commit a05e2e69e7de55b61776631688315698f56f358f
author Shawn O. Pearce <sop@google.com> Wed May 27 12:09:42 2009 -0700
committer Shawn O. Pearce <sop@google.com> Wed May 27 12:09:42 2009 -0700
tree 5ca060aedf1306dc4f160924d3be098521723fea
parent 9a48381d29f161147f6e2ecbad79e53d1df97485

Fix NPE in MergeOp when submit to new branch fails due to dependencies

This resolves the stack trace reported in GERRIT-192, where we hit an
NPE because mergeTip was still null, as no changes were chosen to be
merged into the stillborn branch, due to missing dependencies.

Bug: GERRIT-192
Signed-off-by: Shawn O. Pearce <sop@google.com>

src/main/java/com/google/gerrit/git/MergeOp.java

diff --git a/src/main/java/com/google/gerrit/git/MergeOp.java b/src/main/java/com/google/gerrit/git/MergeOp.java
index 939b0ef..9d40429 100644
--- a/src/main/java/com/google/gerrit/git/MergeOp.java
+++ b/src/main/java/com/google/gerrit/git/MergeOp.java
@@ -421,6 +421,14 @@
   }
 
   private void markCleanMerges() throws MergeException {
+    if (mergeTip == null) {
+      // If mergeTip is null here, branchTip was null, indicating a new branch
+      // at the start of the merge process. We also elected to merge nothing,
+      // probably due to missing dependencies. Nothing was cleanly merged.
+      //
+      return;
+    }
+
     try {
       rw.reset();
       rw.sort(RevSort.TOPO);