Fix panic in redaction handling

matrix/history.go

@@ -123,7 +123,7 @@ func (hm *HistoryManager) Update(room *rooms.Room, eventID string, update func(e
 		}
 		stream := tx.Bucket(bucketRoomStreams).Bucket(rid)
 		eventData := stream.Get(streamIndex)
-		if eventData == nil {
+		if eventData == nil || len(eventData) == 0 {
 			return EventNotFoundError
 		}
 

matrix/matrix.go

@@ -321,7 +321,7 @@ func (c *Container) HandleRedaction(source EventSource, evt *mautrix.Event) {
 		debug.Print("Failed to mark", evt.Redacts, "as redacted:", err)
 	}
 
-	if !room.Loaded() {
+	if !room.Loaded() || redactedEvt == nil {
 		return
 	}