Issue #2737817 by Dave Reid, joelstein, xlin1003: Undefined property:...

  return implode('<br />', $summary);

}

/**

 * Implements hook_field_formatter_prepare_view().

 */

function file_entity_field_formatter_prepare_view($entity_type, $entities, $field, $instances, $langcode, &$items, $displays) {

  // File and image fields set item values to NULL if a file cannot be loaded.

  // Remove those empty items so we can simply iterate through $items normally

  // in file_entity_field_formatter_view().

  foreach (array_keys($entities) as $id) {

    $items[$id] = array_filter($items[$id]);

  }

}

/**

 * Implements hook_field_formatter_view().

 */

    case 'file_audio':

      $multiple_file_behavior = $settings['multiple_file_behavior'];

      // Prevent 'empty' fields from causing a WSOD.

      $items = array_filter($items);

      // Build an array of sources for each <audio> element.

      $source_lists = array();

      if ($multiple_file_behavior == 'tags') {

    case 'file_video':

      $multiple_file_behavior = $settings['multiple_file_behavior'];

      // Prevent 'empty' fields from causing a WSOD.

      $items = array_filter($items);

      // Build an array of sources for each <video> element.

      $source_lists = array();

      if ($multiple_file_behavior == 'tags') {