Re: [PATCH] Update python-pip to 9.0.1

[Maxim Cournoyer]

Hi Ludovic!

Apologies for my delayed answer.

address@hidden (Ludovic Courtès) writes:

>> From bfd91a59acdf3105505d7dd8483bb9cb97137cbf Mon Sep 17 00:00:00 2001
>> From: Maxim Cournoyer <address@hidden>
>> Date: Mon, 28 Nov 2016 16:30:07 -0800
>> Subject: [PATCH] gnu: python-pip: Update to 9.0.1
>>
>> * gnu/packages/python.scm (python-pip, python2-pip): Update to 9.0.1.
>
> I applied and expounded the commit log a bit.

Thanks!

>
> One thing which I discovered while testing pip on Guix was that
> depending on how you use Python on Guix the PYTHONPATH differs:
>
>> # PYTHONPATH in an environment
>> $ guix environment python-wrapper
>> [env]$ python3 -c 'import sys; print(sys.path)'
>> ['',
>> '/gnu/store/ar7k7ds90ikxv40a6lif6jv2g39l7mls-profile/lib/python3.5/site-packages',
>> '/gnu/store/b7zbbavbk1jv40b9virwmglck9bdj43a-python-3.5.2/lib/python35.zip',
>> '/gnu/store/b7zbbavbk1jv40b9virwmglck9bdj43a-python-3.5.2/lib/python3.5',
>> '/gnu/store/b7zbbavbk1jv40b9virwmglck9bdj43a-python-3.5.2/lib/python3.5/plat-linux',
>> '/gnu/store/b7zbbavbk1jv40b9virwmglck9bdj43a-python-3.5.2/lib/python3.5/lib-dynload',
>> '/home/maxim/.local/lib/python3.5/site-packages',
>> '/gnu/store/b7zbbavbk1jv40b9virwmglck9bdj43a-python-3.5.2/lib/python3.5/site-packages']
>
> The above command creates an environment containing the dependencies of
> python-wrapper.
>
> Instead, you probably wanted to run this:
>
> $ ./pre-inst-env guix environment --ad-hoc python-wrapper -- python -c
> 'import sys; print(sys.path)'

Right! Thanks for pointing that out.

> substitute: updating list of substitutes from 
> 'https://mirror.hydra.gnu.org'... 100.0%
> The following derivations will be built:
>    /gnu/store/bxr0cw01qhgd9r741a6nnm5zwx3y12rr-profile.drv
>    /gnu/store/l91wf51q5ravikki293baljfx0bacqm8-info-dir.drv
>    /gnu/store/a4mz2l85sc11w6llh56zxlcc1bmfmzsr-ca-certificate-bundle.drv
>    /gnu/store/3z9hsnrwvqw70h0ssxqw0vy5y2dvzcj4-fonts-dir.drv
> ['', 
> '/gnu/store/w63slncr9gyzjrs09n8ls81xac9fs804-profile/lib/python3.5/site-packages',
>  '/home/ludo/.guix-profile/lib/python3.5/site-packages', 
> '/gnu/store/alk9r3rir93pjmv8im20f8xrvv90219z-python-3.5.2/lib/python35.zip', 
> '/gnu/store/alk9r3rir93pjmv8im20f8xrvv90219z-python-3.5.2/lib/python3.5', 
> '/gnu/store/alk9r3rir93pjmv8im20f8xrvv90219z-python-3.5.2/lib/python3.5/plat-linux',
>  
> '/gnu/store/alk9r3rir93pjmv8im20f8xrvv90219z-python-3.5.2/lib/python3.5/lib-dynload',
>  
> '/gnu/store/alk9r3rir93pjmv8im20f8xrvv90219z-python-3.5.2/lib/python3.5/site-packages']
>
> … although it doesn’t make much of a difference in this particular case
> since python-wrapper has python as its dependency.
>
>> Conclusion: When using python in a "guix environment", the *system*
>> site-packages directory appears _before_ the *user* site-packages
>> directory in the PYTHONPATH, which is wrong and causes pip to not work
>> as intended. [2]
>
> ‘guix environment’ without --pure adds its own entries to the front of
> the search paths, which is why we observe this behavior.
>

Is this specific to 'guix environment' with --pure vs without --pure?
I'll test it out!

Also, would this behavior be observed for any 3rd
party package management system, say, the one for ruby, or <some>
language? If so maybe we could document this behavior somewhere.

> In most cases this is what we want (we want to create an environment
> that prevails over the user’s profile), but I can see why this is
> problematic here.
>
> I would argue that using ‘pip’ in ‘guix environment’ is a bit convoluted
> anyway, but then again I’m no Python expert.  :-)
>

Yes, it is a bit convoluted. But with environments being so convenient,
I can think that people other than me would attempt this ;)

Thanks for the reply!

Maxim

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