diff -r 7e05bdeee7de -r f8aa16533ddf hgext/mq.py
--- a/hgext/mq.py	Wed Aug 15 14:38:18 2007 -0700
+++ b/hgext/mq.py	Wed Aug 15 16:22:12 2007 -0700
@@ -924,8 +924,6 @@
                 if line.startswith('diff --git'):
                     self.diffopts().git = True
                     break
-            patchf.seek(0)
-            patchf.truncate()
 
             msg = opts.get('msg', '').rstrip()
             if msg:
@@ -940,6 +938,10 @@
                             ci += 1
                         del comments[ci]
                 comments.append(msg)
+
+            patchf.seek(0)
+            patchf.truncate()
+
             if comments:
                 comments = "\n".join(comments) + '\n\n'
                 patchf.write(comments)