Use a TOPO sort when processing commits in the merge queue

This ensures we always see all children before a parent, resulting
in a much less confusing graph when we linearize it for processing.

Signed-off-by: Shawn O. Pearce <sop@google.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/src/main/java/com/google/gerrit/git/MergeOp.java b/src/main/java/com/google/gerrit/git/MergeOp.java
index 923ac396cc..352730d206 100644
--- a/src/main/java/com/google/gerrit/git/MergeOp.java
+++ b/src/main/java/com/google/gerrit/git/MergeOp.java
@@ -133,6 +133,7 @@ public class MergeOp {
         return new CodeReviewCommit(id);
       }
     };
+    rw.sort(RevSort.TOPO);
   }
 
   private void openBranch() throws MergeException {
@@ -332,7 +333,8 @@ public class MergeOp {
   private void markCleanMerges() throws MergeException {
     try {
       rw.reset();
-      rw.sort(RevSort.REVERSE);
+      rw.sort(RevSort.TOPO);
+      rw.sort(RevSort.REVERSE, true);
       rw.markStart(mergeTip);
       if (branchTip != null) {
         rw.markUninteresting(branchTip);