diff --git a/git-union-merge.hs b/git-union-merge.hs
index 31c71ba729..6930640452 100644
--- a/git-union-merge.hs
+++ b/git-union-merge.hs
@@ -44,5 +44,5 @@ main = do
 	_ <- Git.Index.override $ tmpIndex g
 	setup g
 	Git.UnionMerge.merge aref bref g
-	_ <- Git.Branch.commit "union merge" newref [aref, bref] g
+	_ <- Git.Branch.commit Git.Branch.ManualCommit False "union merge" newref [aref, bref] g
 	cleanup g