WordPress at a glance
filter is not described

woocommerce_add_to_cart_product_id filter-hook . WC 1.0

Usage

add_filter( 'woocommerce_add_to_cart_product_id', 'filter_function_name_782' );
function filter_function_name_782( $absint ){
	// filter...

	return $absint;
}
$absint
-

Where the hook is called

WC_Form_Handler::add_to_cart_action()
woocommerce_add_to_cart_product_id
WC_AJAX::add_to_cart()
woocommerce_add_to_cart_product_id
WC_Cart_Session::populate_cart_from_order()
woocommerce_add_to_cart_product_id
woocommerce/includes/class-wc-form-handler.php 779
$product_id        = apply_filters( 'woocommerce_add_to_cart_product_id', absint( wp_unslash( $_REQUEST['add-to-cart'] ) ) ); // phpcs:ignore WordPress.Security.NonceVerification.Recommended
woocommerce/includes/class-wc-ajax.php 407
$product_id        = apply_filters( 'woocommerce_add_to_cart_product_id', absint( $_POST['product_id'] ) );
woocommerce/includes/class-wc-cart-session.php 348
$product_id     = (int) apply_filters( 'woocommerce_add_to_cart_product_id', $item->get_product_id() );

Where in WP core the hook is used WooCommerce

Usage not found.