ConfigImportSubscriber::validateModules

protected ConfigImportSubscriber::validateModules(ConfigImporter $config_importer)

protected function validateModules(ConfigImporter $config_importer) {
  $core_extension = $config_importer->getStorageComparer()->getSourceStorage()->read('core.extension');
  // Get a list of modules with dependency weights as values.
  $module_data = $this->getModuleData();
  $nonexistent_modules = array_keys(array_diff_key($core_extension['module'], $module_data));
  foreach ($nonexistent_modules as $module) {
    $config_importer->logError($this->t('Unable to install the %module module since it does not exist.', array('%module' => $module)));
  }

  // Ensure that all modules being installed have their dependencies met.
  $installs = $config_importer->getExtensionChangelist('module', 'install');
  foreach ($installs as $module) {
    $missing_dependencies = [];
    foreach (array_keys($module_data[$module]->requires) as $required_module) {
      if (!isset($core_extension['module'][$required_module])) {
        $missing_dependencies[] = $module_data[$required_module]->info['name'];
      }
    }
    if (!empty($missing_dependencies)) {
      $module_name = $module_data[$module]->info['name'];
      $message = $this->formatPlural(count($missing_dependencies), 
      'Unable to install the %module module since it requires the %required_module module.', 
      'Unable to install the %module module since it requires the %required_module modules.', 
      array('%module' => $module_name, '%required_module' => implode(', ', $missing_dependencies))
      );
      $config_importer->logError($message);
    }
  }

  // Settings is safe to use because settings.php is written before any module
  // is installed.
  $install_profile = Settings::get('install_profile');
  // Ensure that all modules being uninstalled are not required by modules
  // that will be installed after the import.
  $uninstalls = $config_importer->getExtensionChangelist('module', 'uninstall');
  foreach ($uninstalls as $module) {
    foreach (array_keys($module_data[$module]->required_by) as $dependent_module) {
      if ($module_data[$dependent_module]->status && !in_array($dependent_module, $uninstalls, TRUE) && $dependent_module !== $install_profile) {
        $module_name = $module_data[$module]->info['name'];
        $dependent_module_name = $module_data[$dependent_module]->info['name'];
        $config_importer->logError($this->t('Unable to uninstall the %module module since the %dependent_module module is installed.', array('%module' => $module_name, '%dependent_module' => $dependent_module_name)));
      }
    }
  }

  // Ensure that the install profile is not being uninstalled.
  if (in_array($install_profile, $uninstalls)) {
    $profile_name = $module_data[$install_profile]->info['name'];
    $config_importer->logError($this->t('Unable to uninstall the %profile profile since it is the install profile.', array('%profile' => $profile_name)));
  }
}