fix(voice): release the mic after a region hot-swap (#3490)

fluxer_app/src/features/voice/engine/VoiceTrackPublicationUtils.test.ts

@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+import {EventEmitter} from 'node:events';
+import {releaseCaptureWithRepublishedTrack} from '@app/features/voice/engine/VoiceTrackPublicationUtils';
+import {type LocalParticipant, type LocalTrack, type LocalTrackPublication, ParticipantEvent} from 'livekit-client';
+import {describe, expect, it, vi} from 'vitest';
+
+function fakeMediaStreamTrack(): MediaStreamTrack {
+	return {readyState: 'live'} as MediaStreamTrack;
+}
+
+function fakeLocalTrack(mediaStreamTrack: MediaStreamTrack): LocalTrack {
+	return {mediaStreamTrack, stop: vi.fn()} as unknown as LocalTrack;
+}
+
+function fakeRoom(): {participant: LocalParticipant; unpublish(publication: LocalTrackPublication): void} {
+	const emitter = new EventEmitter();
+	return {
+		participant: emitter as unknown as LocalParticipant,
+		unpublish: (publication) => emitter.emit(ParticipantEvent.LocalTrackUnpublished, publication),
+	};
+}
+
+function republish(room: ReturnType<typeof fakeRoom>, sourceTrack: LocalTrack): LocalTrackPublication {
+	const publication = {track: fakeLocalTrack(sourceTrack.mediaStreamTrack)} as LocalTrackPublication;
+	releaseCaptureWithRepublishedTrack(room.participant, publication, sourceTrack);
+	return publication;
+}
+
+function stopTrack(track: MediaStreamTrack): void {
+	Object.assign(track, {readyState: 'ended'});
+}
+
+describe('releaseCaptureWithRepublishedTrack', () => {
+	it('stops the processed microphone capture when its hot-swapped publication is stopped on leave', () => {
+		const processedTrack = fakeMediaStreamTrack();
+		const microphone = fakeLocalTrack(processedTrack);
+		const newRoom = fakeRoom();
+		const publication = republish(newRoom, microphone);
+
+		stopTrack(processedTrack);
+		newRoom.unpublish(publication);
+
+		expect(microphone.stop).toHaveBeenCalledTimes(1);
+	});
+
+	it('keeps the capture running when the publication is handed to another room without stopping', () => {
+		const processedTrack = fakeMediaStreamTrack();
+		const microphone = fakeLocalTrack(processedTrack);
+		const newRoom = fakeRoom();
+		const publication = republish(newRoom, microphone);
+
+		newRoom.unpublish(publication);
+
+		expect(microphone.stop).not.toHaveBeenCalled();
+	});
+
+	it('stops the original capture after a second hot-swap republishes the wrapper track', () => {
+		const processedTrack = fakeMediaStreamTrack();
+		const microphone = fakeLocalTrack(processedTrack);
+		const secondRoom = fakeRoom();
+		const secondPublication = republish(secondRoom, microphone);
+		const thirdRoom = fakeRoom();
+		const thirdPublication = republish(thirdRoom, secondPublication.track!);
+
+		secondRoom.unpublish(secondPublication);
+		stopTrack(processedTrack);
+		thirdRoom.unpublish(thirdPublication);
+
+		expect(microphone.stop).toHaveBeenCalledTimes(1);
+	});
+});

fluxer_app/src/features/voice/engine/VoiceTrackPublicationUtils.ts

@@ -6,12 +6,16 @@ import {
 	VoiceTrackSource as VoiceTrackSourceValue,
 } from '@app/features/voice/engine/VoiceTrackSource';
 import type {LocalParticipant, LocalTrack, LocalTrackPublication} from 'livekit-client';
+import {ParticipantEvent} from 'livekit-client';
 
 interface LocalParticipantWithAudioPublications extends Pick<LocalParticipant, 'audioTrackPublications'> {}
 interface LocalParticipantWithTrackPublications extends Pick<LocalParticipant, 'trackPublications'> {}
 interface LocalParticipantWithUnpublish extends LocalParticipantWithTrackPublications {
 	unpublishTrack: LocalParticipant['unpublishTrack'];
 }
+interface LocalParticipantWithUnpublishEvents extends Pick<LocalParticipant, 'on' | 'off'> {}
+
+const republishedCaptureOwners = new WeakMap<MediaStreamTrack, LocalTrack>();
 
 export type LocalMediaPublicationSlot = 'camera' | 'screen_share';
 
@@ -246,3 +250,20 @@ export function selectLocalMediaPublicationsForConnectionRepublish(
 	}
 	return selected;
 }
+
+export function releaseCaptureWithRepublishedTrack(
+	participant: LocalParticipantWithUnpublishEvents,
+	republished: LocalTrackPublication,
+	sourceTrack: LocalTrack,
+): void {
+	const publishedTrack = sourceTrack.mediaStreamTrack;
+	const captureOwner = republishedCaptureOwners.get(publishedTrack) ?? sourceTrack;
+	republishedCaptureOwners.set(publishedTrack, captureOwner);
+	const republishedTrack = republished.track;
+	const releaseCapture = (publication: LocalTrackPublication): void => {
+		if (publication.track !== republishedTrack || publishedTrack.readyState !== 'ended') return;
+		participant.off(ParticipantEvent.LocalTrackUnpublished, releaseCapture);
+		captureOwner.stop();
+	};
+	participant.on(ParticipantEvent.LocalTrackUnpublished, releaseCapture);
+}

fluxer_app/src/features/voice/engine/v2/VoiceEngineV2AppConnectionHostAdapter.ts

@@ -29,7 +29,10 @@ import {
 	releaseE2EEWorker,
 } from '@app/features/voice/engine/VoiceE2EEKeyProvider';
 import {getSharedVoiceAudioContext} from '@app/features/voice/engine/VoiceSharedAudioContext';
-import {selectLocalMediaPublicationsForConnectionRepublish} from '@app/features/voice/engine/VoiceTrackPublicationUtils';
+import {
+	releaseCaptureWithRepublishedTrack,
+	selectLocalMediaPublicationsForConnectionRepublish,
+} from '@app/features/voice/engine/VoiceTrackPublicationUtils';
 import {
 	assertDisconnectReason,
 	assertNonEmptyString,
@@ -819,6 +822,7 @@ export class VoiceEngineV2AppConnectionHostAdapter extends Store {
 					name: publication.trackName,
 				};
 				const republished = await newParticipant.publishTrack(track.mediaStreamTrack, publishOptions);
+				releaseCaptureWithRepublishedTrack(newParticipant, republished, track);
 				const violation = publishOptions.videoCodec
 					? findVideoPublishCodecPolicyViolation(publishOptions.videoCodec, republished.options?.videoCodec)
 					: null;
@@ -1096,12 +1100,10 @@ export class VoiceEngineV2AppConnectionHostAdapter extends Store {
 	private disconnectPreviousRoom(previousRoom: Room | null, stopTracks = true): void {
 		if (!previousRoom) return;
 		try {
-			if (previousRoom.state === 'connected') {
-				const tracksToStop = stopTracks ? [] : this.getPreviousRoomNonScreenShareTracks(previousRoom);
-				previousRoom.disconnect(stopTracks);
-				this.stopPreviousRoomTracks(tracksToStop);
-				logger.debug('Previous room disconnected', {stopTracks});
-			}
+			const tracksToStop = stopTracks ? [] : this.getPreviousRoomNonScreenShareTracks(previousRoom);
+			previousRoom.disconnect(stopTracks);
+			this.stopPreviousRoomTracks(tracksToStop);
+			logger.debug('Previous room disconnected', {stopTracks});
 		} catch (error) {
 			logger.warn('Failed to disconnect previous room', error);
 		}