按照国际惯例，打开
/vendor/magento/framework/Exception/NoSuchEntityException.php
添加更具体的异常抛出
原代码为：
public function __construct(Phrase $phrase = null, \Exception $cause = null, $code = 0)
{
if ($phrase === null) {
$phrase = new Phrase('No such entity.');
}
parent::__construct($phrase, $cause, $code);
}修改添加后为：
public function __construct(Phrase $phrase = null, \Exception $cause = null, $code = 0)
{
foreach (debug_backtrace() as $_stack) {
echo ($_stack["file"] ? $_stack["file"] : '') . ':' .
($_stack["line"] ? $_stack["line"] : '') . ' - ' .
($_stack["function"] ? $_stack["function"] : '');
}
// exit();
if ($phrase === null) {
$phrase = new Phrase('No such entity.');
}
parent::__construct($phrase, $cause, $code);
}直接输入错误的文件位置，方便排错。
然后惊喜地发现是quote引用问题，进数据库清空Quote_item表，
还有其它的错误？
No such entity with customerId = 3