Update `Events` call-sites which now don't return an error, update `parsedRespState` to sort (#2227)

* Topologically sort with `SendEventWithState`, so that earlier events should satisfy auth for later ones

* Revert "Topologically sort with `SendEventWithState`, so that earlier events should satisfy auth for later ones"

This reverts commit b0cd706012b4c9b6724b11e16f19c4cb732ab286.

* Update to matrix-org/gomatrixserverlib#293

* `Events` no longer returns an error, other tweaks

* Make sure `Events` is sorted for `parsedRespState` too

2 files changed, 19 insertions, 11 deletions

diff --git a/roomserver/api/wrapper.go b/roomserver/api/wrapper.go
index 012094c6..5491d36b 100644
--- a/roomserver/api/wrapper.go
+++ b/roomserver/api/wrapper.go
@@ -51,12 +51,8 @@ func SendEventWithState(
 	state *gomatrixserverlib.RespState, event *gomatrixserverlib.HeaderedEvent,
 	origin gomatrixserverlib.ServerName, haveEventIDs map[string]bool, async bool,
 ) error {
-	outliers, err := state.Events(event.RoomVersion)
-	if err != nil {
-		return err
-	}
-
-	var ires []InputRoomEvent
+	outliers := state.Events(event.RoomVersion)
+	ires := make([]InputRoomEvent, 0, len(outliers))
 	for _, outlier := range outliers {
 		if haveEventIDs[outlier.EventID()] {
 			continue
diff --git a/roomserver/internal/input/input_missing.go b/roomserver/internal/input/input_missing.go
index 4655e92a..a7da9b06 100644
--- a/roomserver/internal/input/input_missing.go
+++ b/roomserver/internal/input/input_missing.go
@@ -23,6 +23,21 @@ type parsedRespState struct {
 	StateEvents []*gomatrixserverlib.Event
 }
 
+func (p *parsedRespState) Events() []*gomatrixserverlib.Event {
+	eventsByID := make(map[string]*gomatrixserverlib.Event, len(p.AuthEvents)+len(p.StateEvents))
+	for i, event := range p.AuthEvents {
+		eventsByID[event.EventID()] = p.AuthEvents[i]
+	}
+	for i, event := range p.StateEvents {
+		eventsByID[event.EventID()] = p.StateEvents[i]
+	}
+	allEvents := make([]*gomatrixserverlib.Event, 0, len(eventsByID))
+	for _, event := range eventsByID {
+		allEvents = append(allEvents, event)
+	}
+	return gomatrixserverlib.ReverseTopologicalOrdering(allEvents, gomatrixserverlib.TopologicalOrderByAuthEvents)
+}
+
 type missingStateReq struct {
 	origin          gomatrixserverlib.ServerName
 	db              storage.Database
@@ -124,11 +139,8 @@ func (t *missingStateReq) processEventWithMissingState(
 	t.hadEventsMutex.Unlock()
 
 	sendOutliers := func(resolvedState *parsedRespState) error {
-		outliers, oerr := gomatrixserverlib.OrderAuthAndStateEvents(resolvedState.AuthEvents, resolvedState.StateEvents, roomVersion)
-		if oerr != nil {
-			return fmt.Errorf("gomatrixserverlib.OrderAuthAndStateEvents: %w", oerr)
-		}
-		var outlierRoomEvents []api.InputRoomEvent
+		outliers := resolvedState.Events()
+		outlierRoomEvents := make([]api.InputRoomEvent, 0, len(outliers))
 		for _, outlier := range outliers {
 			if hadEvents[outlier.EventID()] {
 				continue