Guard against ParticipantUpdate sent before JoinResponse (#1271)

* Guard against ParticipantUpdate sent before JoinResponse

pkg/rtc/participant.go

@@ -909,13 +909,17 @@ func (p *ParticipantImpl) UpdateSubscribedTrackSettings(trackID livekit.TrackID,
 }
 
 func (p *ParticipantImpl) VerifySubscribeParticipantInfo(pID livekit.ParticipantID, version uint32) {
+	if !p.IsReady() {
+		// we have not sent a JoinResponse yet. metadata would be covered in JoinResponse
+		return
+	}
 	if v, ok := p.updateCache.Get(pID); ok && v >= version {
 		return
 	}
 
 	if f := p.params.GetParticipantInfo; f != nil {
 		if info := f(pID); info != nil {
-			p.SendParticipantUpdate([]*livekit.ParticipantInfo{info})
+			_ = p.SendParticipantUpdate([]*livekit.ParticipantInfo{info})
 		}
 	}
 }
@@ -1187,11 +1191,6 @@ func (p *ParticipantImpl) updateState(state livekit.ParticipantInfo_State) {
 
 // when the server has an offer for participant
 func (p *ParticipantImpl) onSubscriberOffer(offer webrtc.SessionDescription) error {
-	if p.State() == livekit.ParticipantInfo_DISCONNECTED {
-		// skip when disconnected
-		return nil
-	}
-
 	p.params.Logger.Infow("sending offer", "transport", livekit.SignalTarget_SUBSCRIBER)
 	return p.writeMessage(&livekit.SignalResponse{
 		Message: &livekit.SignalResponse_Offer{

pkg/rtc/participant_internal_test.go

@@ -58,7 +58,6 @@ func TestIsReady(t *testing.T) {
 func TestTrackPublishing(t *testing.T) {
 	t.Run("should send the correct events", func(t *testing.T) {
 		p := newParticipantForTest("test")
-		p.state.Store(livekit.ParticipantInfo_ACTIVE)
 		track := &typesfakes.FakeMediaTrack{}
 		track.IDReturns("id")
 		published := false
@@ -184,6 +183,7 @@ func TestTrackPublishing(t *testing.T) {
 
 func TestOutOfOrderUpdates(t *testing.T) {
 	p := newParticipantForTest("test")
+	p.updateState(livekit.ParticipantInfo_JOINED)
 	p.SetMetadata("initial metadata")
 	sink := p.getResponseSink().(*routingfakes.FakeMessageSink)
 	pi1 := p.ToProto()
@@ -483,6 +483,7 @@ func newParticipantForTestWithOpts(identity livekit.ParticipantIdentity, opts *p
 		Logger:            LoggerWithParticipant(logger.GetLogger(), identity, sid, false),
 	})
 	p.isPublisher.Store(opts.publisher)
+	p.updateState(livekit.ParticipantInfo_ACTIVE)
 
 	return p
 }

pkg/rtc/participant_signal.go

@@ -30,6 +30,7 @@ func (p *ParticipantImpl) SetResponseSink(sink routing.MessageSink) {
 }
 
 func (p *ParticipantImpl) SendJoinResponse(joinResponse *livekit.JoinResponse) error {
+	// update state prior to sending message, or the message would not be sent
 	if p.State() == livekit.ParticipantInfo_JOINING {
 		p.updateState(livekit.ParticipantInfo_JOINED)
 	}
@@ -43,6 +44,10 @@ func (p *ParticipantImpl) SendJoinResponse(joinResponse *livekit.JoinResponse) e
 }
 
 func (p *ParticipantImpl) SendParticipantUpdate(participantsToUpdate []*livekit.ParticipantInfo) error {
+	if !p.IsReady() {
+		// avoid manipulating cache before it's ready
+		return nil
+	}
 	p.updateLock.Lock()
 	validUpdates := make([]*livekit.ParticipantInfo, 0, len(participantsToUpdate))
 	for _, pi := range participantsToUpdate {
@@ -173,7 +178,7 @@ func (p *ParticipantImpl) sendTrackUnpublished(trackID livekit.TrackID) {
 }
 
 func (p *ParticipantImpl) writeMessage(msg *livekit.SignalResponse) error {
-	if p.State() == livekit.ParticipantInfo_DISCONNECTED {
+	if !p.IsReady() {
 		return nil
 	}