Fix issue with getEventTimeline returning undefined for thread roots in main timeline (#2454)

* Fix test message utils using overload

* Tweak existing tests

* Add test around `MatrixClient::getEventTimeline`

* Fix test to actually exercise the faulty behaviour

* Extract timelineSet thread belongs logic and test it

* tweak method name

spec/integ/matrix-client-event-timeline.spec.js

@@ -70,10 +70,23 @@ const EVENTS = [
     }),
 ];
 
-const THREAD_ROOT = utils.mkMessage({
+const THREAD_ROOT = utils.mkEvent({
     room: roomId,
     user: userId,
-    msg: "thread root",
+    type: "m.room.message",
+    content: {
+        "body": "thread root",
+        "msgtype": "m.text",
+    },
+    unsigned: {
+        "m.relations": {
+            "io.element.thread": {
+                "latest_event": undefined,
+                "count": 1,
+                "current_user_participated": true,
+            },
+        },
+    },
 });
 
 const THREAD_REPLY = utils.mkEvent({
@@ -91,6 +104,8 @@ const THREAD_REPLY = utils.mkEvent({
     },
 });
 
+THREAD_ROOT.unsigned["m.relations"]["io.element.thread"].latest_event = THREAD_REPLY;
+
 // start the client, and wait for it to initialise
 function startClient(httpBackend, client) {
     httpBackend.when("GET", "/versions").respond(200, {});
@@ -540,7 +555,38 @@ describe("MatrixClient event timelines", function() {
             expect(timeline.getEvents().find(e => e.getId() === THREAD_REPLY.event_id)).toBeTruthy();
         });
 
-        it("should return undefined when event is not within a thread but timelineSet is", async () => {
+        it("should return relevant timeline from non-thread timelineSet when asking for the thread root", async () => {
+            client.clientOpts.experimentalThreadSupport = true;
+            Thread.setServerSideSupport(true);
+            client.stopClient(); // we don't need the client to be syncing at this time
+            const room = client.getRoom(roomId);
+            const threadRoot = new MatrixEvent(THREAD_ROOT);
+            const thread = room.createThread(THREAD_ROOT.event_id, threadRoot, [threadRoot], false);
+            const timelineSet = room.getTimelineSets()[0];
+
+            httpBackend.when("GET", "/rooms/!foo%3Abar/context/" + encodeURIComponent(THREAD_ROOT.event_id))
+                .respond(200, function() {
+                    return {
+                        start: "start_token0",
+                        events_before: [],
+                        event: THREAD_ROOT,
+                        events_after: [],
+                        end: "end_token0",
+                        state: [],
+                    };
+                });
+
+            const [timeline] = await Promise.all([
+                client.getEventTimeline(timelineSet, THREAD_ROOT.event_id),
+                httpBackend.flushAllExpected(),
+            ]);
+
+            expect(timeline).not.toBe(thread.liveTimeline);
+            expect(timelineSet.getTimelines()).toContain(timeline);
+            expect(timeline.getEvents().find(e => e.getId() === THREAD_ROOT.event_id)).toBeTruthy();
+        });
+
+        it("should return undefined when event is not in the thread that the given timelineSet is representing", () => {
             client.clientOpts.experimentalThreadSupport = true;
             Thread.setServerSideSupport(true);
             client.stopClient(); // we don't need the client to be syncing at this time
@@ -549,11 +595,6 @@ describe("MatrixClient event timelines", function() {
             const thread = room.createThread(THREAD_ROOT.event_id, threadRoot, [threadRoot], false);
             const timelineSet = thread.timelineSet;
 
-            httpBackend.when("GET", "/rooms/!foo%3Abar/event/" + encodeURIComponent(THREAD_ROOT.event_id))
-                .respond(200, function() {
-                    return THREAD_ROOT;
-                });
-
             httpBackend.when("GET", "/rooms/!foo%3Abar/context/" + encodeURIComponent(EVENTS[0].event_id))
                 .respond(200, function() {
                     return {
@@ -566,14 +607,13 @@ describe("MatrixClient event timelines", function() {
                     };
                 });
 
-            const timelinePromise = client.getEventTimeline(timelineSet, EVENTS[0].event_id);
+            return Promise.all([
-            await httpBackend.flushAllExpected();
+                expect(client.getEventTimeline(timelineSet, EVENTS[0].event_id)).resolves.toBeUndefined(),
-
+                httpBackend.flushAllExpected(),
-            const timeline = await timelinePromise;
+            ]);
-            expect(timeline).toBeUndefined();
         });
 
-        it("should return undefined when event is within a thread but timelineSet is not", async () => {
+        it("should return undefined when event is within a thread but timelineSet is not", () => {
             client.clientOpts.experimentalThreadSupport = true;
             Thread.setServerSideSupport(true);
             client.stopClient(); // we don't need the client to be syncing at this time
@@ -592,11 +632,10 @@ describe("MatrixClient event timelines", function() {
                     };
                 });
 
-            const timelinePromise = client.getEventTimeline(timelineSet, THREAD_REPLY.event_id);
+            return Promise.all([
-            await httpBackend.flushAllExpected();
+                expect(client.getEventTimeline(timelineSet, THREAD_REPLY.event_id)).resolves.toBeUndefined(),
-
+                httpBackend.flushAllExpected(),
-            const timeline = await timelinePromise;
+            ]);
-            expect(timeline).toBeUndefined();
         });
 
         it("should should add lazy loading filter when requested", async () => {

spec/test-utils/test-utils.ts

@@ -74,7 +74,6 @@ interface IEventOpts {
     sender?: string;
     skey?: string;
     content: IContent;
-    event?: boolean;
     user?: string;
     unsigned?: IUnsigned;
     redacts?: string;
@@ -93,7 +92,9 @@ let testEventIndex = 1; // counter for events, easier for comparison of randomly
  * @param {MatrixClient} client If passed along with opts.event=true will be used to set up re-emitters.
  * @return {Object} a JSON object representing this event.
  */
-export function mkEvent(opts: IEventOpts, client?: MatrixClient): object | MatrixEvent {
+export function mkEvent(opts: IEventOpts & { event: true }, client?: MatrixClient): MatrixEvent;
+export function mkEvent(opts: IEventOpts & { event?: false }, client?: MatrixClient): object;
+export function mkEvent(opts: IEventOpts & { event?: boolean }, client?: MatrixClient): object | MatrixEvent {
     if (!opts.type || !opts.content) {
         throw new Error("Missing .type or .content =>" + JSON.stringify(opts));
     }
@@ -143,7 +144,9 @@ interface IPresenceOpts {
  * @param {Object} opts Values for the presence.
  * @return {Object|MatrixEvent} The event
  */
-export function mkPresence(opts: IPresenceOpts): object | MatrixEvent {
+export function mkPresence(opts: IPresenceOpts & { event: true }): MatrixEvent;
+export function mkPresence(opts: IPresenceOpts & { event?: false }): object;
+export function mkPresence(opts: IPresenceOpts & { event?: boolean }): object | MatrixEvent {
     const event = {
         event_id: "$" + Math.random() + "-" + Math.random(),
         type: "m.presence",
@@ -182,7 +185,9 @@ interface IMembershipOpts {
  * @param {boolean} opts.event True to make a MatrixEvent.
  * @return {Object|MatrixEvent} The event
  */
-export function mkMembership(opts: IMembershipOpts): object | MatrixEvent {
+export function mkMembership(opts: IMembershipOpts & { event: true }): MatrixEvent;
+export function mkMembership(opts: IMembershipOpts & { event?: false }): object;
+export function mkMembership(opts: IMembershipOpts & { event?: boolean }): object | MatrixEvent {
     const eventOpts: IEventOpts = {
         ...opts,
         type: EventType.RoomMember,
@@ -220,7 +225,9 @@ interface IMessageOpts {
  * @param {MatrixClient} client If passed along with opts.event=true will be used to set up re-emitters.
  * @return {Object|MatrixEvent} The event
  */
-export function mkMessage(opts: IMessageOpts, client?: MatrixClient): object | MatrixEvent {
+export function mkMessage(opts: IMessageOpts & { event: true }, client?: MatrixClient): MatrixEvent;
+export function mkMessage(opts: IMessageOpts & { event?: false }, client?: MatrixClient): object;
+export function mkMessage(opts: IMessageOpts & { event?: boolean }, client?: MatrixClient): object | MatrixEvent {
     const eventOpts: IEventOpts = {
         ...opts,
         type: EventType.RoomMessage,
@@ -252,7 +259,12 @@ interface IReplyMessageOpts extends IMessageOpts {
  * @param {MatrixClient} client If passed along with opts.event=true will be used to set up re-emitters.
  * @return {Object|MatrixEvent} The event
  */
-export function mkReplyMessage(opts: IReplyMessageOpts, client?: MatrixClient): object | MatrixEvent {
+export function mkReplyMessage(opts: IReplyMessageOpts & { event: true }, client?: MatrixClient): MatrixEvent;
+export function mkReplyMessage(opts: IReplyMessageOpts & { event?: false }, client?: MatrixClient): object;
+export function mkReplyMessage(
+    opts: IReplyMessageOpts & { event?: boolean },
+    client?: MatrixClient,
+): object | MatrixEvent {
     const eventOpts: IEventOpts = {
         ...opts,
         type: EventType.RoomMessage,

spec/unit/event-timeline-set.spec.ts

@@ -25,6 +25,8 @@ import {
     Room,
     DuplicateStrategy,
 } from '../../src';
+import { Thread } from "../../src/models/thread";
+import { ReEmitter } from "../../src/ReEmitter";
 
 describe('EventTimelineSet', () => {
     const roomId = '!foo:bar';
@@ -54,6 +56,7 @@ describe('EventTimelineSet', () => {
 
     beforeEach(() => {
         client = utils.mock(MatrixClient, 'MatrixClient');
+        client.reEmitter = utils.mock(ReEmitter, 'ReEmitter');
         room = new Room(roomId, client, userA);
         eventTimelineSet = new EventTimelineSet(room);
         eventTimeline = new EventTimeline(eventTimelineSet);
@@ -62,14 +65,14 @@ describe('EventTimelineSet', () => {
             user: userA,
             msg: 'Hi!',
             event: true,
-        }) as MatrixEvent;
+        });
         replyEvent = utils.mkReplyMessage({
             room: roomId,
             user: userA,
             msg: 'Hoo!',
             event: true,
             replyToMessage: messageEvent,
-        }) as MatrixEvent;
+        });
     });
 
     describe('addLiveEvent', () => {
@@ -91,7 +94,7 @@ describe('EventTimelineSet', () => {
             // make a duplicate
             const duplicateMessageEvent = utils.mkMessage({
                 room: roomId, user: userA, msg: "dupe", event: true,
-            }) as MatrixEvent;
+            });
             duplicateMessageEvent.event.event_id = messageEvent.getId();
 
             // Adding the duplicate event should replace the `messageEvent`
@@ -220,4 +223,72 @@ describe('EventTimelineSet', () => {
             });
         });
     });
+
+    describe("canContain", () => {
+        const mkThreadResponse = (root: MatrixEvent) => utils.mkEvent({
+            event: true,
+            type: EventType.RoomMessage,
+            user: userA,
+            room: roomId,
+            content: {
+                "body": "Thread response :: " + Math.random(),
+                "m.relates_to": {
+                    "event_id": root.getId(),
+                    "m.in_reply_to": {
+                        "event_id": root.getId(),
+                    },
+                    "rel_type": "m.thread",
+                },
+            },
+        }, room.client);
+
+        let thread: Thread;
+
+        beforeEach(() => {
+            (client.supportsExperimentalThreads as jest.Mock).mockReturnValue(true);
+            thread = new Thread("!thread_id:server", messageEvent, { room, client });
+        });
+
+        it("should throw if timeline set has no room", () => {
+            const eventTimelineSet = new EventTimelineSet(undefined, {}, client);
+            expect(() => eventTimelineSet.canContain(messageEvent)).toThrowError();
+        });
+
+        it("should return false if timeline set is for thread but event is not threaded", () => {
+            const eventTimelineSet = new EventTimelineSet(room, {}, client, thread);
+            expect(eventTimelineSet.canContain(replyEvent)).toBeFalsy();
+        });
+
+        it("should return false if timeline set it for thread but event it for a different thread", () => {
+            const eventTimelineSet = new EventTimelineSet(room, {}, client, thread);
+            const event = mkThreadResponse(replyEvent);
+            expect(eventTimelineSet.canContain(event)).toBeFalsy();
+        });
+
+        it("should return false if timeline set is not for a thread but event is a thread response", () => {
+            const eventTimelineSet = new EventTimelineSet(room, {}, client);
+            const event = mkThreadResponse(replyEvent);
+            expect(eventTimelineSet.canContain(event)).toBeFalsy();
+        });
+
+        it("should return true if the timeline set is not for a thread and the event is a thread root", () => {
+            const eventTimelineSet = new EventTimelineSet(room, {}, client);
+            expect(eventTimelineSet.canContain(messageEvent)).toBeTruthy();
+        });
+
+        it("should return true if the timeline set is for a thread and the event is its thread root", () => {
+            const thread = new Thread(messageEvent.getId(), messageEvent, { room, client });
+            const eventTimelineSet = new EventTimelineSet(room, {}, client, thread);
+            messageEvent.setThread(thread);
+            expect(eventTimelineSet.canContain(messageEvent)).toBeTruthy();
+        });
+
+        it("should return true if the timeline set is for a thread and the event is a response to it", () => {
+            const thread = new Thread(messageEvent.getId(), messageEvent, { room, client });
+            const eventTimelineSet = new EventTimelineSet(room, {}, client, thread);
+            messageEvent.setThread(thread);
+            const event = mkThreadResponse(messageEvent);
+            expect(eventTimelineSet.canContain(event)).toBeTruthy();
+        });
+    });
 });

spec/unit/filter-component.spec.ts

@@ -1,7 +1,4 @@
-import {
+import { RelationType } from "../../src";
-    MatrixEvent,
-    RelationType,
-} from "../../src";
 import { FilterComponent } from "../../src/filter-component";
 import { mkEvent } from '../test-utils/test-utils';
 
@@ -14,7 +11,7 @@ describe("Filter Component", function() {
                 content: { },
                 room: 'roomId',
                 event: true,
-            }) as MatrixEvent;
+            });
 
             const checkResult = filter.check(event);
 
@@ -28,7 +25,7 @@ describe("Filter Component", function() {
                 content: { },
                 room: 'roomId',
                 event: true,
-            }) as MatrixEvent;
+            });
 
             const checkResult = filter.check(event);
 
@@ -55,7 +52,7 @@ describe("Filter Component", function() {
                         },
                     },
                 },
-            }) as MatrixEvent;
+            });
 
             expect(filter.check(threadRootNotParticipated)).toBe(false);
         });
@@ -80,7 +77,7 @@ describe("Filter Component", function() {
                 user: '@someone-else:server.org',
                 room: 'roomId',
                 event: true,
-            }) as MatrixEvent;
+            });
 
             expect(filter.check(threadRootParticipated)).toBe(true);
         });
@@ -100,7 +97,7 @@ describe("Filter Component", function() {
                         [RelationType.Reference]: {},
                     },
                 },
-            }) as MatrixEvent;
+            });
 
             expect(filter.check(referenceRelationEvent)).toBe(false);
         });
@@ -123,7 +120,7 @@ describe("Filter Component", function() {
                 },
                 room: 'roomId',
                 event: true,
-            }) as MatrixEvent;
+            });
 
             const eventWithMultipleRelations = mkEvent({
                 "type": "m.room.message",
@@ -148,7 +145,7 @@ describe("Filter Component", function() {
                 },
                 "room": 'roomId',
                 "event": true,
-            }) as MatrixEvent;
+            });
 
             const noMatchEvent = mkEvent({
                 "type": "m.room.message",
@@ -160,7 +157,7 @@ describe("Filter Component", function() {
                 },
                 "room": 'roomId',
                 "event": true,
-            }) as MatrixEvent;
+            });
 
             expect(filter.check(threadRootEvent)).toBe(true);
             expect(filter.check(eventWithMultipleRelations)).toBe(true);

spec/unit/room.spec.ts

@@ -52,7 +52,7 @@ describe("Room", function() {
         event: true,
         user: userA,
         room: roomId,
-    }, room.client) as MatrixEvent;
+    }, room.client);
 
     const mkReply = (target: MatrixEvent) => utils.mkEvent({
         event: true,
@@ -67,7 +67,7 @@ describe("Room", function() {
                 },
             },
         },
-    }, room.client) as MatrixEvent;
+    }, room.client);
 
     const mkEdit = (target: MatrixEvent, salt = Math.random()) => utils.mkEvent({
         event: true,
@@ -84,7 +84,7 @@ describe("Room", function() {
                 event_id: target.getId(),
             },
         },
-    }, room.client) as MatrixEvent;
+    }, room.client);
 
     const mkThreadResponse = (root: MatrixEvent) => utils.mkEvent({
         event: true,
@@ -101,7 +101,7 @@ describe("Room", function() {
                 "rel_type": "m.thread",
             },
         },
-    }, room.client) as MatrixEvent;
+    }, room.client);
 
     const mkReaction = (target: MatrixEvent) => utils.mkEvent({
         event: true,
@@ -115,7 +115,7 @@ describe("Room", function() {
                 "key": Math.random().toString(),
             },
         },
-    }, room.client) as MatrixEvent;
+    }, room.client);
 
     const mkRedaction = (target: MatrixEvent) => utils.mkEvent({
         event: true,
@@ -124,7 +124,7 @@ describe("Room", function() {
         room: roomId,
         redacts: target.getId(),
         content: {},
-    }, room.client) as MatrixEvent;
+    }, room.client);
 
     beforeEach(function() {
         room = new Room(roomId, new TestClient(userA, "device").client, userA);
@@ -210,11 +210,11 @@ describe("Room", function() {
         const events: MatrixEvent[] = [
             utils.mkMessage({
                 room: roomId, user: userA, msg: "changing room name", event: true,
-            }) as MatrixEvent,
+            }),
             utils.mkEvent({
                 type: EventType.RoomName, room: roomId, user: userA, event: true,
                 content: { name: "New Room Name" },
-            }) as MatrixEvent,
+            }),
         ];
 
         it("Make sure legacy overload passing options directly as parameters still works", () => {
@@ -235,7 +235,7 @@ describe("Room", function() {
             // make a duplicate
             const dupe = utils.mkMessage({
                 room: roomId, user: userA, msg: "dupe", event: true,
-            }) as MatrixEvent;
+            });
             dupe.event.event_id = events[0].getId();
             room.addLiveEvents(events);
             expect(room.timeline[0]).toEqual(events[0]);
@@ -249,7 +249,7 @@ describe("Room", function() {
             // make a duplicate
             const dupe = utils.mkMessage({
                 room: roomId, user: userA, msg: "dupe", event: true,
-            }) as MatrixEvent;
+            });
             dupe.event.event_id = events[0].getId();
             room.addLiveEvents(events);
             expect(room.timeline[0]).toEqual(events[0]);
@@ -277,13 +277,13 @@ describe("Room", function() {
                 const events: MatrixEvent[] = [
                     utils.mkMembership({
                         room: roomId, mship: "invite", user: userB, skey: userA, event: true,
-                    }) as MatrixEvent,
+                    }),
                     utils.mkEvent({
                         type: EventType.RoomName, room: roomId, user: userB, event: true,
                         content: {
                             name: "New room",
                         },
-                    }) as MatrixEvent,
+                    }),
                 ];
                 room.addLiveEvents(events);
                 expect(room.currentState.setStateEvents).toHaveBeenCalledWith(
@@ -318,13 +318,13 @@ describe("Room", function() {
         it("should emit Room.localEchoUpdated when a local echo is updated", function() {
             const localEvent = utils.mkMessage({
                 room: roomId, user: userA, event: true,
-            }) as MatrixEvent;
+            });
             localEvent.status = EventStatus.SENDING;
             const localEventId = localEvent.getId();
 
             const remoteEvent = utils.mkMessage({
                 room: roomId, user: userA, event: true,
-            }) as MatrixEvent;
+            });
             remoteEvent.event.unsigned = { transaction_id: "TXN_ID" };
             const remoteEventId = remoteEvent.getId();
 
@@ -445,11 +445,11 @@ describe("Room", function() {
             const newEv = utils.mkEvent({
                 type: EventType.RoomName, room: roomId, user: userA, event: true,
                 content: { name: "New Room Name" },
-            }) as MatrixEvent;
+            });
             const oldEv = utils.mkEvent({
                 type: EventType.RoomName, room: roomId, user: userA, event: true,
                 content: { name: "Old Room Name" },
-            }) as MatrixEvent;
+            });
             room.addLiveEvents([newEv]);
             expect(newEv.sender).toEqual(sentinel);
             room.addEventsToTimeline([oldEv], true, room.getLiveTimeline());
@@ -482,10 +482,10 @@ describe("Room", function() {
 
             const newEv = utils.mkMembership({
                 room: roomId, mship: "invite", user: userB, skey: userA, event: true,
-            }) as MatrixEvent;
+            });
             const oldEv = utils.mkMembership({
                 room: roomId, mship: "ban", user: userB, skey: userA, event: true,
-            }) as MatrixEvent;
+            });
             room.addLiveEvents([newEv]);
             expect(newEv.target).toEqual(sentinel);
             room.addEventsToTimeline([oldEv], true, room.getLiveTimeline());
@@ -497,13 +497,13 @@ describe("Room", function() {
             const events: MatrixEvent[] = [
                 utils.mkMembership({
                     room: roomId, mship: "invite", user: userB, skey: userA, event: true,
-                }) as MatrixEvent,
+                }),
                 utils.mkEvent({
                     type: EventType.RoomName, room: roomId, user: userB, event: true,
                     content: {
                         name: "New room",
                     },
-                }) as MatrixEvent,
+                }),
             ];
 
             room.addEventsToTimeline(events, true, room.getLiveTimeline());
@@ -631,13 +631,13 @@ describe("Room", function() {
         const events: MatrixEvent[] = [
             utils.mkMessage({
                 room: roomId, user: userA, msg: "1111", event: true,
-            }) as MatrixEvent,
+            }),
             utils.mkMessage({
                 room: roomId, user: userA, msg: "2222", event: true,
-            }) as MatrixEvent,
+            }),
             utils.mkMessage({
                 room: roomId, user: userA, msg: "3333", event: true,
-            }) as MatrixEvent,
+            }),
         ];
 
         it("should handle events in the same timeline", function() {
@@ -778,26 +778,26 @@ describe("Room", function() {
                 type: EventType.RoomJoinRules, room: roomId, user: userA, content: {
                     join_rule: rule,
                 }, event: true,
-            }) as MatrixEvent]);
+            })]);
         };
         const setAltAliases = function(aliases: string[]) {
             room.addLiveEvents([utils.mkEvent({
                 type: EventType.RoomCanonicalAlias, room: roomId, skey: "", content: {
                     alt_aliases: aliases,
                 }, event: true,
-            }) as MatrixEvent]);
+            })]);
         };
         const setAlias = function(alias: string) {
             room.addLiveEvents([utils.mkEvent({
                 type: EventType.RoomCanonicalAlias, room: roomId, skey: "", content: { alias }, event: true,
-            }) as MatrixEvent]);
+            })]);
         };
         const setRoomName = function(name: string) {
             room.addLiveEvents([utils.mkEvent({
                 type: EventType.RoomName, room: roomId, user: userA, content: {
                     name: name,
                 }, event: true,
-            }) as MatrixEvent]);
+            })]);
         };
         const addMember = function(userId: string, state = "join", opts: any = {}) {
             opts.room = roomId;
@@ -805,7 +805,7 @@ describe("Room", function() {
             opts.user = opts.user || userId;
             opts.skey = userId;
             opts.event = true;
-            const event = utils.mkMembership(opts) as MatrixEvent;
+            const event = utils.mkMembership(opts);
             room.addLiveEvents([event]);
             return event;
         };
@@ -1113,7 +1113,7 @@ describe("Room", function() {
         const eventToAck = utils.mkMessage({
             room: roomId, user: userA, msg: "PLEASE ACKNOWLEDGE MY EXISTENCE",
             event: true,
-        }) as MatrixEvent;
+        });
 
         function mkReceipt(roomId: string, records) {
             const content = {};
@@ -1179,7 +1179,7 @@ describe("Room", function() {
                 const nextEventToAck = utils.mkMessage({
                     room: roomId, user: userA, msg: "I AM HERE YOU KNOW",
                     event: true,
-                }) as MatrixEvent;
+                });
                 const ts = 13787898424;
                 room.addReceipt(mkReceipt(roomId, [
                     mkRecord(eventToAck.getId(), "m.read", userB, ts),
@@ -1214,11 +1214,11 @@ describe("Room", function() {
                 const eventTwo = utils.mkMessage({
                     room: roomId, user: userA, msg: "2222",
                     event: true,
-                }) as MatrixEvent;
+                });
                 const eventThree = utils.mkMessage({
                     room: roomId, user: userA, msg: "3333",
                     event: true,
-                }) as MatrixEvent;
+                });
                 const ts = 13787898424;
                 room.addReceipt(mkReceipt(roomId, [
                     mkRecord(eventToAck.getId(), "m.read", userB, ts),
@@ -1266,15 +1266,15 @@ describe("Room", function() {
                     utils.mkMessage({
                         room: roomId, user: userA, msg: "1111",
                         event: true,
-                    }) as MatrixEvent,
+                    }),
                     utils.mkMessage({
                         room: roomId, user: userA, msg: "2222",
                         event: true,
-                    }) as MatrixEvent,
+                    }),
                     utils.mkMessage({
                         room: roomId, user: userA, msg: "3333",
                         event: true,
-                    }) as MatrixEvent,
+                    }),
                 ];
 
                 room.addLiveEvents(events);
@@ -1304,15 +1304,15 @@ describe("Room", function() {
                     utils.mkMessage({
                         room: roomId, user: userA, msg: "1111",
                         event: true,
-                    }) as MatrixEvent,
+                    }),
                     utils.mkMessage({
                         room: roomId, user: userA, msg: "2222",
                         event: true,
-                    }) as MatrixEvent,
+                    }),
                     utils.mkMessage({
                         room: roomId, user: userA, msg: "3333",
                         event: true,
-                    }) as MatrixEvent,
+                    }),
                 ];
 
                 room.addLiveEvents(events);
@@ -1404,14 +1404,14 @@ describe("Room", function() {
             });
             const eventA = utils.mkMessage({
                 room: roomId, user: userA, msg: "remote 1", event: true,
-            }) as MatrixEvent;
+            });
             const eventB = utils.mkMessage({
                 room: roomId, user: userA, msg: "local 1", event: true,
-            }) as MatrixEvent;
+            });
             eventB.status = EventStatus.SENDING;
             const eventC = utils.mkMessage({
                 room: roomId, user: userA, msg: "remote 2", event: true,
-            }) as MatrixEvent;
+            });
             room.addLiveEvents([eventA]);
             room.addPendingEvent(eventB, "TXN1");
             room.addLiveEvents([eventC]);
@@ -1430,14 +1430,14 @@ describe("Room", function() {
             });
             const eventA = utils.mkMessage({
                 room: roomId, user: userA, msg: "remote 1", event: true,
-            }) as MatrixEvent;
+            });
             const eventB = utils.mkMessage({
                 room: roomId, user: userA, msg: "local 1", event: true,
-            }) as MatrixEvent;
+            });
             eventB.status = EventStatus.SENDING;
             const eventC = utils.mkMessage({
                 room: roomId, user: userA, msg: "remote 2", event: true,
-            }) as MatrixEvent;
+            });
             room.addLiveEvents([eventA]);
             room.addPendingEvent(eventB, "TXN1");
             room.addLiveEvents([eventC]);
@@ -1457,7 +1457,7 @@ describe("Room", function() {
             });
             const eventA = utils.mkMessage({
                 room: roomId, user: userA, event: true,
-            }) as MatrixEvent;
+            });
             eventA.status = EventStatus.SENDING;
             const eventId = eventA.getId();
 
@@ -1490,7 +1490,7 @@ describe("Room", function() {
             const room = new Room(roomId, null, userA);
             const eventA = utils.mkMessage({
                 room: roomId, user: userA, event: true,
-            }) as MatrixEvent;
+            });
             eventA.status = EventStatus.SENDING;
             const eventId = eventA.getId();
 
@@ -1567,7 +1567,7 @@ describe("Room", function() {
             room: roomId,
             event: true,
             name: "User A",
-        }) as MatrixEvent;
+        });
 
         it("should load members from server on first call", async function() {
             const client = createClientMock([memberEvent]);
@@ -1587,7 +1587,7 @@ describe("Room", function() {
                 room: roomId,
                 event: true,
                 name: "Ms A",
-            }) as MatrixEvent;
+            });
             const client = createClientMock([memberEvent2], [memberEvent]);
             const room = new Room(roomId, client as any, null, { lazyLoadMembers: true });
 
@@ -1658,7 +1658,7 @@ describe("Room", function() {
                 mship: "join",
                 room: roomId,
                 event: true,
-            }) as MatrixEvent]);
+            })]);
             expect(room.guessDMUserId()).toEqual(userB);
         });
         it("should return self if only member present", function() {
@@ -1691,11 +1691,11 @@ describe("Room", function() {
                 utils.mkMembership({
                     user: userA, mship: "join",
                     room: roomId, event: true, name: "User A",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userB, mship: "join",
                     room: roomId, event: true, name: "User B",
-                }) as MatrixEvent,
+                }),
             ]);
             expect(room.getDefaultRoomName(userA)).toEqual("User B");
         });
@@ -1706,11 +1706,11 @@ describe("Room", function() {
                 utils.mkMembership({
                     user: userA, mship: "join",
                     room: roomId, event: true, name: "User A",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userB, mship: "ban",
                     room: roomId, event: true, name: "User B",
-                }) as MatrixEvent,
+                }),
             ]);
             expect(room.getDefaultRoomName(userA)).toEqual("Empty room (was User B)");
         });
@@ -1721,11 +1721,11 @@ describe("Room", function() {
                 utils.mkMembership({
                     user: userA, mship: "join",
                     room: roomId, event: true, name: "User A",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userB, mship: "invite",
                     room: roomId, event: true, name: "User B",
-                }) as MatrixEvent,
+                }),
             ]);
             expect(room.getDefaultRoomName(userA)).toEqual("User B");
         });
@@ -1736,11 +1736,11 @@ describe("Room", function() {
                 utils.mkMembership({
                     user: userA, mship: "join",
                     room: roomId, event: true, name: "User A",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userB, mship: "leave",
                     room: roomId, event: true, name: "User B",
-                }) as MatrixEvent,
+                }),
             ]);
             expect(room.getDefaultRoomName(userA)).toEqual("Empty room (was User B)");
         });
@@ -1751,15 +1751,15 @@ describe("Room", function() {
                 utils.mkMembership({
                     user: userA, mship: "join",
                     room: roomId, event: true, name: "User A",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userB, mship: "join",
                     room: roomId, event: true, name: "User B",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userC, mship: "join",
                     room: roomId, event: true, name: "User C",
-                }) as MatrixEvent,
+                }),
             ]);
             expect(room.getDefaultRoomName(userA)).toEqual("User B and User C");
         });
@@ -1770,19 +1770,19 @@ describe("Room", function() {
                 utils.mkMembership({
                     user: userA, mship: "join",
                     room: roomId, event: true, name: "User A",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userB, mship: "join",
                     room: roomId, event: true, name: "User B",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userC, mship: "join",
                     room: roomId, event: true, name: "User C",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userD, mship: "join",
                     room: roomId, event: true, name: "User D",
-                }) as MatrixEvent,
+                }),
             ]);
             expect(room.getDefaultRoomName(userA)).toEqual("User B and 2 others");
         });
@@ -1795,18 +1795,18 @@ describe("Room", function() {
                 utils.mkMembership({
                     user: userA, mship: "join",
                     room: roomId, event: true, name: "User A",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userB, mship: "join",
                     room: roomId, event: true, name: "User B",
-                }) as MatrixEvent,
+                }),
                 utils.mkEvent({
                     type: UNSTABLE_ELEMENT_FUNCTIONAL_USERS.name, skey: "",
                     room: roomId, event: true,
                     content: {
                         service_members: [],
                     },
-                }) as MatrixEvent,
+                }),
             ]);
             expect(room.getDefaultRoomName(userA)).toEqual("User B");
         });
@@ -1817,11 +1817,11 @@ describe("Room", function() {
                 utils.mkMembership({
                     user: userA, mship: "join",
                     room: roomId, event: true, name: "User A",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userB, mship: "join",
                     room: roomId, event: true, name: "User B",
-                }) as MatrixEvent,
+                }),
                 utils.mkEvent({
                     type: UNSTABLE_ELEMENT_FUNCTIONAL_USERS.name,
                     skey: "",
@@ -1830,7 +1830,7 @@ describe("Room", function() {
                     content: {
                         service_members: 1,
                     },
-                }) as MatrixEvent,
+                }),
             ]);
             expect(room.getDefaultRoomName(userA)).toEqual("User B");
         });
@@ -1841,18 +1841,18 @@ describe("Room", function() {
                 utils.mkMembership({
                     user: userA, mship: "join",
                     room: roomId, event: true, name: "User A",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userB, mship: "join",
                     room: roomId, event: true, name: "User B",
-                }) as MatrixEvent,
+                }),
                 utils.mkEvent({
                     type: UNSTABLE_ELEMENT_FUNCTIONAL_USERS.name, skey: "",
                     room: roomId, event: true,
                     content: {
                         service_members: userB,
                     },
-                }) as MatrixEvent,
+                }),
             ]);
             expect(room.getDefaultRoomName(userA)).toEqual("User B");
         });
@@ -1863,18 +1863,18 @@ describe("Room", function() {
                 utils.mkMembership({
                     user: userA, mship: "join",
                     room: roomId, event: true, name: "User A",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userB, mship: "join",
                     room: roomId, event: true, name: "User B",
-                }) as MatrixEvent,
+                }),
                 utils.mkEvent({
                     type: UNSTABLE_ELEMENT_FUNCTIONAL_USERS.name, skey: "",
                     room: roomId, event: true,
                     content: {
                         service_members: [userB],
                     },
-                }) as MatrixEvent,
+                }),
             ]);
             expect(room.getDefaultRoomName(userA)).toEqual("Empty room");
         });
@@ -1885,22 +1885,22 @@ describe("Room", function() {
                 utils.mkMembership({
                     user: userA, mship: "join",
                     room: roomId, event: true, name: "User A",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userB, mship: "join",
                     room: roomId, event: true, name: "User B",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userC, mship: "join",
                     room: roomId, event: true, name: "User C",
-                }) as MatrixEvent,
+                }),
                 utils.mkEvent({
                     type: UNSTABLE_ELEMENT_FUNCTIONAL_USERS.name, skey: "",
                     room: roomId, event: true, user: userA,
                     content: {
                         service_members: [userC],
                     },
-                }) as MatrixEvent,
+                }),
             ]);
             expect(room.getDefaultRoomName(userA)).toEqual("User B");
         });
@@ -1911,22 +1911,22 @@ describe("Room", function() {
                 utils.mkMembership({
                     user: userA, mship: "join",
                     room: roomId, event: true, name: "User A",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userB, mship: "join",
                     room: roomId, event: true, name: "User B",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userC, mship: "join",
                     room: roomId, event: true, name: "User C",
-                }) as MatrixEvent,
+                }),
                 utils.mkEvent({
                     type: UNSTABLE_ELEMENT_FUNCTIONAL_USERS.name, skey: "",
                     room: roomId, event: true, user: userA,
                     content: {
                         service_members: [userB, userC],
                     },
-                }) as MatrixEvent,
+                }),
             ]);
             expect(room.getDefaultRoomName(userA)).toEqual("Empty room");
         });
@@ -1937,18 +1937,18 @@ describe("Room", function() {
                 utils.mkMembership({
                     user: userA, mship: "join",
                     room: roomId, event: true, name: "User A",
-                }) as MatrixEvent,
+                }),
                 utils.mkMembership({
                     user: userB, mship: "join",
                     room: roomId, event: true, name: "User B",
-                }) as MatrixEvent,
+                }),
                 utils.mkEvent({
                     type: UNSTABLE_ELEMENT_FUNCTIONAL_USERS.name, skey: "",
                     room: roomId, event: true, user: userA,
                     content: {
                         service_members: [userC],
                     },
-                }) as MatrixEvent,
+                }),
             ]);
             expect(room.getDefaultRoomName(userA)).toEqual("User B");
         });

src/client.ts

@@ -5283,15 +5283,7 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
         ];
 
         if (this.supportsExperimentalThreads()) {
-            const { threadId, shouldLiveInRoom } = timelineSet.room.eventShouldLiveIn(event);
+            if (!timelineSet.canContain(event)) {
-
-            if (!timelineSet.thread && !shouldLiveInRoom) {
-                // Thread response does not belong in this timelineSet
-                return undefined;
-            }
-
-            if (timelineSet.thread?.id !== threadId) {
-                // Event does not belong in this timelineSet
                 return undefined;
             }
 

src/models/event-timeline-set.ts

@@ -842,6 +842,31 @@ export class EventTimelineSet extends TypedEventEmitter<EmittedEvents, EventTime
         // the timelines are not contiguous.
         return null;
     }
+
+    /**
+     * Determine whether a given event can sanely be added to this event timeline set,
+     * for timeline sets relating to a thread, only return true for events in the same
+     * thread timeline, for timeline sets not relating to a thread only return true
+     * for events which should be shown in the main room timeline.
+     * Requires the `room` property to have been set at EventTimelineSet construction time.
+     *
+     * @param event {MatrixEvent} the event to check whether it belongs to this timeline set.
+     * @throws {Error} if `room` was not set when constructing this timeline set.
+     * @return {boolean} whether the event belongs to this timeline set.
+     */
+    public canContain(event: MatrixEvent): boolean {
+        if (!this.room) {
+            throw new Error("Cannot call `EventTimelineSet::canContain without a `room` set. " +
+                "Set the room when creating the EventTimelineSet to call this method.");
+        }
+
+        const { threadId, shouldLiveInRoom } = this.room.eventShouldLiveIn(event);
+
+        if (this.thread) {
+            return this.thread.id === threadId;
+        }
+        return shouldLiveInRoom;
+    }
 }
 
 /**

src/models/event-timeline.ts

@@ -437,7 +437,7 @@ export class EventTimeline {
             }
         }
 
-        let insertIndex;
+        let insertIndex: number;
 
         if (toStartOfTimeline) {
             insertIndex = 0;