Error PHP 8 ?

-- HikaShop version -- : 4.7.1
-- Joomla version -- : 4.2.8
-- PHP version -- : 8.0
-- Error-message(debug-mod must be tuned on) -- : ATTEMPT TO ASSIGN PROPERTY
"SYNCHED_CART_QUANTITY" ON NULL

Hello,
when switching from PHP 7.4.x to 8.0 i get the error as shown in the screenshot.
I am using the "Storefront - eCommerce Joomla! template" storefront.demo.gavick.com/

When i switch back to PHP 7.4. and activate show php errors, i get:

Notice: Undefined property: ProductViewProduct::$row in .../components/com_hikashop/views/product/tmpl/show_quantity.php on line 60

Notice: Trying to get property 'product_id' of non-object in .../com_hikashop/views/product/tmpl/show_quantity.php on line 60

Warning: Creating default object from empty value in .../com_hikashop/views/product/tmpl/show_quantity.php on line 61

Best regards
Maurizio de Matteis

Hallo Philip,
it seems to be a problem with the Storefront template. With Cassiopeia all works well.
II will ask for support.
Thank you and regards
Maurizio

Hallo Philip,
This workaround helped.I posted it to the guys of gavick and they said, this is Hikashop Core Code.
Can you give me advice.
best regards
Maurizio

---

Hello,
I commented out code in /components/com_hikashop/views/product/tmpl/show_quantity.php at line 59
Everything works fine as far as i can see.
Shop is not yet in productive mode.
Regards

$extra_classes = '';
from here:
if($this->config->get('synchronized_add_to_cart', 0)) {
$cartClass = hikashop_get('class.cart');
$cartProductData = $cartClass->getCartProductData($this->row->product_id);
$this->row->synched_cart_quantity = (int)@$cartProductData->cart_product_quantity;
if($quantityLayout == 'show_default')
$quantityLayout = 'show_default_div';
if($this->row->synched_cart_quantity)
$current_quantity = $this->row->synched_cart_quantity;
if($min_quantity == 1)
$min_quantity = 0;
$cartClass->syncInit();
if(in_array($quantityLayout, array('show_select','show_select_price')))
$extra_classes = 'no-chzn';
to here

?>
<input id="<?php echo $id; ?>_synch" class="synchronized_add_to_cart" data-id="<?php echo $id; ?>" data-product-id="<?php echo $this->row->product_id; ?>" data-cart-product-id="<?php echo @$cartProductData->cart_product_id; ?>" type="hidden" name="synched_cart_quantity" value="<?php echo $this->row->synched_cart_quantity; ?>"/>
<?php
}

Hello Nicolas,
works well!

Thanks and with best regards
Maurizio