[Distutils] Distutils changes - end user requirements (Was: Deprecate MANIFEST.in)

[Paul Moore]

2009/4/8 Tarek Ziadé <ziade.tarek at gmail.com>:
>> Nobody seems to be attempting to collect requirements here.
>>
>
> I do, in the wiki. I am trying to synchronize the work done at Pycon, and
> in the future. I am trying to synthethize the needs there.
>
> http://wiki.python.org/moin/DistutilsVersionFight
> http://wiki.python.org/moin/Distutils/ManifestPluginSystem
> http://wiki.python.org/moin/Distutils/Metadata
> http://wiki.python.org/moin/Distutils/StaticMetadata
> http://wiki.python.org/moin/Distutils/StandardizeEggInfo
>
> What will happen in any case, is that I am going to move Distutils
> forward and make decisions for Python 2.7, based on those pages that will
> become PEPs at some point.

I'm aware of this, and sorry if my comments seemed to ignore this (but
see below)

> Some people will complain here as usual, but nevertheless.

:-)

> So, if you and anyone wants to help, read those wiki pages
> and join, by commenting them or completing them.

Hmm, I'm not sure where I'd put my requirements in that lot. So I'll
try putting them here (and risk the flames :-)) Please feel free to
incorporate them in the Wiki in any form you feel is appropriate.

1. (Meta-requirement) I want to be able to download a Windows
installer[1] for *every* package I need.
1a. This means that the barrier for packagers building Windows
installers should be as low as possible.
1b. It also means that other formats (e.g. eggs) should offer no
benefit over Windows installers

I'm willing to concede that not all developers can be expected to
build distributions for Windows (but if they are building *anything*
for Windows, it should be "obvious" that a Windows installer is the
only sane choice[2]). Given that, the following requirements are what
I'd want for stuff I'm expected to build myself:

2. For pure Python extensions, I can take a "standard" source
tarball[3] and simply run the "standard" distutils command to build a
Windows installer.
2a. I can do this on any machine, even if it has no network connection
(obviously I'd get the source tarball on disk or equivalent in that
case).

3. For C extensions with no dependency on external libraries, I could
do the same assuming I had the "correct" C compiler present (mingw or
the right version of MSVC).

4. For C extensions with external dependencies, it gets more complex -
but essentially it should be "easy" for the developer to write
setup.py in such a way that I can download the external dependencies
in some well-defined form, configure a few file locations, then build
a binary without further interaction.
4a. This is certainly possible - it's how Python itself builds
4b. This is the only case, really, where pure distutils currently
fails to satisfy *my* needs. But as I'd much rather have binary builds
in this case, and as I currently simply don't use packages in this
category that don't have binary distributions, I don't have any
specific requirements here.

[1] In current terms, "Windows installer" means either bdist_wininst
or bdist_msi - something that integrates with Windows "Add/Remove
programs".
[2] That's the problem (for me) that setuptools/easy_install has
introduced. There are now packages which build Windows binaries in egg
format only. Clearly there is some advantage to be had currently in
distributing eggs, which is *not* present in Windows installers. That
advantage is not relevant to me, so I lose out because there's no
Windows installer, even though the developer clearly has the means to
produce one.
[3] I don't distribute packages, so I am not 100% sure what a
"standard" is, but I guess sdist is what I mean here, in current
terms.

I hope this helps. It's intended to. I tried very hard to avoid it
being an anti-setuptools comment, but I have to say that before
setuptools/easy_install came along, EVERY SINGLE ONE of my
requirements was satisfied by core distutils (even 4 - as the fact
that building binaries in this context was difficult enough that all
projects in this category supplied bdist_wininst installers as a
matter of course). As a user, it feels to me as if all the benefits of
setuptools (and by association, of this discussion) are for the
developer, at the expense of the end user (well, end users in my
situation, at least). I'd like to be proved wrong over this, of course
:-)

Paul.