[Python-Dev] Edits to Metadata 1.2 to add extras (optional dependencies)

["Martin v. Löwis"]

>> Prepare for a ten-year period of acceptance - so it
>> would be good to be sure that no further additions are desired within
>> the next ten years before seeking approval for the PEP.
>
> However, this point I really don't agree with. The packaging ecosystem
> is currently evolving outside the standard library, but the
> standardisation process for the data interchange formats still falls
> under the authority of python-dev and the PEP process.

Maybe I misphrased. By "accepted" I meant "widely implemented". From
the day this gets published until it is really usable, I still believe
10 years is realistic. For example, setuptools doesn't implement 
Meta-data 1.2, and nearly nobody uses it, 8 years after it was written.

> When the packaging module is finally added (hopefully 3.4, even if
> that means we have to temporarily cull the entire compiler
> subpackage), it will handle the most recent accepted version of the
> metadata format (as well as any previous versions). If more holes
> reveal themselves in the next 18 months, then it's OK if v1.4 is
> created when it becomes clear that it's necessary.

The problem is that flooding people with specifications is a guarantee
that they will not get implemented. So we can have one metadata
specification every ten years; if we have more, none of them will be
implemented (except in the tool of the author of the PEP).

Regards,
Martin