How to edit file 'description' label and help text

Question

I want to edit the file upload description label and the help sentence underneath it:

I tried the below code:

function mymodule_field_widget_form_alter(&$element, FormStateInterface &$form_state, $context) {
  if (isset($element['#field_name'] == 'field_file_description') {
      // Add process callback to change field description.
      $element['#process'][] = 'chg_desc';
    }
  }
}

function chg_desc($element, FormStateInterface $form_state, $form) {
  $element['#description'] = t('Trying to edit desc help');
  return $element;
}

It does not have any impact on the field label and help text. How can they be changed?

Answer 1

I'm going to assume that the machine name of your file field is field_file_description.

According to FileWidget.php#L414, the description is it's own element in the form, so instead of $element['#description'] it should be $element['description']['#description']. I just tested that and it works.

Here is a working code sample:

function mymodule_field_widget_form_alter(&$element, FormStateInterface &$form_state, $context) {
  if (!array_key_exists('#field_name', $element)) {
    return;
  }
  if ($element['#field_name'] == 'field_file_description') {
    // Add process callback to change field description.
    $element['#process'][] = 'mymodule_process_field_file_description';
  }
}

function mymodule_process_field_file_description($element, FormStateInterface $form_state, $form) {
  $element['description']['#title'] = t('Help!!!');
  $element['description']['#description'] = t('Trying to edit desc help');
  return $element;
}