[Python-Dev] exception chaining

Benjamin Peterson benjamin at python.org
Fri Jan 20 18:47:13 CET 2012

2012/1/20 Ethan Furman <ethan at stoneleaf.us>:
> Summary:
> Exception Chaining is cool, unless you are writing libraries that want to
> transform from Exception X to Exception Y as the the previous exception
> context is unnecessary, potentially confusing, and cluttery (yup, just made
> that word up!).
> For all the gory details, see http://bugs.python.org/issue6210.
> I'm going to attempt a patch implementing MRAB's suggestion:
> try:
>    some_op
> except ValueError:
>    raise as OtherError() # `raise` keeps context, `raise as` does not

I dislike this syntax. Raise what as OtherError()? I think the "raise
x from None" idea is preferable, since it indicates you are nulling
the context. The optimal solution would be to have "raise X
nocontext", but that would obviously require another keyword...


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