diff -r 312262ebc223 -r 2cf01eb74842 mercurial/localrepo.py
--- a/mercurial/localrepo.py	Tue Dec 18 02:04:37 2012 +0100
+++ b/mercurial/localrepo.py	Tue Dec 18 01:51:08 2012 +0100
@@ -1106,6 +1106,8 @@
     def invalidatevolatilesets(self):
         self.filteredrevcache.clear()
         obsolete.clearobscaches(self)
+        if 'hiddenrevs' in vars(self):
+            del self.hiddenrevs
 
     def invalidatedirstate(self):
         '''Invalidates the dirstate, causing the next call to dirstate