notes: don't access hash of NULL object_id pointer

diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index e242726f08e2397c8875e0d1794d58561ac4ecd9..d57f36c43844cefcfa9302de4c3118f156f1383d 100644 (file)
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -562,8 +562,8 @@ static void handle_commit(struct commit *commit, struct rev_info *rev)
            get_object_mark(&commit->parents->item->object) != 0 &&
            !full_tree) {
                parse_commit_or_die(commit->parents->item);
-               diff_tree_sha1(commit->parents->item->tree->object.oid.hash,
-                              commit->tree->object.oid.hash, "", &rev->diffopt);
+               diff_tree_oid(&commit->parents->item->tree->object.oid,
+                             &commit->tree->object.oid, "", &rev->diffopt);
        }
        else
                diff_root_tree_oid(&commit->tree->object.oid,