WorkspacesRequirements.php

<?php

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

use Drupal\Core\Extension\InstallRequirementsInterface;

/**
 * Install time requirements for the workspaces module.
 */
class WorkspacesRequirements implements InstallRequirementsInterface {
    
    /**
     * {@inheritdoc}
     */
    public static function getRequirements() : array {
        $requirements = [];
        if (\Drupal::moduleHandler()->moduleExists('workspace')) {
            $requirements['workspace_incompatibility'] = [
                'severity' => REQUIREMENT_ERROR,
                'description' => t('Workspaces can not be installed when the contributed Workspace module is also installed. See the <a href=":link">upgrade path</a> page for more information on how to upgrade.', [
                    ':link' => 'https://www.drupal.org/node/2987783',
                ]),
            ];
        }
        return $requirements;
    }

}