streams: Send event when guest loses access to a user.

This commit adds code to send "realm_user/remove" event
when a guest user loses access to a user due to the user
being unsubscribed from one or more streams.

api_docs/changelog.md

@@ -41,6 +41,9 @@ format used by the Zulip server that they are interacting with.
 * [`GET /events`](/api/get-events): `realm_user` events with `op: "add"`
   are now also sent when a guest user gains access to a user.
 
+* [`GET /events`](/api/get-events): `realm_user` events with `op: "remove"`
+  are now also sent when a guest user loses access to a user.
+
 **Feature level 227**
 
 * [`PATCH /realm/user_settings_defaults`](/api/update-realm-user-settings-defaults),

version.py

@@ -33,7 +33,7 @@ DESKTOP_WARNING_VERSION = "5.9.3"
 # Changes should be accompanied by documentation explaining what the
 # new level means in api_docs/changelog.md, as well as "**Changes**"
 # entries in the endpoint's documentation in `zulip.yaml`.
-API_FEATURE_LEVEL = 227
+API_FEATURE_LEVEL = 228
 
 # Bump the minor PROVISION_VERSION to indicate that folks should provision
 # only when going from an old version of the code to a newer version. Bump

zerver/actions/streams.py

@@ -34,6 +34,7 @@ from zerver.lib.stream_subscription import (
     get_active_subscriptions_for_stream_id,
     get_bulk_stream_subscriber_info,
     get_used_colors_for_user_ids,
+    get_user_ids_for_streams,
     get_users_for_streams,
 )
 from zerver.lib.stream_traffic import get_streams_traffic
@@ -896,6 +897,67 @@ def send_subscription_remove_events(
     )
 
 
+def send_user_remove_events_on_removing_subscriptions(
+    realm: Realm, altered_user_dict: Dict[UserProfile, Set[int]]
+) -> None:
+    altered_stream_ids: Set[int] = set()
+    altered_users = list(altered_user_dict.keys())
+    for stream_ids in altered_user_dict.values():
+        altered_stream_ids |= stream_ids
+
+    users_involved_in_dms = get_users_involved_in_dms_with_target_users(altered_users, realm)
+    subscribers_of_altered_user_subscriptions = get_subscribers_of_target_user_subscriptions(
+        altered_users
+    )
+
+    non_guest_user_ids = active_non_guest_user_ids(realm.id)
+
+    subscribers_dict = get_user_ids_for_streams(altered_stream_ids)
+
+    for user in altered_users:
+        users_in_unsubscribed_streams: Set[int] = set()
+        for stream_id in altered_user_dict[user]:
+            users_in_unsubscribed_streams = (
+                users_in_unsubscribed_streams | subscribers_dict[stream_id]
+            )
+
+        users_who_can_access_altered_user = (
+            set(non_guest_user_ids)
+            | subscribers_of_altered_user_subscriptions[user.id]
+            | users_involved_in_dms[user.id]
+            | {user.id}
+        )
+
+        subscribers_without_access_to_altered_user = (
+            users_in_unsubscribed_streams - users_who_can_access_altered_user
+        )
+
+        if subscribers_without_access_to_altered_user:
+            event_remove_user = dict(
+                type="realm_user",
+                op="remove",
+                person=dict(user_id=user.id, full_name=str(UserProfile.INACCESSIBLE_USER_NAME)),
+            )
+            send_event_on_commit(
+                realm, event_remove_user, list(subscribers_without_access_to_altered_user)
+            )
+
+        if user.is_guest:
+            users_inaccessible_to_altered_user = users_in_unsubscribed_streams - (
+                subscribers_of_altered_user_subscriptions[user.id]
+                | users_involved_in_dms[user.id]
+                | {user.id}
+            )
+
+            for user_id in users_inaccessible_to_altered_user:
+                event_remove_user = dict(
+                    type="realm_user",
+                    op="remove",
+                    person=dict(user_id=user_id, full_name=str(UserProfile.INACCESSIBLE_USER_NAME)),
+                )
+                send_event_on_commit(realm, event_remove_user, [user.id])
+
+
 def bulk_remove_subscriptions(
     realm: Realm,
     users: Iterable[UserProfile],
@@ -978,6 +1040,12 @@ def bulk_remove_subscriptions(
     removed_sub_tuples = [(sub_info.user, sub_info.stream) for sub_info in subs_to_deactivate]
     send_subscription_remove_events(realm, users, streams, removed_sub_tuples)
 
+    if realm.can_access_all_users_group.name != SystemGroups.EVERYONE:
+        altered_user_dict: Dict[UserProfile, Set[int]] = defaultdict(set)
+        for user, stream in removed_sub_tuples:
+            altered_user_dict[user].add(stream.id)
+        send_user_remove_events_on_removing_subscriptions(realm, altered_user_dict)
+
     new_vacant_streams = set(streams_to_unsubscribe) - set(occupied_streams_after)
     new_vacant_private_streams = [stream for stream in new_vacant_streams if stream.invite_only]
 

zerver/lib/event_schema.py

@@ -1206,6 +1206,16 @@ def check_realm_user_update(
     )
 
 
+realm_user_remove_event = event_dict_type(
+    required_keys=[
+        ("type", Equals("realm_user")),
+        ("op", Equals("remove")),
+        ("person", removed_user_type),
+    ],
+)
+check_realm_user_remove = make_checker(realm_user_remove_event)
+
+
 restart_event = event_dict_type(
     required_keys=[
         ("type", Equals("restart")),

zerver/lib/events.py

@@ -63,6 +63,7 @@ from zerver.lib.user_status import get_user_status_dict
 from zerver.lib.user_topics import get_topic_mutes, get_user_topics
 from zerver.lib.users import (
     get_cross_realm_dicts,
+    get_data_for_inaccessible_user,
     get_users_for_api,
     is_administrator_role,
     max_message_id_for_user,
@@ -989,6 +990,12 @@ def apply_event(
                         sub["subscribers"] = [
                             user_id for user_id in sub["subscribers"] if user_id != person_user_id
                         ]
+        elif event["op"] == "remove":
+            if person_user_id in state["raw_users"]:
+                inaccessible_user_dict = get_data_for_inaccessible_user(
+                    user_profile.realm, person_user_id
+                )
+                state["raw_users"][person_user_id] = inaccessible_user_dict
         else:
             raise AssertionError("Unexpected event type {type}/{op}".format(**event))
     elif event["type"] == "realm_bot":

zerver/openapi/zulip.yaml

@@ -1085,7 +1085,9 @@ paths:
                                 }
                             - type: object
                               description: |
-                                No longer sent by modern Zulip servers.
+                                Event sent to guest users when they lose access to a user.
+
+                                **Changes**: Prior to Zulip 8.0 (feature level 228), this event was deprecated.
 
                                 **Changes**: Deprecated and no longer sent since Zulip 8.0 (feature level 222).
 

zerver/tests/test_events.py

@@ -166,6 +166,7 @@ from zerver.lib.event_schema import (
     check_realm_update,
     check_realm_update_dict,
     check_realm_user_add,
+    check_realm_user_remove,
     check_realm_user_update,
     check_scheduled_message_add,
     check_scheduled_message_remove,
@@ -4078,6 +4079,15 @@ class SubscribeActionTest(BaseAction):
         check_subscription_peer_add("events[1]", events[1])
         self.assertEqual(set(events[1]["user_ids"]), {iago.id, othello.id})
 
+        unsubscribe_action = lambda: bulk_remove_subscriptions(
+            realm, [othello, iago], [stream], acting_user=None
+        )
+        events = self.verify_action(unsubscribe_action, num_events=2)
+        check_subscription_peer_remove("events[0]", events[0])
+        self.assertEqual(set(events[0]["user_ids"]), {iago.id, othello.id})
+        check_realm_user_remove("events[1]", events[1])
+        self.assertEqual(events[1]["person"]["user_id"], othello.id)
+
     def test_user_access_events_on_changing_subscriptions_for_guests(self) -> None:
         self.set_up_db_for_testing_user_access()
         polonius = self.example_user("polonius")
@@ -4094,6 +4104,15 @@ class SubscribeActionTest(BaseAction):
         check_realm_user_add("events[2]", events[2])
         self.assertEqual(events[2]["person"]["user_id"], othello.id)
 
+        unsubscribe_action = lambda: bulk_remove_subscriptions(
+            realm, [polonius, self.example_user("iago")], [stream], acting_user=None
+        )
+        events = self.verify_action(unsubscribe_action, num_events=3)
+        check_subscription_remove("events[0]", events[0])
+        check_stream_delete("events[1]", events[1])
+        check_realm_user_remove("events[2]", events[2])
+        self.assertEqual(events[2]["person"]["user_id"], othello.id)
+
 
 class DraftActionTest(BaseAction):
     def do_enable_drafts_synchronization(self, user_profile: UserProfile) -> None: