Duplicate __self prop found error on app launch

[jaeho-jinju]

Description

When launching a React Native app through Radon IDE, the following error screen appears during initial launch, blocking the app from running:

Duplicate __self prop found. You are most likely using the deprecated transform-react-jsx-self Babel plugin. 
Both __source and __self are automatically set when using the automatic runtime. 
Please remove transform-react-jsx-source and transform-react-jsx-self from your Babel config.

This error does not appear when running the same project via Metro (yarn start).

Root Cause

@react-native/babel-preset registers both:

1. @babel/plugin-transform-react-jsx with { runtime: 'automatic' } — which automatically injects __self and __source
2. @babel/plugin-transform-react-jsx-self and @babel/plugin-transform-react-jsx-source in dev mode — which inject __self and __source again

This causes duplicate __self props. Metro suppresses this internally, but Radon IDE's bundler treats it as an error.

Relevant code in @react-native/babel-preset/src/configs/main.js:

// Line 54-58: automatic runtime (already handles __self/__source)
if (!options.useTransformReactJSXExperimental) {
  extraPlugins.push([
    require('@babel/plugin-transform-react-jsx'),
    {runtime: 'automatic'},
  ]);
}

// Line 174-177: duplicates __self/__source in dev mode
if (options && options.dev && !options.useTransformReactJSXExperimental) {
  extraPlugins.push([require('@babel/plugin-transform-react-jsx-source')]);
  extraPlugins.push([require('@babel/plugin-transform-react-jsx-self')]);
}

Workaround

Setting useTransformReactJSXExperimental: true in babel.config.js and manually adding the JSX transform plugin resolves the error, but this requires users to modify their Babel config:

presets: [
  ["module:@react-native/babel-preset", { useTransformReactJSXExperimental: true }],
],
plugins: [
  ["@babel/plugin-transform-react-jsx", { runtime: "automatic" }],
],

Environment

• Radon IDE version: 1.15.1
• Editor: Cursor (VSCode)
• React Native version: 0.79.6
• Platform: macOS (Apple Silicon)

Expected Behavior

The error should not appear. Metro bundler does not show this error with the same Babel config.

[jwajgelt]

Hi @jaeho-jinju
Thanks for reporting the issue, as well as helping us investigate what might be causing it. We'll be looking into it in the coming days.

[pFornagiel]

Hi @jaeho-jinju,

As @jwajgelt mentioned, we’ll be looking into this shortly. In the meantime, if possible, could you please share a bit more context to help us investigate? Specifically, it would be helpful to see your package.json dependencies, metro.config.js and the rest of your Babel configuration file, if you’re able to share that information.

Thank you!

[jaeho-jinju]

Hi @pFornagiel, @jwajgelt 👋

Thank you for looking into this.
As requested, I’m sharing the following files for additional context:

package.json
metro.config.js
babel.config.js

Please let me know if you need any additional information or if there’s anything specific I should highlight.
Thanks again for your support 🙏

babel.config.js
metro.config.js
package.json

[pFornagiel]

Hi @jaeho-jinju,

Thank you for shared files. Unfortunately, as of now, we are unable to reproduce your issue - the configuration you provided, does not produce the error expected and we’re not seeing the behaviour you described.

The only time we’ve observed similar behaviour was when there was an issue with the babel.config.js setup itself. As far as I know, Metro shouldn’t be suppressing this kind of error internally. If you’re seeing additional logs during runtime, especially around the time the issue occurs, it would be very helpful if you could share them.

In the meantime, we’ll continue keeping an eye on this and look into possible causes on our end as well.