code: public function onPostCopy(SaleTransformEvent $event)
      {
          $source = $event->getSource();
          $target = $event->getTarget();
  
          // Origin number
          $target->setOriginNumber($source->getNumber());
  
          // Sample
          if ($source instanceof OrderInterface && $target instanceof OrderInterface) {
              $target->setSample($source->isSample());
          }
  
          // Abort if source sale has no customer
          if (null === $customer = $source->getCustomer()) {
              return;
          }
  
          // If target sale is order and source customer has parent
          if ($target instanceof OrderInterface && $customer->hasParent()) {
              // TODO Duplicate code
              /** @see \Ekyna\Component\Commerce\Order\EventListener\OrderListener::fixCustomers() */
  
              // Sets the parent as customer
              $target->setCustomer($customer->getParent());
  
              // Sets the origin customer
              if (null === $target->getOriginCustomer()) {
                  $target->setOriginCustomer($customer);
              }
          }
      }
docs: Post copy event handler.
  
  @param SaleTransformEvent $event