Issue #3304797: Update request form.

use Drupal\Core\Form\ConfirmFormInterface;

use Drupal\Core\Form\FormStateInterface;

use Drupal\grequest\MembershipRequestManager;

use Drupal\group\Plugin\Validation\Constraint\GroupContentCardinality;

use Drupal\group\Plugin\Validation\Constraint\GroupRelationshipCardinality;

use Symfony\Component\DependencyInjection\ContainerInterface;

/**

    $violations = $this->entity->validate();

    foreach ($violations as $violation) {

      $constraint = $violation->getConstraint();

      if ($constraint instanceof GroupContentCardinality && $constraint->entityMessage == $violation->getMessage()->getUntranslatedString()) {

      if ($constraint instanceof GroupRelationshipCardinality && $constraint->entityMessage == $violation->getMessage()->getUntranslatedString()) {

        $form_state->setError($form, $this->t('You have already sent a request'));

      }

    }