change="_handleDiffPrefsChanged">
+            <input
+                is="iron-input"
+                type="number"
+                id="fontSizeInput"
+                prevent-invalid-input
+                allowed-pattern="[0-9]"
+                bind-value="{{diffPrefs.font_size}}"
+                on-keypress="_handleDiffPrefsChanged"
+                on-change="_handleDiffPrefsChanged">
+          </iron-input>
         </span>
       </section>
       <section>
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-js-api_test.html b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-js-api_test.html
index 78f9650..987b551 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-js-api_test.html
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-annotation-actions-js-api_test.html
@@ -30,7 +30,9 @@
   <template>
     <span hidden id="annotation-span">
       <label for="annotation-checkbox" id="annotation-label"></label>
-      <input is="iron-input" type="checkbox" id="annotation-checkbox" disabled>
+      <iron-input type="checkbox" disabled>
+        <input is="iron-input" type="checkbox" id="annotation-checkbox" disabled>
+      </iron-input>
     </span>
   </template>
 </test-fixture>
diff --git a/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.html b/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.html
index 1ee168d..765345c 100644
--- a/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.html
+++ b/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.html
@@ -15,6 +15,7 @@
 limitations under the License.
 -->
 <link rel="import" href="/bower_components/polymer/polymer.html">
+<link rel="import" href="/bower_components/iron-input/iron-input.html">
 
 <link rel="import" href="../../../behaviors/base-url-behavior/base-url-behavior.html">
 <link rel="import" href="../../../behaviors/gr-url-encoding-behavior/gr-url-encoding-behavior.html">
@@ -68,10 +69,15 @@
     <div id="topContainer">
       <div class="filterContainer">
         <label>Filter:</label>
-        <input is="iron-input"
+        <iron-input
             type="text"
-            id="filter"
             bind-value="{{filter}}">
+          <input
+              is="iron-input"
+              type="text"
+              id="filter"
+              bind-value="{{filter}}">
+        </iron-input>
       </div>
       <div id="createNewContainer"
           class$="[[_computeCreateClass(createNew)]]">
diff --git a/polygerrit-ui/app/polylint_test.sh b/polygerrit-ui/app/polylint_test.sh
index ee69ce2..f6880a1 100755
--- a/polygerrit-ui/app/polylint_test.sh
+++ b/polygerrit-ui/app/polylint_test.sh
@@ -8,13 +8,13 @@
     exit 1
 fi
 
-polylint_bin=$(which polylint)
-if [[ -z "$polylint_bin" ]]; then
-    echo "You must install polylint and its dependencies from NPM."
-    echo "> npm install -g polylint"
+npx_bin=$(which npx)
+if [[ -z "$npx_bin" ]]; then
+    echo "NPX must be on the path."
+    echo "> npm i -g npx"
     exit 1
 fi
 
 unzip -o polygerrit-ui/polygerrit_components.bower_components.zip -d polygerrit-ui/app
 
-${polylint_bin} --root polygerrit-ui/app --input elements/gr-app.html --b 'bower_components'
\ No newline at end of file
+npx polylint --root polygerrit-ui/app --input elements/gr-app.html --b 'bower_components' --verbose
diff --git a/resources/com/google/gerrit/server/mail/InboundEmailRejection.soy b/resources/com/google/gerrit/server/mail/InboundEmailRejection.soy
index e997776..e88c424 100644
--- a/resources/com/google/gerrit/server/mail/InboundEmailRejection.soy
+++ b/resources/com/google/gerrit/server/mail/InboundEmailRejection.soy
@@ -62,3 +62,8 @@
   This might be caused by an ongoing maintenance or a data corruption.
   {call .InboundEmailRejectionFooter /}
 {/template}
+
+{template .InboundEmailRejection_COMMENT_REJECTED kind="text"}
+  Gerrit Code Review rejected one or more comments because they did not pass validation.
+  {call .InboundEmailRejectionFooter /}
+{/template}
diff --git a/resources/com/google/gerrit/server/mail/InboundEmailRejectionHtml.soy b/resources/com/google/gerrit/server/mail/InboundEmailRejectionHtml.soy
index f879270..e17508d 100644
--- a/resources/com/google/gerrit/server/mail/InboundEmailRejectionHtml.soy
+++ b/resources/com/google/gerrit/server/mail/InboundEmailRejectionHtml.soy
@@ -78,3 +78,10 @@
   <p>
   {call .InboundEmailRejectionFooterHtml /}
 {/template}
+
+{template .InboundEmailRejectionHtml_COMMENT_REJECTED}
+  <p>
+    Gerrit Code Review rejected one or more comments because they did not pass validation.
+  </p>
+  {call .InboundEmailRejectionFooterHtml /}
+{/template}
diff --git a/resources/com/google/gerrit/server/mime/mime-types.properties b/resources/com/google/gerrit/server/mime/mime-types.properties
index 8159ac1..6fbd341 100644
--- a/resources/com/google/gerrit/server/mime/mime-types.properties
+++ b/resources/com/google/gerrit/server/mime/mime-types.properties
@@ -124,7 +124,7 @@
 mbox = application/mbox
 md = text/x-markdown
 mirc = text/mirc
-mjs = text/x-mjs
+mjs = text/javascript
 mkd = text/x-markdown
 ml = text/x-ocaml
 mli = text/x-ocaml