diff --git a/synapse/storage/databases/main/roommember.py b/synapse/storage/databases/main/roommember.py
index 5d2fd08495..f62d9f705d 100644
--- a/synapse/storage/databases/main/roommember.py
+++ b/synapse/storage/databases/main/roommember.py
@@ -279,8 +279,19 @@ class RoomMemberWorkerStore(EventsWorkerStore, CacheInvalidationWorkerStore):
@cached(max_entries=100000) # type: ignore[synapse-@cached-mutable]
async def get_room_summary(self, room_id: str) -> Mapping[str, MemberSummary]:
- """Get the details of a room roughly suitable for use by the room
+ """
+ Get the details of a room roughly suitable for use by the room
summary extension to /sync. Useful when lazy loading room members.
+
+ Returns the total count of members in the room by membership type, and a
+ truncated list of members (the heroes). This will be the first 6 members of the
+ room:
+ - We want 5 heroes plus 1, in case one of them is the
+ calling user.
+ - They are ordered by `stream_ordering`, which are joined or
+ invited. When no joined or invited members are available, this also includes
+ banned and left users.
+
Args:
room_id: The room ID to query
Returns:
@@ -308,23 +319,36 @@ class RoomMemberWorkerStore(EventsWorkerStore, CacheInvalidationWorkerStore):
for count, membership in txn:
res.setdefault(membership, MemberSummary([], count))
- # we order by membership and then fairly arbitrarily by event_id so
- # heroes are consistent
- # Note, rejected events will have a null membership field, so
- # we we manually filter them out.
+ # Order by membership (joins -> invites -> leave (former insiders) ->
+ # everything else (outsiders like bans/knocks), then by `stream_ordering` so
+ # the first members in the room show up first and to make the sort stable
+ # (consistent heroes).
+ #
+ # Note: rejected events will have a null membership field, so we we manually
+ # filter them out.
sql = """
SELECT state_key, membership, event_id
FROM current_state_events
WHERE type = 'm.room.member' AND room_id = ?
AND membership IS NOT NULL
ORDER BY
- CASE membership WHEN ? THEN 1 WHEN ? THEN 2 ELSE 3 END ASC,
- event_id ASC
+ CASE membership WHEN ? THEN 1 WHEN ? THEN 2 WHEN ? THEN 3 ELSE 4 END ASC,
+ event_stream_ordering ASC
LIMIT ?
"""
- # 6 is 5 (number of heroes) plus 1, in case one of them is the calling user.
- txn.execute(sql, (room_id, Membership.JOIN, Membership.INVITE, 6))
+ txn.execute(
+ sql,
+ (
+ room_id,
+ # Sort order
+ Membership.JOIN,
+ Membership.INVITE,
+ Membership.LEAVE,
+ # 6 is 5 (number of heroes) plus 1, in case one of them is the calling user.
+ 6,
+ ),
+ )
for user_id, membership, event_id in txn:
summary = res[membership]
# we will always have a summary for this membership type at this
@@ -1509,10 +1533,19 @@ def extract_heroes_from_room_summary(
) -> List[str]:
"""Determine the users that represent a room, from the perspective of the `me` user.
+ This function expects `MemberSummary.members` to already be sorted by
+ `stream_ordering` like the results from `get_room_summary(...)`.
+
The rules which say which users we select are specified in the "Room Summary"
section of
https://spec.matrix.org/v1.4/client-server-api/#get_matrixclientv3sync
+
+ Args:
+ details: Mapping from membership type to member summary. We expect
+ `MemberSummary.members` to already be sorted by `stream_ordering`.
+ me: The user for whom we are determining the heroes for.
+
Returns a list (possibly empty) of heroes' mxids.
"""
empty_ms = MemberSummary([], 0)
@@ -1527,11 +1560,11 @@ def extract_heroes_from_room_summary(
r[0] for r in details.get(Membership.LEAVE, empty_ms).members if r[0] != me
] + [r[0] for r in details.get(Membership.BAN, empty_ms).members if r[0] != me]
- # FIXME: order by stream ordering rather than as returned by SQL
+ # We expect `MemberSummary.members` to already be sorted by `stream_ordering`
if joined_user_ids or invited_user_ids:
- return sorted(joined_user_ids + invited_user_ids)[0:5]
+ return (joined_user_ids + invited_user_ids)[0:5]
else:
- return sorted(gone_user_ids)[0:5]
+ return gone_user_ids[0:5]
@attr.s(slots=True, auto_attribs=True)
|
