[Distutils] PEP 517 again

[Nathaniel Smith]

On Mon, Sep 4, 2017 at 5:09 PM, xoviat <xoviat at gmail.com> wrote:
> Nathaniel:
>
> Pip requires egg_info to discover dependencies of source distributions so
> that it can build wheels all at once after downloading the requirements. I
> need to move pip off of egg_info as soon as possible and dist_info is
> required to do that.

"Requires" is a strong word -- AFAIK this is just a historical
artifact. I don't really know what you're talking about in the second
sentence.

The only reason I can think of that setuptools would need a dist_info
command would be to implement the PEP 517 prepare_wheel_metadata hook.
But this hook is optional and in fact provides no value right now, so
it can't be a blocker for anything. (In fact I can't see any reason
why pip would ever call it before the resolver lands.) So either (a)
there's some other reason you want a dist_info command, (b) there's
some reason I'm missing why prepare_wheel_metadata matters, or (c) one
of us is misunderstanding something :-).

-n

> 2017-09-03 21:00 GMT-05:00 Nathaniel Smith <njs at pobox.com>:
>>
>> On Sun, Sep 3, 2017 at 11:14 AM, xoviat <xoviat at gmail.com> wrote:
>> > Just an update for everyone here:
>> >
>> > 1. We're currently waiting on the implementation of the 'dist_info"
>> > command
>> > in the wheel project.
>> > 2. Once that is done we can switch pip over to reading dist-info rather
>> > than
>> > egg_info.
>> > 3. Then we can move the backend over to setuptools. Because Jacob has a
>> > much
>> > more efficient release system than pip, I anticipate having a release of
>> > setuptools first and then we can switch pip over to requiring a newer
>> > setuptools via PEP 518.
>>
>> I don't think pip actually has any use for the PEP 517
>> prepare_wheel_metadata hook right now though? Historically 'setup.py
>> egg-info' was needed to kluge around unwanted behavior in 'setup.py
>> install', but with a PEP 517 backend that's irrelevant because
>> 'setup.py install' is never used. And in the future when pip has a
>> real resolver, then prepare_wheel_metadata should allow some
>> optimizations. But right now, prepare_wheel_metadata is completely
>> useless AFAIK.
>>
>> So why is 'setup.py dist_info' a blocker for things?
>>
>> -n
>>
>> --
>> Nathaniel J. Smith -- https://vorpus.org
>
>



-- 
Nathaniel J. Smith -- https://vorpus.org