Fix events emit order (#902)

Fixes events emit order after async related fixes

Author: hiroshihorie

lib/livekit_client.dart

@@ -30,7 +30,7 @@ export 'src/managers/event.dart';
 export 'src/options.dart';
 export 'src/participant/local.dart';
 export 'src/participant/participant.dart';
-export 'src/participant/remote.dart';
+export 'src/participant/remote.dart' hide ParticipantCreationResult;
 export 'src/publication/local.dart';
 export 'src/publication/remote.dart';
 export 'src/publication/track_publication.dart';

lib/src/core/room.dart

@@ -636,15 +636,18 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
     return null;
   }
 
-  Future<RemoteParticipant> _getOrCreateRemoteParticipant(String identity, lk_models.ParticipantInfo? info) async {
+  Future<ParticipantCreationResult> _getOrCreateRemoteParticipant(
+      String identity, lk_models.ParticipantInfo? info) async {
     RemoteParticipant? participant = _remoteParticipants[identity];
     if (participant != null) {
-      if (info != null) {
-        await participant.updateFromInfo(info);
-      }
-      return participant;
+      // Return existing participant with no new publications; caller handles updates.
+      return ParticipantCreationResult(
+        participant: participant,
+        newPublications: const [],
+      );
     }
 
+    ParticipantCreationResult result;
     if (info == null) {
       logger.warning('RemoteParticipant.info is null identity: $identity');
       participant = RemoteParticipant(
@@ -653,16 +656,20 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
         identity: identity,
         name: '',
       );
+      result = ParticipantCreationResult(
+        participant: participant,
+        newPublications: const [],
+      );
     } else {
-      participant = await RemoteParticipant.createFromInfo(
+      result = await RemoteParticipant.createFromInfo(
         room: this,
         info: info,
       );
     }
 
-    _remoteParticipants[identity] = participant;
-    _sidToIdentity[participant.sid] = identity;
-    return participant;
+    _remoteParticipants[result.participant.identity] = result.participant;
+    _sidToIdentity[result.participant.sid] = result.participant.identity;
+    return result;
   }
 
   Future<void> _onParticipantUpdateEvent(List<lk_models.ParticipantInfo> updates) async {
@@ -689,14 +696,25 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
         continue;
       }
 
-      final participant = await _getOrCreateRemoteParticipant(info.identity, info);
+      final result = await _getOrCreateRemoteParticipant(info.identity, info);
 
       if (isNew) {
         hasChanged = true;
-        // fire connected event
-        emitWhenConnected(ParticipantConnectedEvent(participant: participant));
+        // Emit connected event
+        emitWhenConnected(ParticipantConnectedEvent(participant: result.participant));
+        // Emit TrackPublishedEvent for each new track
+        if (connectionState == ConnectionState.connected) {
+          for (final pub in result.newPublications) {
+            final event = TrackPublishedEvent(
+              participant: result.participant,
+              publication: pub,
+            );
+            [result.participant.events, events].emit(event);
+          }
+        }
+        _sidToIdentity[info.sid] = info.identity;
       } else {
-        final wasUpdated = await participant.updateFromInfo(info);
+        final wasUpdated = await result.participant.updateFromInfo(info);
         if (wasUpdated) {
           _sidToIdentity[info.sid] = info.identity;
         }

lib/src/participant/remote.dart

@@ -31,6 +31,28 @@ import '../track/remote/video.dart';
 import '../types/other.dart';
 import 'participant.dart';
 
+/// Result of creating a RemoteParticipant with all its initial data populated.
+///
+/// This struct is returned by [RemoteParticipant.createFromInfo] and contains
+/// the fully initialized participant along with the list of track publications
+/// that were added during creation. The caller is responsible for emitting
+/// events in the correct order.
+@internal
+class ParticipantCreationResult {
+  /// The fully initialized remote participant with all basic info and tracks populated.
+  final RemoteParticipant participant;
+
+  /// List of new track publications that were added during participant creation.
+  /// The caller should emit [TrackPublishedEvent] for each of these after
+  /// emitting [ParticipantConnectedEvent].
+  final List<RemoteTrackPublication> newPublications;
+
+  const ParticipantCreationResult({
+    required this.participant,
+    required this.newPublications,
+  });
+}
+
 /// Represents other participant in the [Room].
 class RemoteParticipant extends Participant<RemoteTrackPublication> {
   @internal
@@ -46,18 +68,70 @@ class RemoteParticipant extends Participant<RemoteTrackPublication> {
           name: name,
         );
 
-  static Future<RemoteParticipant> createFromInfo({
+  /// Creates a fully initialized RemoteParticipant without emitting events.
+  ///
+  /// Populates the participant with all data from [info] including metadata, permissions,
+  /// and track publications. No events are emitted, allowing the caller to control event
+  /// timing and order.
+  ///
+  /// Returns [ParticipantCreationResult] with the participant and new track publications.
+  /// The caller should emit [ParticipantConnectedEvent] first, then [TrackPublishedEvent]
+  /// for each track, ensuring the participant is fully populated when connected event fires.
+  ///
+  /// @internal - Should only be called by [Room].
+  @internal
+  static Future<ParticipantCreationResult> createFromInfo({
     required Room room,
     required lk_models.ParticipantInfo info,
   }) async {
     final participant = RemoteParticipant(
       room: room,
-      sid: info.identity,
+      sid: info.sid,
       identity: info.identity,
       name: info.name,
     );
-    await participant.updateFromInfo(info);
-    return participant;
+    // Update basic participant info (state, metadata, etc.)
+    await participant._updateBasicInfo(info);
+    // Add tracks to participant without emitting events
+    final newPubs = await participant._addTracks(info.tracks);
+    // Return result for caller to emit events in correct order
+    return ParticipantCreationResult(
+      participant: participant,
+      newPublications: newPubs,
+    );
+  }
+
+  Future<void> _updateBasicInfo(lk_models.ParticipantInfo info) async {
+    // Only call superclass updateFromInfo to update basic participant state
+    await super.updateFromInfo(info);
+  }
+
+  Future<List<RemoteTrackPublication>> _addTracks(List<lk_models.TrackInfo> tracks) async {
+    final newPubs = <RemoteTrackPublication>[];
+    for (final trackInfo in tracks) {
+      final RemoteTrackPublication? pub = getTrackPublicationBySid(trackInfo.sid);
+      if (pub == null) {
+        final RemoteTrackPublication pub;
+        if (trackInfo.type == lk_models.TrackType.VIDEO) {
+          pub = RemoteTrackPublication<RemoteVideoTrack>(
+            participant: this,
+            info: trackInfo,
+          );
+        } else if (trackInfo.type == lk_models.TrackType.AUDIO) {
+          pub = RemoteTrackPublication<RemoteAudioTrack>(
+            participant: this,
+            info: trackInfo,
+          );
+        } else {
+          throw UnexpectedStateException('Unknown track type');
+        }
+        newPubs.add(pub);
+        addTrackPublication(pub);
+      } else {
+        pub.updateFromInfo(trackInfo);
+      }
+    }
+    return newPubs;
   }
 
   /// A convenience property to get all video tracks.
@@ -189,34 +263,16 @@ class RemoteParticipant extends Participant<RemoteTrackPublication> {
       //return false;
     }
 
-    // figuring out deltas between tracks
-    final newPubs = <RemoteTrackPublication>{};
+    await _updateTracks(info.tracks);
 
-    for (final trackInfo in info.tracks) {
-      final RemoteTrackPublication? pub = getTrackPublicationBySid(trackInfo.sid);
-      if (pub == null) {
-        final RemoteTrackPublication pub;
-        if (trackInfo.type == lk_models.TrackType.VIDEO) {
-          pub = RemoteTrackPublication<RemoteVideoTrack>(
-            participant: this,
-            info: trackInfo,
-          );
-        } else if (trackInfo.type == lk_models.TrackType.AUDIO) {
-          pub = RemoteTrackPublication<RemoteAudioTrack>(
-            participant: this,
-            info: trackInfo,
-          );
-        } else {
-          throw UnexpectedStateException('Unknown track type');
-        }
-        newPubs.add(pub);
-        addTrackPublication(pub);
-      } else {
-        pub.updateFromInfo(trackInfo);
-      }
-    }
+    return true;
+  }
 
-    // always emit events for new publications, Room will not forward them unless it's ready
+  Future<void> _updateTracks(List<lk_models.TrackInfo> tracks) async {
+    // Add new tracks
+    final newPubs = await _addTracks(tracks);
+
+    // Emit events for new publications
     for (final pub in newPubs) {
       final event = TrackPublishedEvent(
         participant: this,
@@ -227,14 +283,12 @@ class RemoteParticipant extends Participant<RemoteTrackPublication> {
       }
     }
 
-    // remove any published track that is not in the info
-    final validSids = info.tracks.map((e) => e.sid);
+    // Remove any published track that is not in the info
+    final validSids = tracks.map((e) => e.sid);
     final removeSids = trackPublications.keys.where((e) => !validSids.contains(e)).toSet();
     for (final sid in removeSids) {
       await removePublishedTrack(sid);
     }
-
-    return true;
   }
 
   Future<void> removePublishedTrack(String trackSid, {bool notify = true}) async {

test/core/room_e2e_test.dart

@@ -68,6 +68,37 @@ void main() {
       expect(room.remoteParticipants.length, 1);
     });
 
+    test('participant join with tracks populated before connected event', () async {
+      // Track whether participant has tracks when connected event fires
+      bool participantHadTracksOnConnect = false;
+      int trackCountOnConnect = 0;
+
+      // Listen for ParticipantConnectedEvent
+      final cancel = room.events.on<ParticipantConnectedEvent>((event) {
+        // Verify participant is fully populated with tracks
+        trackCountOnConnect = event.participant.trackPublications.length;
+        participantHadTracksOnConnect = trackCountOnConnect > 0;
+      });
+
+      // Send participant join with tracks
+      ws.onData(participantJoinResponse.writeToBuffer());
+
+      // Wait for connected event
+      await room.events.waitFor<ParticipantConnectedEvent>(duration: const Duration(seconds: 1));
+
+      // Clean up listener
+      cancel();
+
+      // Verify participant had tracks when connected event was emitted
+      expect(participantHadTracksOnConnect, isTrue,
+          reason: 'Participant should have tracks when ParticipantConnectedEvent is emitted');
+      expect(trackCountOnConnect, greaterThan(0),
+          reason: 'Participant should have at least one track when connected event fires');
+
+      // Verify the participant is in the room
+      expect(room.remoteParticipants.length, 1);
+    });
+
     test('participant disconnect', () async {
       ws.onData(participantJoinResponse.writeToBuffer());
       await room.events.waitFor<ParticipantConnectedEvent>(duration: const Duration(seconds: 1));