Collect lazy loaded members for profile updates in sync response from events

synapse/handlers/sync.py

@@ -2139,9 +2139,11 @@ class SyncHandler:
 
     async def _generate_initial_sync_entry_for_profile_updates(
         self,
+        *,
         user_id: str,
         sync_result_builder: "SyncResultBuilder",
         profile_fields: list[str],
+        include_users: set[str] | None,
     ) -> None:
         """
         Build an initial sync entry for profile updates and attach it to the
@@ -2153,17 +2155,16 @@ class SyncHandler:
             user_id: The Matrix ID of the user to generate the sync entry for.
             sync_result_builder:
             profile_fields: The list of field IDs to filter for.
+            include_users: List of users profiles to include in the sync response,
+                for when we have calculated a list of users in our lazy loading
+                sync and want to only return those.
         """
         # Currently, limited to only local profiles, so filter remote servers out
         user_ids = await self.store.get_local_users_who_share_room_with_user(user_id)
 
-        sync_config = sync_result_builder.sync_config
-        lazy_load_members = sync_config.filter_collection.lazy_load_members()
-        if lazy_load_members:
-            # Only include members we've collected for lazy loading
-            cache_key = (sync_config.user.to_string(), sync_config.device_id)
-            cache = self.get_lazy_loaded_members_cache(cache_key)
-            user_ids = {user_id for user_id in user_ids if cache.get(user_id)}
+        if include_users:
+            # Filter down to selected included users
+            user_ids = {user_id for user_id in user_ids if user_id in include_users}
 
         if not user_ids:
             return
@@ -2213,9 +2214,33 @@ class SyncHandler:
         since_token = sync_result_builder.since_token
         now_token = sync_result_builder.now_token
 
+        sync_config = sync_result_builder.sync_config
+        lazy_load_members = sync_config.filter_collection.lazy_load_members()
+        include_users = None
+        if lazy_load_members:
+            # Collect members from the existing `sync_result_builder` data
+            include_users = set()
+            # invited
+            for invited in sync_result_builder.invited:
+                include_users.add(invited.invite.sender)
+            # joined
+            for joined in sync_result_builder.joined:
+                for timeline_event in joined.timeline.events:
+                    include_users.add(timeline_event.event.sender)
+            # knocked
+            for knocked in sync_result_builder.knocked:
+                include_users.add(knocked.knock.sender)
+            # archived
+            for archived in sync_result_builder.archived:
+                for timeline_event in archived.timeline.events:
+                    include_users.add(timeline_event.event.sender)
+
         if since_token is None:
             await self._generate_initial_sync_entry_for_profile_updates(
-                user_id, sync_result_builder, profile_fields
+                user_id=user_id,
+                sync_result_builder=sync_result_builder,
+                profile_fields=profile_fields,
+                include_users=include_users,
             )
             return
 
@@ -2227,6 +2252,10 @@ class SyncHandler:
             to_id=now_token.profile_updates_key,
             field_names=profile_fields,
         )
+        if include_users:
+            # Filter down to selected included users
+            updates = [update for update in updates if update.user_id in include_users]
+
         if not updates:
             return
 

tests/handlers/test_sync.py

@@ -1372,6 +1372,77 @@ class SyncProfileUpdatesTestCase(tests.unittest.HomeserverTestCase):
             '{"text": "On holiday", "emoji": "\\ud83c\\udfd6"}',
         )
 
+    @override_config({"experimental_features": {"msc4429_enabled": True}})
+    def test_incremental_sync_sends_down_only_interesting_profile_updates_when_lazy_loading(
+        self,
+    ) -> None:
+        third_user = self.register_user("third_user", "password")
+        third_tok = self.login("third_user", "password")
+        second_room = self.helper.create_room_as(self.user, tok=self.tok)
+        self.helper.join(
+            room=second_room,
+            user=third_user,
+            tok=third_tok,
+        )
+
+        requester = create_requester(self.user)
+        initial_result = self.get_success(
+            self.sync_handler.wait_for_sync_for_user(
+                requester,
+                sync_config=generate_sync_config(
+                    user_id=self.user,
+                    filter_collection=FilterCollection(
+                        hs=self.hs,
+                        filter_json={
+                            "org.matrix.msc4429.profile_fields": {
+                                "ids": ["m.status", "displayname", "avatar_url"]
+                            }
+                        },
+                    ),
+                ),
+                request_key=generate_request_key(),
+            )
+        )
+        self.get_success(
+            self.profile_handler.set_field(
+                target_user=UserID.from_string(self.other_user),
+                requester=create_requester(self.other_user),
+                field_name="m.status",
+                new_value=json.dumps({"text": "On holiday", "emoji": "🏖"}),
+            )
+        )
+        self.helper.send_messages(room_id=second_room, num_events=10, tok=third_tok)
+        incremental_result = self.get_success(
+            self.sync_handler.wait_for_sync_for_user(
+                requester,
+                since_token=initial_result.next_batch,
+                sync_config=generate_sync_config(
+                    user_id=self.user,
+                    filter_collection=FilterCollection(
+                        hs=self.hs,
+                        filter_json={
+                            "org.matrix.msc4429.profile_fields": {
+                                "ids": ["m.status", "displayname", "avatar_url"]
+                            },
+                            "room": {
+                                "state": {
+                                    "lazy_load_members": True,
+                                },
+                            },
+                        },
+                    ),
+                ),
+                request_key=generate_request_key(),
+            )
+        )
+        self.assertCountEqual(
+            incremental_result.profile_updates.keys(),
+            [
+                "@third_user:test",
+                "@user:test",
+            ],
+        )
+
     @override_config({"experimental_features": {"msc4429_enabled": True}})
     def test_incremental_sync_sends_down_null_profile_if_user_no_longer_sharing_rooms(
         self,