[Python-ideas] Changing the default install location, script versioning (Packages and PEP 370)

[Brett Cannon]

On Mon, Jul 20, 2009 at 14:50, Jesse Noller <jnoller at gmail.com> wrote:

> On Mon, Jul 20, 2009 at 5:38 PM, Paul Moore<p.f.moore at gmail.com> wrote:
> > 2009/7/20 Jesse Noller <jnoller at gmail.com>:
> >> So python -m "setuptools.commands.easy_install" <args> or python
> >> `which easy_install` is a-ok for people? I find it much easier to tell
> >> someone "run easy_install" or "run pylint" rather than either one of
> >> the previous examples.
> >
> > No, but "python -m easy_install" is fine. The fact that setuptools
> > doesn't provide a form designed for use with python -m doesn't mean
> > that there's a problem with the feature, just that setuptools wasn't
> > designed with it in mind.
> >
> > Paul.
> >
>
> I don't know if easy_install does or doesn't - I simply used it as an
> example. What I don't parse is that python -m <module> is somehow a
> replacement for ./script - the logic within a script can do a lot more
> than just firing off the __main__ of a module. Are we saying that
> "scripts are considered harmful" and recommend people only support -m
> for this?
>
> There's over 7000 packages, applications and libraries in the
> cheeseshop right now. A fair number of them would run face first into
> the non-versioned binary problem. I guess distutils (in a future
> version) should just deprecate the scripts/entry points options
> entirely?
>
> I really don't think this is an edge case, or should be unsupported.
> Sure, the same problem exists outside of the .local directory - you
> run into this installing things into the default system-level
> site-packages and /usr/bin /usr/local/bin directories, but there's no
> real reason we can't make this work better in the context of .local


Taking Paul's follow-up email to this into account, I think we should
definitely encourage people support runpy, but that doesn't do away with the
usefulness of scripts. Ignoring the convenience factor of having short
script names (``hg tip`` is much shorter than ``python2.6 -m mercurial --
tip``), there is also having to remember which interpreter you installed a
tool under. Did I install hg under my Python 2.3, 2.4, 2.5 or 2.6
interpreter? I actually had to check the hg script to find that out.

And there is also the situation where people are not targeting multiple
operating systems and thus have a use for the features a script gives. If I
am writing some Linux app in Python I might have some need to run something
under bash.

So while I totally support pushing people to start using runpy now that
__main__.py support exists for packages, I don't think we can just fluff off
script support.

-Brett
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