How do I make the file description field required?
Code snippet for making a file's description field required:

/**
 * Implements hook_field_widget_form_alter().
 */
function MYMODULE_field_widget_form_alter(&amp;$element, &amp;$form_state, $context) {
  if ($context['field']['field_name'] == 'field_MYFIELD' &amp;&amp; $context['instance']['widget']['type'] == 'file_generic') {
    $element_children = element_children($element, TRUE);
    foreach($element_children as $key) {
      $element[$key]['#process'][] = 'MYMODULE_file_field_description_required';
    }
  }
}

/**
 * Require description to be set.
 */
function MYMODULE_file_field_description_required($element, &amp;$form_state, $form) {
  $element['description']['#required'] = TRUE;
  return $element;
}