--- a/hgext3rd/evolve/firstmergecache.py	Sat Aug 18 00:48:05 2018 +0200
+++ b/hgext3rd/evolve/firstmergecache.py	Sat Aug 18 00:53:12 2018 +0200
@@ -47,30 +47,12 @@
                 self.firstmergecache.clear()
             super(firstmergecacherepo, self).destroyed()
 
-        if util.safehasattr(repo, 'updatecaches'):
-            @localrepo.unfilteredmethod
-            def updatecaches(self, tr=None, **kwargs):
-                if utility.shouldwarmcache(self, tr):
-                    self.firstmergecache.update(self)
-                    self.firstmergecache.save(self)
-                super(firstmergecacherepo, self).updatecaches(tr, **kwargs)
-
-        else:
-            def transaction(self, *args, **kwargs):
-                tr = super(firstmergecacherepo, self).transaction(*args, **kwargs)
-                reporef = weakref.ref(self)
-
-                def _warmcache(tr):
-                    repo = reporef()
-                    if repo is None:
-                        return
-                    repo = repo.unfiltered()
-                    repo.firstmergecache.update(repo)
-                    repo.firstmergecache.save(repo)
-
-                if utility.shouldwarmcache(self, tr):
-                    tr.addpostclose('warmcache-01-firstparentcache', _warmcache)
-                return tr
+        @localrepo.unfilteredmethod
+        def updatecaches(self, tr=None, **kwargs):
+            if utility.shouldwarmcache(self, tr):
+                self.firstmergecache.update(self)
+                self.firstmergecache.save(self)
+            super(firstmergecacherepo, self).updatecaches(tr, **kwargs)
 
     repo.__class__ = firstmergecacherepo