Merge pull request #3955 from OffchainLabs/port-3963

Port - Fix PopulateFeedBacklog implementation (#3953)

Author: joshuacolvin0

arbnode/inbox_tracker.go

@@ -318,8 +318,7 @@ func (t *InboxTracker) PopulateFeedBacklog(broadcastServer *broadcaster.Broadcas
 		}
 		feedMessages = append(feedMessages, feedMessage)
 	}
-	broadcastServer.BroadcastFeedMessages(feedMessages)
-	return nil
+	return broadcastServer.PopulateFeedBacklog(feedMessages)
 }
 
 func (t *InboxTracker) legacyGetDelayedMessageAndAccumulator(ctx context.Context, seqNum uint64) (*arbostypes.L1IncomingMessage, common.Hash, error) {

broadcaster/broadcaster.go

@@ -128,6 +128,14 @@ func (b *Broadcaster) BroadcastFeedMessages(messages []*m.BroadcastFeedMessage)
 	b.server.Broadcast(bm)
 }
 
+func (s *Broadcaster) PopulateFeedBacklog(messages []*m.BroadcastFeedMessage) error {
+	bm := &m.BroadcastMessage{
+		Version:  1,
+		Messages: messages,
+	}
+	return s.server.PopulateFeedBacklog(bm)
+}
+
 func (b *Broadcaster) Confirm(msgIdx arbutil.MessageIndex) {
 	log.Debug("confirming msgIdx", "msgIdx", msgIdx)
 	b.server.Broadcast(&m.BroadcastMessage{

wsbroadcastserver/clientmanager.go

@@ -151,6 +151,31 @@ func (cm *ClientManager) Broadcast(bm *m.BroadcastMessage) {
 	cm.broadcastChan <- bm
 }
 
+// populateFeedBacklog adds the given BroadcastMessage to backlog, and also broadcasts it to feed if the ClientManager is started
+func (cm *ClientManager) populateFeedBacklog(bm *m.BroadcastMessage) error {
+	if cm.Started() {
+		cm.Broadcast(bm)
+		return nil
+	}
+	if len(bm.Messages) == 0 {
+		return cm.backlog.Append(bm)
+	}
+	for i, msg := range bm.Messages {
+		m := &m.BroadcastMessage{
+			Version:  bm.Version,
+			Messages: []*m.BroadcastFeedMessage{msg},
+		}
+		// This ensures that only one message is added to backlog with the confirmed sequence number
+		if i == 0 {
+			m.ConfirmedSequenceNumberMessage = bm.ConfirmedSequenceNumberMessage
+		}
+		if err := cm.backlog.Append(m); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (cm *ClientManager) doBroadcast(bm *m.BroadcastMessage) ([]*ClientConnection, error) {
 	if err := cm.backlog.Append(bm); err != nil {
 		return nil, err

wsbroadcastserver/wsbroadcastserver.go

@@ -536,6 +536,10 @@ func (s *WSBroadcastServer) Broadcast(bm *m.BroadcastMessage) {
 	s.clientManager.Broadcast(bm)
 }
 
+func (s *WSBroadcastServer) PopulateFeedBacklog(bm *m.BroadcastMessage) error {
+	return s.clientManager.populateFeedBacklog(bm)
+}
+
 func (s *WSBroadcastServer) ClientCount() int32 {
 	return s.clientManager.ClientCount()
 }