I have the following code:

$builder->add('category', 'entity', [
                'required'      => false,
                'class'         => 'Ras\Bundle\DomainBundle\Entity\Category',
                'choice_value'  => 'name',
                'choice_label'  => 'label'
            ]);

When I select a category it does not give me the selected category entity, but when I changed choice_value to be id it worked fine. There seem to be an issue when the choice_value is a string attribute

NOTE:
Ras\Bundle\DomainBundle\Entity\Category entity has following attributes: id, name, label