Add requirement to composer:
composer require sokil/php-symfony-validator-converter
Add service to app or bundle services config:
acme.validator.error_converter:
class: Sokil\Converter\ValidationErrorsConverter
<?php
$errors = $this->get('validator')->validate($entity);
if (count($errors) > 0) {
$list = $this
->get('acme.validator.error_converter')
->constraintViolationListToArray($errors);
}