[Distutils] Comments on PEP 426

[Paul Moore]

On 3 September 2013 22:20, M.-A. Lemburg <mal at egenix.com> wrote:

> IMO, a much better way forward would be to integrate useful setuptools
> changes right back into distutils, so that the monkey patching
> no longer happens and python-dev can officially bless those
> set of changes.
>

I'm curious about this possibility. One thing that would ease
experimentation in this area, and which has certainly been discussed
elsewhere in this thread, would be if there was a clearly defined set of
setuptools facilities that are missing from distutils, and which the
"modern infrastructure" relies on. Off the top of my head, the following
items would definitely be needed:

1. An extension to the install command to supply a list of the installed
files (the --record feature of setuptools)
2. A bdist_wheel command
3. Updates to the install (or maybe bdist_egg) commands to emit Metadata
2.0 and dist-info metadata
4. An install_scripts command that created script wrappers from metadata
(may not be needed if the only supported route to install is via wheels)

To be honest, these extensions do seem relatively achievable. But I don't
know if they are complete - can the advocates of setuptools clarify what
facilities of setuptools are needed beyond these (with an indication of
where they are used in the build toolchain).

There are other features of setuptools that I can see would be relevant
(for instance, version parsing and requirement checking) but these seem to
me to be more in the nature of utility library features than distutils
enhancements per se. I'd fully expect that such code could easily be
extracted from setuptools (indeed, it may be that all of that code is
isolated in pkg_resources already) without needing any of the distutils
monkeypatching/extensions.

It may be that such an approach is reinventing the existing wheel that is
setuptools, and indeed it may never go anywhere - but it is an interesting
alternative train of thought.

Paul
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