Improve error handling for `DeviceListener` (#11484)

... particularly for when it races with a client shutdown.

src/DeviceListener.ts

@@ -14,7 +14,15 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import { MatrixEvent, ClientEvent, EventType, MatrixClient, RoomStateEvent, SyncState } from "matrix-js-sdk/src/matrix";
+import {
+    MatrixEvent,
+    ClientEvent,
+    EventType,
+    MatrixClient,
+    RoomStateEvent,
+    SyncState,
+    ClientStoppedError,
+} from "matrix-js-sdk/src/matrix";
 import { logger } from "matrix-js-sdk/src/logger";
 import { CryptoEvent } from "matrix-js-sdk/src/crypto";
 import { IKeyBackupInfo } from "matrix-js-sdk/src/crypto/keybackup";
@@ -260,7 +268,17 @@ export default class DeviceListener {
         return cli?.getRooms().some((r) => cli.isRoomEncrypted(r.roomId)) ?? false;
     }
 
-    private async recheck(): Promise<void> {
+    private recheck(): void {
+        this.doRecheck().catch((e) => {
+            if (e instanceof ClientStoppedError) {
+                // the client was stopped while recheck() was running. Nothing left to do.
+            } else {
+                logger.error("Error during `DeviceListener.recheck`", e);
+            }
+        });
+    }
+
+    private async doRecheck(): Promise<void> {
         if (!this.running || !this.client) return; // we have been stopped
         const cli = this.client;
 

test/DeviceListener-test.ts

@@ -15,7 +15,15 @@ limitations under the License.
 */
 
 import { Mocked, mocked } from "jest-mock";
-import { MatrixEvent, Room, MatrixClient, DeviceVerificationStatus, CryptoApi, Device } from "matrix-js-sdk/src/matrix";
+import {
+    MatrixEvent,
+    Room,
+    MatrixClient,
+    DeviceVerificationStatus,
+    CryptoApi,
+    Device,
+    ClientStoppedError,
+} from "matrix-js-sdk/src/matrix";
 import { logger } from "matrix-js-sdk/src/logger";
 import { CrossSigningInfo } from "matrix-js-sdk/src/crypto/CrossSigning";
 import { CryptoEvent } from "matrix-js-sdk/src/crypto";
@@ -257,6 +265,20 @@ describe("DeviceListener", () => {
 
             expect(mockCrypto!.isCrossSigningReady).not.toHaveBeenCalled();
         });
+        it("correctly handles the client being stopped", async () => {
+            mockCrypto!.isCrossSigningReady.mockImplementation(() => {
+                throw new ClientStoppedError();
+            });
+            await createAndStart();
+            expect(logger.error).not.toHaveBeenCalled();
+        });
+        it("correctly handles other errors", async () => {
+            mockCrypto!.isCrossSigningReady.mockImplementation(() => {
+                throw new Error("blah");
+            });
+            await createAndStart();
+            expect(logger.error).toHaveBeenCalledTimes(1);
+        });
 
         describe("set up encryption", () => {
             const rooms = [{ roomId: "!room1" }, { roomId: "!room2" }] as unknown as Room[];