[Distutils] PEP439 and backward compat / easy_install / distlib

[holger krekel]

Hi Richard, all,

two first notes on PEP439.

backward compat with present-day release files: the PEP should state 
it as a goal or at least discuss it in some depth.  In that context, the
choice of providing a bootstrap for pip rather than easy_install needs
reasoning.  One problem with pip, compared to easy_install, is
that it doesn't support eggs which is a problem particularly on
Windows machines where often no fitting C compiler is available.  If the
remedy here is to support wheels and recommend it's use, it is still a
backward compatibility problem: many users will not be able to use the
builtin-supported installer to install todays existing egg release files.

setuptools and distlib:  Even if Python3.4+ had a mature distlib
providing minimal setuptools functionality, how would it work for the
typical "python setup.py install" which is invoked by pip?  Often those
setup.py scripts depend on a setuptools package.

I am highlighting these two backward-compat aspects because otherwise 
we might run into this problem: http://xkcd.com/927/ and i understood
that most people involved in improving the packaging ecology want
to avoid that :)

best,
holger