python - 为什么没有捕获到多父异常？

Question

我玩弄了一个异常层次结构并意识到 未捕获具有多个父类的异常子类。

例如:

class Error1(Exception): 
    pass

class Error2(Exception): 
    pass

class MixedError(Error1, Error2): 
    pass

try:
    print('before 1')
    raise Error2()
    print('after 1')

except MixedError:
    print('Caught it with a mixin 1!')

except Exception:
    print('Big catcher here 1!')

这打印:

before 1

Big catcher here 1!

为什么没有捕获到多父异常？

Answer 1

您误解了异常 的工作原理。异常由父异常缓存，而不是由子异常缓存:

class Error1(Exception):
    pass

class Error2(Exception):
    pass

class MixedError(Error1, Error2):
    pass

try:
    print('before 1')
    raise MixedError()
    print('after 1')

except Error2:
    print('Caught it with a Error2!')

except Exception:
    print('Big catcher here 1!')

打印:

before 1
Caught it with a Error2!