Sonata Action with custom form - symfony

Question

I have a custom action, based on the editAction from Sonata. Only the form is different.
public function customAction(){
$id = $this->get('request')->get($this->admin->getIdParameter());
$object = $this->admin->getObject($id);
if (!$object) {
throw new NotFoundHttpException(sprintf('unable to find the object with id : %s', $id));
}
if (false === $this->admin->isGranted('EDIT', $object)) {
throw new AccessDeniedException();
}
// On vérifie que l'annonce appartient bien à l'utilisateur connecté
if($this->getUser()->getId() !== $object->getUser()->getId()) {
throw new AccessDeniedException();
}
$em = $this->getDoctrine()->getManager();
$preparechoices = $em->getRepository('AcmeBundle:Entity')->findAll();
foreach($preparechoices as $c){
$choices[$c->getId()] = $c->getLibelle();
}
$form = $this->createFormBuilder(array('choix'=>1))
->add('choix','choice',array('choices'=>$choices))
->add('submit','submit')
->getForm();
$view = $form->createView();
$this->admin->setSubject($object);
$this->get('twig')->getExtension('form')->renderer->setTheme($view, $this->admin->getFormTheme());
return $this->render($this->admin->getTemplate('EDIT'), array(
'action' => 'edit',
'object' => $object,
'form' => $view,
));
}
But I got this error :
Impossible to access a key ("default") on a boolean variable ("")
The error come from this line in the twif file :
{{ form_helper.render_groups(admin, form, admin.formtabs['default'].groups, has_tab) }}
I can't find how to fix it, does anyone know ?

Answer 1

Thanks to Joshua, i was able to fix the error by adding this line:
$this->admin->setFormTabs(array('default'=>array('groups' => array())));
But now, i got a new error :
Impossible to access an attribute ("help") on a null variable
Form form_admin_fields.html.twig, this line, because sonata_admin.field_description is null :
{% if sonata_admin.field_description.help %}
title="{{ sonata_admin.admin.trans(sonata_admin.field_description.help, {}, sonata_admin.field_description.translationDomain)|raw }}"
{% endif %}
I don't know how to fix it, i tried several test, whitout success, in the form definition like :
$form = $this->createFormBuilder(array('choix'=>1))
->add('choix','choice',array('choices'=>$choices,'sonata_admin'=>array('field_description'=>array('help'=>'help_message'))))
->add('submit','submit')
->getForm();