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

[Daniel Holth]

On Mon, Aug 27, 2012 at 4:29 PM, "Martin v. Löwis" <martin at v.loewis.de> wrote:
> Am 27.08.12 16:56, schrieb Daniel Holth:
>
>> On Wed, Aug 15, 2012 at 10:49 AM, Daniel Holth<dholth at gmail.com>  wrote:
>>>
>>> I've drafted some edits to Metadata 1.2 with valuable feedback from
>>
>> ...
>>>
>>> (full changeset on
>>> https://bitbucket.org/dholth/python-peps/changeset/537e83bd4068)
>>
>>
>> Metadata 1.2 is nearly 8 years old and it's Accepted but not Final. Is
>> it better to continue editing it, or create a new PEP for Metadata
>> 1.3?
>
>
> You can't add new fields to the format after the fact, unless the format had
> provided for such additions (which it does not - there is
> no mention of custom fields anywhere, and no elaboration on how
> "unknown" fields should be processed).
>
> So if you want to add new fields, you need to create a new version
> of the metadata. 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.

I don't know of a tool that doesn't reliably ignore extra fields, but
I will put you down as being in favor of an X- fields paragraph:

Extensions (X- Fields)
::::::::::::::::::::::

Metadata files can contain fields that are not part of
the specification, called *extensions*. These fields start with
with `X-`.