--- a/mercurial/hg.py	Thu Nov 05 11:07:01 2009 +0100
+++ b/mercurial/hg.py	Thu Nov 05 11:05:13 2009 +0100
@@ -309,6 +309,8 @@
             if update:
                 if update is not True:
                     checkout = update
+                    if src_repo.local():
+                        checkout = src_repo.lookup(update)
                 for test in (checkout, 'default', 'tip'):
                     if test is None:
                         continue