[Distutils] PEP 426 updated (with more than you ever wanted to know about version schemes)

[Ronald Oussoren]

On 12 Feb, 2013, at 9:33, Nick Coghlan <ncoghlan at gmail.com> wrote:

> On Tue, Feb 12, 2013 at 6:25 PM, Ronald Oussoren <ronaldoussoren at mac.com> wrote:
>>> PEPs 426 and 427 between them should achieve the first objective,
>>> while the other parts of PEP 426 should get us a long way towards
>>> achieving the second (with "./setup.py bdist_wheel" as the interim
>>> build hook, pending the introduction of anything better in a PEP for a
>>> clarified sdist format).
>> 
>> How far do you want to standardize the sdist format? For the goals you
>> mentioned earlier you'd only have to specify that an sdist contains
>> a configuration file that says which builder should be used. It might be
>> nice if the full PKG-INFO contents were also available to extract some
>> metadata without invoking the builder.
> 
> The sdist format already requires PKG-INFO

Ouch, it's glaringly obviously now that you mention it but I never noticed the PKG-INFO file in sdists before :-(

> - it just needs to be
> documented *as* a standard format, rather than implied by "what
> distutils creates when you call 'setup.py sdist'". PEP 426 actually
> takes a fairly big step in that direction already by declaring that
> sdist archives should contain a PKG-INFO file that follows PEP 426
> (see http://www.python.org/dev/peps/pep-0426/#metadata-files)
> 
> The missing piece is a standard hook for invoking the builder to
> create a wheel. Currently, that would be via "./setup.py bdist_wheel",
> but we want to get away from the setup.py format.

I agree with that.  The hook could be one or two new header fields in the PKG-INFO
file, with a PEP that describes those keys and how the builder is invoked and what 
it is supposed to do. Am I understanding this correctly?

Something like:

Extension: pepYYY-builder
pepYYY-builder/dist: bento (>=1.1)
pepYYY-builder/build: bento.builder:run

Ronald

> 
> Cheers,
> Nick.
> 
> -- 
> Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia