diff -r e6069f84abbb -r 346d2c04440a mercurial/util.py
--- a/mercurial/util.py	Mon Feb 10 10:42:16 2025 +0100
+++ b/mercurial/util.py	Fri Dec 20 19:13:06 2024 -0500
@@ -1416,11 +1416,9 @@
     """
 
 
-class transactional:  # pytype: disable=ignored-metaclass
+class transactional(abc.ABC):
     """Base class for making a transactional type into a context manager."""
 
-    __metaclass__ = abc.ABCMeta
-
     @abc.abstractmethod
     def close(self):
         """Successfully closes the transaction."""