Cart for a certain user gets deleted and a new cart is created

Bonjour,

If a logged in user has products in his cart and then logs out (or is logged out because the session expires), if he adds something to his , now empty, cart as a guest and then logs in, the new cart will take over the old cart. If you have the "enable multiple cart" setting turned on, then both carts will be linked to his user account. But if that setting is turned off, then the new cart he had during his guest session will replace the old cart he had while logged in.
I would suppose that it's probably what's going on.

Note that HikaShop doesn't normally create empty carts. Normally, a cart is created because the user clicked on the "add to cart" button of a product and he doesn't already have a cart linked to his current session.
There are ways to create empty carts, like if you click on the "new" button of the Customers>Carts menu in the backend, but that's out of the scope of what you're describing.

Hi,

There is nothing ready-made to do that.
One simple solution is to make view overrides of where add to cart buttons are displayed (in product / quantity and in product / add_to_cart_ajax ). There, you can check if the user is logged in or not and if not, change the "onclick" of the button and the fallback_url to, for example, redirect to the login form with an appropriate message.
That's quite lightweight as a solution. The biggest flaw here is that the user session might expire between the time it displays the page on his browser and the time he clicks on the button, circumventing this check.

A more complex, but more elegant solution, would be to implement the onBeforeProductQuantityCheck(&$products, &$cart, &$options) event in a custom plugin. In it, you can check if the user is logged in, and if not, you can set the "qty" to 0 in the products in the $products array and add a messsage like so:

			$cartClass = hikashop_get('class.cart');
			$cartClass->addMessage($cart, array('msg' => implode('<br/>', $messages), 'product_id' => $id, 'type' => 'error'));