(NOT) NULL doctrine_orm_callback filter with Sonata Admin

PersonAdmin.php

<?php

use Sonata\AdminBundle\Datagrid\DatagridMapper;

use Sonata\CoreBundle\Form\Type\BooleanType;

class PersonAdmin extends Admin
{
    protected function configureDatagridFilters(DatagridMapper $filterMapper)
    {
        $filterMapper
            ->add('user', 'doctrine_orm_callback', array(
                    'label' => 'Login',
                    'translation_domain' => 'SonataCoreBundle',
                    'callback' => function($queryBuilder, $alias, $field, $value) {
                            if (!isset($value['value'])) {
                                return;
                            }

                            if ($value['value'] == BooleanType::TYPE_YES) {
                                $queryBuilder->andWhere(sprintf('$s.$s IS NOT NULL', $alias, $field));
                            }

                            if ($value['value'] == BooleanType::TYPE_NO) {
                                $queryBuilder->andWhere(sprintf('$s.$s IS NULL', $alias, $field));
                            }

                            return true;
                        }
                    ), 'choice', array(
                        'translation_domain' => 'SonataCoreBundle',
                        'choices' => array(
                            BooleanType::TYPE_YES => 'label_type_yes',
                            BooleanType::TYPE_NO  => 'label_type_no'
                        )
                    )
                )
            ;
    }
}

Related issue $field in doctrine_orm_callback is empty:

• sonata-project/SonataDoctrineORMAdminBundle#472

Based on:

• https://gist.github.com/joergbasedow/5964815 by @joergbasedow

FR Filter for a "IS_NULL" Field:

• sonata-project/SonataAdminBundle#279

Just a fill considerations:

1. sprintf should not use %s instead of $s that you used?
2. Under Symfony 2.8+ value and keys in choices are inverted like below:

'choices' => array(
    'label_type_yes' => BooleanType::TYPE_YES,
    'label_type_no'  => BooleanType::TYPE_NO
)

Why $s in $queryBuilder->andWhere(sprintf('$s.$s IS NOT NULL', $alias, $field)); instead %s?