Move redacted messages out of any thread, into main timeline.

For consistency with the spec at room version 11. See
matrix-org/matrix-spec-proposals#3389
for a proposal to make this unnecessary.

spec/unit/models/event.spec.ts

@@ -14,10 +14,19 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import { MockedObject } from "jest-mock";
+
 import { MatrixEvent, MatrixEventEvent } from "../../../src/models/event";
 import { emitPromise } from "../../test-utils/test-utils";
 import { Crypto, IEventDecryptionResult } from "../../../src/crypto";
-import { IAnnotatedPushRule, PushRuleActionName, TweakName } from "../../../src";
+import {
+    IAnnotatedPushRule,
+    MatrixClient,
+    PushRuleActionName,
+    Room,
+    THREAD_RELATION_TYPE,
+    TweakName,
+} from "../../../src";
 
 describe("MatrixEvent", () => {
     it("should create copies of itself", () => {
@@ -77,17 +86,98 @@ describe("MatrixEvent", () => {
         expect(ev.getWireContent().body).toBeUndefined();
         expect(ev.getWireContent().ciphertext).toBe("xyz");
 
+        const mockClient = {} as unknown as MockedObject<MatrixClient>;
+        const room = new Room("!roomid:e.xyz", mockClient, "myname");
         const redaction = new MatrixEvent({
             type: "m.room.redaction",
             redacts: ev.getId(),
         });
 
-        ev.makeRedacted(redaction);
+        ev.makeRedacted(redaction, room);
         expect(ev.getContent().body).toBeUndefined();
         expect(ev.getWireContent().body).toBeUndefined();
         expect(ev.getWireContent().ciphertext).toBeUndefined();
     });
 
+    it("should remain in the main timeline when redacted", async () => {
+        // Given an event in the main timeline
+        const mockClient = {
+            supportsThreads: jest.fn().mockReturnValue(true),
+            decryptEventIfNeeded: jest.fn().mockReturnThis(),
+            getUserId: jest.fn().mockReturnValue("@user:server"),
+        } as unknown as MockedObject<MatrixClient>;
+        const room = new Room("!roomid:e.xyz", mockClient, "myname");
+        const ev = new MatrixEvent({
+            type: "m.room.message",
+            content: {
+                body: "Test",
+            },
+            event_id: "$event1:server",
+        });
+
+        await room.addLiveEvents([ev]);
+        await room.createThreadsTimelineSets();
+        expect(ev.threadRootId).toBeUndefined();
+        expect(mainTimelineLiveEventIds(room)).toEqual(["$event1:server"]);
+
+        // When I redact it
+        const redaction = new MatrixEvent({
+            type: "m.room.redaction",
+            redacts: ev.getId(),
+        });
+        ev.makeRedacted(redaction, room);
+
+        // Then it remains in the main timeline
+        expect(ev.threadRootId).toBeUndefined();
+        expect(mainTimelineLiveEventIds(room)).toEqual(["$event1:server"]);
+    });
+
+    it("should move into the main timeline when redacted", async () => {
+        // Given an event in a thread
+        const mockClient = {
+            supportsThreads: jest.fn().mockReturnValue(true),
+            decryptEventIfNeeded: jest.fn().mockReturnThis(),
+            getUserId: jest.fn().mockReturnValue("@user:server"),
+        } as unknown as MockedObject<MatrixClient>;
+        const room = new Room("!roomid:e.xyz", mockClient, "myname");
+        const threadRoot = new MatrixEvent({
+            type: "m.room.message",
+            content: {
+                body: "threadRoot",
+            },
+            event_id: "$threadroot:server",
+        });
+        const ev = new MatrixEvent({
+            type: "m.room.message",
+            content: {
+                "body": "Test",
+                "m.relates_to": {
+                    rel_type: THREAD_RELATION_TYPE.name,
+                    event_id: "$threadroot:server",
+                },
+            },
+            event_id: "$event1:server",
+        });
+
+        await room.addLiveEvents([threadRoot, ev]);
+        await room.createThreadsTimelineSets();
+        expect(ev.threadRootId).toEqual("$threadroot:server");
+        expect(mainTimelineLiveEventIds(room)).toEqual(["$threadroot:server"]);
+        expect(threadLiveEventIds(room, 0)).toEqual(["$threadroot:server", "$event1:server"]);
+
+        // When I redact it
+        const redaction = new MatrixEvent({
+            type: "m.room.redaction",
+            redacts: ev.getId(),
+        });
+        ev.makeRedacted(redaction, room);
+
+        // Then it disappears from the thread and appears in the main timeline
+        expect(ev.threadRootId).toBeUndefined();
+        expect(mainTimelineLiveEventIds(room)).toEqual(["$threadroot:server", "$event1:server"]);
+        expect(threadLiveEventIds(room, 0)).not.toContain("$event1:server");
+    });
+
     describe("applyVisibilityEvent", () => {
         it("should emit VisibilityChange if a change was made", async () => {
             const ev = new MatrixEvent({
@@ -330,3 +420,19 @@ describe("MatrixEvent", () => {
         expect(stateEvent.threadRootId).toBeUndefined();
     });
 });
+
+function mainTimelineLiveEventIds(room: Room): Array<string> {
+    return room
+        .getLiveTimeline()
+        .getEvents()
+        .map((e) => e.getId()!);
+}
+
+function threadLiveEventIds(room: Room, threadIndex: number): Array<string> {
+    return room
+        .getThreads()
+        [threadIndex].getUnfilteredTimelineSet()
+        .getLiveTimeline()
+        .getEvents()
+        .map((e) => e.getId()!);
+}

spec/unit/room-state.spec.ts

@@ -27,6 +27,7 @@ import { M_BEACON } from "../../src/@types/beacon";
 import { MatrixClient } from "../../src/client";
 import { DecryptionError } from "../../src/crypto/algorithms";
 import { defer } from "../../src/utils";
+import { Room } from "../../src/models/room";
 
 describe("RoomState", function () {
     const roomId = "!foo:bar";
@@ -362,9 +363,11 @@ describe("RoomState", function () {
         });
 
         it("does not add redacted beacon info events to state", () => {
+            const mockClient = {} as unknown as MockedObject<MatrixClient>;
             const redactedBeaconEvent = makeBeaconInfoEvent(userA, roomId);
             const redactionEvent = new MatrixEvent({ type: "m.room.redaction" });
-            redactedBeaconEvent.makeRedacted(redactionEvent);
+            const room = new Room(roomId, mockClient, userA);
+            redactedBeaconEvent.makeRedacted(redactionEvent, room);
             const emitSpy = jest.spyOn(state, "emit");
 
             state.setStateEvents([redactedBeaconEvent]);
@@ -394,11 +397,13 @@ describe("RoomState", function () {
         });
 
         it("destroys and removes redacted beacon events", () => {
+            const mockClient = {} as unknown as MockedObject<MatrixClient>;
             const beaconId = "$beacon1";
             const beaconEvent = makeBeaconInfoEvent(userA, roomId, { isLive: true }, beaconId);
             const redactedBeaconEvent = makeBeaconInfoEvent(userA, roomId, { isLive: true }, beaconId);
             const redactionEvent = new MatrixEvent({ type: "m.room.redaction", redacts: beaconEvent.getId() });
-            redactedBeaconEvent.makeRedacted(redactionEvent);
+            const room = new Room(roomId, mockClient, userA);
+            redactedBeaconEvent.makeRedacted(redactionEvent, room);
 
             state.setStateEvents([beaconEvent]);
             const beaconInstance = state.beacons.get(getBeaconInfoIdentifier(beaconEvent));

spec/unit/room.spec.ts

@@ -3564,7 +3564,7 @@ describe("Room", function () {
             expect(room.polls.get(pollStartEvent.getId()!)).toBeTruthy();
 
             const redactedEvent = new MatrixEvent({ type: "m.room.redaction" });
-            pollStartEvent.makeRedacted(redactedEvent);
+            pollStartEvent.makeRedacted(redactedEvent, room);
 
             await flushPromises();
 

src/models/event.ts

@@ -45,6 +45,8 @@ import { DecryptionError } from "../crypto/algorithms";
 import { CryptoBackend } from "../common-crypto/CryptoBackend";
 import { WITHHELD_MESSAGES } from "../crypto/OlmDevice";
 import { IAnnotatedPushRule } from "../@types/PushRules";
+import { Room } from "./room";
+import { EventTimeline } from "./event-timeline";
 
 export { EventStatus } from "./event-status";
 
@@ -1132,13 +1134,19 @@ export class MatrixEvent extends TypedEventEmitter<MatrixEventEmittedEvents, Mat
         return this.visibility;
     }
 
+    /**
+     * @deprecated In favor of the overload that includes a Room argument
+     */
+    public makeRedacted(redactionEvent: MatrixEvent): void;
     /**
      * Update the content of an event in the same way it would be by the server
      * if it were redacted before it was sent to us
      *
      * @param redactionEvent - event causing the redaction
+     * @param room - the room in which the event exists
      */
-    public makeRedacted(redactionEvent: MatrixEvent): void {
+    public makeRedacted(redactionEvent: MatrixEvent, room: Room): void;
+    public makeRedacted(redactionEvent: MatrixEvent, room?: Room): void {
         // quick sanity-check
         if (!redactionEvent.event) {
             throw new Error("invalid redactionEvent in makeRedacted");
@@ -1182,6 +1190,21 @@ export class MatrixEvent extends TypedEventEmitter<MatrixEventEmittedEvents, Mat
             }
         }
 
+        // If the redacted event was in a thread
+        if (room && this.threadRootId && this.threadRootId !== this.getId()) {
+            // Remove it from its thread
+            this.thread?.timelineSet.removeEvent(this.getId()!);
+            this.setThread(undefined);
+
+            // And insert it into the main timeline
+            const timeline = room.getLiveTimeline();
+            // We use insertEventIntoTimeline to insert it in timestamp order,
+            // because we don't know where it should go (until we have MSC4033).
+            timeline
+                .getTimelineSet()
+                .insertEventIntoTimeline(this, timeline, timeline.getState(EventTimeline.FORWARDS)!);
+        }
+
         this.invalidateExtensibleEvent();
     }
 

src/models/room.ts

@@ -2329,7 +2329,7 @@ export class Room extends ReadReceipt<RoomEmittedEvents, RoomEventHandlerMap> {
             // if we know about this event, redact its contents now.
             const redactedEvent = redactId ? this.findEventById(redactId) : undefined;
             if (redactedEvent) {
-                redactedEvent.makeRedacted(event);
+                redactedEvent.makeRedacted(event, this);
 
                 // If this is in the current state, replace it with the redacted version
                 if (redactedEvent.isState()) {