Symfony\Component\Form\Extension\Core\Type\CollectionType::buildForm PHP Метод

    public function buildForm(FormBuilder $builder, array $options)
    {
        if ($options['allow_add'] && $options['prototype']) {
            $prototype = $builder->create('$$name$$', $options['type'], $options['options']);
            $builder->setAttribute('prototype', $prototype);
        }

        $listener = new ResizeFormListener(
            $builder->getFormFactory(),
            $options['type'],
            $options['options'],
            $options['allow_add'],
            $options['allow_delete']
        );

        $builder
            ->addEventSubscriber($listener)
            ->setAttribute('allow_add', $options['allow_add'])
            ->setAttribute('allow_delete', $options['allow_delete'])
        ;
    }

 /**
  * {@inheritdoc}
  */
 public function buildForm(FormBuilderInterface $builder, array $options)
 {
     parent::buildForm($builder, $options);
     if ($options['allow_add'] && $options['prototype']) {
         $prototype = $builder->create('${id}', $options['type'], $options['options']);
         $builder->setAttribute('prototype', $prototype->getForm());
     }
 }