Temp work-around for BC break in Symfony2 Form component's default option processing

ExampleFormType.php

<?php

namespace Acme\MainBundle\Form\Type;

use Acme\MainBundle\Form\Util;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilder;

class ExampleFormType extends AbstractType
{
    public function buildForm(FormBuilder $builder, array $options)
    {
        $builder
            ->add('foo')
            ->add('bar')
        ;
    }

    public function getName()
    {
        return 'example';
    }

    public function getDefaultOptions(array $options)
    {
        return Util::addEmptyDataOption(array(
            'data_class' => 'Acme\MainBundle\Model\Example',
        ), $options);
    }
}

Util.php

<?php

namespace Acme\MainBundle\Form;

use Symfony\Component\Form\FormInterface;

class Util
{
    /**
     * Adds a default value for the "empty_data" option if none exists.
     *
     * This is similar to what was done by FieldType before a BC break in the
     * Form component.
     *
     * @see https://github.com/symfony/symfony/issues/3354
     * @param array $defaultOptions
     * @param array $options
     * @return array
     */
    public static function addEmptyDataOption(array $defaultOptions, array $options)
    {
        if (isset($defaultOptions['empty_data'])) {
            return $defaultOptions;
        }

        $class = isset($options['data_class']) ? $options['data_class'] : isset($defaultOptions['data_class']) ? $defaultOptions['data_class']: null;

        // If no data class is set explicitly and an object is passed as data,
        // use the class of that object as data class
        if (!$class) {
            $data = isset($options['data']) ? $options['data'] : isset($defaultOptions['data']) ? $defaultOptions['data']: null;

            if (is_object($data)) {
                $defaultOptions['data_class'] = $class = get_class($data);
            }
        }

        if ($class) {
            $defaultOptions['empty_data'] = function (FormInterface $form) use ($class) {
                if ($form->isEmpty() && !$form->isRequired()) {
                    return null;
                }

                return new $class();
            };
        }

        return $defaultOptions;
    }
}