diff -r a7ba57b10530 -r 9c86ef980d9e mercurial/commands.py
--- a/mercurial/commands.py	Mon Jun 04 18:03:23 2012 +0200
+++ b/mercurial/commands.py	Mon Jun 04 15:43:16 2012 +0300
@@ -2695,7 +2695,7 @@
                     stats = mergemod.update(repo, ctx.node(), True, True, False,
                                             ctx.p1().node())
                 finally:
-                    ui.setconfig('ui', 'forcemerge', '')
+                    repo.ui.setconfig('ui', 'forcemerge', '')
                 # drop the second merge parent
                 repo.setparents(current.node(), nullid)
                 repo.dirstate.write()