diff -r cff3c58a5766 -r 81da3c45aabd mercurial/localrepo.py
--- a/mercurial/localrepo.py	Mon Sep 18 17:43:31 2006 +0200
+++ b/mercurial/localrepo.py	Fri Sep 15 15:23:52 2006 -0700
@@ -318,7 +318,7 @@
             f = f[1:]
         return filelog.filelog(self.opener, f, self.revlogversion)
 
-    def changectx(self, changeid):
+    def changectx(self, changeid=None):
         return context.changectx(self, changeid)
 
     def filectx(self, path, changeid=None, fileid=None):