gistfile1.txt

## Formulaire :

        ->add('mediaPath', FineUploaderTypeExtension::class, [
            'label' => 'XXXXXXXXXXX',
            'mapped' => false,
        ])
        
## Service :
AppBundle\Form\Extension\FineUploaderTypeExtension:
    public: false
    tags:
        - { name: form.type_extension, extended_type: Symfony\Component\Form\Extension\Core\Type\FileType }
        
# Extension :
namespace AppBundle\Form\Extension;

use Symfony\Component\Form\AbstractTypeExtension;
use Symfony\Component\Form\Extension\Core\Type\FileType;

class FineUploaderTypeExtension extends AbstractTypeExtension
{
    public function getExtendedType()
    {
        return FileType::class;
    }
}