6.0 点击“立即购买”或“放入购物车”时，弹出购物车中还没有商品，赶紧选购吧！

点击弹出错误：

解决办法：

1、增加等空的判断

路径：\app\app\shop\web\class    web_cart.class.php

  public function tocrat($pid, $para_str, $amount){
    if(!get_met_cookie('id')) {
      return $this->to_cookie_crat($pid, $para_str, $amount);
    }
    
    //if($amount < 0){
    if($amount < 0 || $amount==""){//增加$amount等空的判断 
      $amount = 1;
    }
    
    $goods = $this->get_cart_by_para($pid, $para_str);
    //var_dump($goods);die;
    if($goods){
      $info['id'] = $goods['id'];
      $info['amount'] = $amount + $goods['amount'];
      return $this->save_cart($info);
    }else{
      $info['pid'] = $pid;
      $info['para_str'] = $para_str;
      $info['amount'] = $amount;
      return $this->save_cart($info);
    }

  }

2、同时修改数据库met_shopv2_cart中para_str属性，允许为空值