Merge changes from topic "comment-validation"

* changes:
  Validate comments in MailProcessor using new interface
  Validate comments in ReceiveCommits using new interface
  Validate comments and message in PostReview using new interface
  Add extension point for plugins to validate comments before publishing
diff --git a/.bazelversion b/.bazelversion
index b2525e3..cffeade 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-0.27.0rc3
\ No newline at end of file
+0.27.0rc5
\ No newline at end of file
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..55e5fb8 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -772,24 +772,24 @@
 )
 
 # 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/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/git/receive/ReceiveCommits.java b/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
index 09628ab..b238867 100644
--- a/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
+++ b/java/com/google/gerrit/server/git/receive/ReceiveCommits.java
@@ -558,7 +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) {
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/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