SCons: added versions 4.0.0-4.3.0

[prs513rosewood]

I've added new versions of SCons. I fixed the pypi package attribute because it was preventing fetching of the newer archives. The older (3.1.2 and below) were fetched from Spack's mirror, so I don't know how this change affects the mirroring, feel free to suggest edits if something's wrong. Cheers!

[prs513rosewood]

I followed the python version requirements from the release notes, but I realize this could fail dependency resolution for packages that specify scons@3: and python@:3.5, although I don't know if there's any scons package that has these constraints.

[adamjstewart]

I think you'll need to add a url_for_version function like:

def url_for_version(self, version):
    url = 'https://files.pythonhosted.org/packages/source/{0}/{1}/{1}-{2}.tar.gz'
    if version >= Version('4.0.0'):
        name = 'SCons'
    else:
        name = 'scons'
    return url.format(name[0], name, version)

[prs513rosewood]

Thanks for the pointer on url_for_version. Interestingly, I could still install versions prior to 4.0.0, even with --no-cache, because the source archive was fetched from Spack's mirror.

[adamjstewart]

Yes, we first check the local downloads cache, then check Spack's download mirror, then check the original source. If anything goes wrong with the first two we want the third to still work.

[adamjstewart]

Where do you see this? The setup.cfg still says 3.5 is supported.

[prs513rosewood]

From https://scons.org/scons-430-is-available.html

NOTE: 4.3.0 now requires Python 3.6.0 and above. Python 3.5.x is no longer supported

The description on PyPI also mentions:

As of SCons 4.2.0 support for Python 3.5 is deprecated and will be removed with the next major release.

They may have forgotten to update that requirement everywhere.