Josh English wrote:
> Philip,
>
> Yes, the proper path should be c:\dev\XmlDB, which has the
> setup.py, xmldb subfolder, the docs subfolder, and example
> subfolder, and the other text files proscribed by the package
> development folder.
>
> I could only get it to work, though, by renaming the xmldb folder
> in the site-packages directory, and deleting the egg file created
> in the site-packages directory.
>
> Why the egg file, which doesn't list any paths, would interfere I
> do not know.
>
> But with those changes, the xmldb.pth file is being read.
>
> So I think the preferred search order is:
>
> 1. a folder in the site-packages directory
> 2. an Egg file (still unsure why)
> 3. A .pth file
You say that the egg file was created by the setup script for the
library. Are you sure that this script did not also create or modify a
.pth file of its own, adding the egg to the path?
.pth files do not "redirect" imports from site-packages; they add
EXTRA directories to sys.path. Also note that this means the .pth file
itself is not part of the search path; it's not like you shadow a
package xyz by creating a .pth file xyz.pth "instead". A single .pth
file can list multiple directories, and it's those directories that are
added to the path.
I'm not sure how your package is set up, but easy_install, for
instance, creates an easy_install.pth file in site-packages. This file
contains references to egg files (or, at least in my case, .egg
directories created by unpacking the eggs) for each package installed
with easy_install. As far as I'm aware, Python doesn't have special
rules for putting egg files in the search path, so my guess is that
it's something like that: the "setup script" is creating a .pth file (or
modifying an existing .pth file) to add the egg to the path.
Read http://docs.python.org/library/site.html for the description
of how .PTH files work. I don't think there is a general way to
globally "shadow" a package that exists in site-packages. However,
according to the docs the .pth files are added in alphabetical order, so
if it is indeed easy_install.pth that is adding your egg, you could hack
around it by making a file with an alphabetically earlier name (e.g.,
a_xmldb.pth).
--
--OKB (not okblacke)
Brendan Barnwell
"Do not follow where the path may lead. Go, instead, where there is
no path, and leave a trail."
--author unknown
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