Add possibility to set custom properties to cart item

doc/11_Cart_Manager.md

@@ -178,3 +178,15 @@ Once set, the cart manager uses all specific settings of the currently active ch
 in the configuration (identified by tenant name).
 
 See also [Demo](https://github.com/pimcore/demo/blob/11.x/config/ecommerce/base-ecommerce.yaml#L197) for some examples.  
+
+
+## Adding Custom Properties to Cart Items
+
+Following steps are necessary to add additional custom properties to cart items: 
+
+1) Extend `Pimcore\Bundle\EcommerceFrameworkBundle\CartManager\CartItem` implementation and add your custom properties including getters/setters. 
+2) Extend `Cart::getCartItemClassName` implementation and make sure your custom `CartItem` implementation gets returned.
+3) Provide the custom properties as key-value pairs in `$params` parameter in the following methods:
+   1) `Pimcore\Bundle\EcommerceFrameworkBundle\CartManager\AbstractCart::addItem`
+   2) `Pimcore\Bundle\EcommerceFrameworkBundle\CartManager\AbstractCart::updateItem`
+   3) `Pimcore\Bundle\EcommerceFrameworkBundle\CartManager\CartManagerInterface::addToCart`

src/CartManager/AbstractCart.php

@@ -158,6 +158,10 @@ public function updateItem(string $itemKey, CheckoutableInterface $product, int
             $item->setSubItems($subItems);
         }
 
+        if (method_exists($item, 'setCustomProperties')) {
+            $item->setCustomProperties($params);
+        }
+
         $this->items[$itemKey] = $item;
 
         // trigger cart has been modified

src/CartManager/AbstractCartItem.php

@@ -298,4 +298,20 @@ public function setIsLoading(bool $isLoading): void
     {
         $this->isLoading = $isLoading;
     }
+
+    /**
+     * Sets custom properties to CartItem when provided in AbstractCart::addItem
+     *
+     * @param array $params
+     * @return void
+     */
+    public function setCustomProperties(array $params): void
+    {
+        foreach ($params as $key => $value) {
+            $method = 'set' . ucfirst($key);
+            if (method_exists($this, $method)) {
+                $this->{$method}($value);
+            }
+        }
+    }
 }