diff -r 11748167a78e -r 3a6ddacb7198 mercurial/localrepo.py
--- a/mercurial/localrepo.py	Wed Dec 19 16:56:26 2012 -0800
+++ b/mercurial/localrepo.py	Thu Dec 20 15:32:42 2012 +0100
@@ -6,7 +6,7 @@
 # GNU General Public License version 2 or any later version.
 from node import bin, hex, nullid, nullrev, short
 from i18n import _
-import peer, changegroup, subrepo, discovery, pushkey, obsolete
+import peer, changegroup, subrepo, discovery, pushkey, obsolete, repoview
 import changelog, dirstate, filelog, manifest, context, bookmarks, phases
 import lock, transaction, store, encoding, base85
 import scmutil, util, extensions, hook, error, revset
@@ -303,6 +303,14 @@
         Intended to be ovewritten by filtered repo."""
         return self
 
+    def filtered(self, name):
+        """Return a filtered version of a repository"""
+        # build a new class with the mixin and the current class
+        # (possibily subclass of the repo)
+        class proxycls(repoview.repoview, self.unfiltered().__class__):
+            pass
+        return proxycls(self, name)
+
     @repofilecache('bookmarks')
     def _bookmarks(self):
         return bookmarks.bmstore(self)