Replace MSC3244 support with in-client room version checking

src/components/views/dialogs/CreateRoomDialog.tsx

@@ -30,7 +30,6 @@ import RoomAliasField from "../elements/RoomAliasField";
 import LabelledToggleSwitch from "../elements/LabelledToggleSwitch";
 import DialogButtons from "../elements/DialogButtons";
 import BaseDialog from "../dialogs/BaseDialog";
-import SpaceStore from "../../../stores/spaces/SpaceStore";
 import JoinRuleDropdown from "../elements/JoinRuleDropdown";
 import { getKeyBindingsManager } from "../../../KeyBindingsManager";
 import { KeyBindingAction } from "../../../accessibility/KeyboardShortcuts";
@@ -66,7 +65,7 @@ export default class CreateRoomDialog extends React.Component<IProps, IState> {
     constructor(props) {
         super(props);
 
-        this.supportsRestricted = this.props.parentSpace && !!SpaceStore.instance.restrictedJoinRuleSupport?.preferred;
+        this.supportsRestricted = !!this.props.parentSpace;
 
         let joinRule = JoinRule.Invite;
         if (this.props.defaultPublic) {

src/components/views/dialogs/CreateSubspaceDialog.tsx

@@ -26,7 +26,6 @@ import MatrixClientContext from "../../../contexts/MatrixClientContext";
 import { BetaPill } from "../beta/BetaCard";
 import Field from "../elements/Field";
 import RoomAliasField from "../elements/RoomAliasField";
-import SpaceStore from "../../../stores/spaces/SpaceStore";
 import { createSpace, SpaceCreateForm } from "../spaces/SpaceCreateMenu";
 import { SubspaceSelector } from "./AddExistingToSpaceDialog";
 import JoinRuleDropdown from "../elements/JoinRuleDropdown";
@@ -48,14 +47,10 @@ const CreateSubspaceDialog: React.FC<IProps> = ({ space, onAddExistingSpaceClick
     const [avatar, setAvatar] = useState<File>(null);
     const [topic, setTopic] = useState<string>("");
 
-    const supportsRestricted = !!SpaceStore.instance.restrictedJoinRuleSupport?.preferred;
-
     const spaceJoinRule = space.getJoinRule();
-    let defaultJoinRule = JoinRule.Invite;
+    let defaultJoinRule = JoinRule.Restricted;
     if (spaceJoinRule === JoinRule.Public) {
         defaultJoinRule = JoinRule.Public;
-    } else if (supportsRestricted) {
-        defaultJoinRule = JoinRule.Restricted;
     }
     const [joinRule, setJoinRule] = useState<JoinRule>(defaultJoinRule);
 
@@ -150,7 +145,7 @@ const CreateSubspaceDialog: React.FC<IProps> = ({ space, onAddExistingSpaceClick
                         label={_t("Space visibility")}
                         labelInvite={_t("Private space (invite only)")}
                         labelPublic={_t("Public space")}
-                        labelRestricted={supportsRestricted ? _t("Visible to space members") : undefined}
+                        labelRestricted={_t("Visible to space members")}
                         width={478}
                         value={joinRule}
                         onChange={setJoinRule}

src/components/views/settings/JoinRuleSettings.tsx

@@ -35,6 +35,7 @@ import dis from "../../../dispatcher/dispatcher";
 import { ROOM_SECURITY_TAB } from "../dialogs/RoomSettingsDialog";
 import { Action } from "../../../dispatcher/actions";
 import { ViewRoomPayload } from "../../../dispatcher/payloads/ViewRoomPayload";
+import { doesRoomVersionSupport, PreferredRoomVersions } from "../../../utils/PreferredRoomVersions";
 
 interface IProps {
     room: Room;
@@ -48,11 +49,9 @@ interface IProps {
 const JoinRuleSettings = ({ room, promptUpgrade, aliasWarning, onError, beforeChange, closeSettingsFn }: IProps) => {
     const cli = room.client;
 
-    const restrictedRoomCapabilities = SpaceStore.instance.restrictedJoinRuleSupport;
-    const roomSupportsRestricted = Array.isArray(restrictedRoomCapabilities?.support)
-        && restrictedRoomCapabilities.support.includes(room.getVersion());
+    const roomSupportsRestricted = doesRoomVersionSupport(room.getVersion(), PreferredRoomVersions.RestrictedRooms);
     const preferredRestrictionVersion = !roomSupportsRestricted && promptUpgrade
-        ? restrictedRoomCapabilities?.preferred
+        ? PreferredRoomVersions.RestrictedRooms
         : undefined;
 
     const disabled = !room.currentState.mayClientSendStateEvent(EventType.RoomJoinRules, cli);

src/createRoom.ts

@@ -45,6 +45,7 @@ import { ViewRoomPayload } from "./dispatcher/payloads/ViewRoomPayload";
 import { findDMForUser } from "./utils/direct-messages";
 import { privateShouldBeEncrypted } from "./utils/rooms";
 import { waitForMember } from "./utils/membership";
+import { PreferredRoomVersions } from "./utils/PreferredRoomVersions";
 
 // we define a number of interfaces which take their names from the js-sdk
 /* eslint-disable camelcase */
@@ -191,20 +192,18 @@ export default async function createRoom(opts: IOpts): Promise<string | null> {
         }
 
         if (opts.joinRule === JoinRule.Restricted) {
-            if (SpaceStore.instance.restrictedJoinRuleSupport?.preferred) {
-                createOpts.room_version = SpaceStore.instance.restrictedJoinRuleSupport.preferred;
-
-                createOpts.initial_state.push({
-                    type: EventType.RoomJoinRules,
-                    content: {
-                        "join_rule": JoinRule.Restricted,
-                        "allow": [{
-                            "type": RestrictedAllowType.RoomMembership,
-                            "room_id": opts.parentSpace.roomId,
-                        }],
-                    },
-                });
-            }
+            createOpts.room_version = PreferredRoomVersions.RestrictedRooms;
+
+            createOpts.initial_state.push({
+                type: EventType.RoomJoinRules,
+                content: {
+                    "join_rule": JoinRule.Restricted,
+                    "allow": [{
+                        "type": RestrictedAllowType.RoomMembership,
+                        "room_id": opts.parentSpace.roomId,
+                    }],
+                },
+            });
         }
     }
 

src/stores/spaces/SpaceStore.ts

@@ -18,7 +18,7 @@ import { ListIteratee, Many, sortBy } from "lodash";
 import { EventType, RoomType } from "matrix-js-sdk/src/@types/event";
 import { Room, RoomEvent } from "matrix-js-sdk/src/models/room";
 import { MatrixEvent } from "matrix-js-sdk/src/models/event";
-import { ClientEvent, IRoomCapability } from "matrix-js-sdk/src/client";
+import { ClientEvent } from "matrix-js-sdk/src/client";
 import { logger } from "matrix-js-sdk/src/logger";
 import { RoomMember } from "matrix-js-sdk/src/models/room-member";
 import { RoomStateEvent } from "matrix-js-sdk/src/models/room-state";
@@ -132,7 +132,6 @@ export class SpaceStoreClass extends AsyncStoreWithClient<IState> {
     private _suggestedRooms: ISuggestedRoom[] = [];
     private _invitedSpaces = new Set<Room>();
     private spaceOrderLocalEchoMap = new Map<string, string>();
-    private _restrictedJoinRuleSupport?: IRoomCapability;
     // The following properties are set by onReady as they live in account_data
     private _allRoomsInHome = false;
     private _enabledMetaSpaces: MetaSpace[] = [];
@@ -210,10 +209,6 @@ export class SpaceStoreClass extends AsyncStoreWithClient<IState> {
         }
     }
 
-    public get restrictedJoinRuleSupport(): IRoomCapability {
-        return this._restrictedJoinRuleSupport;
-    }
-
     /**
      * Sets the active space, updates room list filters,
      * optionally switches the user's room back to where they were when they last viewed that space.
@@ -1066,11 +1061,6 @@ export class SpaceStoreClass extends AsyncStoreWithClient<IState> {
         this.matrixClient.on(RoomStateEvent.Members, this.onRoomStateMembers);
         this.matrixClient.on(ClientEvent.AccountData, this.onAccountData);
 
-        this.matrixClient.getCapabilities().then(capabilities => {
-            this._restrictedJoinRuleSupport = capabilities
-                ?.["m.room_versions"]?.["org.matrix.msc3244.room_capabilities"]?.["restricted"];
-        });
-
         const oldMetaSpaces = this._enabledMetaSpaces;
         const enabledMetaSpaces = SettingsStore.getValue("Spaces.enabledMetaSpaces");
         this._enabledMetaSpaces = metaSpaceOrder.filter(k => enabledMetaSpaces[k]);

src/utils/PreferredRoomVersions.ts

@@ -0,0 +1,55 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+/**
+ * The preferred room versions for various features within the app. The
+ * room versions here are selected based on the client's support for the
+ * possible room versions in combination with server support in the
+ * ecosystem.
+ *
+ * Loosely follows https://spec.matrix.org/latest/rooms/#feature-matrix
+ */
+export class PreferredRoomVersions {
+    /**
+     * The room version to use when creating "restricted" rooms.
+     */
+    public static readonly RestrictedRooms = "9";
+
+    private constructor() {
+        // readonly, static, class
+    }
+}
+
+/**
+ * Determines if a room version supports the given feature using heuristics
+ * for how Matrix works.
+ * @param roomVer The room version to check support within.
+ * @param featureVer The room version of the feature. Should be from PreferredRoomVersions.
+ * @see PreferredRoomVersions
+ */
+export function doesRoomVersionSupport(roomVer: string, featureVer: string): boolean {
+    // Assumption: all unstable room versions don't support the feature. Calling code can check for unstable
+    // room versions explicitly if it wants to. The spec reserves [0-9] and `.` for its room versions.
+    if (!roomVer.match(/[\d.]+/)) {
+        return false;
+    }
+
+    // Dev note: While the spec says room versions are not linear, we can make reasonable assumptions
+    // until the room versions prove themselves to be non-linear in the spec. We should see this coming
+    // from a mile away and can course-correct this function if needed.
+    return Number(roomVer) >= Number(featureVer);
+}
+

test/PreferredRoomVersions-test.ts

@@ -0,0 +1,46 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { doesRoomVersionSupport, PreferredRoomVersions } from "../src/utils/PreferredRoomVersions";
+
+describe("doesRoomVersionSupport", () => {
+    it("should detect unstable as unsupported", () => {
+        expect(doesRoomVersionSupport("org.example.unstable", "1")).toBe(false);
+        expect(doesRoomVersionSupport("1.2-beta", "1")).toBe(false);
+    });
+
+    it("should detect support properly", () => {
+        expect(doesRoomVersionSupport("1", "2")).toBe(false); // older
+        expect(doesRoomVersionSupport("2", "2")).toBe(true); // exact
+        expect(doesRoomVersionSupport("3", "2")).toBe(true); // newer
+    });
+
+    it("should handle decimal versions", () => {
+        expect(doesRoomVersionSupport("1.1", "2.2")).toBe(false); // older
+        expect(doesRoomVersionSupport("2.1", "2.2")).toBe(false); // exact-ish
+        expect(doesRoomVersionSupport("2.2", "2.2")).toBe(true); // exact
+        expect(doesRoomVersionSupport("2.3", "2.2")).toBe(true); // exact-ish
+        expect(doesRoomVersionSupport("3.1", "2.2")).toBe(true); // newer
+    });
+
+    it("should detect restricted rooms in v9 and v10", () => {
+        // Dev note: we consider it a feature that v8 rooms have to upgrade considering the bug in v8.
+        // https://spec.matrix.org/v1.3/rooms/v8/#redactions
+        expect(doesRoomVersionSupport("8", PreferredRoomVersions.RestrictedRooms)).toBe(false);
+        expect(doesRoomVersionSupport("9", PreferredRoomVersions.RestrictedRooms)).toBe(true);
+        expect(doesRoomVersionSupport("10", PreferredRoomVersions.RestrictedRooms)).toBe(true);
+    });
+});