setMainVariantId example

$product->setHighlight((bool) $data['__product_topseller']);
        $product->setAllowsNotification((bool) $data['__product_notification']);
        $product->setKeywords($data['__product_keywords']);
        $product->setTemplate($data['__product_template']);
        $product->setHasConfigurator($data['__product_configurator_set_id'] > 0);
        $product->setHasEsd((bool) $data['__product_has_esd']);
        $product->setIsPriceGroupActive((bool) $data['__product_pricegroupActive']);
        $product->setSales((int) $data['__topSeller_sales']);
        $product->setShippingFree((bool) $data['__variant_shippingfree']);
        $product->setStock((int) $data['__variant_instock']);
        $product->setManufacturerNumber($data['__variant_suppliernumber']);
        $product->setMainVariantId((int) $data['__product_main_detail_id']);

        if ($data['__variant_shippingtime']) {
            $product->setShippingTime($data['__variant_shippingtime']);
        } elseif ($data['__product_shippingtime']) {
            $product->setShippingTime($data['__product_shippingtime']);
        }

        if ($data['__variant_releasedate']) {
            $product->setReleaseDate(
                new DateTime($data['__variant_releasedate'])
            );
        }

/** * @deprecated in 5.6, will be removed in 5.7 without replacement */
class StructHelper
{
    public function assignProductData(ListProduct $listProduct, ListProduct $product)
    {
        trigger_error(sprintf('%s:%s is deprecated since Shopware 5.6 and will be removed with 5.7. Will be removed without replacement.', __CLASS__, __METHOD__), E_USER_DEPRECATED);

        $product->setShippingFree($listProduct->isShippingFree());
        $product->setMainVariantId($listProduct->getMainVariantId());
        $product->setAllowsNotification($listProduct->allowsNotification());
        $product->setHighlight($listProduct->highlight());
        $product->setUnit($listProduct->getUnit());
        $product->setTax($listProduct->getTax());
        $product->setPrices($listProduct->getPrices());
        $product->setManufacturer($listProduct->getManufacturer());
        $product->setCover($listProduct->getCover());
        $product->setCheapestPrice($listProduct->getCheapestPrice());
        $product->setName($listProduct->getName());
        $product->setAdditional($listProduct->getAdditional());
        $product->setCloseouts($listProduct->isCloseouts());