--- a/mercurial/localrepo.py	Mon Mar 16 13:41:45 2015 -0500
+++ b/mercurial/localrepo.py	Sun Aug 17 11:35:31 2014 +0900
@@ -465,7 +465,8 @@
 
     def __contains__(self, changeid):
         try:
-            return bool(self.lookup(changeid))
+            self[changeid]
+            return True
         except error.RepoLookupError:
             return False