From a2939252803d5cd4b68340da08820174c30a53e6 Mon Sep 17 00:00:00 2001
From: Tim Yung <yungsters@meta.com>
Date: Wed, 11 Jun 2025 07:16:10 -0700
Subject: [PATCH] RN: Remove "js engine" Suffix from Error Stacks (#51913)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/51913

Removes the non-standard "js engine" suffix from `Error` stack traces.

Changelog:
[General][Changed] - Errors will no longer have the "js engine" suffix.

Reviewed By: robhogan

Differential Revision: D76319439

fbshipit-source-id: e0d8e4f451df7010f48e3076bc244981bf590402
---
 .../Libraries/Core/ExceptionsManager.js       |  3 --
 .../Core/__tests__/ExceptionsManager-test.js  | 45 -------------------
 .../jserrorhandler/JsErrorHandler.cpp         |  7 +--
 3 files changed, 1 insertion(+), 54 deletions(-)

diff --git a/packages/react-native/Libraries/Core/ExceptionsManager.js b/packages/react-native/Libraries/Core/ExceptionsManager.js
index 429893ad690..bc1237e81a6 100644
--- a/packages/react-native/Libraries/Core/ExceptionsManager.js
+++ b/packages/react-native/Libraries/Core/ExceptionsManager.js
@@ -76,9 +76,6 @@ function reportException(
     message = namePrefix + message;
   }
 
-  message =
-    e.jsEngine == null ? message : `${message}, js engine: ${e.jsEngine}`;
-
   // $FlowFixMe[unclear-type]
   const extraData: Object = {
     // $FlowFixMe[incompatible-use] we can't define a type with a Symbol-keyed field in flow
diff --git a/packages/react-native/Libraries/Core/__tests__/ExceptionsManager-test.js b/packages/react-native/Libraries/Core/__tests__/ExceptionsManager-test.js
index 75441310468..904e627e39e 100644
--- a/packages/react-native/Libraries/Core/__tests__/ExceptionsManager-test.js
+++ b/packages/react-native/Libraries/Core/__tests__/ExceptionsManager-test.js
@@ -175,51 +175,6 @@ function runExceptionsManagerTests() {
         expect(console.error).toBeCalledWith(formattedMessage);
       });
 
-      test('adds the JS engine to the message', () => {
-        const error = new Error('Some error happened');
-        // $FlowFixMe[prop-missing]
-        error.jsEngine = 'hermes';
-        // Copy all the data we care about before any possible mutation.
-        const {message, jsEngine} = error;
-
-        ReactFiberErrorDialog.showErrorDialog({
-          ...capturedErrorDefaults,
-          error,
-        });
-
-        let exceptionData;
-
-        if (__DEV__) {
-          expect(logBoxAddConsoleLog).not.toBeCalled();
-          expect(nativeReportException).not.toBeCalled();
-          expect(logBoxAddException).toBeCalledTimes(1);
-          exceptionData = logBoxAddException.mock.calls[0][0];
-        } else {
-          expect(logBoxAddConsoleLog).not.toBeCalled();
-          expect(logBoxAddException).not.toBeCalled();
-          expect(nativeReportException).toBeCalledTimes(1);
-          exceptionData = nativeReportException.mock.calls[0][0];
-        }
-        expect(exceptionData.message).toBe(
-          'Error: ' +
-            message +
-            '\n\n' +
-            'This error is located at:' +
-            capturedErrorDefaults.componentStack +
-            ', js engine: ' +
-            jsEngine,
-        );
-        expect(console.error).toBeCalledWith(
-          'Error: ' +
-            message +
-            '\n\n' +
-            'This error is located at:' +
-            capturedErrorDefaults.componentStack +
-            ', js engine: ' +
-            jsEngine,
-        );
-      });
-
       test('wraps string in an Error and sends to handleException', () => {
         const message = 'Some error happened';
 
diff --git a/packages/react-native/ReactCommon/jserrorhandler/JsErrorHandler.cpp b/packages/react-native/ReactCommon/jserrorhandler/JsErrorHandler.cpp
index 5e64d48879e..bc630ca9625 100644
--- a/packages/react-native/ReactCommon/jserrorhandler/JsErrorHandler.cpp
+++ b/packages/react-native/ReactCommon/jserrorhandler/JsErrorHandler.cpp
@@ -276,12 +276,6 @@ void JsErrorHandler::handleErrorWithCppPipeline(
     message = *name + ": " + message;
   }
 
-  auto jsEngineValue = errorObj.getProperty(runtime, "jsEngine");
-
-  if (!isLooselyNull(jsEngineValue)) {
-    message += ", js engine: " + stringifyToCpp(runtime, jsEngineValue);
-  }
-
   auto extraDataKey = jsi::PropNameID::forUtf8(runtime, "RN$ErrorExtraDataKey");
   auto extraDataValue = errorObj.getProperty(runtime, extraDataKey);
 
@@ -290,6 +284,7 @@ void JsErrorHandler::handleErrorWithCppPipeline(
     objectAssign(runtime, extraData, extraDataValue.asObject(runtime));
   }
 
+  auto jsEngineValue = errorObj.getProperty(runtime, "jsEngine");
   auto isDEV =
       isTruthy(runtime, runtime.global().getProperty(runtime, "__DEV__"));