[Distutils] PEP 517: Build frontend responsibilities

[xoviat]

I assume that the outstanding issues mentioned are related to sys.path in
the build tree. My view on that is the following: the build frontend should
be responsible using any mechanism that it chooses for invoking the build
backend, which must be imported with '' at the front of sys.path. This
obviously means that if the build frontend experiences faults before it
manages to import and invoke the backend, then it's the build frontend's
fault.

The only potential issue remaining that I can think of then is: what about
modules that are already imported when the build backend is called? WRT
standard library modules, we could simply say that build backends must be
prepared to function in any environment where standard library modules are
already imported, which I think is a reasonable requirement. But what about
imports that aren't standard library modules but are fairly common, like
pip imports? The simplest way to simplify the interface is probably to say
that all non-standard library modules must be removed from sys.modules
(unloaded) before the build backend is called.

What do others think?

2017-08-18 23:41 GMT-04:00 Nick Coghlan <ncoghlan at gmail.com>:

> On 19 August 2017 at 05:28, Thomas Kluyver <thomas at kluyver.me.uk> wrote:
> > We've probably all wished that the discussion could be brought to a swift
> > conclusion. But there are real questions to work out, and people have
> many
> > other things to pay attention to. I'm frustrated by how long it's taking
> as
> > well, but there's no magic button anyone can press to make it go quickly.
>
> Technically, commercial redistributors do have a magic button we could
> press called "ongoing funding for sustaining engineering in the
> upstream Python ecosystem" (since that kind of funding can also cover
> needs-driven UX improvements), but alas, whether or not we ever
> actually press that is conditional on potential customers pressing the
> "customer demand" button hard enough and often enough to light up the
> "viable business opportunity" sign :P
>
> I'm actually genuine curious to see how those commercial dynamics
> start changing as the end date for community support of the Python 2.x
> series gets closer :)
>
> Cheers,
> Nick.
>
> --
> Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia
>
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