parsemail: Detect git send-email emails without X-Mailer headers

git send-email has an option to omit the X-Mailer header (--no-xmailer
aka sendemail.xmailer). If the user decides to use this, then our git
send-email detection fails.

In those cases, we can still fall back to looking at the Message-ID. git
send-email helpfully uses the 'git-send-email' string in its
Message-IDs.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>

patchwork/bin/parsemail.py

@@ -309,6 +309,11 @@ def parse_series_marker(subject_prefixes):
     return (None, None)
 
 
+def is_git_send_email(mail):
+    return mail.get('X-Mailer', '').startswith('git-send-email ') or \
+           'git-send-email' in mail.get('Message-ID', '')
+
+
 def find_content(project, mail):
     patchbuf = None
     commentbuf = ''
@@ -375,10 +380,9 @@ def find_content(project, mail):
     is_root = refs == []
     is_cover_letter = is_root and x == 0
     is_patch = patchbuf is not None
-    is_git_send_email = mail.get('X-Mailer', '').startswith('git-send-email ')
 
     drop_patch = not is_attachment and \
-                 project.git_send_email_only and not is_git_send_email
+                 project.git_send_email_only and not is_git_send_email(mail)
 
     if pullurl or (is_patch and not drop_patch):
         ret.patch_order = x or 1

patchwork/tests/test_patchparser.py

@@ -705,6 +705,17 @@ def testSettingOnGitSendEmail(self):
         parse_mail(email)
         self._assertNPatches(1)
 
+    def testSettingOnGitSendEmailNoXMailer(self):
+        """git_send_email_only is true and email has been sent with
+           git send-email --no-xmailer"""
+        self.p1.git_send_email_only = True
+        self.p1.save()
+        email = self.get_email()
+        del email['Message-Id']
+        email['Message-Id'] = '<1454600601-21900-1-git-send-email-cpaul@redhat.com>'
+        parse_mail(email)
+        self._assertNPatches(1)
+
     def testSettingOnNoGitSendEmail(self):
         """git_send_email_only is true and email has been not sent with
            git send-email"""