[Python-Dev] Removing PendingDeprecationWarning

[Steve Dower]

On 22Mar2019 1101, Brett Cannon wrote:
> On Fri, Mar 22, 2019 at 10:37 AM Inada Naoki <songofacandy at gmail.com 
> <mailto:songofacandy at gmail.com>> wrote:
>     There might be some small troubles.  But it was small enough for
>     Python minor versions, I think.
> 
> 
>   I don't think it's worth the cost to users. We can just choose to stop 
> using it in the stdlib and not use PendingDeprecationWarning. And if 
> people want to force others to define their own 
> PendingDeprecationWarning by deprecating that's fine, but the aliasing 
> where it could cause unintended exception swallowing for something 
> related to breaking changes seems unnecessarily risky to me simply 
> because we don't want to ask users to update their code in a 
> backwards-compatible fashion.

What does it mean to put DeprecationWarning on PendingDeprecationWarning 
and then alias PendingDeprecationWarning to DeprecationWarning?

"If the implementation is hard to explain, it's a bad idea." :)

(FWIW, agree with Brett. We can simply stop using it ourselves without 
breaking anyone. Of all the things in the stdlib that are hard to 
maintain, this is nowhere near the top of the list.)

Cheers,
Steve