Update upstream source from tag 'upstream/1.51.0'

Update to upstream version '1.51.0'
with Debian dir 20ec082880941c65b5b91d008de1a402fcdf2fe1

17 files changed, 161 insertions, 129 deletions

diff --git a/synapse/handlers/account_data.py b/synapse/handlers/account_data.py
index 96273e2f..bad48713 100644
--- a/synapse/handlers/account_data.py
+++ b/synapse/handlers/account_data.py
@@ -77,7 +77,7 @@ class AccountDataHandler:
     async def add_account_data_for_user(
         self, user_id: str, account_data_type: str, content: JsonDict
     ) -> int:
-        """Add some account_data to a room for a user.
+        """Add some global account_data for a user.
 
         Args:
             user_id: The user to add a tag for.
diff --git a/synapse/handlers/admin.py b/synapse/handlers/admin.py
index 85157a13..00ab5e79 100644
--- a/synapse/handlers/admin.py
+++ b/synapse/handlers/admin.py
@@ -55,21 +55,47 @@ class AdminHandler:
 
     async def get_user(self, user: UserID) -> Optional[JsonDict]:
         """Function to get user details"""
-        ret = await self.store.get_user_by_id(user.to_string())
-        if ret:
-            profile = await self.store.get_profileinfo(user.localpart)
-            threepids = await self.store.user_get_threepids(user.to_string())
-            external_ids = [
-                ({"auth_provider": auth_provider, "external_id": external_id})
-                for auth_provider, external_id in await self.store.get_external_ids_by_user(
-                    user.to_string()
-                )
-            ]
-            ret["displayname"] = profile.display_name
-            ret["avatar_url"] = profile.avatar_url
-            ret["threepids"] = threepids
-            ret["external_ids"] = external_ids
-        return ret
+        user_info_dict = await self.store.get_user_by_id(user.to_string())
+        if user_info_dict is None:
+            return None
+
+        # Restrict returned information to a known set of fields. This prevents additional
+        # fields added to get_user_by_id from modifying Synapse's external API surface.
+        user_info_to_return = {
+            "name",
+            "admin",
+            "deactivated",
+            "shadow_banned",
+            "creation_ts",
+            "appservice_id",
+            "consent_server_notice_sent",
+            "consent_version",
+            "user_type",
+            "is_guest",
+        }
+
+        # Restrict returned keys to a known set.
+        user_info_dict = {
+            key: value
+            for key, value in user_info_dict.items()
+            if key in user_info_to_return
+        }
+
+        # Add additional user metadata
+        profile = await self.store.get_profileinfo(user.localpart)
+        threepids = await self.store.user_get_threepids(user.to_string())
+        external_ids = [
+            ({"auth_provider": auth_provider, "external_id": external_id})
+            for auth_provider, external_id in await self.store.get_external_ids_by_user(
+                user.to_string()
+            )
+        ]
+        user_info_dict["displayname"] = profile.display_name
+        user_info_dict["avatar_url"] = profile.avatar_url
+        user_info_dict["threepids"] = threepids
+        user_info_dict["external_ids"] = external_ids
+
+        return user_info_dict
 
     async def export_user_data(self, user_id: str, writer: "ExfiltrationWriter") -> Any:
         """Write all data we have on the user to the given writer.
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 84724b20..bd1a3225 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -168,25 +168,25 @@ def login_id_phone_to_thirdparty(identifier: JsonDict) -> Dict[str, str]:
     }
 
 
-@attr.s(slots=True)
+@attr.s(slots=True, auto_attribs=True)
 class SsoLoginExtraAttributes:
     """Data we track about SAML2 sessions"""
 
     # time the session was created, in milliseconds
-    creation_time = attr.ib(type=int)
-    extra_attributes = attr.ib(type=JsonDict)
+    creation_time: int
+    extra_attributes: JsonDict
 
 
-@attr.s(slots=True, frozen=True)
+@attr.s(slots=True, frozen=True, auto_attribs=True)
 class LoginTokenAttributes:
     """Data we store in a short-term login token"""
 
-    user_id = attr.ib(type=str)
+    user_id: str
 
-    auth_provider_id = attr.ib(type=str)
+    auth_provider_id: str
     """The SSO Identity Provider that the user authenticated with, to get this token."""
 
-    auth_provider_session_id = attr.ib(type=Optional[str])
+    auth_provider_session_id: Optional[str]
     """The session ID advertised by the SSO Identity Provider."""
 
 
@@ -2281,7 +2281,7 @@ class PasswordAuthProvider:
         # call all of the on_logged_out callbacks
         for callback in self.on_logged_out_callbacks:
             try:
-                callback(user_id, device_id, access_token)
+                await callback(user_id, device_id, access_token)
             except Exception as e:
                 logger.warning("Failed to run module API callback %s: %s", callback, e)
                 continue
diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index 76654252..b184a48c 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -948,8 +948,16 @@ class DeviceListUpdater:
             devices = []
             ignore_devices = True
         else:
+            prev_stream_id = await self.store.get_device_list_last_stream_id_for_remote(
+                user_id
+            )
             cached_devices = await self.store.get_cached_devices_for_user(user_id)
-            if cached_devices == {d["device_id"]: d for d in devices}:
+
+            # To ensure that a user with no devices is cached, we skip the resync only
+            # if we have a stream_id from previously writing a cache entry.
+            if prev_stream_id is not None and cached_devices == {
+                d["device_id"]: d for d in devices
+            }:
                 logging.info(
                     "Skipping device list resync for %s, as our cache matches already",
                     user_id,
diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py
index 14360b4e..d4dfddf6 100644
--- a/synapse/handlers/e2e_keys.py
+++ b/synapse/handlers/e2e_keys.py
@@ -1321,14 +1321,14 @@ def _one_time_keys_match(old_key_json: str, new_key: JsonDict) -> bool:
     return old_key == new_key_copy
 
 
-@attr.s(slots=True)
+@attr.s(slots=True, auto_attribs=True)
 class SignatureListItem:
     """An item in the signature list as used by upload_signatures_for_device_keys."""
 
-    signing_key_id = attr.ib(type=str)
-    target_user_id = attr.ib(type=str)
-    target_device_id = attr.ib(type=str)
-    signature = attr.ib(type=JsonDict)
+    signing_key_id: str
+    target_user_id: str
+    target_device_id: str
+    signature: JsonDict
 
 
 class SigningKeyEduUpdater:
diff --git a/synapse/handlers/events.py b/synapse/handlers/events.py
index 1b996c42..bac5de05 100644
--- a/synapse/handlers/events.py
+++ b/synapse/handlers/events.py
@@ -20,7 +20,6 @@ from synapse.api.constants import EduTypes, EventTypes, Membership
 from synapse.api.errors import AuthError, SynapseError
 from synapse.events import EventBase
 from synapse.handlers.presence import format_user_presence_state
-from synapse.logging.utils import log_function
 from synapse.streams.config import PaginationConfig
 from synapse.types import JsonDict, UserID
 from synapse.visibility import filter_events_for_client
@@ -43,7 +42,6 @@ class EventStreamHandler:
         self._server_notices_sender = hs.get_server_notices_sender()
         self._event_serializer = hs.get_event_client_serializer()
 
-    @log_function
     async def get_stream(
         self,
         auth_user_id: str,
@@ -119,7 +117,7 @@ class EventStreamHandler:
 
             events.extend(to_add)
 
-            chunks = await self._event_serializer.serialize_events(
+            chunks = self._event_serializer.serialize_events(
                 events,
                 time_now,
                 as_client_event=as_client_event,
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 26b8e3f4..a37ae0ca 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -51,7 +51,6 @@ from synapse.logging.context import (
     preserve_fn,
     run_in_background,
 )
-from synapse.logging.utils import log_function
 from synapse.replication.http.federation import (
     ReplicationCleanRoomRestServlet,
     ReplicationStoreRoomOnOutlierMembershipRestServlet,
@@ -556,7 +555,6 @@ class FederationHandler:
 
             run_in_background(self._handle_queued_pdus, room_queue)
 
-    @log_function
     async def do_knock(
         self,
         target_hosts: List[str],
@@ -928,7 +926,6 @@ class FederationHandler:
 
         return event
 
-    @log_function
     async def on_make_knock_request(
         self, origin: str, room_id: str, user_id: str
     ) -> EventBase:
@@ -1039,7 +1036,6 @@ class FederationHandler:
         else:
             return []
 
-    @log_function
     async def on_backfill_request(
         self, origin: str, room_id: str, pdu_list: List[str], limit: int
     ) -> List[EventBase]:
@@ -1056,7 +1052,6 @@ class FederationHandler:
 
         return events
 
-    @log_function
     async def get_persisted_pdu(
         self, origin: str, event_id: str
     ) -> Optional[EventBase]:
@@ -1118,7 +1113,6 @@ class FederationHandler:
 
         return missing_events
 
-    @log_function
     async def exchange_third_party_invite(
         self, sender_user_id: str, target_user_id: str, room_id: str, signed: JsonDict
     ) -> None:
diff --git a/synapse/handlers/federation_event.py b/synapse/handlers/federation_event.py
index 11771f3c..3905f60b 100644
--- a/synapse/handlers/federation_event.py
+++ b/synapse/handlers/federation_event.py
@@ -56,7 +56,6 @@ from synapse.events import EventBase
 from synapse.events.snapshot import EventContext
 from synapse.federation.federation_client import InvalidResponseError
 from synapse.logging.context import nested_logging_context, run_in_background
-from synapse.logging.utils import log_function
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.replication.http.devices import ReplicationUserDevicesResyncRestServlet
 from synapse.replication.http.federation import (
@@ -275,7 +274,6 @@ class FederationEventHandler:
 
         await self._process_received_pdu(origin, pdu, state=None)
 
-    @log_function
     async def on_send_membership_event(
         self, origin: str, event: EventBase
     ) -> Tuple[EventBase, EventContext]:
@@ -472,7 +470,6 @@ class FederationEventHandler:
 
             return await self.persist_events_and_notify(room_id, [(event, context)])
 
-    @log_function
     async def backfill(
         self, dest: str, room_id: str, limit: int, extremities: Collection[str]
     ) -> None:
diff --git a/synapse/handlers/initial_sync.py b/synapse/handlers/initial_sync.py
index 601bab67..346a06ff 100644
--- a/synapse/handlers/initial_sync.py
+++ b/synapse/handlers/initial_sync.py
@@ -170,7 +170,7 @@ class InitialSyncHandler:
                 d["inviter"] = event.sender
 
                 invite_event = await self.store.get_event(event.event_id)
-                d["invite"] = await self._event_serializer.serialize_event(
+                d["invite"] = self._event_serializer.serialize_event(
                     invite_event,
                     time_now,
                     as_client_event=as_client_event,
@@ -222,7 +222,7 @@ class InitialSyncHandler:
 
                 d["messages"] = {
                     "chunk": (
-                        await self._event_serializer.serialize_events(
+                        self._event_serializer.serialize_events(
                             messages,
                             time_now=time_now,
                             as_client_event=as_client_event,
@@ -232,7 +232,7 @@ class InitialSyncHandler:
                     "end": await end_token.to_string(self.store),
                 }
 
-                d["state"] = await self._event_serializer.serialize_events(
+                d["state"] = self._event_serializer.serialize_events(
                     current_state.values(),
                     time_now=time_now,
                     as_client_event=as_client_event,
@@ -376,16 +376,14 @@ class InitialSyncHandler:
             "messages": {
                 "chunk": (
                     # Don't bundle aggregations as this is a deprecated API.
-                    await self._event_serializer.serialize_events(messages, time_now)
+                    self._event_serializer.serialize_events(messages, time_now)
                 ),
                 "start": await start_token.to_string(self.store),
                 "end": await end_token.to_string(self.store),
             },
             "state": (
                 # Don't bundle aggregations as this is a deprecated API.
-                await self._event_serializer.serialize_events(
-                    room_state.values(), time_now
-                )
+                self._event_serializer.serialize_events(room_state.values(), time_now)
             ),
             "presence": [],
             "receipts": [],
@@ -404,7 +402,7 @@ class InitialSyncHandler:
         # TODO: These concurrently
         time_now = self.clock.time_msec()
         # Don't bundle aggregations as this is a deprecated API.
-        state = await self._event_serializer.serialize_events(
+        state = self._event_serializer.serialize_events(
             current_state.values(), time_now
         )
 
@@ -480,7 +478,7 @@ class InitialSyncHandler:
             "messages": {
                 "chunk": (
                     # Don't bundle aggregations as this is a deprecated API.
-                    await self._event_serializer.serialize_events(messages, time_now)
+                    self._event_serializer.serialize_events(messages, time_now)
                 ),
                 "start": await start_token.to_string(self.store),
                 "end": await end_token.to_string(self.store),
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 5e3d3886..b37250aa 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -246,7 +246,7 @@ class MessageHandler:
                 room_state = room_state_events[membership_event_id]
 
         now = self.clock.time_msec()
-        events = await self._event_serializer.serialize_events(room_state.values(), now)
+        events = self._event_serializer.serialize_events(room_state.values(), now)
         return events
 
     async def get_joined_members(self, requester: Requester, room_id: str) -> dict:
diff --git a/synapse/handlers/pagination.py b/synapse/handlers/pagination.py
index 7469cc55..973f2629 100644
--- a/synapse/handlers/pagination.py
+++ b/synapse/handlers/pagination.py
@@ -537,14 +537,16 @@ class PaginationHandler:
                 state_dict = await self.store.get_events(list(state_ids.values()))
                 state = state_dict.values()
 
+        aggregations = await self.store.get_bundled_aggregations(events, user_id)
+
         time_now = self.clock.time_msec()
 
         chunk = {
             "chunk": (
-                await self._event_serializer.serialize_events(
+                self._event_serializer.serialize_events(
                     events,
                     time_now,
-                    bundle_aggregations=True,
+                    bundle_aggregations=aggregations,
                     as_client_event=as_client_event,
                 )
             ),
@@ -553,7 +555,7 @@ class PaginationHandler:
         }
 
         if state:
-            chunk["state"] = await self._event_serializer.serialize_events(
+            chunk["state"] = self._event_serializer.serialize_events(
                 state, time_now, as_client_event=as_client_event
             )
 
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index c781fefb..067c43ae 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -55,7 +55,6 @@ from synapse.api.presence import UserPresenceState
 from synapse.appservice import ApplicationService
 from synapse.events.presence_router import PresenceRouter
 from synapse.logging.context import run_in_background
-from synapse.logging.utils import log_function
 from synapse.metrics import LaterGauge
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.replication.http.presence import (
@@ -1542,7 +1541,6 @@ class PresenceEventSource(EventSource[int, UserPresenceState]):
         self.clock = hs.get_clock()
         self.store = hs.get_datastore()
 
-    @log_function
     async def get_new_events(
         self,
         user: UserID,
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index b9c1cbff..f963078e 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -393,7 +393,9 @@ class RoomCreationHandler:
         user_id = requester.user.to_string()
 
         if not await self.spam_checker.user_may_create_room(user_id):
-            raise SynapseError(403, "You are not permitted to create rooms")
+            raise SynapseError(
+                403, "You are not permitted to create rooms", Codes.FORBIDDEN
+            )
 
         creation_content: JsonDict = {
             "room_version": new_room_version.identifier,
@@ -685,7 +687,9 @@ class RoomCreationHandler:
                 invite_3pid_list,
             )
         ):
-            raise SynapseError(403, "You are not permitted to create rooms")
+            raise SynapseError(
+                403, "You are not permitted to create rooms", Codes.FORBIDDEN
+            )
 
         if ratelimit:
             await self.request_ratelimiter.ratelimit(requester)
@@ -1177,6 +1181,22 @@ class RoomContextHandler:
         # `filtered` rather than the event we retrieved from the datastore.
         results["event"] = filtered[0]
 
+        # Fetch the aggregations.
+        aggregations = await self.store.get_bundled_aggregations(
+            [results["event"]], user.to_string()
+        )
+        aggregations.update(
+            await self.store.get_bundled_aggregations(
+                results["events_before"], user.to_string()
+            )
+        )
+        aggregations.update(
+            await self.store.get_bundled_aggregations(
+                results["events_after"], user.to_string()
+            )
+        )
+        results["aggregations"] = aggregations
+
         if results["events_after"]:
             last_event_id = results["events_after"][-1].event_id
         else:
diff --git a/synapse/handlers/room_summary.py b/synapse/handlers/room_summary.py
index b2cfe537..4844b69a 100644
--- a/synapse/handlers/room_summary.py
+++ b/synapse/handlers/room_summary.py
@@ -153,6 +153,9 @@ class RoomSummaryHandler:
         rooms_result: List[JsonDict] = []
         events_result: List[JsonDict] = []
 
+        if max_rooms_per_space is None or max_rooms_per_space > MAX_ROOMS_PER_SPACE:
+            max_rooms_per_space = MAX_ROOMS_PER_SPACE
+
         while room_queue and len(rooms_result) < MAX_ROOMS:
             queue_entry = room_queue.popleft()
             room_id = queue_entry.room_id
@@ -167,7 +170,7 @@ class RoomSummaryHandler:
             # The client-specified max_rooms_per_space limit doesn't apply to the
             # room_id specified in the request, so we ignore it if this is the
             # first room we are processing.
-            max_children = max_rooms_per_space if processed_rooms else None
+            max_children = max_rooms_per_space if processed_rooms else MAX_ROOMS
 
             if is_in_room:
                 room_entry = await self._summarize_local_room(
@@ -209,7 +212,7 @@ class RoomSummaryHandler:
                         # Before returning to the client, remove the allowed_room_ids
                         # and allowed_spaces keys.
                         room.pop("allowed_room_ids", None)
-                        room.pop("allowed_spaces", None)
+                        room.pop("allowed_spaces", None)  # historical
 
                         rooms_result.append(room)
                         events.extend(room_entry.children_state_events)
@@ -395,7 +398,7 @@ class RoomSummaryHandler:
                     None,
                     room_id,
                     suggested_only,
-                    # TODO Handle max children.
+                    # Do not limit the maximum children.
                     max_children=None,
                 )
 
@@ -525,6 +528,10 @@ class RoomSummaryHandler:
         rooms_result: List[JsonDict] = []
         events_result: List[JsonDict] = []
 
+        # Set a limit on the number of rooms to return.
+        if max_rooms_per_space is None or max_rooms_per_space > MAX_ROOMS_PER_SPACE:
+            max_rooms_per_space = MAX_ROOMS_PER_SPACE
+
         while room_queue and len(rooms_result) < MAX_ROOMS:
             room_id = room_queue.popleft()
             if room_id in processed_rooms:
@@ -583,7 +590,9 @@ class RoomSummaryHandler:
 
         # Iterate through each child and potentially add it, but not its children,
         # to the response.
-        for child_room in root_room_entry.children_state_events:
+        for child_room in itertools.islice(
+            root_room_entry.children_state_events, MAX_ROOMS_PER_SPACE
+        ):
             room_id = child_room.get("state_key")
             assert isinstance(room_id, str)
             # If the room is unknown, skip it.
@@ -633,8 +642,8 @@ class RoomSummaryHandler:
             suggested_only: True if only suggested children should be returned.
                 Otherwise, all children are returned.
             max_children:
-                The maximum number of children rooms to include. This is capped
-                to a server-set limit.
+                The maximum number of children rooms to include. A value of None
+                means no limit.
 
         Returns:
             A room entry if the room should be returned. None, otherwise.
@@ -656,8 +665,13 @@ class RoomSummaryHandler:
             # we only care about suggested children
             child_events = filter(_is_suggested_child_event, child_events)
 
-        if max_children is None or max_children > MAX_ROOMS_PER_SPACE:
-            max_children = MAX_ROOMS_PER_SPACE
+        # TODO max_children is legacy code for the /spaces endpoint.
+        if max_children is not None:
+            child_iter: Iterable[EventBase] = itertools.islice(
+                child_events, max_children
+            )
+        else:
+            child_iter = child_events
 
         stripped_events: List[JsonDict] = [
             {
@@ -668,7 +682,7 @@ class RoomSummaryHandler:
                 "sender": e.sender,
                 "origin_server_ts": e.origin_server_ts,
             }
-            for e in itertools.islice(child_events, max_children)
+            for e in child_iter
         ]
         return _RoomEntry(room_id, room_entry, stripped_events)
 
@@ -766,6 +780,7 @@ class RoomSummaryHandler:
         try:
             (
                 room_response,
+                children_state_events,
                 children,
                 inaccessible_children,
             ) = await self._federation_client.get_room_hierarchy(
@@ -790,7 +805,7 @@ class RoomSummaryHandler:
         }
 
         return (
-            _RoomEntry(room_id, room_response, room_response.pop("children_state", ())),
+            _RoomEntry(room_id, room_response, children_state_events),
             children_by_room_id,
             set(inaccessible_children),
         )
@@ -988,12 +1003,14 @@ class RoomSummaryHandler:
             "canonical_alias": stats["canonical_alias"],
             "num_joined_members": stats["joined_members"],
             "avatar_url": stats["avatar"],
+            # plural join_rules is a documentation error but kept for historical
+            # purposes. Should match /publicRooms.
             "join_rules": stats["join_rules"],
+            "join_rule": stats["join_rules"],
             "world_readable": (
                 stats["history_visibility"] == HistoryVisibility.WORLD_READABLE
             ),
             "guest_can_join": stats["guest_access"] == "can_join",
-            "creation_ts": create_event.origin_server_ts,
             "room_type": create_event.content.get(EventContentFields.ROOM_TYPE),
         }
 
diff --git a/synapse/handlers/search.py b/synapse/handlers/search.py
index ab7eaab2..0b153a68 100644
--- a/synapse/handlers/search.py
+++ b/synapse/handlers/search.py
@@ -420,10 +420,10 @@ class SearchHandler:
         time_now = self.clock.time_msec()
 
         for context in contexts.values():
-            context["events_before"] = await self._event_serializer.serialize_events(
+            context["events_before"] = self._event_serializer.serialize_events(
                 context["events_before"], time_now
             )
-            context["events_after"] = await self._event_serializer.serialize_events(
+            context["events_after"] = self._event_serializer.serialize_events(
                 context["events_after"], time_now
             )
 
@@ -441,9 +441,7 @@ class SearchHandler:
             results.append(
                 {
                     "rank": rank_map[e.event_id],
-                    "result": (
-                        await self._event_serializer.serialize_event(e, time_now)
-                    ),
+                    "result": self._event_serializer.serialize_event(e, time_now),
                     "context": contexts.get(e.event_id, {}),
                 }
             )
@@ -457,7 +455,7 @@ class SearchHandler:
         if state_results:
             s = {}
             for room_id, state_events in state_results.items():
-                s[room_id] = await self._event_serializer.serialize_events(
+                s[room_id] = self._event_serializer.serialize_events(
                     state_events, time_now
                 )
 
diff --git a/synapse/handlers/sso.py b/synapse/handlers/sso.py
index 65c27bc6..0bb8b092 100644
--- a/synapse/handlers/sso.py
+++ b/synapse/handlers/sso.py
@@ -126,45 +126,45 @@ class SsoIdentityProvider(Protocol):
         raise NotImplementedError()
 
 
-@attr.s
+@attr.s(auto_attribs=True)
 class UserAttributes:
     # the localpart of the mxid that the mapper has assigned to the user.
     # if `None`, the mapper has not picked a userid, and the user should be prompted to
     # enter one.
-    localpart = attr.ib(type=Optional[str])
-    display_name = attr.ib(type=Optional[str], default=None)
-    emails = attr.ib(type=Collection[str], default=attr.Factory(list))
+    localpart: Optional[str]
+    display_name: Optional[str] = None
+    emails: Collection[str] = attr.Factory(list)
 
 
-@attr.s(slots=True)
+@attr.s(slots=True, auto_attribs=True)
 class UsernameMappingSession:
     """Data we track about SSO sessions"""
 
     # A unique identifier for this SSO provider, e.g.  "oidc" or "saml".
-    auth_provider_id = attr.ib(type=str)
+    auth_provider_id: str
 
     # user ID on the IdP server
-    remote_user_id = attr.ib(type=str)
+    remote_user_id: str
 
     # attributes returned by the ID mapper
-    display_name = attr.ib(type=Optional[str])
-    emails = attr.ib(type=Collection[str])
+    display_name: Optional[str]
+    emails: Collection[str]
 
     # An optional dictionary of extra attributes to be provided to the client in the
     # login response.
-    extra_login_attributes = attr.ib(type=Optional[JsonDict])
+    extra_login_attributes: Optional[JsonDict]
 
     # where to redirect the client back to
-    client_redirect_url = attr.ib(type=str)
+    client_redirect_url: str
 
     # expiry time for the session, in milliseconds
-    expiry_time_ms = attr.ib(type=int)
+    expiry_time_ms: int
 
     # choices made by the user
-    chosen_localpart = attr.ib(type=Optional[str], default=None)
-    use_display_name = attr.ib(type=bool, default=True)
-    emails_to_use = attr.ib(type=Collection[str], default=())
-    terms_accepted_version = attr.ib(type=Optional[str], default=None)
+    chosen_localpart: Optional[str] = None
+    use_display_name: bool = True
+    emails_to_use: Collection[str] = ()
+    terms_accepted_version: Optional[str] = None
 
 
 # the HTTP cookie used to track the mapping session id
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 7baf3f19..ffc6b748 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -60,10 +60,6 @@ if TYPE_CHECKING:
 
 logger = logging.getLogger(__name__)
 
-# Debug logger for https://github.com/matrix-org/synapse/issues/4422
-issue4422_logger = logging.getLogger("synapse.handler.sync.4422_debug")
-
-
 # Counts the number of times we returned a non-empty sync. `type` is one of
 # "initial_sync", "full_state_sync" or "incremental_sync", `lazy_loaded` is
 # "true" or "false" depending on if the request asked for lazy loaded members or
@@ -102,6 +98,9 @@ class TimelineBatch:
     prev_batch: StreamToken
     events: List[EventBase]
     limited: bool
+    # A mapping of event ID to the bundled aggregations for the above events.
+    # This is only calculated if limited is true.
+    bundled_aggregations: Optional[Dict[str, Dict[str, Any]]] = None
 
     def __bool__(self) -> bool:
         """Make the result appear empty if there are no updates. This is used
@@ -634,10 +633,19 @@ class SyncHandler:
 
             prev_batch_token = now_token.copy_and_replace("room_key", room_key)
 
+        # Don't bother to bundle aggregations if the timeline is unlimited,
+        # as clients will have all the necessary information.
+        bundled_aggregations = None
+        if limited or newly_joined_room:
+            bundled_aggregations = await self.store.get_bundled_aggregations(
+                recents, sync_config.user.to_string()
+            )
+
         return TimelineBatch(
             events=recents,
             prev_batch=prev_batch_token,
             limited=limited or newly_joined_room,
+            bundled_aggregations=bundled_aggregations,
         )
 
     async def get_state_after_event(
@@ -1161,13 +1169,8 @@ class SyncHandler:
 
         num_events = 0
 
-        # debug for https://github.com/matrix-org/synapse/issues/4422
+        # debug for https://github.com/matrix-org/synapse/issues/9424
         for joined_room in sync_result_builder.joined:
-            room_id = joined_room.room_id
-            if room_id in newly_joined_rooms:
-                issue4422_logger.debug(
-                    "Sync result for newly joined room %s: %r", room_id, joined_room
-                )
             num_events += len(joined_room.timeline.events)
 
         log_kv(
@@ -1740,18 +1743,6 @@ class SyncHandler:
                         old_mem_ev_id, allow_none=True
                     )
 
-                # debug for #4422
-                if has_join:
-                    prev_membership = None
-                    if old_mem_ev:
-                        prev_membership = old_mem_ev.membership
-                    issue4422_logger.debug(
-                        "Previous membership for room %s with join: %s (event %s)",
-                        room_id,
-                        prev_membership,
-                        old_mem_ev_id,
-                    )
-
                 if not old_mem_ev or old_mem_ev.membership != Membership.JOIN:
                     newly_joined_rooms.append(room_id)
 
@@ -1893,13 +1884,6 @@ class SyncHandler:
                     upto_token=since_token,
                 )
 
-            if newly_joined:
-                # debugging for https://github.com/matrix-org/synapse/issues/4422
-                issue4422_logger.debug(
-                    "RoomSyncResultBuilder events for newly joined room %s: %r",
-                    room_id,
-                    entry.events,
-                )
             room_entries.append(entry)
 
         return _RoomChanges(
@@ -2077,14 +2061,6 @@ class SyncHandler:
             # `_load_filtered_recents` can't find any events the user should see
             # (e.g. due to having ignored the sender of the last 50 events).
 
-            if newly_joined:
-                # debug for https://github.com/matrix-org/synapse/issues/4422
-                issue4422_logger.debug(
-                    "Timeline events after filtering in newly-joined room %s: %r",
-                    room_id,
-                    batch,
-                )
-
             # When we join the room (or the client requests full_state), we should
             # send down any existing tags. Usually the user won't have tags in a
             # newly joined room, unless either a) they've joined before or b) the