diff --git a/builtin/commit.c b/builtin/commit.c
index e69f466..6adc908 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -313,7 +313,7 @@ static void create_base_index(const struct commit *current_head)
 	opts.dst_index = &the_index;
 
 	opts.fn = oneway_merge;
-	tree = parse_tree_indirect(current_head->object.oid.hash);
+	tree = parse_tree_indirect(&current_head->object.oid);
 	if (!tree)
 		die(_("failed to unpack HEAD tree object"));
 	parse_tree(tree);