--- a/mercurial/store.py	Fri Jul 07 23:19:31 2017 +0900
+++ b/mercurial/store.py	Fri Jul 07 23:40:00 2017 +0900
@@ -475,9 +475,9 @@
             self._load()
         return iter(self.entries)
 
-class _fncachevfs(vfsmod.abstractvfs, vfsmod.auditvfs):
+class _fncachevfs(vfsmod.abstractvfs, vfsmod.proxyvfs):
     def __init__(self, vfs, fnc, encode):
-        vfsmod.auditvfs.__init__(self, vfs)
+        vfsmod.proxyvfs.__init__(self, vfs)
         self.fncache = fnc
         self.encode = encode