[Distutils] PEP 453 - virtualenv change to Scripts/bin directory

[Nick Coghlan]

On 16 Oct 2013 06:20, "Paul Moore" <p.f.moore at gmail.com> wrote:
>
> On 15 October 2013 20:31, Paul Moore <p.f.moore at gmail.com> wrote:
> > On 15 October 2013 19:25, Ned Deily <nad at acm.org> wrote:
> >> It might be worthwhile reviewing the discussion that took place on
python-dev
> >> last year when Van Lindberg proposed changing the Windows file layout,
> >> including the scripts path.
> >>
> >> https://mail.python.org/pipermail/python-dev/2012-March/117552.html
> >
> > Thanks, I thought this had come up before. As the PEP 453 (bundling
> > PIP) proposal was originally made by Nick, maybe he would like to
> > check that any issues covered there are addressed. Personally, I'm
> > going to focus on the implied virtualenv change, on the assumption
> > taht PEP 453 is accepted with the Scripts->bin change included (which
> > is not to say that I won't read that thread, just that I don't
> > personally have any means to change the PEP itself).
>
> I've read a reasonable chunk of that thread. The things that struck me
were:
>
> 1. It's very confused between a number of proposals, making it
> extremely hard to identify which arguments apply to a simple
> Scripts->bin renaming (both at the time, and now in hindsight).
> 2. As far as I can see, on the subject of Scripts->bin, the thread
> from python-dev was essentially neutral, nobody could see a benefit
> that justified the cost. (PEP 453 doesn't say much on the benefits,
> either, FWIW).
>
> By the way, PEP 453 is actually misleading in one respect, distutils
> (and setuptools) installs scripts to PythonXY\Scripts (which is
> created on first use, not at install time), it's only the
> core-supplied scripts that go into PythonXY\Tools\Scripts.
>
> Personally, I'd like to see a better justification than "to improve
> consistency". I'd also like the point that the *existing* Scripts
> directory (managed by distutils/setuptools installs) will have the
> contents of Tools/Scripts dumped into it made explicit and discussed.
> (For example, there's a diff.py in Tools/Scripts. Will the new bin
> directory be put at the start or end of PATH? If I have .py in my
> PATHEXT that matters to me, as diff.py could end up overriding my
> existing diff.exe). And I'd like to see the actual patch that
> implements the Scripts->bin change - I suspect that it would benefit
> from careful review.
>
> Overall, I'm -0 on the proposal, The arguments either way are weak,
> and I don't see why backward compatibility is being ignored quite so
> calmly. It is entirely peripheral to the PEP as far as I can see, and
> not worth including in there.

It's only there because MvL didn't really want to add the existing Scripts
directory to PATH.

As for compatibility, the view is that the filesystem layout is an
implementation detail, with sysconfig as the stable API with backwards
compatibility guarantees.

Cheers,
Nick.

>
> But once again, that's separate from my point here, which is that I
> need to collect information on whether virtualenv users will be
> impacted by the corresponding change in virtualenv.
>
> I suggest that virtualenv comments remain on distutils-sig, but
> comments on the PEP proposal to rename Scripts be redirected to
> python-dev which is where the PEP discussion is taking place. I
> *haven't* cross-posted to python-dev, because that would only start a
> 2-list thread, but can people redirect appropriately any responses?
>
> Paul
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