[Distutils] requiring python 2.5

[Rick Ratzel]

   Arg...I thought I had this working, but it turns out I had a setuptools 0.7
dev release installed.  When I go to a setuptools 0.6 release, I get the same
old problem.  Here are more details...

   Enstaller is started with a script generated when easy_install installs the
egg, so right away pkg_resources is imported and I have no chance to do anything
before.  I put the following in enstaller's __init__.py as recommended:

from os import path
import enthought
enthought.__path__ = [path.dirname( path.dirname( __file__ ) )]

   and confirmed that it is indeed setting the __path__ for enthought correctly
with a "print enthought.__path__" in another enstaller module imported later,
which produced:

['c:\\python25\\lib\\site-packages\\enstaller-2.1.0b1-py2.5-win32.egg\\enthought']

   This is compared to the two screenfuls of 'enthought.' paths without that
code.  As mentioned, this works great for setuptools 0.7, but as soon as I
switch out 0.7 for 0.6, I get ImportErrors from package mismatches as python
finds other incompatible 'enthought.' packages on the system instead of the ones
bundled in the enstaller egg.  If I leave the above code out completely, neither
0.6 or 0.7 work (as expected).

   Can you point out what, if anything, I'm doing wrong, since I thought setting
enthought.__path__ is supposed to work with 0.6?

   I think I have three options at this point: 

1.) have enstaller require setuptools>=0.7 (which enthought is hosting and will
  be found automatically by the enstaller install script)

2.) write a function in the enstaller egg build script that bundles all the
  packages into a namespace other than 'enthought.' inside of the egg, say
  'bundle.' for example, and does a global search-and-replace of 'enthought.'
  with 'bundle.'  Assuming the script gets everything, this seems like it would
  be the most straightforward and would not require me to fiddle with the
  python/setuptools import machinery.

3.) find the silly mistake I made which is causing the initial fix to break for
  0.6, if possible.

   Thanks in advance!


>    Date: Sat, 09 Jun 2007 16:04:45 -0400
>    From: "Phillip J. Eby" <pje at telecommunity.com>
> 
>    At 09:26 PM 6/8/2007 -0500, Rick Ratzel wrote:
> 
>    >    Is there a way to have my package tell setuptools to "ignore" 
>    > certain other
>    >packages?
> 
>    Only through version specifications; i.e., request the exact versions you want.
> 
> 
>    >    I've tried removing all the "enthought." eggs from sys.path 
>    > before anything
>    >else gets imported, but even that doesn't work (and it just felt wrong, and
>    >probably is).
> 
>    If "enthought" is a namespace package, you would need to either be 
>    using an 0.7-development version of setuptools (i.e., a trunk SVN 
>    version), or else you'd need to remove those eggs from the path 
>    *before* pkg_resources is first imported.  Otherwise, it would indeed not work.
> 
> 
>    >I looked at the docs for manipulating the WorkingSet, but made no
>    >progress there either...python always managed to find the incompatible
>    >enthought.traits code in the enthought.traits egg.  When I remove the
>    >incompatible enthought.traits, all works fine.
>    >
>    >    What I'd like to do is simply say "do not use any enthought.* 
>    > eggs".  Is this
>    >possible?  Thanks in advance!
> 
>    Not without using an 0.7 version of setuptools, or manipulating 
>    enthought.__path__.  The straightforward way to do it would be for 
>    enstaller's __init__.py to do this:
> 
>        import enthought, os
>        enthought.__path__ = os.path.dirname(os.path.dirname(__file__))
> 
>    This will ensure that all enthought.* modules imported from then on 
>    will only be from within the parent directory of enstaller.
> 
>    I don't think I'd recommend this to anyone in the general case, but 
>    this might be a reasonable workaround if you truly want to 
>    "de-namespace" the package.  (It will *not*, however, prevent new 
>    eggs from being added to __path__ if you add anything to sys.path or 
>    the working set afterward.)
> 
> 

-- 
Rick Ratzel - Enthought, Inc.
515 Congress Avenue, Suite 2100 - Austin, Texas 78701
512-536-1057 x229 - Fax: 512-536-1059
http://www.enthought.com