raise_from don't work

描述

from future.utils import raise_from

def fa():
    try:
        b()
    except Exception as ex:
        raise_from(Exception('fa'), ex)

def b():
    raise Exception('b')

if __name__ == "__main__":
    fa()

Traceback (most recent call last):
  File ".\mod.py", line 20, in <module>
    fa()
  File ".\mod.py", line 8, in fa
    raise_from(Exception('fa'), ex)
  File "C:\Python27\lib\site-packages\future\utils\__init__.py", line 454, in raise_from
    raise e
Exception: fa

贡献者指南

技术栈

python

领域

backend

议题类型

bug

难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。

3

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half day

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stale

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clear

前置要求

Python exception handlingfuture library internals

新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。

40

研究方向

Investigate the raise from function in future/utils/ init .py (line 454). The issue reports that the original exception chain is lost when using raise from. In Python 2, raise from is not natively supported; the library attempts to simulate it. Study the current implementation and compare with Python 3's raise from behavior. Ensure the raised exception includes the cause attribute set to the original exception. Test with the provided script in Python 2.7. Consider improving the implementation to preserve the traceback chain.