Ecshop系统添加免运费赠品后购物车变为收取运费解决办法

/* 添加赠品到购物车 */
foreach ($favourable['gift'] as $gift)
{
    if (in_array($gift['id'], $_POST['gift']))
    {
        add_gift_to_cart($act_id, $gift['id'], $gift['price']);
    }
}

function add_gift_to_cart($act_id, $id, $price)
{
    $sql = "INSERT INTO " . $GLOBALS['ecs']->table('cart') . " (" .
                "user_id, session_id, goods_id, goods_sn, goods_name, market_price, goods_price, ".
                "goods_number, is_real, extension_code, parent_id, is_gift, rec_type, is_shipping ) ".
            "SELECT '$_SESSION[user_id]', '" . SESS_ID . "', goods_id, goods_sn, goods_name,

market_price, ".
                "'$price', 1, is_real, extension_code, 0, '$act_id', '" . CART_GENERAL_GOODS . "' ,

is_shipping " .
            "FROM " . $GLOBALS['ecs']->table('goods') .
            " WHERE goods_id = '$id'";
    $GLOBALS['db']->query($sql);
}