--- a/contrib/perf.py	Tue Jul 17 18:21:49 2012 +0200
+++ b/contrib/perf.py	Wed Jul 18 07:51:20 2012 -0700
@@ -177,7 +177,7 @@
     ui.popbuffer()
 
 def perfcca(ui, repo):
-    timer(lambda: scmutil.casecollisionauditor(ui, False, repo[None]))
+    timer(lambda: scmutil.casecollisionauditor(ui, False, repo.dirstate))
 
 def perffncacheload(ui, repo):
     from mercurial import scmutil, store