sys.path in python3.3

[Ned Deily]

In article 
<CAAu18hebtFp8CAhsYzfXYTuL4Od2MWf1_NM3R1B=wEGF3WAG-g at mail.gmail.com>,
 Nicholas Cole <nicholas.cole at gmail.com> wrote:
> The only user configuration I've done is to create the following
> configuration file:
> 
> NPSC:~ nicholas$ cat .pydistutils.cfg
> [install]
> install_lib = ~/Library/Python/$py_version_short/site-packages
> install_scripts = ~/bin
> 
> I should say, this has been a problem for all of the python3.3 alpha
> and beta releases, on previous releases of OS X.
> 
> I can't understand why it works on your setup, though, because I
> haven't done anything at all (that I can think of) that ought of
> affect it.  I wonder if the logic that adds the directory to sys.path
> is being too clever for everyone's good?

Ah, now I know what the problem is.  If you look carefully, you'll see 
that the path created in the Distribute example, effectively by using 
setup.py --install, is slightly different from the install_lib path in 
your .pydistutils.cfg.

What happened is that Python 2.7 and Python 3.2 introduced a change in 
the user site path for OS X framework builds.  The rationale was to make 
the ~/Library/Python user site directory look more like the existing 
framework structure.  This change was somewhat controversial and has not 
yet been resolved to everyone's satisfaction.  
(http://bugs.python.org/issue8084)

A contributing factor is that feature changes to Distutils have been on 
hold with the planned introduction of its replacement, packaging.  
However, late in the 3.3 release cycle, it was decided that packaging 
wasn't quite ready for release and we never got around to taking another 
look at other pending Distutils-related issues, like this one.  OTOH, 
this has now been the behavior for the lifetime of 2.7 and 3.2 and now 
for 3.3 and it is documented if you know where to look:
http://docs.python.org/py3k/library/site.html
It is not likely that, at this point, it will be changed back to 2.6/3.1 
behavior nor to the exact original PEP-370 proposal either.

So, for the current Python releases (2.7, 3.2, 3.3), one solution is to 
change the install_lib definition in .pydistutils.cfg to:

install_lib = ~/Library/Python/$py_version_short/lib/python/site-packages

Or just user--user on setup.py install commands.

I'm sorry that I don't have a better story for now.  That said, I think 
that installation is likely to be a major focus for Python 3.4 and that 
there will be a push to rationalize things in this rather murky area of 
Python.

-- 
 Ned Deily,
 nad at acm.org