Bugfixes for 'If remote user leaves room we no longer receive device updates'

are-we-synapse-yet.list

@@ -831,6 +831,7 @@ psh Trying to get push rules with unknown scope fails with 400
 psh Trying to get push rules with unknown template fails with 400 
 psh Trying to get push rules with unknown attribute fails with 400 
 psh Trying to get push rules with unknown rule_id fails with 404
+psh Rooms with names are correctly named in pushes
 v1s GET /initialSync with non-numeric 'limit' 
 v1s GET /events with non-numeric 'limit' 
 v1s GET /events with negative 'limit' 
@@ -839,7 +840,7 @@ ath Event size limits
 syn Check creating invalid filters returns 4xx 
 f,pre New federated private chats get full presence information (SYN-115) 
 pre Left room members do not cause problems for presence 
-crm Rooms can be created with an initial invite list (SYN-205) 
+crm Rooms can be created with an initial invite list (SYN-205) (1 subtests)
 typ Typing notifications don't leak 
 ban Non-present room members cannot ban others 
 psh Getting push rules doesn't corrupt the cache SYN-390 

keyserver/internal/device_list_update.go

@@ -230,6 +230,7 @@ func (u *DeviceListUpdater) worker(ch chan gomatrixserverlib.ServerName) {
 	}
 
 	// on failure, spin up a short-lived goroutine to inject the server name again.
+	scheduledRetries := make(map[gomatrixserverlib.ServerName]time.Time)
 	inject := func(srv gomatrixserverlib.ServerName, duration time.Duration) {
 		time.Sleep(duration)
 		ch <- srv
@@ -237,13 +238,20 @@ func (u *DeviceListUpdater) worker(ch chan gomatrixserverlib.ServerName) {
 
 	for serverName := range ch {
 		if !shouldProcess(serverName) {
-			// do not inject into the channel as we know there will be a sleeping goroutine
+			if time.Now().Before(scheduledRetries[serverName]) {
-			// which will do it after the cooloff period expires
+				// do not inject into the channel as we know there will be a sleeping goroutine
-			continue
+				// which will do it after the cooloff period expires
+				continue
+			} else {
+				scheduledRetries[serverName] = time.Now().Add(cooloffPeriod)
+				go inject(serverName, cooloffPeriod) // TODO: Backoff?
+				continue
+			}
 		}
 		lastProcessed[serverName] = time.Now()
 		shouldRetry := u.processServer(serverName)
 		if shouldRetry {
+			scheduledRetries[serverName] = time.Now().Add(cooloffPeriod)
 			go inject(serverName, cooloffPeriod) // TODO: Backoff?
 		}
 	}

syncapi/internal/keychange.go

@@ -96,7 +96,8 @@ func DeviceListCatchup(
 		return hasNew, nil
 	}
 	// QueryKeyChanges gets ALL users who have changed keys, we want the ones who share rooms with the user.
-	queryRes.UserIDs = filterSharedUsers(ctx, stateAPI, userID, queryRes.UserIDs)
+	var sharedUsersMap map[string]int
+	sharedUsersMap, queryRes.UserIDs = filterSharedUsers(ctx, stateAPI, userID, queryRes.UserIDs)
 	util.GetLogger(ctx).Debugf(
 		"QueryKeyChanges request p=%d,off=%d,to=%d response p=%d off=%d uids=%v",
 		partition, offset, toOffset, queryRes.Partition, queryRes.Offset, queryRes.UserIDs,
@@ -114,13 +115,20 @@ func DeviceListCatchup(
 	}
 	// if the response has any join/leave events, add them now.
 	// TODO: This is sub-optimal because we will add users to `changed` even if we already shared a room with them.
-	for _, userID := range membershipEvents(res) {
+	joinUserIDs, leaveUserIDs := membershipEvents(res)
+	for _, userID := range joinUserIDs {
 		if !userSet[userID] {
 			res.DeviceLists.Changed = append(res.DeviceLists.Changed, userID)
 			hasNew = true
 			userSet[userID] = true
 		}
 	}
+	for _, userID := range leaveUserIDs {
+		if sharedUsersMap[userID] == 0 {
+			// we no longer share a room with this user when they left, so add to left list.
+			res.DeviceLists.Left = append(res.DeviceLists.Left, userID)
+		}
+	}
 	// set the new token
 	to.SetLog(DeviceListLogName, &types.LogPosition{
 		Partition: queryRes.Partition,
@@ -221,7 +229,7 @@ func TrackChangedUsers(
 
 func filterSharedUsers(
 	ctx context.Context, stateAPI currentstateAPI.CurrentStateInternalAPI, userID string, usersWithChangedKeys []string,
-) []string {
+) (map[string]int, []string) {
 	var result []string
 	var sharedUsersRes currentstateAPI.QuerySharedUsersResponse
 	err := stateAPI.QuerySharedUsers(ctx, &currentstateAPI.QuerySharedUsersRequest{
@@ -229,7 +237,7 @@ func filterSharedUsers(
 	}, &sharedUsersRes)
 	if err != nil {
 		// default to all users so we do needless queries rather than miss some important device update
-		return usersWithChangedKeys
+		return nil, usersWithChangedKeys
 	}
 	// We forcibly put ourselves in this list because we should be notified about our own device updates
 	// and if we are in 0 rooms then we don't technically share any room with ourselves so we wouldn't
@@ -241,7 +249,7 @@ func filterSharedUsers(
 			result = append(result, uid)
 		}
 	}
-	return result
+	return sharedUsersRes.UserIDsToCount, result
 }
 
 func joinedRooms(res *types.Response, userID string) []string {
@@ -288,16 +296,16 @@ func membershipEventPresent(events []gomatrixserverlib.ClientEvent, userID strin
 // "For optimal performance, Alice should be added to changed in Bob's sync only when she adds a new device,
 // or when Alice and Bob now share a room but didn't share any room previously. However, for the sake of simpler
 // logic, a server may add Alice to changed when Alice and Bob share a new room, even if they previously already shared a room."
-func membershipEvents(res *types.Response) (userIDs []string) {
+func membershipEvents(res *types.Response) (joinUserIDs, leaveUserIDs []string) {
 	for _, room := range res.Rooms.Join {
 		for _, ev := range room.Timeline.Events {
 			if ev.Type == gomatrixserverlib.MRoomMember && ev.StateKey != nil {
 				if strings.Contains(string(ev.Content), `"join"`) {
-					userIDs = append(userIDs, *ev.StateKey)
+					joinUserIDs = append(joinUserIDs, *ev.StateKey)
 				} else if strings.Contains(string(ev.Content), `"leave"`) {
-					userIDs = append(userIDs, *ev.StateKey)
+					leaveUserIDs = append(leaveUserIDs, *ev.StateKey)
 				} else if strings.Contains(string(ev.Content), `"ban"`) {
-					userIDs = append(userIDs, *ev.StateKey)
+					leaveUserIDs = append(leaveUserIDs, *ev.StateKey)
 				}
 			}
 		}

sytest-whitelist

@@ -142,6 +142,7 @@ Server correctly handles incoming m.device_list_update
 Device deletion propagates over federation
 If remote user leaves room, changes device and rejoins we see update in sync
 If remote user leaves room, changes device and rejoins we see update in /keys/changes
+If remote user leaves room we no longer receive device updates
 Can query remote device keys using POST after notification
 Can add account data
 Can add account data to room