diff -r 520defbc0335 -r 949e8c626d19 mercurial/merge.py
--- a/mercurial/merge.py	Sat Oct 17 01:15:34 2015 +0900
+++ b/mercurial/merge.py	Sat Oct 17 01:15:34 2015 +0900
@@ -1244,9 +1244,7 @@
         wlock.release()
 
     if not partial:
-        def updatehook(parent1=xp1, parent2=xp2, error=stats[3]):
-            repo.hook('update', parent1=parent1, parent2=parent2, error=error)
-        repo._afterlock(updatehook)
+        repo.hook('update', parent1=xp1, parent2=xp2, error=stats[3])
     return stats
 
 def graft(repo, ctx, pctx, labels):