diff -r e6e34c17b1cc -r a1a1bd09e4f4 mercurial/cmdutil.py
--- a/mercurial/cmdutil.py	Wed Apr 16 02:04:41 2014 +0900
+++ b/mercurial/cmdutil.py	Wed Apr 16 02:38:11 2014 +0900
@@ -1948,6 +1948,8 @@
             if not message:
                 editmsg = True
                 message = old.description()
+            elif opts.get('edit'):
+                editmsg = True
 
             pureextra = extra.copy()
             extra['amend_source'] = old.hex()