--- a/mercurial/mdiff.py	Sat Sep 28 19:11:39 2024 -0400
+++ b/mercurial/mdiff.py	Sat Sep 28 19:12:18 2024 -0400
@@ -20,9 +20,13 @@
     pycompat,
     util,
 )
+from .interfaces import (
+    modules as intmod,
+)
+
 from .utils import dateutil
 
-bdiff = policy.importmod('bdiff')
+bdiff: intmod.BDiff = policy.importmod('bdiff')
 mpatch = policy.importmod('mpatch')
 
 blocks = bdiff.blocks