异常必须从 BaseException 派生

Question

我在这里想念什么？

import sys

class MyBaseError(BaseException):
    def __init__(self, message, base_message=None, *args):
        
        self.message = message
        self.base_message = base_message
        super(MyBaseError, self).__init__()
        
        
    def __str__(self):
        if self.base_message is None:
            return self.message
        
        return self.message + " '" + str(self.base_message) + "'"
        
        
class MyError(MyBaseError):
    """
    """
    
class MyTypeError(MyError):
    """
    """

def run_me():
    raise MyTypeError("run_me")
    

def sayonara():
    try:
        run_me()
    except (MyBaseError) as e:
        raise(MyBaseError("unable to run",
                           e,
                           e.args),
                sys.exc_info()[2])
        
sayonara()

错误：

Traceback (most recent call last):
  File "main.py", line 32, in sayonara
    run_me()
  File "main.py", line 27, in run_me
    raise MyTypeError("run_me")
__main__.MyTypeError: run_me

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "main.py", line 42, in <module>
    sayonara()
  File "main.py", line 40, in sayonara
    sys.exc_info()[2])
TypeError: exceptions must derive from BaseException

MyBaseError class 已经从 BaseException 派生。

Answer 1

在您的sayonara() function 中，您似乎正试图引发一组异常。 问题是sys.exc_info()[2]是回溯，而不是异常，这是您中断的原因。 我通过将以下行放在异常块的顶部来验证这一点：

print(type(sys.exc_info()[2]))

我不确定您确实要做什么，但是sayonara()的工作版本如下：

def sayonara():
    try:
        run_me()
    except (MyBaseError) as e:
        raise MyBaseError("unable to run", e, e.args)

如果要包含回溯，则需要更新自定义错误类以处理传递的参数。

Answer 2

这意味着您应该引发异常 class 或其实例。 例如

try:
   1 + "String"
except TypeError:
   raise TypeError("unsupported operand type(s) for +: 'int' and 'str'")