/**
* Checks that the configuration synchronization is valid.
*
* This event listener prevents deleting all configuration. If there is
* nothing to import then event propagation is stopped because there is no
* config import to validate.
*
* @param \Drupal\Core\Config\ConfigImporterEvent $event
* The config import event.
*/
public function onConfigImporterValidateNotEmpty(ConfigImporterEvent $event)
{
$importList = $event->getConfigImporter()->getStorageComparer()->getSourceStorage()->listAll();
if (empty($importList)) {
$event->getConfigImporter()->logError($this->t('This import is empty and if applied would delete all of your configuration, so has been rejected.'));
$event->stopPropagation();
}
}
