Re: [gentoo-python] distutils-r1 -- support for out-of-source builds?

["Michał Górny" <mgorny@gentoo.org>]

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On Sun, 28 Oct 2012 12:04:04 -0400
Mike Gilbert <floppym@gentoo.org> wrote:

> On Sun, Oct 28, 2012 at 11:55 AM, Michał Górny <mgorny@gentoo.org> wrote:
> > On Sun, 28 Oct 2012 08:57:05 +0100
> > Michał Górny <mgorny@gentoo.org> wrote:
> >
> >> On the other hand, we would introduce a tiny bit of additional code.
> >
> > I did a bit research on the topic, and the code introduced is circa 100
> > lines, including docs and esetuppy() which would be probably added
> > anyway. There are other potential problems however.
> >
> > The main issue is how distutils is designed. The only command accepting
> > build-dir is the 'build' command. Other commands which need to access
> > the build tree just use some weird method of getting parameters for
> > other commands. Effectively, if you need to provide a build-dir, you
> > always have to run 'build'.
> >
> > So, the install command would grow from:
> >
> >   ./setup.py install ...
> >
> > to:
> >
> >   ./setup.py build -b ... install ...
> >
> > Of course, all other commands accessing the build-dir would need to
> > be prepended with the 'build -b ...' as well. For that reason,
> > the patches I'm going to attach add that thing to esetuppy() directly.
> >
> > This has the following implications:
> >
> > 1) all calls to esetuppy() involve running build,
> >
> > 2) if build takes additional arguments, they may need to be passed
> > consistently to all esetuppy calls (like: 'build --foo' in args).
> > Otherwise, a rebuild with different options may happen (but that's
> > probably a case already anyway).
> >
> > In any case, I wouldn't say it's very elegant of Python. It will work
> > flawlessly for the most of Python packages, and likely most
> > of the remaining ones would require running in-source builds anyway
> > (and that can be enabled with a single variable).
> >
> > Well, best just look at the code and tell me what you think.
> >
> 
> I don't really see any need for out-of-source builds, but if you want
> to write the code for it I certainly don't mind having it there.
> 
> I will say that doing out-of-source builds occasionally makes writing
> src_test a bit tricky; you have to play with the working directory and
> PYTHONPATH.

Yes, I have fixed gentoopm to make it compile Python modules (in tests)
in build-dir rather than sourcedir.

https://bitbucket.org/mgorny/gentoopm/changeset/f46c4057d76
https://bitbucket.org/mgorny/gentoopm/changeset/975fd2dde55

The first commit should be enough for most packages out there.
The second one is necessary if any of the modules were loaded before
(e.g. in gentoopm to get PV). But probably getting the PV like that was
a bad idea anyway...

-- 
Best regards,
Michał Górny

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