Merge pull request #5068 from matrix-org/dbkr/fix_soft_logout_crash

Fix crash on logging in again after soft logout

src/stores/AsyncStoreWithClient.ts

@@ -35,11 +35,13 @@ export abstract class AsyncStoreWithClient<T extends Object> extends AsyncStore<
         await this.onAction(payload);
 
         if (payload.action === 'MatrixActions.sync') {
-            // Filter out anything that isn't the first PREPARED sync.
+            // Only set the client on the transition into the PREPARED state.
+            // Everything after this is unnecessary (we only need to know once we have a client)
+            // and we intentionally don't set the client before this point to avoid stores
+            // updating for every event emitted during the cached sync.
             if (!(payload.prevState === 'PREPARED' && payload.state !== 'PREPARED')) {
                 return;
             }
-
             this.matrixClient = payload.matrixClient;
             await this.onReady();
         } else if (payload.action === 'on_client_not_viable' || payload.action === 'on_logged_out') {

src/stores/BreadcrumbsStore.ts

@@ -55,7 +55,7 @@ export class BreadcrumbsStore extends AsyncStoreWithClient<IState> {
     }
 
     private get meetsRoomRequirement(): boolean {
-        return this.matrixClient.getVisibleRooms().length >= 20;
+        return this.matrixClient && this.matrixClient.getVisibleRooms().length >= 20;
     }
 
     protected async onAction(payload: ActionPayload) {