edlp_d8/core/modules/menu_link_content/menu_link_content.install

<?php

/**
 * @file
 * Install, update and uninstall functions for the menu_link_content module.
 */

/**
 * Implements hook_install().
 */
function menu_link_content_install() {
  // Add a higher weight so that menu_link_content_path_update() is called after
  // system_path_update() clears the path alias cache.
  // @todo remove this when the cache clearing is moved to path module or if
  //   caching is removed for path aliases due to
  //   https://www.drupal.org/node/1965074
  module_set_weight('menu_link_content', 1);
}

/**
 * Add the publishing status entity key to custom menu links.
 */
function menu_link_content_update_8601() {
  $definition_update_manager = \Drupal::entityDefinitionUpdateManager();
  $entity_type = $definition_update_manager->getEntityType('menu_link_content');

  // Add the published entity key to the menu_link_content entity type.
  $entity_keys = $entity_type->getKeys();
  $entity_keys['published'] = 'enabled';
  $entity_type->set('entity_keys', $entity_keys);
  $definition_update_manager->updateEntityType($entity_type);

  // @todo The above should be enough, since that is the only definition that
  //   changed. But \Drupal\Core\Entity\Sql\SqlContentEntityStorageSchema varies
  //   field schema by whether a field is an entity key, so invoke
  //   EntityDefinitionUpdateManagerInterface::updateFieldStorageDefinition()
  //   with an unmodified field storage definition to trigger the necessary
  //   changes. SqlContentEntityStorageSchema::onEntityTypeUpdate() should be
  //   fixed to automatically handle this.
  //   @see https://www.drupal.org/node/2554245
  $definition_update_manager->updateFieldStorageDefinition($definition_update_manager->getFieldStorageDefinition('enabled', 'menu_link_content'));

  return t('The publishing status entity key has been added to custom menu links.');
}