EntityWorkspaceConflictConstraint.php

<?php

namespace Drupal\workspaces\Plugin\Validation\Constraint;

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

/**
 * Validation constraint for an entity being edited in multiple workspaces.
 */
class EntityWorkspaceConflictConstraint extends SymfonyConstraint {
  public function __construct(mixed $options = NULL, public $message = 'The content is being edited in the @label workspace. As a result, your changes cannot be saved.', ?array $groups = NULL, mixed $payload = NULL) {
    parent::__construct($options, $groups, $payload);
  }

}