diff -r 839086b25c36 -r a8f136f430da mercurial/commands.py
--- a/mercurial/commands.py	Sun May 01 18:43:20 2011 +0200
+++ b/mercurial/commands.py	Mon May 02 01:29:51 2011 +0900
@@ -339,7 +339,7 @@
             side = good and state['bad'] or state['good']
             num = len(set(i.node() for i in parents) & set(side))
             if num == 1:
-                 return parents[0].ancestor(parents[1])
+                return parents[0].ancestor(parents[1])
         return None
 
     def print_result(nodes, good):