diff -r dc7010ed0101 -r b11d181b87ba mercurial/commands.py
--- a/mercurial/commands.py	Sun Oct 14 20:27:55 2012 +0200
+++ b/mercurial/commands.py	Sat May 05 15:30:54 2012 -0500
@@ -5848,7 +5848,7 @@
 
     # with no argument, we also move the current bookmark, if any
     movemarkfrom = None
-    if rev is None or node == '':
+    if rev is None:
         movemarkfrom = repo['.'].node()
 
     # if we defined a bookmark, we have to remember the original bookmark name