--- a/mercurial/branchmap.py	Mon Sep 16 15:36:38 2024 +0200
+++ b/mercurial/branchmap.py	Mon Sep 16 15:36:44 2024 +0200
@@ -5,6 +5,7 @@
 # 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 struct