Updates and tests

spec/unit/matrixrtc/MatrixRTCSession.spec.ts

@@ -18,7 +18,6 @@ import { encodeBase64, EventType, MatrixClient, type MatrixError, type MatrixEve
 import { KnownMembership } from "../../../src/@types/membership";
 import { MatrixRTCSession, MatrixRTCSessionEvent } from "../../../src/matrixrtc/MatrixRTCSession";
 import { Status, type EncryptionKeysEventContent } from "../../../src/matrixrtc/types";
-import { secureRandomString } from "../../../src/randomstring";
 import { makeMockEvent, makeMockRoom, membershipTemplate, makeKey, type MembershipData, mockRoomState } from "./mocks";
 import { RTCEncryptionManager } from "../../../src/matrixrtc/RTCEncryptionManager.ts";
 
@@ -47,91 +46,111 @@ describe("MatrixRTCSession", () => {
         sess = undefined;
     });
 
-    describe("roomSessionForRoom", () => {
-        it("creates a room-scoped session from room state", () => {
-            const mockRoom = makeMockRoom([membershipTemplate]);
+    describe.each([
+        {
+            listenForStickyEvents: true,
+            listenForMemberStateEvents: true,
+            testCreateSticky: false,
+        },
+        {
+            listenForStickyEvents: false,
+            listenForMemberStateEvents: true,
+            testCreateSticky: false,
+        },
+        {
+            listenForStickyEvents: true,
+            listenForMemberStateEvents: true,
+            testCreateSticky: true,
+        },
+        {
+            listenForStickyEvents: true,
+            listenForMemberStateEvents: false,
+            testCreateSticky: true,
+        },
+    ])(
+        "roomSessionForRoom listenForSticky=$listenForStickyEvents listenForMemberStateEvents=$listenForStickyEvents testCreateSticky=$testCreateSticky",
+        (testConfig) => {
+            it("creates a room-scoped session from room state", () => {
+                const mockRoom = makeMockRoom([membershipTemplate], testConfig.testCreateSticky);
 
-            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
-            expect(sess?.memberships.length).toEqual(1);
-            expect(sess?.memberships[0].sessionDescription.id).toEqual("");
-            expect(sess?.memberships[0].scope).toEqual("m.room");
-            expect(sess?.memberships[0].application).toEqual("m.call");
-            expect(sess?.memberships[0].deviceId).toEqual("AAAAAAA");
-            expect(sess?.memberships[0].isExpired()).toEqual(false);
-            expect(sess?.sessionDescription.id).toEqual("");
-        });
-
-        it("ignores memberships where application is not m.call", () => {
-            const testMembership = Object.assign({}, membershipTemplate, {
-                application: "not-m.call",
+                sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession, testConfig);
+                expect(sess?.memberships.length).toEqual(1);
+                expect(sess?.memberships[0].sessionDescription.id).toEqual("");
+                expect(sess?.memberships[0].scope).toEqual("m.room");
+                expect(sess?.memberships[0].application).toEqual("m.call");
+                expect(sess?.memberships[0].deviceId).toEqual("AAAAAAA");
+                expect(sess?.memberships[0].isExpired()).toEqual(false);
+                expect(sess?.sessionDescription.id).toEqual("");
             });
-            const mockRoom = makeMockRoom([testMembership]);
-            const sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
-            expect(sess?.memberships).toHaveLength(0);
-        });
 
-        it("ignores memberships where callId is not empty", () => {
-            const testMembership = Object.assign({}, membershipTemplate, {
-                call_id: "not-empty",
-                scope: "m.room",
+            it("ignores memberships where application is not m.call", () => {
+                const testMembership = Object.assign({}, membershipTemplate, {
+                    application: "not-m.call",
+                });
+                const mockRoom = makeMockRoom([testMembership], testConfig.testCreateSticky);
+                const sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession, testConfig);
+                expect(sess?.memberships).toHaveLength(0);
             });
-            const mockRoom = makeMockRoom([testMembership]);
-            const sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
-            expect(sess?.memberships).toHaveLength(0);
-        });
 
-        it("ignores expired memberships events", () => {
-            jest.useFakeTimers();
-            const expiredMembership = Object.assign({}, membershipTemplate);
-            expiredMembership.expires = 1000;
-            expiredMembership.device_id = "EXPIRED";
-            const mockRoom = makeMockRoom([membershipTemplate, expiredMembership]);
+            it("ignores memberships where callId is not empty", () => {
+                const testMembership = Object.assign({}, membershipTemplate, {
+                    call_id: "not-empty",
+                    scope: "m.room",
+                });
+                const mockRoom = makeMockRoom([testMembership], testConfig.testCreateSticky);
+                const sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession, testConfig);
+                expect(sess?.memberships).toHaveLength(0);
+            });
 
-            jest.advanceTimersByTime(2000);
-            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
-            expect(sess?.memberships.length).toEqual(1);
-            expect(sess?.memberships[0].deviceId).toEqual("AAAAAAA");
-            jest.useRealTimers();
-        });
+            it("ignores expired memberships events", () => {
+                jest.useFakeTimers();
+                const expiredMembership = Object.assign({}, membershipTemplate);
+                expiredMembership.expires = 1000;
+                expiredMembership.device_id = "EXPIRED";
+                const mockRoom = makeMockRoom([membershipTemplate, expiredMembership], testConfig.testCreateSticky);
 
-        it("ignores memberships events of members not in the room", () => {
-            const mockRoom = makeMockRoom([membershipTemplate]);
-            mockRoom.hasMembershipState = (state) => state === KnownMembership.Join;
-            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
-            expect(sess?.memberships.length).toEqual(0);
-        });
+                jest.advanceTimersByTime(2000);
+                sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession, testConfig);
+                expect(sess?.memberships.length).toEqual(1);
+                expect(sess?.memberships[0].deviceId).toEqual("AAAAAAA");
+                jest.useRealTimers();
+            });
 
-        it("honours created_ts", () => {
-            jest.useFakeTimers();
-            jest.setSystemTime(500);
-            const expiredMembership = Object.assign({}, membershipTemplate);
-            expiredMembership.created_ts = 500;
-            expiredMembership.expires = 1000;
-            const mockRoom = makeMockRoom([expiredMembership]);
-            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
-            expect(sess?.memberships[0].getAbsoluteExpiry()).toEqual(1500);
-            jest.useRealTimers();
-        });
+            it("ignores memberships events of members not in the room", () => {
+                const mockRoom = makeMockRoom([membershipTemplate], testConfig.testCreateSticky);
+                mockRoom.hasMembershipState = (state) => state === KnownMembership.Join;
+                sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession, testConfig);
+                expect(sess?.memberships.length).toEqual(0);
+            });
 
-        it("returns empty session if no membership events are present", () => {
-            const mockRoom = makeMockRoom([]);
-            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
-            expect(sess?.memberships).toHaveLength(0);
-        });
+            it("honours created_ts", () => {
+                jest.useFakeTimers();
+                jest.setSystemTime(500);
+                const expiredMembership = Object.assign({}, membershipTemplate);
+                expiredMembership.created_ts = 500;
+                expiredMembership.expires = 1000;
+                const mockRoom = makeMockRoom([expiredMembership], testConfig.testCreateSticky);
+                sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession, testConfig);
+                expect(sess?.memberships[0].getAbsoluteExpiry()).toEqual(1500);
+                jest.useRealTimers();
+            });
 
-        it("safely ignores events with no memberships section", () => {
-            const roomId = secureRandomString(8);
-            const event = {
-                getType: jest.fn().mockReturnValue(EventType.GroupCallMemberPrefix),
-                getContent: jest.fn().mockReturnValue({}),
-                getSender: jest.fn().mockReturnValue("@mock:user.example"),
-                getTs: jest.fn().mockReturnValue(1000),
-                getLocalAge: jest.fn().mockReturnValue(0),
-            };
-            const mockRoom = {
-                ...makeMockRoom([]),
-                roomId,
-                getLiveTimeline: jest.fn().mockReturnValue({
+            it("returns empty session if no membership events are present", () => {
+                const mockRoom = makeMockRoom([], testConfig.testCreateSticky);
+                sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession, testConfig);
+                expect(sess?.memberships).toHaveLength(0);
+            });
+
+            it("safely ignores events with no memberships section", () => {
+                const event = {
+                    getType: jest.fn().mockReturnValue(EventType.GroupCallMemberPrefix),
+                    getContent: jest.fn().mockReturnValue({}),
+                    getSender: jest.fn().mockReturnValue("@mock:user.example"),
+                    getTs: jest.fn().mockReturnValue(1000),
+                    getLocalAge: jest.fn().mockReturnValue(0),
+                };
+                const mockRoom = makeMockRoom([]);
+                mockRoom.getLiveTimeline = jest.fn().mockReturnValue({
                     getState: jest.fn().mockReturnValue({
                         on: jest.fn(),
                         off: jest.fn(),
@@ -148,25 +167,21 @@ describe("MatrixRTCSession", () => {
                             ],
                         ]),
                     }),
-                }),
-            };
-            sess = MatrixRTCSession.sessionForRoom(client, mockRoom as unknown as Room, callSession);
-            expect(sess.memberships).toHaveLength(0);
-        });
+                });
+                sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession, testConfig);
+                expect(sess.memberships).toHaveLength(0);
+            });
 
-        it("safely ignores events with junk memberships section", () => {
-            const roomId = secureRandomString(8);
-            const event = {
-                getType: jest.fn().mockReturnValue(EventType.GroupCallMemberPrefix),
-                getContent: jest.fn().mockReturnValue({ memberships: ["i am a fish"] }),
-                getSender: jest.fn().mockReturnValue("@mock:user.example"),
-                getTs: jest.fn().mockReturnValue(1000),
-                getLocalAge: jest.fn().mockReturnValue(0),
-            };
-            const mockRoom = {
-                ...makeMockRoom([]),
-                roomId,
-                getLiveTimeline: jest.fn().mockReturnValue({
+            it("safely ignores events with junk memberships section", () => {
+                const event = {
+                    getType: jest.fn().mockReturnValue(EventType.GroupCallMemberPrefix),
+                    getContent: jest.fn().mockReturnValue({ memberships: ["i am a fish"] }),
+                    getSender: jest.fn().mockReturnValue("@mock:user.example"),
+                    getTs: jest.fn().mockReturnValue(1000),
+                    getLocalAge: jest.fn().mockReturnValue(0),
+                };
+                const mockRoom = makeMockRoom([]);
+                mockRoom.getLiveTimeline = jest.fn().mockReturnValue({
                     getState: jest.fn().mockReturnValue({
                         on: jest.fn(),
                         off: jest.fn(),
@@ -183,28 +198,28 @@ describe("MatrixRTCSession", () => {
                             ],
                         ]),
                     }),
-                }),
-            };
-            sess = MatrixRTCSession.sessionForRoom(client, mockRoom as unknown as Room, callSession);
-            expect(sess.memberships).toHaveLength(0);
-        });
+                });
+                sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession, testConfig);
+                expect(sess.memberships).toHaveLength(0);
+            });
 
-        it("ignores memberships with no device_id", () => {
-            const testMembership = Object.assign({}, membershipTemplate);
-            (testMembership.device_id as string | undefined) = undefined;
-            const mockRoom = makeMockRoom([testMembership]);
-            const sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
-            expect(sess.memberships).toHaveLength(0);
-        });
+            it("ignores memberships with no device_id", () => {
+                const testMembership = Object.assign({}, membershipTemplate);
+                (testMembership.device_id as string | undefined) = undefined;
+                const mockRoom = makeMockRoom([testMembership]);
+                const sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession, testConfig);
+                expect(sess.memberships).toHaveLength(0);
+            });
 
-        it("ignores memberships with no call_id", () => {
-            const testMembership = Object.assign({}, membershipTemplate);
-            (testMembership.call_id as string | undefined) = undefined;
-            const mockRoom = makeMockRoom([testMembership]);
-            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
-            expect(sess.memberships).toHaveLength(0);
-        });
-    });
+            it("ignores memberships with no call_id", () => {
+                const testMembership = Object.assign({}, membershipTemplate);
+                (testMembership.call_id as string | undefined) = undefined;
+                const mockRoom = makeMockRoom([testMembership]);
+                sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession, testConfig);
+                expect(sess.memberships).toHaveLength(0);
+            });
+        },
+    );
 
     describe("getOldestMembership", () => {
         it("returns the oldest membership event", () => {

spec/unit/matrixrtc/mocks.ts

@@ -74,10 +74,11 @@ export function makeMockClient(userId: string, deviceId: string): MockClient {
 
 export function makeMockRoom(
     membershipData: MembershipData[],
+    useStickyEvents = false,
 ): Room & { emitTimelineEvent: (event: MatrixEvent) => void } {
     const roomId = secureRandomString(8);
     // Caching roomState here so it does not get recreated when calling `getLiveTimeline.getState()`
-    const roomState = makeMockRoomState(membershipData, roomId);
+    const roomState = makeMockRoomState(useStickyEvents ? [] : membershipData, roomId);
     const room = Object.assign(new EventEmitter(), {
         roomId: roomId,
         hasMembershipState: jest.fn().mockReturnValue(true),
@@ -85,7 +86,9 @@ export function makeMockRoom(
             getState: jest.fn().mockReturnValue(roomState),
         }),
         getVersion: jest.fn().mockReturnValue("default"),
-        unstableGetStickyEvents: jest.fn().mockReturnValue([]),
+        unstableGetStickyEvents: jest
+            .fn()
+            .mockReturnValue(useStickyEvents ? membershipData.map((m) => mockRTCEvent(m, roomId)) : []),
     }) as unknown as Room;
     return Object.assign(room, {
         emitTimelineEvent: (event: MatrixEvent) =>

src/matrixrtc/MatrixRTCSession.ts

@@ -25,7 +25,7 @@ import { type ISendEventResponse } from "../@types/requests.ts";
 import { CallMembership } from "./CallMembership.ts";
 import { RoomStateEvent } from "../models/room-state.ts";
 import { type Focus } from "./focus.ts";
-import { MembershipManager } from "./MembershipManager.ts";
+import { MembershipManager, StickyEventMembershipManager } from "./MembershipManager.ts";
 import { EncryptionManager, type IEncryptionManager } from "./EncryptionManager.ts";
 import { deepCompare, logDurationSync } from "../utils.ts";
 import {
@@ -117,14 +117,6 @@ export interface SessionDescription {
 // - we use a `Ms` postfix if the option is a duration to avoid using words like:
 //   `time`, `duration`, `delay`, `timeout`... that might be mistaken/confused with technical terms.
 export interface MembershipConfig {
-    /**
-     * Use the new Manager.
-     *
-     * Default: `false`.
-     * @deprecated does nothing anymore we always default to the new membership manager.
-     */
-    useNewMembershipManager?: boolean;
-
     /**
      * The timeout (in milliseconds) after we joined the call, that our membership should expire
      * unless we have explicitly updated it.
@@ -188,10 +180,11 @@ export interface MembershipConfig {
     delayedLeaveEventRestartLocalTimeoutMs?: number;
 
     /**
-     * If the membership manager should publish its own membership via sticky events or via the room state.
-     * @default false (room state)
+     * Send membership using sticky events rather than state events.
+     *
+     * **WARNING**: This is an unstable feature and not all clients will support it.
      */
-    useStickyEvents?: boolean;
+    unstableSendStickyEvents?: boolean;
 }
 
 export interface EncryptionConfig {
@@ -237,6 +230,11 @@ export interface EncryptionConfig {
 }
 export type JoinSessionConfig = SessionConfig & MembershipConfig & EncryptionConfig;
 
+interface SessionMembershipsForRoomOpts {
+    listenForStickyEvents: boolean;
+    listenForMemberStateEvents: boolean;
+}
+
 /**
  * A MatrixRTCSession manages the membership & properties of a MatrixRTC session.
  * This class doesn't deal with media at all, just membership & properties of a session.
@@ -315,18 +313,21 @@ export class MatrixRTCSession extends TypedEventEmitter<
         sessionDescription: SessionDescription,
         // default both true this implied we combine sticky and state events for the final call state
         // (prefer sticky events in case of a duplicate)
-        useStickyEvents: boolean = true,
-        useStateEvents: boolean = true,
+        { listenForStickyEvents, listenForMemberStateEvents }: SessionMembershipsForRoomOpts = {
+            listenForStickyEvents: true,
+            listenForMemberStateEvents: true,
+        },
     ): CallMembership[] {
         const logger = rootLogger.getChild(`[MatrixRTCSession ${room.roomId}]`);
         let callMemberEvents = [] as MatrixEvent[];
-        if (useStickyEvents) {
+        if (listenForStickyEvents) {
+            logger.info("useStickyEvents");
             // prefill with sticky events
             callMemberEvents = Array.from(room.unstableGetStickyEvents()).filter(
                 (e) => e.getType() === EventType.GroupCallMemberPrefix,
             );
         }
-        if (useStateEvents) {
+        if (listenForMemberStateEvents) {
             const roomState = room.getLiveTimeline().getState(EventTimeline.FORWARDS);
             if (!roomState) {
                 logger.warn("Couldn't get state for room " + room.roomId);
@@ -337,7 +338,7 @@ export class MatrixRTCSession extends TypedEventEmitter<
             callMemberStateEvents.filter((e) =>
                 callMemberEvents.some((stickyEvent) => stickyEvent.getContent().state_key === e.getStateKey()),
             );
-            callMemberEvents.concat(callMemberStateEvents);
+            callMemberEvents = callMemberEvents.concat(callMemberStateEvents);
         }
 
         const callMemberships: CallMembership[] = [];
@@ -406,8 +407,16 @@ export class MatrixRTCSession extends TypedEventEmitter<
      *
      * @deprecated Use `MatrixRTCSession.sessionForRoom` with sessionDescription `{ id: "", application: "m.call" }` instead.
      */
-    public static roomSessionForRoom(client: MatrixClient, room: Room): MatrixRTCSession {
-        const callMemberships = MatrixRTCSession.sessionMembershipsForRoom(room, { id: "", application: "m.call" });
+    public static roomSessionForRoom(
+        client: MatrixClient,
+        room: Room,
+        opts?: SessionMembershipsForRoomOpts,
+    ): MatrixRTCSession {
+        const callMemberships = MatrixRTCSession.sessionMembershipsForRoom(
+            room,
+            { id: "", application: "m.call" },
+            opts,
+        );
         return new MatrixRTCSession(client, room, callMemberships, { id: "", application: "m.call" });
     }
 
@@ -420,8 +429,9 @@ export class MatrixRTCSession extends TypedEventEmitter<
         client: MatrixClient,
         room: Room,
         sessionDescription: SessionDescription,
+        opts?: SessionMembershipsForRoomOpts,
     ): MatrixRTCSession {
-        const callMemberships = MatrixRTCSession.sessionMembershipsForRoom(room, sessionDescription);
+        const callMemberships = MatrixRTCSession.sessionMembershipsForRoom(room, sessionDescription, opts);
 
         return new MatrixRTCSession(client, room, callMemberships, sessionDescription);
     }
@@ -507,6 +517,7 @@ export class MatrixRTCSession extends TypedEventEmitter<
         roomState?.off(RoomStateEvent.Members, this.onRoomMemberUpdate);
         this.roomSubset.off(RoomEvent.StickyEvents, this.onStickyEventUpdate);
     }
+
     private reEmitter = new TypedReEmitter<
         MatrixRTCSessionEvent | RoomAndToDeviceEvents | MembershipManagerEvent,
         MatrixRTCSessionEventHandlerMap & RoomAndToDeviceEventsHandlerMap & MembershipManagerEventHandlerMap
@@ -532,15 +543,23 @@ export class MatrixRTCSession extends TypedEventEmitter<
             return;
         } else {
             // Create MembershipManager and pass the RTCSession logger (with room id info)
-
-            this.membershipManager = new MembershipManager(
-                joinConfig,
-                this.roomSubset,
-                this.client,
-                () => this.getOldestMembership(),
-                this.sessionDescription,
-                this.logger,
-            );
+            this.membershipManager = joinConfig?.unstableSendStickyEvents
+                ? new StickyEventMembershipManager(
+                      joinConfig,
+                      this.roomSubset,
+                      this.client,
+                      () => this.getOldestMembership(),
+                      this.sessionDescription,
+                      this.logger,
+                  )
+                : new MembershipManager(
+                      joinConfig,
+                      this.roomSubset,
+                      this.client,
+                      () => this.getOldestMembership(),
+                      this.sessionDescription,
+                      this.logger,
+                  );
 
             this.reEmitter.reEmit(this.membershipManager!, [
                 MembershipManagerEvent.ProbablyLeft,
@@ -790,7 +809,7 @@ export class MatrixRTCSession extends TypedEventEmitter<
         this.recalculateSessionMembers();
     };
 
-    private onStickyEventUpdate = (added: MatrixEvent[], _removed: MatrixEvent[], room: Room): void => {
+    private onStickyEventUpdate = (added: MatrixEvent[], _removed: MatrixEvent[]): void => {
         if ([...added, ..._removed].some((e) => e.getType() === EventType.GroupCallMemberPrefix)) {
             this.recalculateSessionMembers();
         }

src/matrixrtc/MembershipManager.ts

@@ -144,6 +144,18 @@ export interface MembershipManagerState {
     probablyLeft: boolean;
 }
 
+function createInsertActionUpdate(type: MembershipActionType, offset?: number): ActionUpdate {
+    return {
+        insert: [{ ts: Date.now() + (offset ?? 0), type }],
+    };
+}
+
+function createReplaceActionUpdate(type: MembershipActionType, offset?: number): ActionUpdate {
+    return {
+        replace: [{ ts: Date.now() + (offset ?? 0), type }],
+    };
+}
+
 /**
  * This class is responsible for sending all events relating to the own membership of a matrixRTC call.
  * It has the following tasks:
@@ -313,7 +325,7 @@ export class MembershipManager
      */
     public constructor(
         private joinConfig: (SessionConfig & MembershipConfig) | undefined,
-        private room: Pick<Room, "getLiveTimeline" | "roomId" | "getVersion">,
+        protected room: Pick<Room, "roomId" | "getVersion">,
         private client: Pick<
             MatrixClient,
             | "getUserId"
@@ -321,8 +333,6 @@ export class MembershipManager
             | "sendStateEvent"
             | "_unstable_sendDelayedStateEvent"
             | "_unstable_updateDelayedEvent"
-            | "_unstable_sendStickyEvent"
-            | "_unstable_sendStickyDelayedEvent"
         >,
         private getOldestMembership: () => CallMembership | undefined,
         public readonly sessionDescription: SessionDescription,
@@ -380,7 +390,7 @@ export class MembershipManager
     }
     // Membership Event static parameters:
     private deviceId: string;
-    private stateKey: string;
+    protected stateKey: string;
     private fociPreferred?: Focus[];
     private focusActive?: Focus;
 
@@ -403,7 +413,7 @@ export class MembershipManager
             this.membershipEventExpiryHeadroomMs
         );
     }
-    private get delayedLeaveEventDelayMs(): number {
+    protected get delayedLeaveEventDelayMs(): number {
         return this.delayedLeaveEventDelayMsOverride ?? this.joinConfig?.delayedLeaveEventDelayMs ?? 8_000;
     }
     private get delayedLeaveEventRestartMs(): number {
@@ -420,10 +430,6 @@ export class MembershipManager
         return this.joinConfig?.delayedLeaveEventRestartLocalTimeoutMs ?? 2000;
     }
 
-    private get useStickyEvents(): boolean {
-        return this.joinConfig?.useStickyEvents ?? false;
-    }
-
     // LOOP HANDLER:
     private async membershipLoopHandler(type: MembershipActionType): Promise<ActionUpdate> {
         switch (type) {
@@ -479,27 +485,16 @@ export class MembershipManager
     }
 
     // an abstraction to switch between sending state or a sticky event
-    private clientSendDelayedEvent: (myMembership: EmptyObject) => Promise<SendDelayedEventResponse> = (
+    protected clientSendDelayedEvent: (myMembership: EmptyObject) => Promise<SendDelayedEventResponse> = (
         myMembership,
     ) =>
-        this.useStickyEvents
-            ? this.client._unstable_sendStickyDelayedEvent(
-                  this.room.roomId,
-                  STICK_DURATION_MS,
-                  { delay: this.delayedLeaveEventDelayMs },
-                  null,
-                  EventType.GroupCallMemberPrefix,
-                  Object.assign(myMembership, { sticky_key: this.stateKey }),
-              )
-            : this.client._unstable_sendDelayedStateEvent(
-                  this.room.roomId,
-                  { delay: this.delayedLeaveEventDelayMs },
-                  EventType.GroupCallMemberPrefix,
-                  myMembership,
-                  this.stateKey,
-              );
-    private sendDelayedEventMethodName: () => string = () =>
-        this.useStickyEvents ? "_unstable_sendStickyDelayedEvent" : "_unstable_sendDelayedStateEvent";
+        this.client._unstable_sendDelayedStateEvent(
+            this.room.roomId,
+            { delay: this.delayedLeaveEventDelayMs },
+            EventType.GroupCallMemberPrefix,
+            myMembership,
+            this.stateKey,
+        );
 
     // HANDLERS (used in the membershipLoopHandler)
     private async sendOrResendDelayedLeaveEvent(): Promise<ActionUpdate> {
@@ -531,7 +526,7 @@ export class MembershipManager
                 if (this.manageMaxDelayExceededSituation(e)) {
                     return createInsertActionUpdate(repeatActionType);
                 }
-                const update = this.actionUpdateFromErrors(e, repeatActionType, this.sendDelayedEventMethodName());
+                const update = this.actionUpdateFromErrors(e, repeatActionType, "_unstable_sendDelayedStateEvent");
                 if (update) return update;
 
                 if (this.state.hasMemberStateEvent) {
@@ -687,25 +682,10 @@ export class MembershipManager
             });
     }
 
-    private clientSendMembership: (myMembership: SessionMembershipData | EmptyObject) => Promise<ISendEventResponse> = (
-        myMembership,
-    ) =>
-        this.useStickyEvents
-            ? this.client._unstable_sendStickyEvent(
-                  this.room.roomId,
-                  STICK_DURATION_MS,
-                  null,
-                  EventType.GroupCallMemberPrefix,
-                  Object.assign(myMembership, { sticky_key: this.stateKey }),
-              )
-            : this.client.sendStateEvent(
-                  this.room.roomId,
-                  EventType.GroupCallMemberPrefix,
-                  myMembership,
-                  this.stateKey,
-              );
-    private sendMembershipMethodName: () => string = () =>
-        this.useStickyEvents ? "_unstable_sendStickyEvent" : "sendStateEvent";
+    protected clientSendMembership: (myMembership: SessionMembershipData | EmptyObject) => Promise<ISendEventResponse> =
+        (myMembership) =>
+            this.client.sendStateEvent(this.room.roomId, EventType.GroupCallMemberPrefix, myMembership, this.stateKey);
+
     private async sendJoinEvent(): Promise<ActionUpdate> {
         return await this.clientSendMembership(this.makeMyMembership(this.membershipEventExpiryMs))
             .then(() => {
@@ -739,11 +719,7 @@ export class MembershipManager
                 };
             })
             .catch((e) => {
-                const update = this.actionUpdateFromErrors(
-                    e,
-                    MembershipActionType.SendJoinEvent,
-                    this.sendMembershipMethodName(),
-                );
+                const update = this.actionUpdateFromErrors(e, MembershipActionType.SendJoinEvent, "sendStateEvent");
                 if (update) return update;
                 throw e;
             });
@@ -768,11 +744,7 @@ export class MembershipManager
                 };
             })
             .catch((e) => {
-                const update = this.actionUpdateFromErrors(
-                    e,
-                    MembershipActionType.UpdateExpiry,
-                    this.sendMembershipMethodName(),
-                );
+                const update = this.actionUpdateFromErrors(e, MembershipActionType.UpdateExpiry, "sendStateEvent");
                 if (update) return update;
 
                 throw e;
@@ -786,11 +758,7 @@ export class MembershipManager
                 return { replace: [] };
             })
             .catch((e) => {
-                const update = this.actionUpdateFromErrors(
-                    e,
-                    MembershipActionType.SendLeaveEvent,
-                    this.sendMembershipMethodName(),
-                );
+                const update = this.actionUpdateFromErrors(e, MembershipActionType.SendLeaveEvent, "sendStateEvent");
                 if (update) return update;
                 throw e;
             });
@@ -857,7 +825,7 @@ export class MembershipManager
         return false;
     }
 
-    private actionUpdateFromErrors(
+    protected actionUpdateFromErrors(
         error: unknown,
         type: MembershipActionType,
         method: string,
@@ -905,7 +873,7 @@ export class MembershipManager
             return createInsertActionUpdate(type, resendDelay);
         }
 
-        throw Error("Exceeded maximum retries for " + type + " attempts (client." + method + "): " + (error as Error));
+        throw Error("Exceeded maximum retries for " + type + " attempts (client." + method + ")", { cause: error });
     }
 
     /**
@@ -1049,14 +1017,64 @@ export class MembershipManager
     }
 }
 
-function createInsertActionUpdate(type: MembershipActionType, offset?: number): ActionUpdate {
-    return {
-        insert: [{ ts: Date.now() + (offset ?? 0), type }],
-    };
-}
+/**
+ * Implementation of the Membership manager that uses sticky events
+ * rather than state events.
+ */
+export class StickyEventMembershipManager extends MembershipManager {
+    public constructor(
+        joinConfig: (SessionConfig & MembershipConfig) | undefined,
+        room: Pick<Room, "getLiveTimeline" | "roomId" | "getVersion">,
+        private readonly clientWithSticky: Pick<
+            MatrixClient,
+            | "getUserId"
+            | "getDeviceId"
+            | "sendStateEvent"
+            | "_unstable_sendDelayedStateEvent"
+            | "_unstable_updateDelayedEvent"
+            | "_unstable_sendStickyEvent"
+            | "_unstable_sendStickyDelayedEvent"
+        >,
+        getOldestMembership: () => CallMembership | undefined,
+        sessionDescription: SessionDescription,
+        parentLogger?: Logger,
+    ) {
+        super(joinConfig, room, clientWithSticky, getOldestMembership, sessionDescription, parentLogger);
+    }
 
-function createReplaceActionUpdate(type: MembershipActionType, offset?: number): ActionUpdate {
-    return {
-        replace: [{ ts: Date.now() + (offset ?? 0), type }],
-    };
+    protected clientSendDelayedEvent: (myMembership: EmptyObject) => Promise<SendDelayedEventResponse> = (
+        myMembership,
+    ) =>
+        this.clientWithSticky._unstable_sendStickyDelayedEvent(
+            this.room.roomId,
+            STICK_DURATION_MS,
+            { delay: this.delayedLeaveEventDelayMs },
+            null,
+            EventType.GroupCallMemberPrefix,
+            Object.assign(myMembership, { sticky_key: this.stateKey }),
+        );
+
+    protected clientSendMembership: (myMembership: SessionMembershipData | EmptyObject) => Promise<ISendEventResponse> =
+        (myMembership) =>
+            this.clientWithSticky._unstable_sendStickyEvent(
+                this.room.roomId,
+                STICK_DURATION_MS,
+                null,
+                EventType.GroupCallMemberPrefix,
+                Object.assign(myMembership, { sticky_key: this.stateKey }),
+            );
+
+    protected actionUpdateFromErrors(
+        error: unknown,
+        type: MembershipActionType,
+        method: string,
+    ): ActionUpdate | undefined {
+        // Override method name.
+        if (method === "sendStateEvent") {
+            method = "_unstable_sendStickyEvent";
+        } else if (method === "_unstable_sendDelayedStateEvent") {
+            method = "_unstable_sendStickyDelayedEvent";
+        }
+        return super.actionUpdateFromErrors(error, type, method);
+    }
 }