Store refactor: make it easier to test stores (#9290)

* refactor: convert RoomViewStore from flux Store to standard EventEmitter

Parts of a series of experimental changes to improve the design of stores.

* Use a gen5 store for RoomViewStore for now due to lock handling

* Revert "Use a gen5 store for RoomViewStore for now due to lock handling"

This reverts commit 1076af0.

* Add untilEmission and tweak untilDispatch; use it in RoomViewStore

* Add more RVS tests; remove custom room ID listener code and use EventEmitter

* Better comments

* Null guard `dis` as tests mock out `defaultDispatcher`

* Additional tests

Author: kegsay

src/components/structures/RoomView.tsx

@@ -24,7 +24,6 @@ import React, { createRef, ReactElement, ReactNode, RefObject, useContext } from
 import classNames from 'classnames';
 import { IRecommendedVersion, NotificationCountType, Room, RoomEvent } from "matrix-js-sdk/src/models/room";
 import { IThreadBundledRelationship, MatrixEvent, MatrixEventEvent } from "matrix-js-sdk/src/models/event";
-import { EventSubscription } from "fbemitter";
 import { ISearchResults } from 'matrix-js-sdk/src/@types/search';
 import { logger } from "matrix-js-sdk/src/logger";
 import { EventTimeline } from 'matrix-js-sdk/src/models/event-timeline';
@@ -366,7 +365,6 @@ function LocalRoomCreateLoader(props: ILocalRoomCreateLoaderProps): ReactElement
 
 export class RoomView extends React.Component<IRoomProps, IRoomState> {
     private readonly dispatcherRef: string;
-    private readonly roomStoreToken: EventSubscription;
     private settingWatchers: string[];
 
     private unmounted = false;
@@ -439,7 +437,7 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
         context.on(CryptoEvent.KeysChanged, this.onCrossSigningKeysChanged);
         context.on(MatrixEventEvent.Decrypted, this.onEventDecrypted);
         // Start listening for RoomViewStore updates
-        this.roomStoreToken = RoomViewStore.instance.addListener(this.onRoomViewStoreUpdate);
+        RoomViewStore.instance.on(UPDATE_EVENT, this.onRoomViewStoreUpdate);
 
         RightPanelStore.instance.on(UPDATE_EVENT, this.onRightPanelStoreUpdate);
 
@@ -883,10 +881,7 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
 
         window.removeEventListener('beforeunload', this.onPageUnload);
 
-        // Remove RoomStore listener
-        if (this.roomStoreToken) {
-            this.roomStoreToken.remove();
-        }
+        RoomViewStore.instance.off(UPDATE_EVENT, this.onRoomViewStoreUpdate);
 
         RightPanelStore.instance.off(UPDATE_EVENT, this.onRightPanelStoreUpdate);
         WidgetEchoStore.removeListener(UPDATE_EVENT, this.onWidgetEchoStoreUpdate);

src/components/views/right_panel/TimelineCard.tsx

@@ -15,7 +15,6 @@ limitations under the License.
 */
 
 import React from 'react';
-import { EventSubscription } from "fbemitter";
 import { IEventRelation, MatrixEvent } from 'matrix-js-sdk/src/models/event';
 import { EventTimelineSet } from 'matrix-js-sdk/src/models/event-timeline-set';
 import { NotificationCountType, Room } from 'matrix-js-sdk/src/models/room';
@@ -42,6 +41,7 @@ import JumpToBottomButton from '../rooms/JumpToBottomButton';
 import { ViewRoomPayload } from "../../../dispatcher/payloads/ViewRoomPayload";
 import Measured from '../elements/Measured';
 import Heading from '../typography/Heading';
+import { UPDATE_EVENT } from '../../../stores/AsyncStore';
 
 interface IProps {
     room: Room;
@@ -77,7 +77,6 @@ export default class TimelineCard extends React.Component<IProps, IState> {
     private layoutWatcherRef: string;
     private timelinePanel = React.createRef<TimelinePanel>();
     private card = React.createRef<HTMLDivElement>();
-    private roomStoreToken: EventSubscription;
     private readReceiptsSettingWatcher: string;
 
     constructor(props: IProps) {
@@ -92,7 +91,7 @@ export default class TimelineCard extends React.Component<IProps, IState> {
     }
 
     public componentDidMount(): void {
-        this.roomStoreToken = RoomViewStore.instance.addListener(this.onRoomViewStoreUpdate);
+        RoomViewStore.instance.addListener(UPDATE_EVENT, this.onRoomViewStoreUpdate);
         this.dispatcherRef = dis.register(this.onAction);
         this.readReceiptsSettingWatcher = SettingsStore.watchSetting("showReadReceipts", null, (...[,,, value]) =>
             this.setState({ showReadReceipts: value as boolean }),
@@ -103,9 +102,7 @@ export default class TimelineCard extends React.Component<IProps, IState> {
     }
 
     public componentWillUnmount(): void {
-        // Remove RoomStore listener
-
-        this.roomStoreToken?.remove();
+        RoomViewStore.instance.removeListener(UPDATE_EVENT, this.onRoomViewStoreUpdate);
 
         if (this.readReceiptsSettingWatcher) {
             SettingsStore.unwatchSetting(this.readReceiptsSettingWatcher);

src/components/views/rooms/RoomList.tsx

@@ -14,7 +14,6 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import * as fbEmitter from "fbemitter";
 import { EventType, RoomType } from "matrix-js-sdk/src/@types/event";
 import { Room } from "matrix-js-sdk/src/models/room";
 import React, { ComponentType, createRef, ReactComponentElement, RefObject } from "react";
@@ -37,6 +36,7 @@ import { UIComponent } from "../../../settings/UIFeature";
 import { RoomNotificationStateStore } from "../../../stores/notifications/RoomNotificationStateStore";
 import { ITagMap } from "../../../stores/room-list/algorithms/models";
 import { DefaultTagID, TagID } from "../../../stores/room-list/models";
+import { UPDATE_EVENT } from "../../../stores/AsyncStore";
 import RoomListStore, { LISTS_UPDATE_EVENT } from "../../../stores/room-list/RoomListStore";
 import { RoomViewStore } from "../../../stores/RoomViewStore";
 import {
@@ -403,7 +403,6 @@ const TAG_AESTHETICS: ITagAestheticsMap = {
 
 export default class RoomList extends React.PureComponent<IProps, IState> {
     private dispatcherRef;
-    private roomStoreToken: fbEmitter.EventSubscription;
     private treeRef = createRef<HTMLDivElement>();
     private favouriteMessageWatcher: string;
 
@@ -422,7 +421,7 @@ export default class RoomList extends React.PureComponent<IProps, IState> {
 
     public componentDidMount(): void {
         this.dispatcherRef = defaultDispatcher.register(this.onAction);
-        this.roomStoreToken = RoomViewStore.instance.addListener(this.onRoomViewStoreUpdate);
+        RoomViewStore.instance.on(UPDATE_EVENT, this.onRoomViewStoreUpdate);
         SpaceStore.instance.on(UPDATE_SUGGESTED_ROOMS, this.updateSuggestedRooms);
         RoomListStore.instance.on(LISTS_UPDATE_EVENT, this.updateLists);
         this.favouriteMessageWatcher =
@@ -437,7 +436,7 @@ export default class RoomList extends React.PureComponent<IProps, IState> {
         RoomListStore.instance.off(LISTS_UPDATE_EVENT, this.updateLists);
         SettingsStore.unwatchSetting(this.favouriteMessageWatcher);
         defaultDispatcher.unregister(this.dispatcherRef);
-        if (this.roomStoreToken) this.roomStoreToken.remove();
+        RoomViewStore.instance.off(UPDATE_EVENT, this.onRoomViewStoreUpdate);
     }
 
     private onRoomViewStoreUpdate = () => {

src/components/views/voip/PipView.tsx

@@ -16,7 +16,6 @@ limitations under the License.
 
 import React, { createRef } from 'react';
 import { CallEvent, CallState, MatrixCall } from 'matrix-js-sdk/src/webrtc/call';
-import { EventSubscription } from 'fbemitter';
 import { logger } from "matrix-js-sdk/src/logger";
 import classNames from 'classnames';
 import { Room } from "matrix-js-sdk/src/models/room";
@@ -35,6 +34,7 @@ import LegacyCallViewHeader from './LegacyCallView/LegacyCallViewHeader';
 import ActiveWidgetStore, { ActiveWidgetStoreEvent } from '../../../stores/ActiveWidgetStore';
 import WidgetStore, { IApp } from "../../../stores/WidgetStore";
 import { ViewRoomPayload } from "../../../dispatcher/payloads/ViewRoomPayload";
+import { UPDATE_EVENT } from '../../../stores/AsyncStore';
 
 const SHOW_CALL_IN_STATES = [
     CallState.Connected,
@@ -116,7 +116,6 @@ function getPrimarySecondaryCallsForPip(roomId: string): [MatrixCall, MatrixCall
  */
 
 export default class PipView extends React.Component<IProps, IState> {
-    private roomStoreToken: EventSubscription;
     private settingsWatcherRef: string;
     private movePersistedElement = createRef<() => void>();
 
@@ -141,7 +140,7 @@ export default class PipView extends React.Component<IProps, IState> {
     public componentDidMount() {
         LegacyCallHandler.instance.addListener(LegacyCallHandlerEvent.CallChangeRoom, this.updateCalls);
         LegacyCallHandler.instance.addListener(LegacyCallHandlerEvent.CallState, this.updateCalls);
-        this.roomStoreToken = RoomViewStore.instance.addListener(this.onRoomViewStoreUpdate);
+        RoomViewStore.instance.addListener(UPDATE_EVENT, this.onRoomViewStoreUpdate);
         MatrixClientPeg.get().on(CallEvent.RemoteHoldUnhold, this.onCallRemoteHold);
         const room = MatrixClientPeg.get()?.getRoom(this.state.viewedRoomId);
         if (room) {
@@ -157,7 +156,7 @@ export default class PipView extends React.Component<IProps, IState> {
         LegacyCallHandler.instance.removeListener(LegacyCallHandlerEvent.CallChangeRoom, this.updateCalls);
         LegacyCallHandler.instance.removeListener(LegacyCallHandlerEvent.CallState, this.updateCalls);
         MatrixClientPeg.get().removeListener(CallEvent.RemoteHoldUnhold, this.onCallRemoteHold);
-        this.roomStoreToken?.remove();
+        RoomViewStore.instance.removeListener(UPDATE_EVENT, this.onRoomViewStoreUpdate);
         SettingsStore.unwatchSetting(this.settingsWatcherRef);
         const room = MatrixClientPeg.get().getRoom(this.state.viewedRoomId);
         if (room) {

src/stores/RoomViewStore.tsx

@@ -17,7 +17,6 @@ limitations under the License.
 */
 
 import React, { ReactNode } from "react";
-import { Store } from 'flux/utils';
 import { MatrixError } from "matrix-js-sdk/src/http-api";
 import { logger } from "matrix-js-sdk/src/logger";
 import { ViewRoom as ViewRoomEvent } from "@matrix-org/analytics-events/types/typescript/ViewRoom";
@@ -26,13 +25,13 @@ import { JoinRule } from "matrix-js-sdk/src/@types/partials";
 import { Room } from "matrix-js-sdk/src/models/room";
 import { MatrixEvent } from "matrix-js-sdk/src/models/event";
 import { Optional } from "matrix-events-sdk";
+import EventEmitter from "events";
 
-import dis from '../dispatcher/dispatcher';
+import { defaultDispatcher, MatrixDispatcher } from '../dispatcher/dispatcher';
 import { MatrixClientPeg } from '../MatrixClientPeg';
 import Modal from '../Modal';
 import { _t } from '../languageHandler';
 import { getCachedRoomIDForAlias, storeRoomAliasInCache } from '../RoomAliasCache';
-import { ActionPayload } from "../dispatcher/payloads";
 import { Action } from "../dispatcher/actions";
 import { retry } from "../utils/promise";
 import { TimelineRenderingType } from "../contexts/RoomContext";
@@ -50,6 +49,7 @@ import { ActiveRoomChangedPayload } from "../dispatcher/payloads/ActiveRoomChang
 import SettingsStore from "../settings/SettingsStore";
 import { SlidingSyncManager } from "../SlidingSyncManager";
 import { awaitRoomDownSync } from "../utils/RoomUpgrade";
+import { UPDATE_EVENT } from "./AsyncStore";
 
 const NUM_JOIN_RETRY = 5;
 
@@ -90,47 +90,34 @@ const INITIAL_STATE = {
 type Listener = (isActive: boolean) => void;
 
 /**
- * A class for storing application state for RoomView. This is the RoomView's interface
-*  with a subset of the js-sdk.
- *  ```
+ * A class for storing application state for RoomView.
  */
-export class RoomViewStore extends Store<ActionPayload> {
+export class RoomViewStore extends EventEmitter {
     // Important: This cannot be a dynamic getter (lazily-constructed instance) because
     // otherwise we'll miss view_room dispatches during startup, breaking relaunches of
     // the app. We need to eagerly create the instance.
-    public static readonly instance = new RoomViewStore();
+    public static readonly instance = new RoomViewStore(defaultDispatcher);
 
     private state = INITIAL_STATE; // initialize state
 
-    // Keep these out of state to avoid causing excessive/recursive updates
-    private roomIdActivityListeners: Record<string, Listener[]> = {};
+    private dis: MatrixDispatcher;
+    private dispatchToken: string;
 
-    public constructor() {
-        super(dis);
+    public constructor(dis: MatrixDispatcher) {
+        super();
+        this.resetDispatcher(dis);
     }
 
     public addRoomListener(roomId: string, fn: Listener): void {
-        if (!this.roomIdActivityListeners[roomId]) this.roomIdActivityListeners[roomId] = [];
-        this.roomIdActivityListeners[roomId].push(fn);
+        this.on(roomId, fn);
     }
 
     public removeRoomListener(roomId: string, fn: Listener): void {
-        if (this.roomIdActivityListeners[roomId]) {
-            const i = this.roomIdActivityListeners[roomId].indexOf(fn);
-            if (i > -1) {
-                this.roomIdActivityListeners[roomId].splice(i, 1);
-            }
-        } else {
-            logger.warn("Unregistering unrecognised listener (roomId=" + roomId + ")");
-        }
+        this.off(roomId, fn);
     }
 
     private emitForRoom(roomId: string, isActive: boolean): void {
-        if (!this.roomIdActivityListeners[roomId]) return;
-
-        for (const fn of this.roomIdActivityListeners[roomId]) {
-            fn.call(null, isActive);
-        }
+        this.emit(roomId, isActive);
     }
 
     private setState(newState: Partial<typeof INITIAL_STATE>): void {
@@ -156,17 +143,17 @@ export class RoomViewStore extends Store<ActionPayload> {
 
             // Fired so we can reduce dependency on event emitters to this store, which is relatively
             // central to the application and can easily cause import cycles.
-            dis.dispatch<ActiveRoomChangedPayload>({
+            this.dis.dispatch<ActiveRoomChangedPayload>({
                 action: Action.ActiveRoomChanged,
                 oldRoomId: lastRoomId,
                 newRoomId: this.state.roomId,
             });
         }
 
-        this.__emitChange();
+        this.emit(UPDATE_EVENT);
     }
 
-    protected __onDispatch(payload): void { // eslint-disable-line @typescript-eslint/naming-convention
+    private onDispatch(payload): void { // eslint-disable-line @typescript-eslint/naming-convention
         switch (payload.action) {
             // view_room:
             //      - room_alias:   '#somealias:matrix.org'
@@ -243,7 +230,7 @@ export class RoomViewStore extends Store<ActionPayload> {
                 // both room and search timeline rendering types, search will get auto-closed by RoomView at this time.
                 if ([TimelineRenderingType.Room, TimelineRenderingType.Search].includes(payload.context)) {
                     if (payload.event && payload.event.getRoomId() !== this.state.roomId) {
-                        dis.dispatch<ViewRoomPayload>({
+                        this.dis.dispatch<ViewRoomPayload>({
                             action: Action.ViewRoom,
                             room_id: payload.event.getRoomId(),
                             replyingToEvent: payload.event,
@@ -283,9 +270,9 @@ export class RoomViewStore extends Store<ActionPayload> {
                 });
             }
             if (SettingsStore.getValue("feature_sliding_sync") && this.state.roomId !== payload.room_id) {
-                if (this.state.roomId) {
+                if (this.state.subscribingRoomId && this.state.subscribingRoomId !== payload.room_id) {
                     // unsubscribe from this room, but don't await it as we don't care when this gets done.
-                    SlidingSyncManager.instance.setRoomVisible(this.state.roomId, false);
+                    SlidingSyncManager.instance.setRoomVisible(this.state.subscribingRoomId, false);
                 }
                 this.setState({
                     subscribingRoomId: payload.room_id,
@@ -306,11 +293,11 @@ export class RoomViewStore extends Store<ActionPayload> {
                 // Whilst we were subscribing another room was viewed, so stop what we're doing and
                 // unsubscribe
                 if (this.state.subscribingRoomId !== payload.room_id) {
-                    SlidingSyncManager.instance.setRoomVisible(this.state.roomId, false);
+                    SlidingSyncManager.instance.setRoomVisible(payload.room_id, false);
                     return;
                 }
                 // Re-fire the payload: we won't re-process it because the prev room ID == payload room ID now
-                dis.dispatch({
+                this.dis.dispatch({
                     ...payload,
                 });
                 return;
@@ -346,7 +333,7 @@ export class RoomViewStore extends Store<ActionPayload> {
             this.setState(newState);
 
             if (payload.auto_join) {
-                dis.dispatch<JoinRoomPayload>({
+                this.dis.dispatch<JoinRoomPayload>({
                     ...payload,
                     action: Action.JoinRoom,
                     roomId: payload.room_id,
@@ -378,7 +365,7 @@ export class RoomViewStore extends Store<ActionPayload> {
                     roomId = result.room_id;
                 } catch (err) {
                     logger.error("RVS failed to get room id for alias: ", err);
-                    dis.dispatch<ViewRoomErrorPayload>({
+                    this.dis.dispatch<ViewRoomErrorPayload>({
                         action: Action.ViewRoomError,
                         room_id: null,
                         room_alias: payload.room_alias,
@@ -389,7 +376,7 @@ export class RoomViewStore extends Store<ActionPayload> {
             }
 
             // Re-fire the payload with the newly found room_id
-            dis.dispatch({
+            this.dis.dispatch({
                 ...payload,
                 room_id: roomId,
             });
@@ -427,13 +414,13 @@ export class RoomViewStore extends Store<ActionPayload> {
             // We do *not* clear the 'joining' flag because the Room object and/or our 'joined' member event may not
             // have come down the sync stream yet, and that's the point at which we'd consider the user joined to the
             // room.
-            dis.dispatch<JoinRoomReadyPayload>({
+            this.dis.dispatch<JoinRoomReadyPayload>({
                 action: Action.JoinRoomReady,
                 roomId,
                 metricsTrigger: payload.metricsTrigger,
             });
         } catch (err) {
-            dis.dispatch({
+            this.dis.dispatch({
                 action: Action.JoinRoomError,
                 roomId,
                 err,
@@ -493,6 +480,24 @@ export class RoomViewStore extends Store<ActionPayload> {
         this.state = Object.assign({}, INITIAL_STATE);
     }
 
+    /**
+     * Reset which dispatcher should be used to listen for actions. The old dispatcher will be
+     * unregistered.
+     * @param dis The new dispatcher to use.
+     */
+    public resetDispatcher(dis: MatrixDispatcher) {
+        if (this.dispatchToken) {
+            this.dis.unregister(this.dispatchToken);
+        }
+        this.dis = dis;
+        if (dis) {
+            // Some tests mock the dispatcher file resulting in an empty defaultDispatcher
+            // so rather than dying here, just ignore it. When we no longer mock files like this,
+            // we should remove the null check.
+            this.dispatchToken = this.dis.register(this.onDispatch.bind(this));
+        }
+    }
+
     // The room ID of the room currently being viewed
     public getRoomId(): Optional<string> {
         return this.state.roomId;

src/stores/room-list/RoomListStore.ts

@@ -39,6 +39,7 @@ import { SpaceWatcher } from "./SpaceWatcher";
 import { IRoomTimelineActionPayload } from "../../actions/MatrixActionCreators";
 import { RoomListStore as Interface, RoomListStoreEvent } from "./Interface";
 import { SlidingRoomListStoreClass } from "./SlidingRoomListStore";
+import { UPDATE_EVENT } from "../AsyncStore";
 
 interface IState {
     // state is tracked in underlying classes
@@ -104,7 +105,7 @@ export class RoomListStoreClass extends AsyncStoreWithClient<IState> implements
             this.readyStore.useUnitTestClient(forcedClient);
         }
 
-        RoomViewStore.instance.addListener(() => this.handleRVSUpdate({}));
+        RoomViewStore.instance.addListener(UPDATE_EVENT, () => this.handleRVSUpdate({}));
         this.algorithm.on(LIST_UPDATED_EVENT, this.onAlgorithmListUpdated);
         this.algorithm.on(FILTER_CHANGED, this.onAlgorithmFilterUpdated);
         this.setupWatchers();