commerce-8.x-2.8/modules/cart/tests/modules/commerce_cart_test/commerce_cart_test.module

<?php

/**
 * @file
 * Test module for Cart.
 */

use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Entity\EntityMalformedException;

/**
 * Implements hook_ENTITY_TYPE_update().
 *
 * Checks that no entity save-within-a-save has occurred (which results in
 * $entity->original being empty).
 */
function commerce_cart_test_commerce_order_update(EntityInterface $entity) {
  if (!$entity->isNew() && empty($entity->original)) {
    throw new EntityMalformedException('$entity->original not found');
  }
}