Include bundled aggregations in /sync and related fixes (#11478)

Due to updates to MSC2675 this includes a few fixes:

* Include bundled aggregations for /sync.
* Do not include bundled aggregations for /initialSync and /events.
* Do not bundle aggregations for state events.
* Clarifies comments and variable names.

4 files changed, 10 insertions, 23 deletions

diff --git a/synapse/rest/admin/rooms.py b/synapse/rest/admin/rooms.py
index 6bbc5510f0..669ab44a45 100644
--- a/synapse/rest/admin/rooms.py
+++ b/synapse/rest/admin/rooms.py
@@ -449,13 +449,7 @@ class RoomStateRestServlet(RestServlet):
         event_ids = await self.store.get_current_state_ids(room_id)
         events = await self.store.get_events(event_ids.values())
         now = self.clock.time_msec()
-        room_state = await self._event_serializer.serialize_events(
-            events.values(),
-            now,
-            # We don't bother bundling aggregations in when asked for state
-            # events, as clients won't use them.
-            bundle_relations=False,
-        )
+        room_state = await self._event_serializer.serialize_events(events.values(), now)
         ret = {"state": room_state}
 
         return HTTPStatus.OK, ret
@@ -789,10 +783,7 @@ class RoomEventContextServlet(RestServlet):
             results["events_after"], time_now
         )
         results["state"] = await self._event_serializer.serialize_events(
-            results["state"],
-            time_now,
-            # No need to bundle aggregations for state events
-            bundle_relations=False,
+            results["state"], time_now
         )
 
         return HTTPStatus.OK, results
diff --git a/synapse/rest/client/relations.py b/synapse/rest/client/relations.py
index b1a3304849..fc4e6921c5 100644
--- a/synapse/rest/client/relations.py
+++ b/synapse/rest/client/relations.py
@@ -224,14 +224,13 @@ class RelationPaginationServlet(RestServlet):
         )
 
         now = self.clock.time_msec()
-        # We set bundle_relations to False when retrieving the original
-        # event because we want the content before relations were applied to
-        # it.
+        # Do not bundle aggregations when retrieving the original event because
+        # we want the content before relations are applied to it.
         original_event = await self._event_serializer.serialize_event(
-            event, now, bundle_relations=False
+            event, now, bundle_aggregations=False
         )
         # The relations returned for the requested event do include their
-        # bundled relations.
+        # bundled aggregations.
         serialized_events = await self._event_serializer.serialize_events(events, now)
 
         return_value = pagination_chunk.to_dict()
diff --git a/synapse/rest/client/room.py b/synapse/rest/client/room.py
index 3598967be0..f48e2e6ca2 100644
--- a/synapse/rest/client/room.py
+++ b/synapse/rest/client/room.py
@@ -716,10 +716,7 @@ class RoomEventContextServlet(RestServlet):
             results["events_after"], time_now
         )
         results["state"] = await self._event_serializer.serialize_events(
-            results["state"],
-            time_now,
-            # No need to bundle aggregations for state events
-            bundle_relations=False,
+            results["state"], time_now
         )
 
         return 200, results
diff --git a/synapse/rest/client/sync.py b/synapse/rest/client/sync.py
index b6a2485732..88e4f5e063 100644
--- a/synapse/rest/client/sync.py
+++ b/synapse/rest/client/sync.py
@@ -520,9 +520,9 @@ class SyncRestServlet(RestServlet):
             return self._event_serializer.serialize_events(
                 events,
                 time_now=time_now,
-                # We don't bundle "live" events, as otherwise clients
-                # will end up double counting annotations.
-                bundle_relations=False,
+                # Don't bother to bundle aggregations if the timeline is unlimited,
+                # as clients will have all the necessary information.
+                bundle_aggregations=room.timeline.limited,
                 token_id=token_id,
                 event_format=event_formatter,
                 only_event_fields=only_fields,