CreatePasswordFormType.php

<?php

namespace Foo\AccountBundle\Form;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilder;
use Symfony\Component\Validator\Constraints\Callback;
    
class CreatePasswordFormType extends AbstractType
{
    public $notmatch_message = "The passwords don't match, please try again";
    public $length_message = "Your password should be %s characters in length";
    public $password_length = 8;


    public function buildForm(FormBuilder $builder, array $options)
    {
        $builder->add('first', 'password', array("error_bubbling"=>true))
                  ->add('second', 'password');

        $notmatch_message = $this->notmatch_message;
        $length_message = $this->length_message;
        $length = $this->password_length;

        $builder->setAttribute('validation_constraint', new Callback(array('methods' => array(
            'validate' => function ($data, $context) use ($notmatch_message, $length_message, $length) {
                if ($data["first"] !== $data["second"]) {
                    
                    $context->setPropertyPath('children[first]');
                    $context->addViolation($notmatch_message, array(), null);

                } elseif (strlen($data["first"]) < $length) {

                    $context->setPropertyPath('children[first]');
                    $context->addViolation(sprintf($length_message, $length), array(), null);
                }
            }
        ))));
    }
}