Why no upload file, but required_with still fired

[tommy66374]

Leave all empty and click submit button

<input type="file" name="avatar">
<input type="text" name="rename">

the error included avatar is required OK, but why this also display rename error ?

        return [
            'avatar' => ['required', 'file', 'image'],
            'rename' => ['required_with:avatar', 'string', 'between:10,50'],
        ];

the question is how to fire the rule 'rename' ONLY if has upload avatar ?