MultisiteValidator.php

<?php

declare (strict_types=1);
namespace Drupal\package_manager\Validator;

use Drupal\Core\StringTranslation\StringTranslationTrait;
use Drupal\package_manager\Event\PreOperationStageEvent;
use Drupal\package_manager\PathLocator;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

/**
 * Checks that the current site is not part of a multisite.
 *
 * @internal
 *   This is an internal part of Package Manager and may be changed or removed
 *   at any time without warning. External code should not interact with this
 *   class.
 */
final class MultisiteValidator implements EventSubscriberInterface {
    use BaseRequirementValidatorTrait;
    use StringTranslationTrait;
    public function __construct(PathLocator $pathLocator) {
    }
    
    /**
     * Validates that the current site is not part of a multisite.
     */
    public function validate(PreOperationStageEvent $event) : void {
        if ($this->isMultisite()) {
            $event->addError([
                $this->t('Drupal multisite is not supported by Package Manager.'),
            ]);
        }
    }
    
    /**
     * Detects if the current site is part of a multisite.
     *
     * @return bool
     *   TRUE if the current site is part of a multisite, otherwise FALSE.
     */
    private function isMultisite() : bool {
        $web_root = $this->pathLocator
            ->getWebRoot();
        if ($web_root) {
            $web_root .= '/';
        }
        $sites_php_path = $this->pathLocator
            ->getProjectRoot() . '/' . $web_root . 'sites/sites.php';
        if (!file_exists($sites_php_path)) {
            return FALSE;
        }
        // @see \Drupal\Core\DrupalKernel::findSitePath()
        $sites = [];
        include $sites_php_path;
        // @see example.sites.php
        return count(array_unique($sites)) > 1;
    }

}