bugdown: Fully remove mentions matching @name.

Given typeahed and the fact that this only worked if the person had a
full name that didn't contain whitespace, this side effect of the
original @shortname mentionfeature that we removed was experienced by
users as a bug.

Fixes #6142.

zerver/lib/bugdown/__init__.py

@@ -1104,24 +1104,20 @@ class RealmFilterPattern(markdown.inlinepatterns.Pattern):
                         m.group("name"))
 
 class UserMentionPattern(markdown.inlinepatterns.Pattern):
-    def find_user_for_mention(self, name):
-        # type: (Text) -> Tuple[bool, Optional[Dict[str, Any]]]
-        if db_data is None:
-            return (False, None)
-
-        if mention.user_mention_matches_wildcard(name):
-            return (True, None)
-
-        user = db_data['full_names'].get(name.lower(), None)
-
-        return (False, user)
-
     def handleMatch(self, m):
         # type: (Match[Text]) -> Optional[Element]
-        name = m.group(2) or m.group(3)
+        match = m.group(2)
 
-        if current_message:
-            wildcard, user = self.find_user_for_mention(name)
+        if current_message and db_data is not None:
+            if match.startswith("**") and match.endswith("**"):
+                name = match[2:-2]
+            else:
+                if not mention.user_mention_matches_wildcard(match):
+                    return
+                name = match
+
+            wildcard = mention.user_mention_matches_wildcard(name)
+            user = db_data['full_names'].get(name.lower(), None)
 
             if wildcard:
                 current_message.mentions_wildcard = True

zerver/lib/mention.py

@@ -3,7 +3,7 @@ from __future__ import absolute_import
 from typing import Text
 # Match multi-word string between @** ** or match any one-word
 # sequences after @
-find_mentions = r'(?<![^\s\'\"\(,:<])@(?:\*\*([^\*]+)\*\*|(\w+))'
+find_mentions = r'(?<![^\s\'\"\(,:<])@(\*\*[^\*]+\*\*|\w+)'
 
 wildcards = ['all', 'everyone']
 

zerver/tests/test_bugdown.py

@@ -714,6 +714,17 @@ class BugdownTest(ZulipTestCase):
                          '<p><span class="user-mention" data-user-email="*" data-user-id="*">@everyone</span> test</p>')
         self.assertTrue(msg.mentions_wildcard)
 
+    def test_mention_everyone(self):
+        # type: () -> None
+        user_profile = self.example_user('othello')
+        msg = Message(sender=user_profile, sending_client=get_client("test"))
+
+        content = "@aaron test"
+        self.assertEqual(render_markdown(msg, content),
+                         '<p>@aaron test</p>')
+        self.assertFalse(msg.mentions_wildcard)
+        self.assertEqual(msg.mentions_user_ids, set([]))
+
     def test_mention_single(self):
         # type: () -> None
         sender_user_profile = self.example_user('othello')