diff -r d04ba50e104d -r d035ede73434 mercurial/cmdutil.py
--- a/mercurial/cmdutil.py	Fri May 06 19:55:46 2011 +0300
+++ b/mercurial/cmdutil.py	Sun May 08 17:48:29 2011 +0200
@@ -335,7 +335,7 @@
 def updatedir(ui, repo, patches, similarity=0):
     '''Update dirstate after patch application according to metadata'''
     if not patches:
-        return
+        return []
     copies = []
     removes = set()
     cfiles = patches.keys()