patch.extract: do not prepend subject if the description already starts with it

mercurial/patch.py

@@ -50,7 +50,7 b' def extract(ui, fileobj):'
     try:
         msg = email.Parser.Parser().parse(fileobj)
 
-        message = msg['Subject']
+        subject = msg['Subject']
         user = msg['From']
         # should try to parse msg['Date']
         date = None
@@ -58,13 +58,13 b' def extract(ui, fileobj):'
         branch = None
         parents = []
 
-        if message:
-            if message.startswith('[PATCH'):
-                pend = message.find(']')
+        if subject:
+            if subject.startswith('[PATCH'):
+                pend = subject.find(']')
                 if pend >= 0:
-                    message = message[pend+1:].lstrip()
-            message = message.replace('\n\t', ' ')
-            ui.debug('Subject: %s\n' % message)
+                    subject = subject[pend+1:].lstrip()
+            subject = subject.replace('\n\t', ' ')
+            ui.debug('Subject: %s\n' % subject)
         if user:
             ui.debug('From: %s\n' % user)
         diffs_seen = 0
@@ -84,9 +84,6 b' def extract(ui, fileobj):'
                 ui.debug(_('found patch at byte %d\n') % m.start(0))
                 diffs_seen += 1
                 cfp = cStringIO.StringIO()
-                if message:
-                    cfp.write(message)
-                    cfp.write('\n')
                 for line in payload[:m.start(0)].splitlines():
                     if line.startswith('# HG changeset patch'):
                         ui.debug(_('patch generated by hg export\n'))
@@ -123,6 +120,8 b' def extract(ui, fileobj):'
         os.unlink(tmpname)
         raise
 
+    if subject and not message.startswith(subject):
+        message = '%s\n%s' % (subject, message)
     tmpfp.close()
     if not diffs_seen:
         os.unlink(tmpname)