menu_lock-1.0.0-rc1/menu_lock.module

<?php

/**
 * @file
 * Hook implementations for module menu_lock.
 */

use Drupal\Core\Form\FormStateInterface;

/**
 * Implements hook_form_FORM_ID_alter().
 *
 * Limit menu link 'Parent link' to the current menu when using the Menu UI at
 * /admin/structure/menu/item/%mlid/edit. This prevents users from moving items
 * from one menu (e.g. footer) to another (e.g. main menu).
 *
 * @see https://www.drupal.org/project/drupal/issues/3110371
 * @see https://www.drupal.org/node/3250632
 *
 * @todo deprecate when supported by Drupal core
 */
function menu_lock_form_menu_link_content_menu_link_content_form_alter(array &$form, FormStateInterface $form_state, string $form_id): void {
  // Retrieve current user account + menu link object.
  $account = \Drupal::currentUser()->getAccount();
  /** @var Drupal\menu_link_content\Form\MenuLinkContentForm */
  $form_object = $form_state->getFormObject();
  /** @var Drupal\menu_link_content\Entity\MenuLinkContent */
  $menu_link = $form_object->getEntity();

  // Limit options in 'Parent link' field.
  if (!empty($form['menu_parent']['#options']) && !$account->hasPermission('move menu links across menus')) {
    foreach ($form['menu_parent']['#options'] as $parent => $menu_link_title) {
      $parent_parts = explode(':', $parent);
      $parent_menu_name = $parent_parts[0];
      if ($parent_menu_name != $menu_link->getMenuName()) {
        unset($form['menu_parent']['#options'][$parent]);
      }
    }
  }
}