Populate comment parentUuid field

Also adds regression tests to ensure the inReplyTo field of comments is
respected.

Bug: Issue 5330
Change-Id: I908ceff31315ea963d0c63098a952fb1e613090a

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/server/change/CommentsIT.java

@@ -149,6 +149,40 @@ public class CommentsIT extends AbstractDaemonTest {
     }
   }
 
+  @Test
+  public void postCommentWithReply() throws Exception {
+    for (Integer line : lines) {
+      String file = "file";
+      String contents = "contents " + line;
+      PushOneCommit push = pushFactory.create(db, admin.getIdent(), testRepo,
+          "first subject", file, contents);
+      PushOneCommit.Result r = push.to("refs/for/master");
+      String changeId = r.getChangeId();
+      String revId = r.getCommit().getName();
+      ReviewInput input = new ReviewInput();
+      CommentInput comment =
+          newComment(file, Side.REVISION, line, "comment 1", false);
+      input.comments = new HashMap<>();
+      input.comments.put(comment.path, Lists.newArrayList(comment));
+      revision(r).review(input);
+      Map<String, List<CommentInfo>> result =
+          getPublishedComments(changeId, revId);
+      CommentInfo actual = Iterables.getOnlyElement(result.get(comment.path));
+
+      input = new ReviewInput();
+      comment = newComment(file, Side.REVISION, line, "comment 1 reply", false);
+      comment.inReplyTo = actual.id;
+      input.comments = new HashMap<>();
+      input.comments.put(comment.path, Lists.newArrayList(comment));
+      revision(r).review(input);
+      result = getPublishedComments(changeId, revId);
+      actual = result.get(comment.path).get(1);
+      assertThat(comment).isEqualTo(infoToInput(file).apply(actual));
+      assertThat(comment).isEqualTo(infoToInput(file).apply(
+          getPublishedComment(changeId, revId, actual.id)));
+    }
+  }
+
   @Test
   public void postCommentWithUnresolved() throws Exception {
     for (Integer line : lines) {
@@ -786,5 +820,6 @@ public class CommentsIT extends AbstractDaemonTest {
     to.message = from.message;
     to.range = from.range;
     to.unresolved = from.unresolved;
+    to.inReplyTo = from.inReplyTo;
   }
 }

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/server/notedb/ChangeRebuilderIT.java

@@ -208,7 +208,18 @@ public class ChangeRebuilderIT extends AbstractDaemonTest {
   public void publishedComment() throws Exception {
     PushOneCommit.Result r = createChange();
     Change.Id id = r.getPatchSetId().getParentKey();
-    putComment(user, id, 1, "comment");
+    putComment(user, id, 1, "comment", null);
+    checker.rebuildAndCheckChanges(id);
+  }
+
+  @Test
+  public void publishedCommentAndReply() throws Exception {
+    PushOneCommit.Result r = createChange();
+    Change.Id id = r.getPatchSetId().getParentKey();
+    putComment(user, id, 1, "comment", null);
+    Map<String, List<CommentInfo>> comments = getPublishedComments(id);
+    String parentUuid = comments.get("a.txt").get(0).id;
+    putComment(user, id, 1, "comment", parentUuid);
     checker.rebuildAndCheckChanges(id);
   }
 
@@ -242,7 +253,7 @@ public class ChangeRebuilderIT extends AbstractDaemonTest {
     PushOneCommit.Result r = createChange();
     Change.Id id = r.getPatchSetId().getParentKey();
     putDraft(user, id, 1, "draft comment", null);
-    putComment(user, id, 1, "published comment");
+    putComment(user, id, 1, "published comment", null);
     checker.rebuildAndCheckChanges(id);
   }
 
@@ -1283,11 +1294,12 @@ public class ChangeRebuilderIT extends AbstractDaemonTest {
     }
   }
 
-  private void putComment(TestAccount account, Change.Id id, int line, String msg)
-      throws Exception {
+  private void putComment(TestAccount account, Change.Id id, int line,
+      String msg, String inReplyTo) throws Exception {
     CommentInput in = new CommentInput();
     in.line = line;
     in.message = msg;
+    in.inReplyTo = inReplyTo;
     ReviewInput rin = new ReviewInput();
     rin.comments = new HashMap<>();
     rin.comments.put(PushOneCommit.FILE_NAME, ImmutableList.of(in));
@@ -1348,4 +1360,8 @@ public class ChangeRebuilderIT extends AbstractDaemonTest {
     saveProjectConfig(allProjects, cfg);
   }
 
+  private Map<String, List<CommentInfo>> getPublishedComments(Change.Id id)
+      throws Exception {
+    return gApi.changes().id(id.get()).current().comments();
+  }
 }

gerrit-server/src/main/java/com/google/gerrit/server/CommentsUtil.java

@@ -169,6 +169,7 @@ public class CommentsUtil {
         new Comment.Key(ChangeUtil.messageUuid(), path, psId.get()),
         ctx.getUser().getAccountId(), ctx.getWhen(), side, message, serverId,
         unresolved);
+    c.parentUuid = parentUuid;
     ctx.getUser().updateRealAccountId(c::setRealAuthor);
     return c;
   }