[Python-Dev] vendor-packages directory

Thu Sep 22 22:03:22 CEST 2005

On Sep 22, 2005, at 3:56 PM, Phillip J. Eby wrote:
> At 12:04 PM 9/22/2005 -0700, Rich Burridge wrote:
>>> Phillip J. Eby wrote:
>>>>>> Recently I asked about the inclusion of a "vendor-packages"
>>>> directory for Python on the Python mailing list.
>>>>>>>> See the thread started at:
>>>>>>>> http://mail.python.org/pipermail/python-list/2005-September/ 
>>>> 300029.html
>>>>>>>> for the full reasoning behind this request, and the replies
>>>> I received.
>>>>>>>>>> I'm with Terry on this, it needs a better rationale. Why can't 
>>> you just
>>> add a .pth file to the site-packages directory? It seems that would
>>> address the issue nicely.
>>> (See http://docs.python.org/lib/module-site.html for 
>>> documentation of the
>>> .pth mechanism, which would let you implement a separate vendor- 
>>> packages
>>> directory without modifying Python, and would still allow local 
>>> overrides
>>> of your vendor packages.)
>>>>>>> I understand how .pth files work.
>>>> The rationale for requesting the "vendor-packages" approach, is that
>> Python files,
>> as supplied by the vendor (Sun, Apple, RedHat ...) with their 
>> operating
>> system
>> software, should go in a totally separate base directory, to 
>> differentiate
>> them
>> from Python files installed specifically at one site.
>>>> Right - I'm proposing you add a vendor-packages.pth file to site- 
> pacakges,
> that points to a "totally separate base directory" where those 
> files are
> installed, not that you install the packages themselves under
> site-packages. To make sure we're disagreeing about the same thing 
> <0.5
> wink>, here's what I'm suggesting:
>> 1. Install your packages in /usr/lib/python2.4/vendor-packages (so 
> far, so
> good, we agree on this part)
>> 2. Create a 'vendor-packages.pth' file in /usr/lib/python2.4/site- 
> packages,
> containing the line:
>> /usr/lib/python2.4/vendor-packages
>> This will ensure that your vendor-packages "just work", unless locally
> overridden in site-packages.

vendor-packages.pth should look like this (evil, but practical):
import site; site.addsitedir('/usr/lib/python2.4/vendor-packages')
Otherwise packages like Numeric, PIL, PyObjC, etc. that take 
advantage of pth files will not work when installed to that location.
-bob