重新引发链时捕获链中的特定异常不是一个选项

Question

考虑以下 Python 代码：

def say(words):
    for word in words:
        if word == "Ni":
            raise ValueError("We are no longer the knights who say Ni!")
        print(word)

def blackbox(function, sentence):
    words = sentence.split()
    try:
        function(words)
    except Exception as e:
        raise RuntimeError("Generic Error")

blackbox(say, "Foo Ni Bar")

它打印以下回溯：

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
Input In [35], in blackbox(function, sentence)
      9 try:
---> 10     function(words)
     11 except Exception as e:

Input In [35], in say(words)
      3 if word == "Ni":
----> 4     raise ValueError("We are no longer the knights who say Ni!")
      5 print(word)

ValueError: We are no longer the knights who say Ni!

During handling of the above exception, another exception occurred:

RuntimeError                              Traceback (most recent call last)
Input In [35], in <cell line: 14>()
     11     except Exception as e:
     12         raise RuntimeError("Generic Error")
---> 14 blackbox(say, "Foo Ni Bar")

Input In [35], in blackbox(function, sentence)
     10     function(words)
     11 except Exception as e:
---> 12     raise RuntimeError("Generic Error")

RuntimeError: Generic Error

假设我只对第一个错误感兴趣。我可以简单地通过将

raise RuntimeError("Generic Error")

中的

raise e

替换为

blackbox()

来重新提高它：故事结束。

除了（！）我无法修改属于外部库的

blackbox()

的代码。

如何在不碰它的情况下获得相同的结果？我的猜测是，我可以将对

blackbox()

的调用包装在

try... except...

中，检索异常链，然后选择我感兴趣的异常。但我没能在任何地方找到如何做这样的事情。

编辑：更改了第二个函数的名称和签名以使约束更清晰。

Answer 1

回答我自己的问题。捕获最终的异常及其上下文就足够了，即将最后一行替换为：

raise

追溯：

try:
    blackbox(say, "Foo Ni Bar")
except Exception as e:
    raise e.__context__