content_migrate.text.inc

/**
 * Implements hook_content_migrate_data_record_alter().
 *
 * Tweaks individual records in a field.
 */
function content_migrate_text_data_record_alter(&$record, $field, $instance) {
  $existing_formats = &drupal_static(__FUNCTION__);
  if (empty($existing_formats)) {
    $existing_formats = db_query("SELECT format FROM {filter_format}")->fetchCol();
  }

  switch($field_value['module']) {
    case 'text':
      if (!empty($instance['settings']['text_processing'])) {
        // Adapted from node_update_7006(), to adjust the filter format values 
        // from the old numeric to the new text formats. Ensure we have a valid value.
        if (!in_array($record[$field['field_name'] . '_format'], $existing_formats)) {
          $record[$field['field_name'] . '_format'] = variable_get('filter_default_format', 1);
        }
      }
  }
}

switch($field_value['module']) {

will never be entered because there is NO avaliable value $field_value