webhooks/gogs: Include title in message body if not in topic.

This is a follow-up in response to Tim's comments on #9951.

In instances where all messages from a Gogs integration are
grouped under one user specified topic (specified in the URL), we
should include the title of the PR in the message body, since
the availability of a user-specified topic precludes us from
including it in the topic itself (which was the default behaviour).

zerver/webhooks/gogs/tests.py

@@ -69,6 +69,13 @@ class GogsHookTests(WebhookTestCase):
 from `feature` to `master`"""
         self.send_and_test_stream_message('pull_request_opened', expected_subject, expected_message, HTTP_X_GOGS_EVENT='pull_request')
 
+    def test_pull_request_opened_with_custom_topic_in_url(self) -> None:
+        self.url = self.build_webhook_url(topic='notifications')
+        expected_subject = u"notifications"
+        expected_message = u"""john opened [PR #1 Title Text for Pull Request](http://localhost:3000/john/try-git/pulls/1)
+from `feature` to `master`"""
+        self.send_and_test_stream_message('pull_request_opened', expected_subject, expected_message, HTTP_X_GOGS_EVENT='pull_request')
+
     def test_pull_request_closed(self) -> None:
         expected_subject = u"try-git / PR #1 Title Text for Pull Request"
         expected_message = u"""john closed [PR #1](http://localhost:3000/john/try-git/pulls/1)

zerver/webhooks/gogs/view.py

@@ -43,7 +43,8 @@ def format_new_branch_event(payload: Dict[str, Any]) -> str:
     }
     return get_create_branch_event_message(**data)
 
-def format_pull_request_event(payload: Dict[str, Any]) -> str:
+def format_pull_request_event(payload: Dict[str, Any],
+                              include_title: Optional[bool]=False) -> str:
 
     data = {
         'user_name': payload['pull_request']['user']['username'],
@@ -52,6 +53,7 @@ def format_pull_request_event(payload: Dict[str, Any]) -> str:
         'number': payload['pull_request']['number'],
         'target_branch': payload['pull_request']['head_branch'],
         'base_branch': payload['pull_request']['base_branch'],
+        'title': payload['pull_request']['title'] if include_title else None
     }
 
     if payload['pull_request']['merged']:
@@ -64,7 +66,8 @@ def format_pull_request_event(payload: Dict[str, Any]) -> str:
 @has_request_variables
 def api_gogs_webhook(request: HttpRequest, user_profile: UserProfile,
                      payload: Dict[str, Any]=REQ(argument_type='body'),
-                     branches: Optional[str]=REQ(default=None)) -> HttpResponse:
+                     branches: Optional[str]=REQ(default=None),
+                     user_specified_topic: Optional[str]=REQ("topic", default=None)) -> HttpResponse:
 
     repo = payload['repository']['name']
     event = validate_extract_webhook_http_header(request, 'X_GOGS_EVENT', 'Gogs')
@@ -84,7 +87,10 @@ def api_gogs_webhook(request: HttpRequest, user_profile: UserProfile,
             branch=payload['ref']
         )
     elif event == 'pull_request':
-        body = format_pull_request_event(payload)
+        body = format_pull_request_event(
+            payload,
+            include_title=user_specified_topic is not None
+        )
         topic = SUBJECT_WITH_PR_OR_ISSUE_INFO_TEMPLATE.format(
             repo=repo,
             type='PR',