Symfony 4 support

[simonschaufi]

Thank you for this package! I would like to use it for an open source symfony 4 based application because Carbon makes my life so much easier but I'm getting a DateTime object in my form instead of a Carbon instance.

Could you use carbondate/carbon as dependency (as nesbot doesn't support symfony 4 yet) and make this package compatible? It would be of highly appreciated!

[jifer]

There is no need to use such bundle. Just put this 2 somewhere and register CarbonExtension as service and you're done.

use Carbon\Carbon;
use DateTime;
use Symfony\Component\Form\DataTransformerInterface;
use Symfony\Component\Form\Exception\UnexpectedTypeException;

/**
 * Class CarbonToDateTimeTransformer
 */
final class CarbonToDateTimeTransformer implements DataTransformerInterface
{
    /**
     * @inheritDoc
     */
    public function transform($carbon)
    {
        return $carbon; // No conversion required
    }

    /**
     * @param DateTime|null $dateTime
     * @return Carbon|null
     */
    public function reverseTransform($dateTime): ?Carbon
    {
        if (null === $dateTime) {
            return null;
        }

        if ($dateTime instanceof DateTime) {
            return Carbon::instance($dateTime);
        }

        throw new UnexpectedTypeException($dateTime, '\DateTime or null');
    }
}

and TypeExtension that must be registered as service like that YourNamespace\CarbonExtension: ~

use Symfony\Component\Form\AbstractTypeExtension;
use Symfony\Component\Form\Extension\Core\Type\DateTimeType;
use Symfony\Component\Form\Extension\Core\Type\DateType;
use Symfony\Component\Form\Extension\Core\Type\TimeType;
use Symfony\Component\Form\FormBuilderInterface;

/**
 * Class CarbonExtension
 */
final class CarbonExtension extends AbstractTypeExtension
{
    /**
     * @inheritDoc
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->addModelTransformer(new CarbonToDateTimeTransformer());
    }

    /**
     * @inheritDoc
     */
    public static function getExtendedTypes(): iterable
    {
        return [DateType::class, DateTimeType::class, TimeType::class];
    }
}