tree-diff: don't access hash of NULL object_id pointer

diff --git a/patch-ids.c b/patch-ids.c
index aaf462c03085e164f6b93a686fb8d2575b5bb7ba..9c0ab9e67a80b54f87d9b9d52fa08de7167aec4a 100644 (file)
--- a/patch-ids.c
+++ b/patch-ids.c
@@ -17,8 +17,8 @@ int commit_patch_id(struct commit *commit, struct diff_options *options,
                return -1;
 
        if (commit->parents)
-               diff_tree_sha1(commit->parents->item->object.oid.hash,
-                              commit->object.oid.hash, "", options);
+               diff_tree_oid(&commit->parents->item->object.oid,
+                             &commit->object.oid, "", options);
        else
                diff_root_tree_oid(&commit->object.oid, "", options);
        diffcore_std(options);