Log warning if multiple tracks of the same source are published

.changeset/mighty-carpets-dream.md

@@ -0,0 +1,5 @@
+---
+'livekit-client': patch
+---
+
+Log warning if multiple tracks of the same source are published

src/room/participant/LocalParticipant.ts

@@ -434,6 +434,23 @@ export default class LocalParticipant extends Participant {
     if (opts.source) {
       track.source = opts.source;
     }
+    const existingTrackOfSource = Array.from(this.tracks.values()).find(
+      (publishedTrack) => track instanceof LocalTrack && publishedTrack.source === track.source,
+    );
+    if (existingTrackOfSource) {
+      try {
+        // throw an Error in order to capture the stack trace
+        throw Error(`publishing a second track with the same source: ${track.source}`);
+      } catch (e: unknown) {
+        if (e instanceof Error) {
+          log.warn(e.message, {
+            oldTrack: existingTrackOfSource,
+            newTrack: track,
+            trace: e.stack,
+          });
+        }
+      }
+    }
     if (opts.stopMicTrackOnMute && track instanceof LocalAudioTrack) {
       track.stopOnMute = true;
     }

src/room/participant/RemoteParticipant.ts

@@ -220,6 +220,25 @@ export default class RemoteParticipant extends Participant {
     // always emit events for new publications, Room will not forward them unless it's ready
     newTracks.forEach((publication) => {
       this.emit(ParticipantEvent.TrackPublished, publication);
+      const existingTrackOfSource = Array.from(this.tracks.values()).find(
+        (publishedTrack) => publishedTrack.source === publication.source,
+      );
+      if (existingTrackOfSource) {
+        try {
+          // throw an Error in order to capture the stack trace
+          throw Error(
+            `received a second track publication with the same source: ${publication.source}`,
+          );
+        } catch (e: unknown) {
+          if (e instanceof Error) {
+            log.warn(e.message, {
+              oldTrack: existingTrackOfSource,
+              newTrack: publication,
+              trace: e.stack,
+            });
+          }
+        }
+      }
     });
 
     // detect removed tracks