--- a/mercurial/cmdutil.py	Sun Apr 29 16:18:46 2012 +0200
+++ b/mercurial/cmdutil.py	Sun Apr 29 22:25:55 2012 +0200
@@ -1384,7 +1384,7 @@
         newid = repo.commitctx(new)
         if newid != old.node():
             # Reroute the working copy parent to the new changeset
-            repo.dirstate.setparents(newid, nullid)
+            repo.setparents(newid, nullid)
 
             # Move bookmarks from old parent to amend commit
             bms = repo.nodebookmarks(old.node())