Add same product to cart twice instead of changing quantity in Cart

By default, WooCommerce allows customers to change the quantity of a product in the cart by updating the quantity input field on the cart page. If the quantity is increased, the product will be added to the cart only once with the updated quantity. However, if you want to allow customers to add the same product multiple times as separate items in the cart, you’ll need to customize the cart behavior.

To achieve this, you can use the `woocommerce_add_cart_item_data` filter hook to append a unique key to the cart item data. This unique key will make each product added to the cart appear as a separate item, even if it’s the same product.

Here’s how you can add the same product to the cart multiple times as separate items:

1. Add a Unique Key to Cart Item Data:

In your theme’s `functions.php` file or a custom plugin, add the following code:

function custom_add_cart_item_data($cart_item_data, $product_id, $variation_id, $quantity) {
    $unique_key = md5(microtime().rand()); // Generate a unique key for each cart item

    $cart_item_data['unique_key'] = $unique_key;

    return $cart_item_data;
}
add_filter('woocommerce_add_cart_item_data', 'custom_add_cart_item_data', 10, 4);

The `woocommerce_add_cart_item_data` filter hook is triggered when an item is added to the cart. In this function, we generate a unique key using `md5(microtime().rand())` and add it to the cart item data.

2. Display Unique Items in the Cart:

Next, you’ll want to display each unique item as a separate line item in the cart. By default, WooCommerce combines identical items into one line with an updated quantity. We can customize this behavior using the following code:

function custom_render_cart_item_name($product_name, $cart_item, $cart_item_key) {
    if (isset($cart_item['unique_key'])) {
        $product_name .= ' (' . $cart_item['unique_key'] . ')';
    }
    return $product_name;
}
add_filter('woocommerce_cart_item_name', 'custom_render_cart_item_name', 10, 3);

This filter hook allows us to modify the product name displayed in the cart. In this function, we append the unique key to the product name.

With these changes, when customers add the same product to the cart multiple times, they will see each item as a separate line in the cart, each with a unique identifier. This way, the cart will treat each instance of the same product as an individual item with its own quantity.

Keep in mind that modifying the cart behavior in this way may affect the user experience and may not be suitable for all scenarios. Before implementing any customizations, it’s a good idea to test them thoroughly on a staging site to ensure they work as expected and provide the desired user experience.