[Python-Dev] PEP 409 update [was: PEP 409 - final?]

[Yury Selivanov]

I got it, and I think it's fine to use explicit __cause__ reset,
using Ellipsis, or even some __NoException__ special object if 
we decide to introduce one.

I'm against allowing 'from ...' syntax.

On 2012-02-03, at 12:29 PM, Ethan Furman wrote:

> Yury Selivanov wrote:
>> While the example is valid, I doubt that it is in any sense "common" case.
> 
> No it is a corner case.  Another way to spell it is:
> 
> try:
>    try:
>        raise IndexError()
>    except:
>        raise CustomError() from None
> except CustomError as e:
>    # nevermind, let's see the whole thing after all
>    e.__cause__ = Ellipsis
>    raise e
> 
> Ethan