Merge pull request #3706 from element-hq/valere/fix_remove_livekit_alias_signaling

The advertised livekit_alias in membership is deprecated

src/state/CallViewModel/localMember/LocalMember.ts

@@ -17,6 +17,7 @@ import { observeParticipantEvents } from "@livekit/components-core";
 import {
   Status as RTCSessionStatus,
   type LivekitTransport,
+  type LivekitTransportConfig,
   type MatrixRTCSession,
 } from "matrix-js-sdk/lib/matrixrtc";
 import {
@@ -125,7 +126,7 @@ interface Props {
   muteStates: MuteStates;
   connectionManager: IConnectionManager;
   createPublisherFactory: (connection: Connection) => Publisher;
-  joinMatrixRTC: (transport: LivekitTransport) => void;
+  joinMatrixRTC: (transport: LivekitTransportConfig) => void;
   homeserverConnected: HomeserverConnected;
   localTransport$: Behavior<LocalTransportWithSFUConfig | null>;
   matrixRTCSession: Pick<
@@ -717,7 +718,7 @@ interface EnterRTCSessionOptions {
 export function enterRTCSession(
   rtcSession: MatrixRTCSession,
   ownMembershipIdentity: CallMembershipIdentityParts,
-  transport: LivekitTransport,
+  transport: LivekitTransportConfig,
   options: EnterRTCSessionOptions,
 ): void {
   const { encryptMedia, matrixRTCMode } = options;
@@ -735,12 +736,26 @@ export function enterRTCSession(
   const multiSFU =
     matrixRTCMode === MatrixRTCMode.Compatibility ||
     matrixRTCMode === MatrixRTCMode.Matrix_2_0;
+
+  // For backwards compatibility with Element Call versions that do not do Matrix 2.0,
+  // we add the livekit alias to the transport.
+  let backwardCompatibleTransport: LivekitTransport | LivekitTransportConfig;
+  if (matrixRTCMode === MatrixRTCMode.Matrix_2_0) {
+    backwardCompatibleTransport = transport;
+  } else {
+    backwardCompatibleTransport = {
+      livekit_alias: rtcSession.room.roomId,
+      ...transport,
+    };
+  }
+
   // Multi-sfu does not need a preferred foci list. just the focus that is actually used.
   // TODO where/how do we track errors originating from the ongoing rtcSession?
+
   rtcSession.joinRTCSession(
     ownMembershipIdentity,
-    multiSFU ? [] : [transport],
-    multiSFU ? transport : undefined,
+    multiSFU ? [] : [backwardCompatibleTransport],
+    multiSFU ? backwardCompatibleTransport : undefined,
     {
       notificationType,
       callIntent,