Add raw error to analytics E2E error event context (#8447)

* Add raw error to analytics E2E error context

* Fix code style

Co-authored-by: Michael Telatynski <7t3chguy@gmail.com>

src/DecryptionFailureTracker.ts

@@ -31,18 +31,19 @@ export class DecryptionFailure {
 
 type ErrorCode = "OlmKeysNotSentError" | "OlmIndexError" | "UnknownError" | "OlmUnspecifiedError";
 
-type TrackingFn = (count: number, trackedErrCode: ErrorCode) => void;
+type TrackingFn = (count: number, trackedErrCode: ErrorCode, rawError: string) => void;
 
 export type ErrCodeMapFn = (errcode: string) => ErrorCode;
 
 export class DecryptionFailureTracker {
-    private static internalInstance = new DecryptionFailureTracker((total, errorCode) => {
+    private static internalInstance = new DecryptionFailureTracker((total, errorCode, rawError) => {
         Analytics.trackEvent('E2E', 'Decryption failure', errorCode, String(total));
         for (let i = 0; i < total; i++) {
             PosthogAnalytics.instance.trackEvent<ErrorEvent>({
                 eventName: "Error",
                 domain: "E2EE",
                 name: errorCode,
+                context: `mxc_crypto_error_type_${rawError}`,
             });
         }
     }, (errorCode) => {
@@ -236,7 +237,7 @@ export class DecryptionFailureTracker {
             if (this.failureCounts[errorCode] > 0) {
                 const trackedErrorCode = this.errorCodeMapFn(errorCode);
 
-                this.fn(this.failureCounts[errorCode], trackedErrorCode);
+                this.fn(this.failureCounts[errorCode], trackedErrorCode, errorCode);
                 this.failureCounts[errorCode] = 0;
             }
         }

test/DecryptionFailureTracker-test.js

@@ -57,6 +57,33 @@ describe('DecryptionFailureTracker', function() {
         done();
     });
 
+    it('tracks a failed decryption with expected raw error for a visible event', function(done) {
+        const failedDecryptionEvent = createFailedDecryptionEvent();
+
+        let count = 0;
+        let reportedRawCode = "";
+        const tracker = new DecryptionFailureTracker((total, errcode, rawCode) => {
+            count += total;
+            reportedRawCode = rawCode;
+        }, () => "UnknownError");
+
+        tracker.addVisibleEvent(failedDecryptionEvent);
+
+        const err = new MockDecryptionError('INBOUND_SESSION_MISMATCH_ROOM_ID');
+        tracker.eventDecrypted(failedDecryptionEvent, err);
+
+        // Pretend "now" is Infinity
+        tracker.checkFailures(Infinity);
+
+        // Immediately track the newest failures
+        tracker.trackFailures();
+
+        expect(count).not.toBe(0, 'should track a failure for an event that failed decryption');
+        expect(reportedRawCode).toBe('INBOUND_SESSION_MISMATCH_ROOM_ID', 'Should add the rawCode to the event context');
+
+        done();
+    });
+
     it('tracks a failed decryption for an event that becomes visible later', function(done) {
         const failedDecryptionEvent = createFailedDecryptionEvent();