EntityHasFieldConstraint.php

<?php

namespace Drupal\Core\Entity\Plugin\Validation\Constraint;

use Drupal\Core\StringTranslation\TranslatableMarkup;
use Drupal\Core\Validation\Attribute\Constraint;
use Symfony\Component\Validator\Constraint as SymfonyConstraint;

/**
 * Checks if a value is an entity that has a specific field.
 */
class EntityHasFieldConstraint extends SymfonyConstraint {
    
    /**
     * The default violation message.
     *
     * @var string
     */
    public $message = 'The entity must have the %field_name field.';
    
    /**
     * The violation message for non-fieldable entities.
     *
     * @var string
     */
    public $notFieldableMessage = 'The entity does not support fields.';
    
    /**
     * The field name option.
     *
     * @var string
     */
    // phpcs:ignore Drupal.NamingConventions.ValidVariableName.LowerCamelName
    public $field_name;
    
    /**
     * {@inheritdoc}
     */
    public function getDefaultOption() : ?string {
        return 'field_name';
    }
    
    /**
     * {@inheritdoc}
     */
    public function getRequiredOptions() : array {
        return (array) $this->getDefaultOption();
    }

}