has_uncommitted_changes(): fall back to empty tree

diff --git a/diff-lib.c b/diff-lib.c
index 8104603a3b36f2fd73761db34efde44d5938f68f..7eea70e8139672749733c812db3e9848055f53c5 100644 (file)
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -513,6 +513,9 @@ int run_diff_index(struct rev_info *revs, int cached)
 {
        struct object_array_entry *ent;
 
+       if (revs->pending.nr != 1)
+               BUG("run_diff_index must be passed exactly one tree");
+
        ent = revs->pending.objects;
        if (diff_cache(revs, &ent->item->oid, ent->name, cached))
                exit(128);