Code-Snippets-Functions/Execute a function on a child site/WooCommerce/mandatory-coupon-for-specific-products.txt

add_action( 'woocommerce_check_cart_items', 'mandatory_coupon_for_specific_items' );
function mandatory_coupon_for_specific_items() {
    $targeted_ids  = array(40, 41, 42, 43, 44); // The targeted product ids (in this array)
    $coupon_codes  = array('summer1', 'summer2', 'summer3', 'summer4', 'summer5'); // Array of required coupon codes

    $coupons_found = array_intersect( array_filter( array_map( 'sanitize_title', $coupon_codes) ), WC()->cart->get_applied_coupons() );

    // Loop through cart items
    foreach(WC()->cart->get_cart() as $item ) {
        // Check cart item for defined product Ids and applied coupon
        if( in_array( $item['product_id'], $targeted_ids ) && empty($coupons_found) ) {
            wc_clear_notices(); // Clear all other notices

            // Avoid checkout displaying an error notice
            wc_add_notice( sprintf( 'The product"%s" requires a coupon for checkout.', $item['data']->get_name() ), 'error' );
            break; // stop the loop
        }
    }
}