src/Extension/Core/Type/ActionType.php
public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(
            [
                'redirect_uri' => null,
                'content' => null,
                'attr' => [],
                'url_attr' => [],
                'url' => null,
                'uri_scheme' => null,

                // Remove requirement for label
                'label' => function (Options $options) {
                    return $options['content'];
                },
            ]
        );

        $resolver->setAllowedTypes('redirect_uri', ['string', 'null', 'callable']);
        $resolver->setAllowedTypes('url', ['string', 'null']);
        $resolver->setAllowedTypes('uri_scheme', ['string', 'callable', 'null']);
        $resolver->setAllowedTypes('content', ['null', 'string', 'callable']);
        $resolver->setAllowedTypes('attr', ['array']);
        $resolver->setAllowedTypes('url_attr', ['array']);
    }
public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(
            [
                'redirect_uri' => null,
                'content' => null,
                'attr' => [],
                'url_attr' => [],
                'url' => null,
                'uri_scheme' => null,

                // Remove requirement for label
                'label' => function (Options $options) {
                    return $options['content'];
                },
            ]
        );

        $resolver->setAllowedTypes('redirect_uri', ['string', 'null', 'callable']);
        $resolver->setAllowedTypes('url', ['string', 'null']);
        $resolver->setAllowedTypes('uri_scheme', ['string', 'callable', 'null']);
        $resolver->setAllowedTypes('content', ['null', 'string', 'callable']);
        $resolver->setAllowedTypes('attr', ['array']);
        $resolver->setAllowedTypes('url_attr', ['array']);
    }
{@inheritdoc}