Fix all megolm error reported as unknown (#8916)

* Fix all megolm error reported as unknown

* code review

* bad paste in comment

src/DecryptionFailureTracker.ts

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import { MatrixError } from "matrix-js-sdk/src/http-api";
+import { DecryptionError } from "matrix-js-sdk/src/crypto/algorithms";
 import { MatrixEvent } from "matrix-js-sdk/src/models/event";
 import { Error as ErrorEvent } from "@matrix-org/analytics-events/types/typescript/Error";
 
@@ -129,9 +129,13 @@ export class DecryptionFailureTracker {
     //     localStorage.setItem('mx-decryption-failure-event-ids', JSON.stringify([...this.trackedEvents]));
     // }
 
-    public eventDecrypted(e: MatrixEvent, err: MatrixError): void {
+    public eventDecrypted(e: MatrixEvent, err: DecryptionError): void {
+        // for now we only track megolm decrytion failures
+        if (e.getWireContent().algorithm != "m.megolm.v1.aes-sha2") {
+            return;
+        }
         if (err) {
-            this.addDecryptionFailure(new DecryptionFailure(e.getId(), err.errcode));
+            this.addDecryptionFailure(new DecryptionFailure(e.getId(), err.code));
         } else {
             // Could be an event in the failures, remove it
             this.removeDecryptionFailuresForEvent(e);

src/components/structures/MatrixChat.tsx

@@ -32,6 +32,7 @@ import { logger } from "matrix-js-sdk/src/logger";
 import { throttle } from "lodash";
 import { CryptoEvent } from "matrix-js-sdk/src/crypto";
 import { RoomType } from "matrix-js-sdk/src/@types/event";
+import { DecryptionError } from 'matrix-js-sdk/src/crypto/algorithms';
 
 // focus-visible is a Polyfill for the :focus-visible CSS pseudo-attribute used by various components
 import 'focus-visible';
@@ -1452,7 +1453,7 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
 
         // When logging out, stop tracking failures and destroy state
         cli.on(HttpApiEvent.SessionLoggedOut, () => dft.stop());
-        cli.on(MatrixEventEvent.Decrypted, (e, err) => dft.eventDecrypted(e, err as MatrixError));
+        cli.on(MatrixEventEvent.Decrypted, (e, err) => dft.eventDecrypted(e, err as DecryptionError));
 
         cli.on(ClientEvent.Room, (room) => {
             if (MatrixClientPeg.get().isCryptoEnabled()) {

test/DecryptionFailureTracker-test.js

@@ -22,13 +22,16 @@ class MockDecryptionError extends Error {
     constructor(code) {
         super();
 
-        this.errcode = code || 'MOCK_DECRYPTION_ERROR';
+        this.code = code || 'MOCK_DECRYPTION_ERROR';
     }
 }
 
 function createFailedDecryptionEvent() {
     const event = new MatrixEvent({
         event_id: "event-id-" + Math.random().toString(16).slice(2),
+        content: {
+            algorithm: "m.megolm.v1.aes-sha2",
+        },
     });
     event.setClearData(event.badEncryptedMessage(":("));
     return event;