From c51c222c479ba26297e0b40c9b55861b2a8b00a0 Mon Sep 17 00:00:00 2001
From: Hampus <hampus@fluxer.com>
Date: Thu, 8 Oct 2026 03:04:10 +0200
Subject: [PATCH] fix(voice): stop stale mute echoes from toggling mute (#3268)

---
 .../core/reducers/gateway.reconcile.test.ts   | 53 +++++++++++++++++++
 .../src/core/reducers/gateway.ts              |  7 +--
 2 files changed, 57 insertions(+), 3 deletions(-)

diff --git a/packages/voice_engine_v2/src/core/reducers/gateway.reconcile.test.ts b/packages/voice_engine_v2/src/core/reducers/gateway.reconcile.test.ts
index 4bd26a8d8..2e9303a29 100644
--- a/packages/voice_engine_v2/src/core/reducers/gateway.reconcile.test.ts
+++ b/packages/voice_engine_v2/src/core/reducers/gateway.reconcile.test.ts
@@ -265,6 +265,7 @@ describe('shouldApplyGatewayVoiceStateEcho', () => {
 
 	it('applies the echo when it matches the pending local write', () => {
 		const snapshot = connectedSnapshot({
+			desiredVoiceState: desired({selfMute: false}),
 			desiredVoiceStateWrite: {
 				guildId: 'guild-1',
 				channelId: 'channel-1',
@@ -279,6 +280,7 @@ describe('shouldApplyGatewayVoiceStateEcho', () => {
 
 	it('rejects a stale echo that differs from the pending local write', () => {
 		const snapshot = connectedSnapshot({
+			desiredVoiceState: desired({selfMute: false}),
 			desiredVoiceStateWrite: {
 				guildId: 'guild-1',
 				channelId: 'channel-1',
@@ -290,4 +292,55 @@ describe('shouldApplyGatewayVoiceStateEcho', () => {
 		});
 		expect(shouldApplyGatewayVoiceStateEcho(snapshot, reported({selfMute: true}))).toBe(false);
 	});
+
+	it('rejects the echo of a pending write the user has already reverted', () => {
+		const snapshot = connectedSnapshot({
+			selfVoiceState: reported({selfMute: false}),
+			desiredVoiceState: desired({selfMute: false}),
+			desiredVoiceStateWrite: {
+				guildId: 'guild-1',
+				channelId: 'channel-1',
+				selfMute: true,
+				selfDeaf: false,
+				selfVideo: false,
+				selfStream: false,
+			},
+		});
+		expect(shouldApplyGatewayVoiceStateEcho(snapshot, reported({selfMute: true}))).toBe(false);
+	});
+
+	it('settles on the last intent after a mute and unmute faster than the echo', () => {
+		let snapshot = connectedSnapshot({selfVoiceState: reported({selfMute: false})});
+		const muted = transitionVoiceEngineV2(snapshot, {
+			type: 'gateway.desiredVoiceStateChanged',
+			desired: desired({selfMute: true}),
+		});
+		expect(muted.commands).toMatchObject([{type: 'gateway.voiceState.write', options: {selfMute: true}}]);
+		snapshot = transitionVoiceEngineV2(muted.snapshot, {
+			type: 'gateway.voiceStateWriteSucceeded',
+			operationId: muted.snapshot.gateway.operationId as number,
+		}).snapshot;
+		const unmuted = transitionVoiceEngineV2(snapshot, {
+			type: 'gateway.desiredVoiceStateChanged',
+			desired: desired({selfMute: false}),
+		});
+		expect(unmuted.commands).toEqual([]);
+		snapshot = unmuted.snapshot;
+
+		const staleEcho = reported({selfMute: true});
+		expect(shouldApplyGatewayVoiceStateEcho(snapshot, staleEcho)).toBe(false);
+		snapshot = transitionVoiceEngineV2(snapshot, {type: 'gateway.voiceStateUpdated', voiceState: staleEcho}).snapshot;
+		const corrective = transitionVoiceEngineV2(snapshot, {type: 'gateway.voiceStateReconcileRequested'});
+		expect(corrective.commands).toMatchObject([{type: 'gateway.voiceState.write', options: {selfMute: false}}]);
+		snapshot = transitionVoiceEngineV2(corrective.snapshot, {
+			type: 'gateway.voiceStateWriteSucceeded',
+			operationId: corrective.snapshot.gateway.operationId as number,
+		}).snapshot;
+
+		const finalEcho = reported({selfMute: false});
+		expect(shouldApplyGatewayVoiceStateEcho(snapshot, finalEcho)).toBe(true);
+		snapshot = transitionVoiceEngineV2(snapshot, {type: 'gateway.voiceStateUpdated', voiceState: finalEcho}).snapshot;
+		expect(snapshot.gateway.desiredVoiceStateWrite).toBeNull();
+		expect(transitionVoiceEngineV2(snapshot, {type: 'gateway.voiceStateReconcileRequested'}).commands).toEqual([]);
+	});
 });
diff --git a/packages/voice_engine_v2/src/core/reducers/gateway.ts b/packages/voice_engine_v2/src/core/reducers/gateway.ts
index 7423d2d64..a4f6efb57 100644
--- a/packages/voice_engine_v2/src/core/reducers/gateway.ts
+++ b/packages/voice_engine_v2/src/core/reducers/gateway.ts
@@ -226,9 +226,10 @@ export function shouldApplyGatewayVoiceStateEcho(
 ): boolean {
 	assert.ok(snapshot != null, 'shouldApplyGatewayVoiceStateEcho snapshot must not be null');
 	assert.ok(echo != null, 'shouldApplyGatewayVoiceStateEcho echo must not be null');
-	const pending = snapshot.gateway.desiredVoiceStateWrite;
-	if (pending == null) return true;
-	return gatewayVoiceStateWriteMatchesReported(pending, echo);
+	if (snapshot.gateway.desiredVoiceStateWrite == null) return true;
+	const desired = deriveVoiceEngineV2DesiredGatewayVoiceState(snapshot);
+	if (desired == null) return false;
+	return gatewayVoiceStateWriteMatchesReported(desired, echo);
 }
 
 export function gatewayVoiceStateWriteMatchesReported(