diff -r 96189d60d810 -r 471f30d360ea mercurial/hg.py
--- a/mercurial/hg.py	Mon Aug 06 12:03:07 2012 -0500
+++ b/mercurial/hg.py	Wed Aug 08 10:04:02 2012 -0500
@@ -398,7 +398,7 @@
 
             if update:
                 if update is not True:
-                    checkout = srcrepo.lookup(update)
+                    checkout = srcpeer.lookup(update)
                 for test in (checkout, 'default', 'tip'):
                     if test is None:
                         continue