builtin/merge.c: fix a bug with trivial merges

diff --git a/builtin/merge.c b/builtin/merge.c
index 41467e427770d02f40df5e8d5ca0a27ab483c4af..eb9415119f0b3d4738d235b593f5aff0ab51be49 100644 (file)
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -822,6 +822,14 @@ static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
 {
        unsigned char result_tree[20], result_commit[20];
        struct commit_list *parents, **pptr = &parents;
+       static struct lock_file lock;
+
+       hold_locked_index(&lock, 1);
+       refresh_cache(REFRESH_QUIET);
+       if (active_cache_changed &&
+           write_locked_index(&the_index, &lock, COMMIT_LOCK))
+               return error(_("Unable to write index."));
+       rollback_lock_file(&lock);
 
        write_tree_trivial(result_tree);
        printf(_("Wonderful.\n"));