--- a/mercurial/revlogutils/deltas.py	Tue Jul 23 19:14:16 2024 -0400
+++ b/mercurial/revlogutils/deltas.py	Tue Jul 23 19:20:22 2024 -0400
@@ -11,6 +11,7 @@
 import abc
 import collections
 import struct
+import typing
 
 # import stuff from node for others to import from revlog
 from ..node import nullrev
@@ -31,6 +32,11 @@
 
 from ..thirdparty import attr
 
+# Force pytype to use the non-vendored package
+if typing.TYPE_CHECKING:
+    # noinspection PyPackageRequirements
+    import attr
+
 from .. import (
     error,
     mdiff,