[Pythonmac-SIG] Round 2 with Leopard+Python

[Brian Granger]

Hi,

In the process of working through the issues with sys.path on Leopard,
I have found another potential Leopard bug that is particularly nasty.

In Tiger, sudo preserves environment variables:

$ export FOO=/tmp
$ python -c "import os; print os.environ['FOO']"
/tmp
$ sudo python -c "import os; print os.environ['FOO']"
/tmp

But, in Leopard, sudo does not perserve environment variables:

$ export FOO=/tmp
$ python -c "import os; print os.environ['FOO']"
/tmp
$ sudo python -c "import os; print os.environ['FOO']"
Password:
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/UserDict.py",
line 22, in __getitem__
    raise KeyError(key)
KeyError: 'FOO'

This is a big problem.  First, if you have set PYTHONPATH to point
sys.path at the site-packages in /Library, this setting will be lost
when you do:

sudo python setup.py install

On another package.  I encountered this in building pytables, which
requires numpy >= 1.0.3.  I had installed numpy 1.0.4, and set my
PYTHONPATH to point to it.  But, the pytables setup.py script failts
because PYTHONPATH is lost and it only sees the older (1.0.1) builtin
numpy.

Second, some setup.py scripts use environment variables to determine
how things are built, find other dependencies, etc.  Currently, this
will fail on Leopard if such packages are installed into locations
that require sudo.  I haven't tried it yet, but I expect that this
will also hold true for other python installations.  The behavior also
shows up with ruby on Leopard.

The solution currently is to install all packages to locations that
don't require sudo to write to.  I will file a bug report, but until
the bug is fixed, we should explore putting a note on the numpy/scipy
site - and even possibly on the python.org site to describe the
problem and its workaround.

Brian