topic_mentions: Fetch users to be notified of @topic mentions.

This commit adds the 'topic_wildcard_mention_user_ids' and
'topic_wildcard_mention_in_followed_topic_user_ids'
attributes to the 'RecipientInfoResult' dataclass.

Only topic participants are notified of @topic mentions.

Topic participants are anyone who sent a message to a topic
or reacted to a message on the topic.

'topic_wildcard_mention_in_followed_topic_user_ids' stores the
ids of the topic participants who follow the topic and have
enabled the wildcard mention notifications for followed topics.

'topic_wildcard_mention_user_ids' stores the ids of the topic
participants for whom 'user_allows_notifications_in_StreamTopic'
with setting 'wildcard_mentions_notify' returns True.

zerver/actions/message_edit.py

@@ -466,6 +466,7 @@ def do_update_message(
             recipient=target_message.recipient,
             sender_id=target_message.sender_id,
             stream_topic=stream_topic,
+            possible_topic_wildcard_mention=mention_data.message_has_topic_wildcards(),
             possible_stream_wildcard_mention=mention_data.message_has_stream_wildcards(),
         )
 

zerver/actions/message_send.py

@@ -69,7 +69,10 @@ from zerver.lib.stream_topic import StreamTopicTarget
 from zerver.lib.streams import access_stream_for_send_message, ensure_stream
 from zerver.lib.string_validation import check_stream_name
 from zerver.lib.timestamp import timestamp_to_datetime
-from zerver.lib.topic import filter_by_exact_message_topic
+from zerver.lib.topic import (
+    filter_by_exact_message_topic,
+    participants_for_topic,
+)
 from zerver.lib.url_preview.types import UrlEmbedData
 from zerver.lib.user_message import UserMessageLite, bulk_insert_ums
 from zerver.lib.validator import check_widget_content
@@ -166,9 +169,11 @@ class RecipientInfoResult:
     pm_mention_push_disabled_user_ids: Set[int]
     stream_email_user_ids: Set[int]
     stream_push_user_ids: Set[int]
+    topic_wildcard_mention_user_ids: Set[int]
     stream_wildcard_mention_user_ids: Set[int]
     followed_topic_email_user_ids: Set[int]
     followed_topic_push_user_ids: Set[int]
+    topic_wildcard_mention_in_followed_topic_user_ids: Set[int]
     stream_wildcard_mention_in_followed_topic_user_ids: Set[int]
     muted_sender_user_ids: Set[int]
     um_eligible_user_ids: Set[int]
@@ -195,13 +200,16 @@ def get_recipient_info(
     sender_id: int,
     stream_topic: Optional[StreamTopicTarget],
     possibly_mentioned_user_ids: AbstractSet[int] = set(),
+    possible_topic_wildcard_mention: bool = True,
     possible_stream_wildcard_mention: bool = True,
 ) -> RecipientInfoResult:
     stream_push_user_ids: Set[int] = set()
     stream_email_user_ids: Set[int] = set()
+    topic_wildcard_mention_user_ids: Set[int] = set()
     stream_wildcard_mention_user_ids: Set[int] = set()
     followed_topic_push_user_ids: Set[int] = set()
     followed_topic_email_user_ids: Set[int] = set()
+    topic_wildcard_mention_in_followed_topic_user_ids: Set[int] = set()
     stream_wildcard_mention_in_followed_topic_user_ids: Set[int] = set()
     muted_sender_user_ids: Set[int] = get_muting_users(sender_id)
 
@@ -217,12 +225,23 @@ def get_recipient_info(
         # of this function for different message types.
         assert stream_topic is not None
 
+        topic_participant_user_ids: Set[int] = set()
+        if possible_topic_wildcard_mention:
+            # A topic participant is anyone who either sent or reacted to messages in the topic.
+            # It is expensive to call `participants_for_topic` if the topic has a large number
+            # of messages. But it is fine to call it here, as this gets called only if the message
+            # has syntax that might be a @topic mention without having confirmed the syntax isn't, say,
+            # in a code block.
+            topic_participant_user_ids = participants_for_topic(
+                recipient.id, stream_topic.topic_name
+            )
         subscription_rows = (
             get_subscriptions_for_send_message(
                 realm_id=realm_id,
                 stream_id=stream_topic.stream_id,
                 topic_name=stream_topic.topic_name,
                 possible_stream_wildcard_mention=possible_stream_wildcard_mention,
+                topic_participant_user_ids=topic_participant_user_ids,
                 possibly_mentioned_user_ids=possibly_mentioned_user_ids,
             )
             .annotate(
@@ -293,16 +312,33 @@ def get_recipient_info(
         )
         followed_topic_push_user_ids = followed_topic_notification_recipients("push_notifications")
 
-        if possible_stream_wildcard_mention:
-            # We calculate `stream_wildcard_mention_user_ids` and `followed_topic_wildcard_mention_user_ids`
-            # only if there's a possible stream wildcard mention in the message. This is important so as
-            # to avoid unnecessarily sending huge user ID lists with thousands of elements to the
-            # event queue (which can happen because these settings are `True` by default for new users.)
-            stream_wildcard_mention_user_ids = notification_recipients("wildcard_mentions_notify")
-            stream_wildcard_mention_in_followed_topic_user_ids = (
+        if possible_stream_wildcard_mention or possible_topic_wildcard_mention:
+            # We calculate `wildcard_mentions_notify_user_ids` and `followed_topic_wildcard_mentions_notify_user_ids`
+            # only if there's a possible stream or topic wildcard mention in the message.
+            # This is important so as to avoid unnecessarily sending huge user ID lists with
+            # thousands of elements to the event queue (which can happen because these settings
+            # are `True` by default for new users.)
+            wildcard_mentions_notify_user_ids = notification_recipients("wildcard_mentions_notify")
+            followed_topic_wildcard_mentions_notify_user_ids = (
                 followed_topic_notification_recipients("wildcard_mentions_notify")
             )
 
+        if possible_stream_wildcard_mention:
+            stream_wildcard_mention_user_ids = wildcard_mentions_notify_user_ids
+            stream_wildcard_mention_in_followed_topic_user_ids = (
+                followed_topic_wildcard_mentions_notify_user_ids
+            )
+
+        if possible_topic_wildcard_mention:
+            topic_wildcard_mention_user_ids = topic_participant_user_ids.intersection(
+                wildcard_mentions_notify_user_ids
+            )
+            topic_wildcard_mention_in_followed_topic_user_ids = (
+                topic_participant_user_ids.intersection(
+                    followed_topic_wildcard_mentions_notify_user_ids
+                )
+            )
+
     elif recipient.type == Recipient.HUDDLE:
         message_to_user_ids = get_huddle_user_ids(recipient)
 
@@ -418,9 +454,11 @@ def get_recipient_info(
         pm_mention_push_disabled_user_ids=pm_mention_push_disabled_user_ids,
         stream_push_user_ids=stream_push_user_ids,
         stream_email_user_ids=stream_email_user_ids,
+        topic_wildcard_mention_user_ids=topic_wildcard_mention_user_ids,
         stream_wildcard_mention_user_ids=stream_wildcard_mention_user_ids,
         followed_topic_push_user_ids=followed_topic_push_user_ids,
         followed_topic_email_user_ids=followed_topic_email_user_ids,
+        topic_wildcard_mention_in_followed_topic_user_ids=topic_wildcard_mention_in_followed_topic_user_ids,
         stream_wildcard_mention_in_followed_topic_user_ids=stream_wildcard_mention_in_followed_topic_user_ids,
         muted_sender_user_ids=muted_sender_user_ids,
         um_eligible_user_ids=um_eligible_user_ids,
@@ -541,6 +579,7 @@ def build_message_send_dict(
         sender_id=message.sender_id,
         stream_topic=stream_topic,
         possibly_mentioned_user_ids=mention_data.get_user_ids(),
+        possible_topic_wildcard_mention=mention_data.message_has_topic_wildcards(),
         possible_stream_wildcard_mention=mention_data.message_has_stream_wildcards(),
     )
 

zerver/lib/stream_subscription.py

@@ -307,6 +307,7 @@ def get_subscriptions_for_send_message(
     stream_id: int,
     topic_name: str,
     possible_stream_wildcard_mention: bool,
+    topic_participant_user_ids: AbstractSet[int],
     possibly_mentioned_user_ids: AbstractSet[int],
 ) -> QuerySet[Subscription]:
     """This function optimizes an important use case for large
@@ -352,6 +353,7 @@ def get_subscriptions_for_send_message(
         | Q(email_notifications=True)
         | (Q(email_notifications=None) & Q(user_profile__enable_stream_email_notifications=True))
         | Q(user_profile_id__in=possibly_mentioned_user_ids)
+        | Q(user_profile_id__in=topic_participant_user_ids)
         | Q(
             user_profile_id__in=AlertWord.objects.filter(realm_id=realm_id).values_list(
                 "user_profile_id"

zerver/lib/topic.py

@@ -1,15 +1,15 @@
 from datetime import datetime
-from typing import Any, Dict, List, Optional, Tuple
+from typing import Any, Dict, List, Optional, Set, Tuple
 
 import orjson
 from django.db import connection
-from django.db.models import Q, QuerySet
+from django.db.models import Q, QuerySet, Subquery
 from sqlalchemy.sql import ColumnElement, column, func, literal
 from sqlalchemy.types import Boolean, Text
 
 from zerver.lib.request import REQ
 from zerver.lib.types import EditHistoryEvent
-from zerver.models import Message, Stream, UserMessage, UserProfile
+from zerver.models import Message, Reaction, Stream, UserMessage, UserProfile
 
 # Only use these constants for events.
 ORIG_TOPIC = "orig_subject"
@@ -284,3 +284,22 @@ def get_topic_resolution_and_bare_name(stored_name: str) -> Tuple[bool, str]:
         return (True, stored_name[len(RESOLVED_TOPIC_PREFIX) :])
 
     return (False, stored_name)
+
+
+def participants_for_topic(recipient_id: int, topic_name: str) -> Set[int]:
+    """
+    Users who either sent or reacted to the messages in the topic.
+    The function is expensive for large numbers of messages in the topic.
+    """
+    messages = Message.objects.filter(recipient_id=recipient_id, subject__iexact=topic_name)
+    participants = set(
+        UserProfile.objects.filter(
+            Q(id__in=Subquery(messages.values("sender_id")))
+            | Q(
+                id__in=Subquery(
+                    Reaction.objects.filter(message__in=messages).values("user_profile_id")
+                )
+            )
+        ).values_list("id", flat=True)
+    )
+    return participants

zerver/tests/test_soft_deactivation.py

@@ -624,6 +624,7 @@ class SoftDeactivationMessageTest(ZulipTestCase):
             expected_count: int,
             *,
             possible_stream_wildcard_mention: bool = False,
+            topic_participant_user_ids: AbstractSet[int] = set(),
             possibly_mentioned_user_ids: AbstractSet[int] = set(),
         ) -> None:
             self.assertEqual(
@@ -633,6 +634,7 @@ class SoftDeactivationMessageTest(ZulipTestCase):
                         stream_id=stream_id,
                         topic_name=topic_name,
                         possible_stream_wildcard_mention=possible_stream_wildcard_mention,
+                        topic_participant_user_ids=topic_participant_user_ids,
                         possibly_mentioned_user_ids=possibly_mentioned_user_ids,
                     )
                 ),

zerver/tests/test_users.py

@@ -1755,6 +1755,7 @@ class RecipientInfoTest(ZulipTestCase):
             recipient=recipient,
             sender_id=hamlet.id,
             stream_topic=stream_topic,
+            possible_topic_wildcard_mention=False,
             possible_stream_wildcard_mention=False,
         )
 
@@ -1767,9 +1768,11 @@ class RecipientInfoTest(ZulipTestCase):
             pm_mention_push_disabled_user_ids=set(),
             stream_push_user_ids=set(),
             stream_email_user_ids=set(),
+            topic_wildcard_mention_user_ids=set(),
             stream_wildcard_mention_user_ids=set(),
             followed_topic_push_user_ids=set(),
             followed_topic_email_user_ids=set(),
+            topic_wildcard_mention_in_followed_topic_user_ids=set(),
             stream_wildcard_mention_in_followed_topic_user_ids=set(),
             muted_sender_user_ids=set(),
             um_eligible_user_ids=all_user_ids,
@@ -1820,6 +1823,59 @@ class RecipientInfoTest(ZulipTestCase):
         )
         self.assertEqual(info.stream_wildcard_mention_user_ids, {hamlet.id, othello.id})
 
+        do_change_user_setting(
+            hamlet,
+            "wildcard_mentions_notify",
+            True,
+            acting_user=None,
+        )
+        info = get_recipient_info(
+            realm_id=realm.id,
+            recipient=recipient,
+            sender_id=hamlet.id,
+            stream_topic=stream_topic,
+            possible_topic_wildcard_mention=True,
+            possible_stream_wildcard_mention=False,
+        )
+        self.assertEqual(info.stream_wildcard_mention_user_ids, set())
+        self.assertEqual(info.topic_wildcard_mention_user_ids, set())
+
+        # User who sent a message to the topic, or reacted to a message on the topic
+        # is only considered as a possible user to be notified for topic mention.
+        self.send_stream_message(hamlet, stream_name, content="test message", topic_name=topic_name)
+        info = get_recipient_info(
+            realm_id=realm.id,
+            recipient=recipient,
+            sender_id=hamlet.id,
+            stream_topic=stream_topic,
+            possible_topic_wildcard_mention=True,
+            possible_stream_wildcard_mention=False,
+        )
+        self.assertEqual(info.stream_wildcard_mention_user_ids, set())
+        self.assertEqual(info.topic_wildcard_mention_user_ids, {hamlet.id})
+
+        info = get_recipient_info(
+            realm_id=realm.id,
+            recipient=recipient,
+            sender_id=hamlet.id,
+            stream_topic=stream_topic,
+            possible_topic_wildcard_mention=False,
+            possible_stream_wildcard_mention=True,
+        )
+        self.assertEqual(info.stream_wildcard_mention_user_ids, {hamlet.id, othello.id})
+        self.assertEqual(info.topic_wildcard_mention_user_ids, set())
+
+        info = get_recipient_info(
+            realm_id=realm.id,
+            recipient=recipient,
+            sender_id=hamlet.id,
+            stream_topic=stream_topic,
+            possible_topic_wildcard_mention=True,
+            possible_stream_wildcard_mention=True,
+        )
+        self.assertEqual(info.stream_wildcard_mention_user_ids, {hamlet.id, othello.id})
+        self.assertEqual(info.topic_wildcard_mention_user_ids, {hamlet.id})
+
         sub = get_subscription(stream_name, hamlet)
         sub.push_notifications = False
         sub.save()