file_field_widget_form() broken when submitting programmatically a form having a multiple file field

The following lines have been added as per #1059268: Files are lost when adding multiple files to multiple file fields at the same time → .

  // Load the items for form rebuilds from the field state as they might not be
  // in $form_state['values'] because of validation limitations. Also, they are
  // only passed in as $items when editing existing entities.
  $field_state = field_form_get_state($element['#field_parents'], $field['field_name'], $langcode, $form_state);
  if (isset($field_state['items'])) {
    $items = $field_state['items'];
  }

The code that has been removed as per that issue is the following one.

  // Retrieve any values set in $form_state, as will be the case during Ajax
  // rebuilds of this form.
  if (isset($form_state['values'])) {
    $path = array_merge($element['#field_parents'], array($field['field_name'], $langcode));
    $path_exists = FALSE;
    $values = drupal_array_get_nested_value($form_state['values'], $path, $path_exists);
    if ($path_exists) {
      $items = $values;
      drupal_array_set_nested_value($form_state['values'], $path, NULL);
    }
  }

  foreach ($items as $delta => $item) {
    $items[$delta] = array_merge($defaults, $items[$delta]);
    // Remove any items from being displayed that are not needed.
    if ($items[$delta]['fid'] == 0) {
      unset($items[$delta]);
    }
  }

The issue explains why that code has been added. Removing the && empty($form_state['programmed']) condition will probably mean refacing the bug that issue fixed.

Drupal 9.5 is still using that condition.

    $empty_single_allowed = $cardinality == 1 && $delta == 0;
    $empty_multiple_allowed = ($cardinality == FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED || $delta < $cardinality) && !$form_state->isProgrammed();

    // Add one more empty row for new uploads except when this is a programmed
    // multiple form as it is not necessary.
    if ($empty_single_allowed || $empty_multiple_allowed) {
      // Create a new empty item.
      $items->appendItem();
      $element = [
        '#title' => $title,
        '#description' => $description,
      ];
      $element = $this->formSingleElement($items, $delta, $element, $form, $form_state);
      if ($element) {
        $element['#required'] = $element['#required'] && $delta == 0;
        $elements[$delta] = $element;
      }
    }

If that condition needs to be removed, it needs to first be removed in the current Drupal version.