UnexpectedTypeException when trying to create a custom validation constraint

Question

I'm trying to create a custom validation constraint, this is the relevant code:

ValidCoupon.php

<?php
namespace Bcg\UtilsBundle\Validator\Constraints;

use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;


/**
 * @Annotation
 */
class ValidCoupon extends Constraint
{
    public function validatedBy()
    {
        return 'valid_coupon';
    }
    public $message = 'The coupon is not valid.';
}

class ValidCouponValidator extends ConstraintValidator
{
    public function validate($value, Constraint $constraint)
    {
        var_dump($value);
        if (true) {
            $this->context->addViolation(
                $constraint->message,
                array()
            );
        }
    }
}

I call the service in the config.yml like this:

services:
    validator.unique.valid_coupon:
        class: Bcg\UtilsBundle\Validator\Constraints\ValidCoupon
        tags:
            - { name: validator.constraint_validator, alias: valid_coupon }

The validation.yml looks like this:

Bcg\UtilsBundle\Entity\Order:
    properties:
        coupon:
            - Bcg\UtilsBundle\Validator\Constraints\ValidCoupon: ~

And the error I get is the following:

Expected argument of type "Symfony\Component\Validator\ConstraintValidatorInterface", "Bcg\UtilsBundle\Validator\Constraints\ValidCoupon" given 500 Internal Server Error - UnexpectedTypeException

Full stack trace here.

I'm pretty stuck, it doesn't seem to find ValidCouponValidator I don't really know how to continue from here, I know that the public function validateBy() is executed, so it should be correctly overridden but it doesn't seem so...

Answer 1

Seems like you have a type in your validator service configuration :

You declare your ValidCoupon class as a validator instead of your ValidCouponValidator (which indeed implements the ConstraintValidatorInterface as the error complains about).

Try this:

services:
    validator.unique.valid_coupon:
        class: Bcg\UtilsBundle\Validator\Constraints\ValidCouponValidator
        tags:
            - { name: validator.constraint_validator, alias: valid_coupon }