UserRequirements.php

<?php

declare (strict_types=1);
namespace Drupal\user\Hook;

use Drupal\Core\Database\Connection;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\Core\Hook\Attribute\Hook;
use Drupal\Core\StringTranslation\StringTranslationTrait;

/**
 * Requirements for the User module.
 */
class UserRequirements {
    use StringTranslationTrait;
    public function __construct(EntityTypeManagerInterface $entityTypeManager, Connection $connection) {
    }
    
    /**
     * Implements hook_runtime_requirements().
     */
    public function runtime() : array {
        $requirements = [];
        $result = (bool) $this->entityTypeManager
            ->getStorage('user')
            ->getQuery()
            ->accessCheck(FALSE)
            ->condition('uid', 0)
            ->range(0, 1)
            ->execute();
        if ($result === FALSE) {
            $requirements['anonymous user'] = [
                'title' => $this->t('Anonymous user'),
                'description' => $this->t('The anonymous user does not exist. See the <a href=":url">restore the anonymous (user ID 0) user record</a> for more information', [
                    ':url' => 'https://www.drupal.org/node/1029506',
                ]),
                'severity' => REQUIREMENT_WARNING,
            ];
        }
        $query = $this->connection
            ->select('users_field_data');
        $query->addExpression('LOWER(mail)', 'lower_mail');
        $query->isNotNull('mail');
        $query->groupBy('lower_mail');
        $query->having('COUNT(uid) > :matches', [
            ':matches' => 1,
        ]);
        $conflicts = $query->countQuery()
            ->execute()
            ->fetchField();
        if ($conflicts > 0) {
            $requirements['conflicting emails'] = [
                'title' => $this->t('Conflicting user emails'),
                'description' => $this->t('Some user accounts have email addresses that differ only by case. For example, one account might have alice@example.com and another might have Alice@Example.com. See <a href=":url">Conflicting User Emails</a> for more information.', [
                    ':url' => 'https://www.drupal.org/node/3486109',
                ]),
                'severity' => REQUIREMENT_WARNING,
            ];
        }
        return $requirements;
    }

}