What changed: The Product Button block will exclude items an extension identifies as children of another cart item from its cart count. This includes the button within Add to Cart with Options. Extensions can declare the relationship through the new woocommerce_store_api_cart_item_parent_item_key filter, with a read-only parent_item_key field exposed in Store API cart items. WooCommerce does not assign these relationships automatically.
Who is affected
The change concerns businesses developing WooCommerce extensions that add products on behalf of another cart item, such as bundles or composite products, and stores using those extensions.
What it means for your business
For businesses using WooCommerce, a product added through a bundle will no longer contribute to its product button count as a standalone addition when the extension declares the relationship. Products added by extensions that do not adopt the filter will continue counting as before.
What to do
Add the parent product to the cart and inspect the Product Button count for a product added alongside it. If you develop the extension and the linked product counts as a standalone addition, store the parent's cart item key in the child's data and return it through the new filter; do not use the product ID.
When it takes effect
The change is announced for WooCommerce 11.3; the source gives no effective date.
Source: https://developer.woocommerce.com/2026/10/27/cart-item-children/
