Drupal, if views filter without options we remove it from output on hook_form_alter().

gistfile1.txt

  if (isset($form['#id']) && $form['#id'] == 'VIEW_FILTER_ID') {
    $filters_list = array();

    // Get filters names.
    foreach($form['#info'] as $filter_name => $filter_info) {
      // Return filter name without 'filter-' prefix.
      $filters_list[] = substr($filter_name, 7);
    }

    foreach($filters_list as $filter) {
      // If filter without options, we remove it.
      if (isset($form[$filter]) && empty($form[$filter]['#options'])) {
        unset($form['#info']["filter-{$filter}"]);
      }
    }
  }