Options have parametr "data"
Example usage:
/**
* @{inerhitDoc}
*/
public function buildForm(FormBuilderInterface $builder, array $options)
{
$region = $options['data'];
$builder
->add('name', 'text');
}
And control usage type with OptionsResolver
public function setDefaultOptions(OptionsResolverInterface $resolver)
{
$resolver
->setDefaults(array(
'region' => new Region
))
->addAllowedTypes(array(
'region' => 'Acme\DemoBundle\Entity\Region',
))
;
}