notifications: Fix incorrect advertising in missed-message emails.

Missed-message email replies using the reply-to of
noreply@zulipchat.com shouldn't advertise that "just replying" will
work.

Rebased and commit message rewritten by tabbott.

Fixes #3965.

zerver/lib/notifications.py

@@ -253,12 +253,24 @@ def do_send_missedmessage_events_reply_in_zulip(user_profile, missed_messages, m
         'name': user_profile.full_name,
         'messages': build_message_list(user_profile, missed_messages),
         'message_count': message_count,
-        'reply_warning': False,
         'mention': missed_messages[0].recipient.type == Recipient.STREAM,
-        'reply_to_zulip': True,
         'unsubscribe_link': unsubscribe_link,
     })
 
+    # If this setting (email mirroring integration) is enabled, only then
+    # can users reply to email to send message to Zulip. Thus, one must
+    # ensure to display warning in the template.
+    if settings.EMAIL_GATEWAY_PATTERN:
+        template_payload.update({
+            'reply_warning': False,
+            'reply_to_zulip': True,
+        })
+    else:
+        template_payload.update({
+            'reply_warning': True,
+            'reply_to_zulip': False,
+        })
+
     headers = {}
     from zerver.lib.email_mirror import create_missed_message_address
     address = create_missed_message_address(user_profile, missed_messages[0])
@@ -279,6 +291,10 @@ def do_send_missedmessage_events_reply_in_zulip(user_profile, missed_messages, m
         headers['Sender'] = from_email
         sender = missed_messages[0].sender
         from_email = '"%s" <%s>' % (sender_str, sender.email)
+        template_payload.update({
+            'reply_warning': False,
+            'reply_to_zulip': False,
+        })
 
     text_content = loader.render_to_string('zerver/missed_message_email.txt', template_payload)
     html_content = loader.render_to_string('zerver/missed_message_email.html', template_payload)

zerver/tests/test_notifications.py

@@ -32,7 +32,10 @@ class TestMissedMessages(ZulipTestCase):
         othello = get_user_profile_by_email('othello@zulip.com')
         hamlet = get_user_profile_by_email('hamlet@zulip.com')
         handle_missedmessage_emails(hamlet.id, [{'message_id': msg_id}])
+        if settings.EMAIL_GATEWAY_PATTERN != "":
             reply_to_addresses = [settings.EMAIL_GATEWAY_PATTERN % (u'mm' + t) for t in tokens]
+        else:
+            reply_to_addresses = ["noreply@example.com"]
         msg = mail.outbox[0]
         sender = 'Zulip <{}>'.format(settings.NOREPLY_EMAIL_ADDRESS)
         from_email = sender
@@ -71,6 +74,30 @@ class TestMissedMessages(ZulipTestCase):
         body = 'You and Othello, the Moor of Venice Extremely personal message!'
         self._test_cases(tokens, msg_id, body, send_as_user)
 
+    @patch('zerver.lib.email_mirror.generate_random_token')
+    def _reply_to_email_in_personal_missed_stream_messages(self, send_as_user, mock_random_token):
+        # type: (bool, MagicMock) -> None
+        tokens = self._get_tokens()
+        mock_random_token.side_effect = tokens
+
+        msg_id = self.send_message("othello@zulip.com", "hamlet@zulip.com",
+                                   Recipient.PERSONAL,
+                                   'Extremely personal message!')
+        body = 'Or just reply to this email.'
+        self._test_cases(tokens, msg_id, body, send_as_user)
+
+    @patch('zerver.lib.email_mirror.generate_random_token')
+    def _reply_warning_in_personal_missed_stream_messages(self, send_as_user, mock_random_token):
+        # type: (bool, MagicMock) -> None
+        tokens = self._get_tokens()
+        mock_random_token.side_effect = tokens
+
+        msg_id = self.send_message("othello@zulip.com", "hamlet@zulip.com",
+                                   Recipient.PERSONAL,
+                                   'Extremely personal message!')
+        body = 'Please do not reply to this automated message.'
+        self._test_cases(tokens, msg_id, body, send_as_user)
+
     @patch('zerver.lib.email_mirror.generate_random_token')
     def _extra_context_in_huddle_missed_stream_messages(self, send_as_user, mock_random_token):
         # type: (bool, MagicMock) -> None
@@ -95,6 +122,15 @@ class TestMissedMessages(ZulipTestCase):
         # type: () -> None
         self._extra_context_in_missed_stream_messages(False)
 
+    def test_reply_to_email_in_personal_missed_stream_messages(self):
+        # type: () -> None
+        self._reply_to_email_in_personal_missed_stream_messages(False)
+
+    @override_settings(EMAIL_GATEWAY_PATTERN="")
+    def test_reply_warning_in_personal_missed_stream_messages(self):
+        # type: () -> None
+        self._reply_warning_in_personal_missed_stream_messages(False)
+
     @override_settings(SEND_MISSED_MESSAGE_EMAILS_AS_USER=True)
     def test_extra_context_in_personal_missed_stream_messages_as_user(self):
         # type: () -> None