lib: Add support for extended mention syntax.

We are checking for the extended syntax only on the basis of the
user id so that we can handle cases where a bot is renamed.

zulip_bots/zulip_bots/lib.py

@@ -5,6 +5,7 @@ import os
 import signal
 import sys
 import time
+import re
 
 
 from typing import Any, Optional, List, Dict, IO, Text
@@ -238,10 +239,18 @@ def extract_query_without_mention(message: Dict[str, Any], client: ExternalBotHa
     If the bot is the first @mention in the message, then this function returns
     the stripped message with the bot's @mention removed.  Otherwise, it returns None.
     """
+    content = message['content']
     mention = '@**' + client.full_name + '**'
-    if not message['content'].startswith(mention):
+    extended_mention_regex = re.compile(r'^@\*\*.*\|' + str(client.user_id) + r'\*\*')
-        return None
+    extended_mention_match = extended_mention_regex.match(content)
-    return message['content'][len(mention):].lstrip()
+
+    if extended_mention_match:
+        return content[extended_mention_match.end():].lstrip()
+
+    if content.startswith(mention):
+        return content[len(mention):].lstrip()
+
+    return None
 
 
 def is_private_message_from_another_user(message_dict: Dict[str, Any], current_user_id: int) -> bool:

zulip_bots/zulip_bots/tests/test_lib.py

@@ -4,6 +4,7 @@ from zulip_bots.lib import (
     ExternalBotHandler,
     StateHandler,
     run_message_handler_for_bot,
+    extract_query_without_mention
 )
 
 import io
@@ -192,6 +193,23 @@ class LibTest(TestCase):
 
         client.upload_file.assert_called_once_with(file)
 
+    def test_extract_query_without_mention(self):
+        client = FakeClient()
+        handler = ExternalBotHandler(
+            client=client,
+            root_dir=None,
+            bot_details=None,
+            bot_config_file=None
+        )
+        message = {'content': "@**Alice** Hello World"}
+        self.assertEqual(extract_query_without_mention(message, handler), "Hello World")
+        message = {'content': "@**Alice|alice** Hello World"}
+        self.assertEqual(extract_query_without_mention(message, handler), "Hello World")
+        message = {'content': "@**Alice Renamed|alice** Hello World"}
+        self.assertEqual(extract_query_without_mention(message, handler), "Hello World")
+        message = {'content': "Not at start @**Alice|alice** Hello World"}
+        self.assertEqual(extract_query_without_mention(message, handler), None)
+
     def _create_client_and_handler_for_file_upload(self):
         client = FakeClient()
         client.upload_file = MagicMock()