symfony2 EWZRecaptchaBundle extra Fields - symfony

Question

I have a problem with the EWZRecaptcha Bunlde (dev-master) and symfony 2.1.0.
The reCaptcha is displayed correctly and the image changes so i think the configuration is ok. But the reCaptcha is not validated and after submitting, $form->getErrorsAsString() says: This form should not contain extra fields.
Well, i think the extra fields are recaptcha_challenge_field and recaptcha_response_field that are sent from reCaptcha but i don think that i missed something in the docu so what can be wrong with them?
For validation i use the code from the docu: (i also tried the alternative, that was mentioned there)
use EWZ\Bundle\RecaptchaBundle\Validator\Constraints as Recaptcha;
//...
/**
* #Recaptcha\True
*/
public $recaptcha;
//...
in config:
framework:
validation: { enable_annotations: true }
i added the field like this:
$builder->add('recaptcha', 'ewz_recaptcha', array(
'property_path' => false,
'attr' => array(
'options' => array(
'theme' => 'clean'
)
)
));
Maybe i forgot something essential, that was not mentioned in the docu?

Answer 1

Possibly try adding a 'constraints' option to the builder. My recaptcha builder add looks like this:
$builder->add('recaptcha', 'ewz_recaptcha', array(
'attr' => array(
'options' => array(
'theme' => 'red'
)
),
'label' => "Verification",
'property_path' => false,
'constraints' => array(
new True()
),
'help' => "Enter the words in the box for verification purposes."
));
So add a 'use' statement for the constraint:
use EWZ\Bundle\RecaptchaBundle\Validator\Constraints\True;
and then add the constraint option:
'constraints' => array(
new True()
),

Answer 2

finally found the solution!
to get rid of the extra fields i added those two fields in my form class:
$builder->add('recaptcha_challenge_field', 'hidden', array('property_path' => false));
$builder->add('recaptcha_response_field', 'hidden', array('property_path' => false));
the validation then works with:
use EWZ\Bundle\RecaptchaBundle\Validator\Constraints\True;
...
'constraints' => array(
new True()
)
the annotation doesn`t work for me:
use EWZ\Bundle\RecaptchaBundle\Validator\Constraints AS Recaptcha;
...
/**
* #Recaptcha\True
*/
public $recaptcha;