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