LayoutDiscoveryRequirements.php

<?php

declare (strict_types=1);
namespace Drupal\layout_discovery\Install\Requirements;

use Drupal\Core\Extension\InstallRequirementsInterface;
use Drupal\Core\Extension\Requirement\RequirementSeverity;

/**
 * Install time requirements for the layout_discovery module.
 */
class LayoutDiscoveryRequirements implements InstallRequirementsInterface {
    
    /**
     * {@inheritdoc}
     */
    public static function getRequirements() : array {
        $requirements = [];
        if (\Drupal::moduleHandler()->moduleExists('layout_plugin')) {
            $requirements['layout_discovery'] = [
                'description' => t('Layout Discovery cannot be installed because the Layout Plugin module is installed and incompatible.'),
                'severity' => RequirementSeverity::Error,
            ];
        }
        return $requirements;
    }

}