--- a/mercurial/diffutil.py	Mon Sep 16 15:36:38 2024 +0200
+++ b/mercurial/diffutil.py	Mon Sep 16 15:36:44 2024 +0200
@@ -7,6 +7,8 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
+from __future__ import annotations
+
 import typing
 
 from typing import (