Bug 1869371 - Strip NS_ERROR_* codes from submitted telemetry r=markh,sync-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D200969

services/sync/modules/telemetry.sys.mjs

@@ -241,10 +241,14 @@ export class ErrorSanitizer {
     NotAllowedError: this.E_PERMISSION_DENIED,
   };
 
+  // IOUtils error messages include the specific nsresult error code that caused them.
+  static NS_ERROR_RE = new RegExp(/ \(NS_ERROR_.*\)$/);
+
   static #cleanOSErrorMessage(message, error = undefined) {
     if (DOMException.isInstance(error)) {
       const sub = this.DOMErrorSubstitutions[error.name];
       message = message.replaceAll("\\", "/");
+      message = message.replace(this.NS_ERROR_RE, "");
       if (sub) {
         return `${sub} ${message}`;
       }

services/sync/tests/unit/test_telemetry.js

@@ -734,7 +734,7 @@ add_task(async function test_clean_real_os_error() {
       equal(failureReason.name, "unexpectederror");
       equal(
         failureReason.error,
-        "OS error [File/Path not found] Could not open the file at [profileDir]/no/such/path.json"
+        "OS error [File/Path not found] Could not open `[profileDir]/no/such/path.json': file does not exist"
       );
     });
   } finally {