Implement MSC3946 for AdvancedRoomSettingsTab

Author: andybalaam

src/components/views/settings/tabs/room/AdvancedRoomSettingsTab.tsx

@@ -26,6 +26,7 @@ import dis from "../../../../../dispatcher/dispatcher";
 import { Action } from "../../../../../dispatcher/actions";
 import CopyableText from "../../../elements/CopyableText";
 import { ViewRoomPayload } from "../../../../../dispatcher/payloads/ViewRoomPayload";
+import SettingsStore from "../../../../../settings/SettingsStore";
 
 interface IProps {
     roomId: string;
@@ -49,6 +50,8 @@ export default class AdvancedRoomSettingsTab extends React.Component<IProps, ISt
     public constructor(props, context) {
         super(props, context);
 
+        const msc3946ProcessDynamicPredecessor = SettingsStore.getValue("feature_dynamic_room_predecessors");
+
         this.state = {
             // This is eventually set to the value of room.getRecommendedVersion()
             upgradeRecommendation: null,
@@ -60,11 +63,10 @@ export default class AdvancedRoomSettingsTab extends React.Component<IProps, ISt
             const tombstone = room.currentState.getStateEvents(EventType.RoomTombstone, "");
 
             const additionalStateChanges: Partial<IState> = {};
-            const createEvent = room.currentState.getStateEvents(EventType.RoomCreate, "");
-            const predecessor = createEvent ? createEvent.getContent().predecessor : null;
-            if (predecessor && predecessor.room_id) {
-                additionalStateChanges.oldRoomId = predecessor.room_id;
-                additionalStateChanges.oldEventId = predecessor.event_id;
+            const predecessor = room.findPredecessor(msc3946ProcessDynamicPredecessor);
+            if (predecessor) {
+                additionalStateChanges.oldRoomId = predecessor.roomId;
+                additionalStateChanges.oldEventId = predecessor.eventId;
             }
 
             this.setState({

src/i18n/strings/en_EN.json

@@ -955,6 +955,8 @@
     "New group call experience": "New group call experience",
     "Live Location Sharing": "Live Location Sharing",
     "Temporary implementation. Locations persist in room history.": "Temporary implementation. Locations persist in room history.",
+    "Dynamic room predecessors": "Dynamic room predecessors",
+    "Enable MSC3946 (to support late-arriving room archives)": "Enable MSC3946 (to support late-arriving room archives)",
     "Favourite Messages": "Favourite Messages",
     "Under active development.": "Under active development.",
     "Force 15s voice broadcast chunk length": "Force 15s voice broadcast chunk length",

src/settings/Settings.tsx

@@ -439,6 +439,15 @@ export const SETTINGS: { [setting: string]: ISetting } = {
         shouldWarn: true,
         default: false,
     },
+    "feature_dynamic_room_predecessors": {
+        isFeature: true,
+        labsGroup: LabGroup.Rooms,
+        supportedLevels: LEVELS_FEATURE,
+        displayName: _td("Dynamic room predecessors"),
+        description: _td("Enable MSC3946 (to support late-arriving room archives)"),
+        shouldWarn: true,
+        default: false,
+    },
     "feature_favourite_messages": {
         isFeature: true,
         labsGroup: LabGroup.Messaging,

test/components/views/settings/tabs/room/AdvancedRoomSettingsTab-test.tsx

@@ -26,6 +26,7 @@ import { mkEvent, mkStubRoom, stubClient } from "../../../../../test-utils";
 import dis from "../../../../../../src/dispatcher/dispatcher";
 import { Action } from "../../../../../../src/dispatcher/actions";
 import { MatrixClientPeg } from "../../../../../../src/MatrixClientPeg";
+import SettingsStore from "../../../../../../src/settings/SettingsStore";
 
 jest.mock("../../../../../../src/dispatcher/dispatcher");
 
@@ -43,6 +44,12 @@ describe("AdvancedRoomSettingsTab", () => {
         cli = MatrixClientPeg.get();
         room = mkStubRoom(roomId, "test room", cli);
         mocked(cli.getRoom).mockReturnValue(room);
+        mocked(dis.dispatch).mockReset();
+        mocked(room.findPredecessor).mockImplementation((msc3946: boolean) =>
+            msc3946
+                ? { roomId: "old_room_id_via_predecessor", eventId: null }
+                : { roomId: "old_room_id", eventId: "tombstone_event_id" },
+        );
     });
 
     it("should render as expected", () => {
@@ -71,6 +78,17 @@ describe("AdvancedRoomSettingsTab", () => {
             room: room.roomId,
         });
 
+        // Because we're mocking Room.findPredecessor, it may not be necessary
+        // to provide the actual event here, but we do need the create event,
+        // and in future this may be needed, so included for symmetry.
+        const predecessorEvent = mkEvent({
+            event: true,
+            user: "@a:b.com",
+            type: EventType.RoomPredecessor,
+            content: { predecessor_room_id: "old_room_id_via_predecessor" },
+            room: room.roomId,
+        });
+
         type GetStateEvents2Args = (eventType: EventType | string, stateKey: string) => MatrixEvent | null;
 
         const getStateEvents = jest.spyOn(
@@ -82,6 +100,8 @@ describe("AdvancedRoomSettingsTab", () => {
             switch (eventType) {
                 case EventType.RoomCreate:
                     return createEvent;
+                case EventType.RoomPredecessor:
+                    return predecessorEvent;
                 default:
                     return null;
             }
@@ -101,4 +121,26 @@ describe("AdvancedRoomSettingsTab", () => {
             metricsViaKeyboard: false,
         });
     });
+
+    describe("When MSC3946 support is enabled", () => {
+        beforeEach(() => {
+            jest.spyOn(SettingsStore, "getValue")
+                .mockReset()
+                .mockImplementation((settingName) => settingName === "feature_dynamic_room_predecessors");
+        });
+
+        it("should link to predecessor room via MSC3946 if enabled", async () => {
+            mockStateEvents(room);
+            const tab = renderTab();
+            const link = await tab.findByText("View older messages in test room.");
+            fireEvent.click(link);
+            expect(dis.dispatch).toHaveBeenCalledWith({
+                action: Action.ViewRoom,
+                event_id: null,
+                room_id: "old_room_id_via_predecessor",
+                metricsTrigger: "WebPredecessorSettings",
+                metricsViaKeyboard: false,
+            });
+        });
+    });
 });