[Distutils] Anyone stuck with easy_install / has .pth file issues -- this is for you!

[Garrett Cooper]

Hi P.J.!

On Mon, May 4, 2009 at 8:20 AM, P.J. Eby <pje at telecommunity.com> wrote:
> At 02:43 AM 5/4/2009 -0700, Garrett Cooper wrote:
>>
>> Hi guys,
>>    Just thought I'd might provide this script to fellow developers
>> which fixes .pth files (easy-install.pth / .egg was the prime target
>> -- see the comments for more details):
>> <http://yaneurabeya.livejournal.com/3929.html>.
>>    Comments are more than welcome.
>
> As far as I can tell, it doesn't do anything that "easy_install -mxN"
> doesn't, although it appears to also convert paths of this form:
>
>   /foo/bar/baz/foo/bar/spam
>
> into:
>
>   ./baz./spam
>
> if I'm reading the code correctly.  It also seems to have no protection
> against adding multiple versions of the same project to a .pth file

You're right -- it doesn't protect against the following (><):

/full/path/to/package.egg
./package.egg

It does protect against ./package.egg in .pth not existing in the
filesystem, and vice versa, depending on the glob of choice employed.
I'll fix that gap tonight :).

BTW, wasn't -m deprecated? I mean, -m's `delivered' functionality
doesn't even work because python stores all loaded package / module
entries in .pth files as keys in a dictionary _anyhow_ (hence the
proposal I made a few weeks ago with __import__ to do version
checking)..

setuptools can't even fix this behavior (python does a BFS-like
package search based on the module / package name and returns the
first entry found), even though it's _sort_ of supposed to (look for
"A more complete solution" on
<http://mail.python.org/pipermail/distutils-sig/2006-March/006123.html>).
Feel free to check sys.modules if you don't believe me :). Hence the
need for virtualenv.

I have no idea how -xN factor into this though -- maybe I'm missing an
important easy-install usage note... either way, we're stuck with
0.6c3 at work because the folks we inherited it from hacked the code
(in an ugly way... ew) and I don't have time to fix it now, so does
this still apply ;\...?

> and to ignore development eggs, whether or not their directories still exist.

By default, no. If one wants to avoid a series of directories, they
can omit entries with [a] relevant expression(s) via the -g / -r
option(s).

> In contrast, easy_install already removes non-existent files/directories
> whenever it touches easy_install.pth, and if you gave it a command line
> globbing the same files as this tool (i.e., just "easy_install [list of
> eggs]"), you'd at least end up without any duplicates in the .pth file.
>
> In short, AFAICT, you could replace the entire tool with a short note on how
> to accomplish the same things using easy_install, or by simply having it
> invoke easy_install internally.

- The duplicates erasure was just gravy, and purely an exercise on my
part getting used to set's in python. The real point was the missing
package in .pth functionality, caused by easy_install / setuptools
lacking proper MP-safe logic.
- It's a simple tool (took a while to think up, but took 1.5 hours to
code / validate) designed to function outside of easy_install /
setuptools, even though that was the piece I was trying to target...
so if someone hand edits a .pth file (heaven forbid) it would note
that the file needed to be fixed / fix the file =].

Thanks for the comments!
-Garrett