if (!parents) {
/* Deduce parent commit from t->ref */
struct object_id parent_oid;
- if (!read_ref(t->ref, parent_oid.hash)) {
+ if (!read_ref(t->ref, &parent_oid)) {
struct commit *parent = lookup_commit(&parent_oid);
if (parse_commit(parent))
die("Failed to find/parse commit %s", t->ref);