function field_system_info_alter in Drupal 7

Implements hook_system_info_alter().

Goes through a list of all modules that provide a field type, and makes them required if there are any active fields of that type.

Related topics

File

modules/field/field.module, line 366

Attach custom data fields to Drupal entities.

Code

function field_system_info_alter(&$info, $file, $type) {
  if ($type == 'module' && module_hook($file->name, 'field_info')) {
    $fields = field_read_fields(array(
      'module' => $file->name,
    ), array(
      'include_deleted' => TRUE,
    ));
    if ($fields) {
      $info['required'] = TRUE;

      // Provide an explanation message (only mention pending deletions if there
      // remains no actual, non-deleted fields)
      $non_deleted = FALSE;
      foreach ($fields as $field) {
        if (empty($field['deleted'])) {
          $non_deleted = TRUE;
          break;
        }
      }
      if ($non_deleted) {
        if (module_exists('field_ui')) {
          $explanation = t('Field type(s) in use - see <a href="@fields-page">Field list</a>', array(
            '@fields-page' => url('admin/reports/fields'),
          ));
        }
        else {
          $explanation = t('Fields type(s) in use');
        }
      }
      else {
        $explanation = t('Fields pending deletion');
      }
      $info['explanation'] = $explanation;
    }
  }
}