Allow replication of refs that point to non-commit objects

Bug: Issue 15425
Change-Id: I3c5f6fae8bf0c2d2be542aade899392ff95cff04

src/main/java/com/googlesource/gerrit/plugins/replication/pull/RevisionReader.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/pull/RevisionReader.java b/src/main/java/com/googlesource/gerrit/plugins/replication/pull/RevisionReader.java
index 5718249..a99256f 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/pull/RevisionReader.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/pull/RevisionReader.java
@@ -34,6 +34,7 @@
 import org.eclipse.jgit.errors.LargeObjectException;
 import org.eclipse.jgit.errors.MissingObjectException;
 import org.eclipse.jgit.errors.RepositoryNotFoundException;
+import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ObjectLoader;
 import org.eclipse.jgit.lib.Ref;
@@ -73,6 +74,13 @@
       totalRefSize += commitLoader.getSize();
       verifySize(totalRefSize, commitLoader);
 
+      if (commitLoader.getType() != Constants.OBJ_COMMIT) {
+        repLog.trace(
+            "Ref %s for project %s points to an object type %d",
+            refName, project, commitLoader.getType());
+        return Optional.empty();
+      }
+
       RevCommit commit = RevCommit.parse(commitLoader.getCachedBytes());
       RevisionObjectData commitRev =
           new RevisionObjectData(commit.getType(), commitLoader.getCachedBytes());

src/test/java/com/googlesource/gerrit/plugins/replication/pull/RevisionReaderIT.java

diff --git a/src/test/java/com/googlesource/gerrit/plugins/replication/pull/RevisionReaderIT.java b/src/test/java/com/googlesource/gerrit/plugins/replication/pull/RevisionReaderIT.java
index d1a4c85..fdd63d2 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/replication/pull/RevisionReaderIT.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/replication/pull/RevisionReaderIT.java
@@ -18,6 +18,7 @@
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.truth.Truth8;
 import com.google.gerrit.acceptance.LightweightPluginDaemonTest;
 import com.google.gerrit.acceptance.PushOneCommit.Result;
 import com.google.gerrit.acceptance.TestPlugin;
@@ -29,6 +30,7 @@
 import com.google.gerrit.extensions.api.changes.ReviewInput.CommentInput;
 import com.google.gerrit.extensions.client.Comment;
 import com.google.gerrit.extensions.config.FactoryModule;
+import com.google.gerrit.server.notedb.Sequences;
 import com.google.inject.Scopes;
 import com.googlesource.gerrit.plugins.replication.ReplicationConfig;
 import com.googlesource.gerrit.plugins.replication.ReplicationFileBasedConfig;
@@ -104,6 +106,15 @@
     assertThat(blobObject.getContent()).isNotEmpty();
   }
 
+  @Test
+  public void shouldNotReadRefsSequences() throws Exception {
+    createChange().assertOkStatus();
+    Optional<RevisionData> revisionDataOption =
+        objectUnderTest.read(allProjects, RefNames.REFS_SEQUENCES + Sequences.NAME_CHANGES);
+
+    Truth8.assertThat(revisionDataOption).isEmpty();
+  }
+
   private CommentInput createCommentInput(
       int startLine, int startCharacter, int endLine, int endCharacter, String message) {
     CommentInput comment = new CommentInput();