typing: Add support for empty topic name.

zerver/tornado/event_queue.py

@@ -1618,6 +1618,18 @@ def process_user_topic_event(event: Mapping[str, Any], users: Iterable[int]) ->
             client.add_event(event)
 
 
+def process_stream_typing_notification_event(event: Mapping[str, Any], users: Iterable[int]) -> None:
+    for user_profile_id in users:
+        for client in get_client_descriptors_for_user(user_profile_id):
+            if not client.accepts_event(event):
+                continue
+
+            if event.get("topic") == "" and not client.empty_topic_name:
+                event["topic"] = "general chat"
+
+            client.add_event(event)
+
+
 def process_notification(notice: Mapping[str, Any]) -> None:
     event: Mapping[str, Any] = notice["event"]
     users: list[int] | list[Mapping[str, Any]] = notice["users"]
@@ -1648,6 +1660,8 @@ def process_notification(notice: Mapping[str, Any]) -> None:
         process_user_group_name_update_event(event, cast(list[int], users))
     elif event["type"] == "user_topic":
         process_user_topic_event(event, cast(list[int], users))
+    elif event["type"] == "typing" and event["message_type"] == "stream":
+        process_stream_typing_notification_event(event, cast(list[int], users))
     elif event["type"] == "cleanup_queue":
         # cleanup_event_queue may generate this event to forward cleanup
         # requests to the right shard.

zerver/views/typing.py

@@ -8,6 +8,7 @@ from zerver.actions.typing import check_send_typing_notification, do_send_stream
 from zerver.lib.exceptions import JsonableError
 from zerver.lib.response import json_success
 from zerver.lib.streams import access_stream_by_id, access_stream_for_send_message
+from zerver.lib.topic import maybe_rename_general_chat_to_empty_topic
 from zerver.lib.typed_endpoint import ApiParamConfig, OptionalTopic, typed_endpoint
 from zerver.models import UserProfile
 
@@ -44,6 +45,7 @@ def send_notification_backend(
         # permission to send messages to it.
         stream = access_stream_by_id(user_profile, stream_id)[0]
         access_stream_for_send_message(user_profile, stream, forwarder_user_profile=None)
+        topic = maybe_rename_general_chat_to_empty_topic(topic)
         do_send_stream_typing_notification(user_profile, operator, stream, topic)
     else:
         if notification_to is None: