Exclude discount for the backorder product

Exclude discounts for backordered products.

add_filter('advanced_woo_discount_rules_filter_passed', function ($filter_passed, $rule, $product, $sale_badge, $product_table, $conditionFailed) {
    if(is_object($product) && method_exists($product, 'is_on_backorder')){
        if($product->is_on_backorder()){
                return false;
        }
    }
    return $filter_passed;
}, 10, 6);