Don't create reply notifications for "fake" users

Now that there are topics being posted automatically by the "fake" user,
we don't want to be generating reply notifications for that user
whenever someone posts a comment in them. These serve no purpose and
would just pile up forever without being read. The same problem could
have already been happening if people replied back to a comment with the
"unknown user" author.

tildes/tests/test_comment_user_mentions.py

@@ -36,15 +36,10 @@ def test_get_mentions_for_comment(db, user_list, comment):
         assert mentions[index].user == user
 
 
-def test_mention_filtering_parent_comment(mocker, db, topic, user_list):
+def test_mention_filtering_parent_comment(db, topic, user_list):
     """Test notification filtering for parent comments."""
     parent_comment = Comment(topic, user_list[0], "Comment content.")
-    parent_comment.user_id = user_list[0].user_id
-    comment = mocker.Mock(
-        user_id=user_list[1].user_id,
-        markdown=f"@{user_list[0].username}",
-        parent_comment=parent_comment,
-    )
+    comment = Comment(topic, user_list[1], f"@{user_list[0].username}", parent_comment)
     mentions = CommentNotification.get_mentions_for_comment(db, comment)
     assert not mentions
 

tildes/tildes/models/comment/comment.py

@@ -5,7 +5,7 @@
 
 from collections import Counter
 from datetime import datetime, timedelta
-from typing import Any, Optional, Sequence, Tuple, TYPE_CHECKING
+from typing import Any, Optional, Sequence, Tuple, TYPE_CHECKING, Union
 
 from pyramid.security import Allow, Authenticated, Deny, DENY_ALL, Everyone
 from sqlalchemy import Boolean, Column, ForeignKey, Integer, Text, TIMESTAMP
@@ -228,6 +228,14 @@ class Comment(DatabaseModel):
         """Return the comment's ID in ID36 format."""
         return id_to_id36(self.comment_id)
 
+    @property
+    def parent(self) -> Union["Comment", Topic]:
+        """Return what the comment is replying to (a topic or another comment)."""
+        if self.parent_comment:
+            return self.parent_comment
+
+        return self.topic
+
     @property
     def parent_comment_id36(self) -> str:
         """Return the parent comment's ID in ID36 format."""

tildes/tildes/models/comment/comment_notification.py

@@ -55,6 +55,12 @@ class CommentNotification(DatabaseModel):
         self, user: User, comment: Comment, notification_type: CommentNotificationType
     ):
         """Create a new notification for a user from a comment."""
+        if notification_type in (
+            CommentNotificationType.COMMENT_REPLY,
+            CommentNotificationType.TOPIC_REPLY,
+        ) and not self.should_create_reply_notification(comment):
+            raise ValueError("That comment shouldn't create a reply notification")
+
         self.user = user
         self.comment = comment
         self.notification_type = notification_type
@@ -66,6 +72,18 @@ class CommentNotification(DatabaseModel):
         acl.append(DENY_ALL)
         return acl
 
+    @classmethod
+    def should_create_reply_notification(cls, comment: Comment) -> bool:
+        """Return whether a comment should generate a reply notification."""
+        # User is replying to their own post
+        if comment.parent.user == comment.user:
+            return False
+
+        if not comment.parent.user.is_real_user:
+            return False
+
+        return True
+
     @property
     def is_comment_reply(self) -> bool:
         """Return whether this is a comment reply notification."""
@@ -95,19 +113,14 @@ class CommentNotification(DatabaseModel):
             .all()
         )
 
-        parent_comment = comment.parent_comment
-
         for user in users_to_mention:
             # prevent the user from mentioning themselves
             if comment.user == user:
                 continue
 
-            if parent_comment:
-                # prevent comment replies from mentioning that comment's poster
-                if parent_comment.user == user:
-                    continue
-            # prevent top-level comments from mentioning the thread creator
-            elif comment.topic.user == user:
+            # prevent mentioning the user they're replying to
+            # (they'll already get a reply notification)
+            if comment.parent.user == user:
                 continue
 
             mention_notification = cls(

tildes/tildes/views/api/web/comment.py

@@ -95,7 +95,7 @@ def post_toplevel_comment(request: Request, markdown: str) -> dict:
 
     request.db_session.add(LogComment(LogEventType.COMMENT_POST, request, new_comment))
 
-    if topic.user != request.user and not topic.is_deleted:
+    if CommentNotification.should_create_reply_notification(new_comment):
         notification = CommentNotification(
             topic.user, new_comment, CommentNotificationType.TOPIC_REPLY
         )
@@ -135,7 +135,7 @@ def post_comment_reply(request: Request, markdown: str) -> dict:
 
     request.db_session.add(LogComment(LogEventType.COMMENT_POST, request, new_comment))
 
-    if parent_comment.user != request.user:
+    if CommentNotification.should_create_reply_notification(new_comment):
         notification = CommentNotification(
             parent_comment.user, new_comment, CommentNotificationType.COMMENT_REPLY
         )

tildes/tildes/views/topic.py

@@ -415,7 +415,7 @@ def post_comment_on_topic(request: Request, markdown: str) -> HTTPFound:
 
     request.db_session.add(LogComment(LogEventType.COMMENT_POST, request, new_comment))
 
-    if topic.user != request.user and not topic.is_deleted:
+    if CommentNotification.should_create_reply_notification(new_comment):
         notification = CommentNotification(
             topic.user, new_comment, CommentNotificationType.TOPIC_REPLY
         )