From 2d386556a671af6b7ced1f89d7918a9a508353da Mon Sep 17 00:00:00 2001
From: Janne Mareike Koschinski <janne@kuschku.de>
Date: Wed, 18 May 2022 15:15:25 +0200
Subject: [PATCH] ensure metaspace changes correctly notify listeners (#8611)

---
 src/stores/spaces/SpaceStore.ts |  6 ++++++
 test/stores/SpaceStore-test.ts  | 23 +++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/src/stores/spaces/SpaceStore.ts b/src/stores/spaces/SpaceStore.ts
index 4f455faee56..f00b527c1dc 100644
--- a/src/stores/spaces/SpaceStore.ts
+++ b/src/stores/spaces/SpaceStore.ts
@@ -1072,6 +1072,7 @@ export class SpaceStoreClass extends AsyncStoreWithClient<IState> {
                 ?.["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]);
 
@@ -1079,6 +1080,11 @@ export class SpaceStoreClass extends AsyncStoreWithClient<IState> {
         this.sendUserProperties();
 
         this.rebuildSpaceHierarchy(); // trigger an initial update
+        // rebuildSpaceHierarchy will only send an update if the spaces have changed.
+        // If only the meta spaces have changed, we need to send an update ourselves.
+        if (arrayHasDiff(oldMetaSpaces, this._enabledMetaSpaces)) {
+            this.emit(UPDATE_TOP_LEVEL_SPACES, this.spacePanelSpaces, this.enabledMetaSpaces);
+        }
 
         // restore selected state from last session if any and still valid
         const lastSpaceId = window.localStorage.getItem(ACTIVE_SPACE_LS_KEY);
diff --git a/test/stores/SpaceStore-test.ts b/test/stores/SpaceStore-test.ts
index 47c3f974b23..d83bc21f224 100644
--- a/test/stores/SpaceStore-test.ts
+++ b/test/stores/SpaceStore-test.ts
@@ -14,6 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import { EventEmitter } from "events";
 import { mocked } from 'jest-mock';
 import { EventType } from "matrix-js-sdk/src/@types/event";
 import { RoomMember } from "matrix-js-sdk/src/models/room-member";
@@ -1221,4 +1222,26 @@ describe("SpaceStore", () => {
         expect(SpaceStore.instance.spacePanelSpaces.map(r => r.roomId)).toStrictEqual([rootSpace.roomId]);
         await prom;
     });
+
+    it("correctly emits events for metaspace changes during onReady", async () => {
+        // similar to useEventEmitterState, but for use inside of tests
+        function testEventEmitterState(
+            emitter: EventEmitter | undefined,
+            eventName: string | symbol,
+            callback: (...args: any[]) => void,
+        ): () => void {
+            callback();
+            emitter.addListener(eventName, callback);
+            return () => emitter.removeListener(eventName, callback);
+        }
+
+        let metaSpaces;
+        const removeListener = testEventEmitterState(store, UPDATE_TOP_LEVEL_SPACES, () => {
+            metaSpaces = store.enabledMetaSpaces;
+        });
+        expect(metaSpaces).toEqual(store.enabledMetaSpaces);
+        await run();
+        expect(metaSpaces).toEqual(store.enabledMetaSpaces);
+        removeListener();
+    });
 });