Merge branch 'stable-2.15' into stable-2.16

* stable-2.15:
  StarredChangesUtil: Fix NPE when ref to be deleted doesn't exist
  StarredChangesUtil: Throw LockFailureException on LOCK_FAILURE
  Add test for creating a change on a non-existing base change
  Rebase: Do not fail with 500 ISE if non-existing change is given as base
  Fix detecting changes of parent trees when computing change kind for merge commit

Change-Id: I8ec9c55d86c3b425e0bce289f4c92cd5b6adbc80

java/com/google/gerrit/server/StarredChangesUtil.java

@@ -40,6 +40,7 @@ import com.google.gerrit.server.change.ChangeResource;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.extensions.events.GitReferenceUpdated;
 import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.gerrit.server.git.LockFailureException;
 import com.google.gerrit.server.index.change.ChangeField;
 import com.google.gerrit.server.index.change.ChangeIndexer;
 import com.google.gerrit.server.logging.TraceContext;
@@ -248,15 +249,21 @@ public class StarredChangesUtil {
       for (Account.Id accountId : byChangeFromIndex(changeId).keySet()) {
         String refName = RefNames.refsStarredChanges(changeId, accountId);
         Ref ref = repo.getRefDatabase().getRef(refName);
-        batchUpdate.addCommand(new ReceiveCommand(ref.getObjectId(), ObjectId.zeroId(), refName));
+        if (ref != null) {
+          batchUpdate.addCommand(new ReceiveCommand(ref.getObjectId(), ObjectId.zeroId(), refName));
+        }
       }
       batchUpdate.execute(rw, NullProgressMonitor.INSTANCE);
       for (ReceiveCommand command : batchUpdate.getCommands()) {
         if (command.getResult() != ReceiveCommand.Result.OK) {
-          throw new IOException(
+          String message =
               String.format(
                   "Unstar change %d failed, ref %s could not be deleted: %s",
-                  changeId.get(), command.getRefName(), command.getResult()));
+                  changeId.get(), command.getRefName(), command.getResult());
+          if (command.getResult() == ReceiveCommand.Result.LOCK_FAILURE) {
+            throw new LockFailureException(message, batchUpdate);
+          }
+          throw new IOException(message);
         }
       }
       indexer.index(dbProvider.get(), project, changeId);

java/com/google/gerrit/server/change/ChangeKindCacheImpl.java

@@ -214,13 +214,13 @@ public class ChangeKindCacheImpl implements ChangeKindCache {
         rw.parseBody(next);
 
         if (!next.getFullMessage().equals(prior.getFullMessage())) {
-          if (isSameDeltaAndTree(prior, next)) {
+          if (isSameDeltaAndTree(rw, prior, next)) {
             return ChangeKind.NO_CODE_CHANGE;
           }
           return ChangeKind.REWORK;
         }
 
-        if (isSameDeltaAndTree(prior, next)) {
+        if (isSameDeltaAndTree(rw, prior, next)) {
           return ChangeKind.NO_CHANGE;
         }
 
@@ -284,7 +284,8 @@ public class ChangeKindCacheImpl implements ChangeKindCache {
       return FluentIterable.from(Arrays.asList(parents)).skip(1).toSet();
     }
 
-    private static boolean isSameDeltaAndTree(RevCommit prior, RevCommit next) {
+    private static boolean isSameDeltaAndTree(RevWalk rw, RevCommit prior, RevCommit next)
+        throws IOException {
       if (!Objects.equals(next.getTree(), prior.getTree())) {
         return false;
       }
@@ -298,6 +299,10 @@ public class ChangeKindCacheImpl implements ChangeKindCache {
       // Make sure that the prior/next delta is the same - not just the tree.
       // This is done by making sure that the parent trees are equal.
       for (int i = 0; i < prior.getParentCount(); i++) {
+        // Parse parent commits so that their trees are available.
+        rw.parseCommit(prior.getParent(i));
+        rw.parseCommit(next.getParent(i));
+
         if (!Objects.equals(next.getParent(i).getTree(), prior.getParent(i).getTree())) {
           return false;
         }

java/com/google/gerrit/server/restapi/change/Rebase.java

@@ -24,6 +24,7 @@ import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.RestModifyView;
+import com.google.gerrit.extensions.restapi.UnprocessableEntityException;
 import com.google.gerrit.extensions.webui.UiAction;
 import com.google.gerrit.reviewdb.client.Branch;
 import com.google.gerrit.reviewdb.client.Change;
@@ -159,10 +160,17 @@ public class Rebase extends RetryingRestModifyView<RevisionResource, RebaseInput
       return destRef.getObjectId();
     }
 
-    Base base = rebaseUtil.parseBase(rsrc, str);
+    Base base;
-    if (base == null) {
+    try {
-      throw new ResourceConflictException("base revision is missing: " + str);
+      base = rebaseUtil.parseBase(rsrc, str);
+      if (base == null) {
+        throw new ResourceConflictException("base revision is missing: " + str);
+      }
+    } catch (NoSuchChangeException e) {
+      throw new UnprocessableEntityException(
+          String.format("Base change not found: %s", input.base));
     }
+
     PatchSet.Id baseId = base.patchSet().getId();
     if (change.getId().equals(baseId.getParentKey())) {
       throw new ResourceConflictException("cannot rebase change onto itself");

javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java

@@ -952,6 +952,16 @@ public class ChangeIT extends AbstractDaemonTest {
     assertThat(ri2.commit.parents.get(0).commit).isEqualTo(r1.getCommit().name());
   }
 
+  @Test
+  public void rebaseOnNonExistingChange() throws Exception {
+    String changeId = createChange().getChangeId();
+    RebaseInput in = new RebaseInput();
+    in.base = "999999";
+    exception.expect(UnprocessableEntityException.class);
+    exception.expectMessage("Base change not found: " + in.base);
+    gApi.changes().id(changeId).rebase(in);
+  }
+
   @Test
   public void rebaseNotAllowedWithoutPermission() throws Exception {
     // Create two changes both with the same parent

javatests/com/google/gerrit/acceptance/api/change/StickyApprovalsIT.java

@@ -247,6 +247,23 @@ public class StickyApprovalsIT extends AbstractDaemonTest {
     assertNotSticky(EnumSet.of(REWORK, NO_CODE_CHANGE, TRIVIAL_REBASE));
   }
 
+  @Test
+  public void notStickyWithCopyOnNoChangeWhenSecondParentIsUpdated() throws Exception {
+    try (ProjectConfigUpdate u = updateProject(project)) {
+      u.getConfig().getLabelSections().get("Code-Review").setCopyAllScoresIfNoChange(true);
+      u.save();
+    }
+
+    String changeId = createChangeForMergeCommit();
+    vote(admin, changeId, 2, 1);
+    vote(user, changeId, -2, -1);
+
+    updateSecondParent(changeId);
+    ChangeInfo c = detailedChange(changeId);
+    assertVotes(c, admin, 0, 0, null);
+    assertVotes(c, user, 0, 0, null);
+  }
+
   @Test
   public void removedVotesNotSticky() throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
@@ -512,6 +529,24 @@ public class StickyApprovalsIT extends AbstractDaemonTest {
     assertThat(getChangeKind(changeId)).isEqualTo(MERGE_FIRST_PARENT_UPDATE);
   }
 
+  private void updateSecondParent(String changeId) throws Exception {
+    ChangeInfo c = detailedChange(changeId);
+    List<CommitInfo> parents = c.revisions.get(c.currentRevision).commit.parents;
+    String parent1 = parents.get(0).commit;
+    String parent2 = parents.get(1).commit;
+    RevCommit commitParent1 = testRepo.getRevWalk().parseCommit(ObjectId.fromString(parent1));
+
+    testRepo.reset(parent2);
+    PushOneCommit.Result newParent2 = createChange("new parent 2", "p2-2.txt", "content 2-2");
+
+    PushOneCommit merge = pushFactory.create(db, admin.getIdent(), testRepo, changeId);
+    merge.setParents(ImmutableList.of(commitParent1, newParent2.getCommit()));
+    PushOneCommit.Result result = merge.to("refs/for/master");
+    result.assertOkStatus();
+
+    assertThat(getChangeKind(changeId)).isEqualTo(REWORK);
+  }
+
   private String cherryPick(String changeId, ChangeKind changeKind) throws Exception {
     switch (changeKind) {
       case REWORK:

javatests/com/google/gerrit/acceptance/rest/change/CreateChangeIT.java

@@ -246,6 +246,14 @@ public class CreateChangeIT extends AbstractDaemonTest {
         String.format("Commit %s doesn't exist on ref refs/heads/foo", input.baseCommit));
   }
 
+  @Test
+  public void createChangeOnNonExistingBaseChangeFails() throws Exception {
+    ChangeInput input = newChangeInput(ChangeStatus.NEW);
+    input.baseChange = "999999";
+    assertCreateFails(
+        input, UnprocessableEntityException.class, "Base change not found: " + input.baseChange);
+  }
+
   @Test
   public void createChangeWithoutAccessToParentCommitFails() throws Exception {
     Map<String, PushOneCommit.Result> results =