Re: Down with PYTHONPATH!

[Konrad Hinsen <konrad.hinsen@fastmail.net>]

Hi Ricardo,

> here’s a half-baked idea that I think is worth considering: let’s patch
> our Python package to respect GUIX_PYTHONPATH and use GUIX_PYTHONPATH in
> our wrappers.
...

I agree with the reasoning behind this and at first sight, your proposal
looks good. But real life is always messier than anybody's theory, so
this needs to be stress-tested before general deployment, in my opinion.

> PYTHONPATH is the wrong mechanism for Guix to use.  We have previously

True, but it's also the wrong mechanism for just about everything else.
The kind of idea that was reasonable in 1990 but didn't scale to more
complex environments.

Nowadays, in the wider world (beyond Guix), PYTHONPATH is mainly a
newbie trap. Experienced pythonistas have abandoned it for virtual
environments. So if it can be turned into a mechanism for supporting
Guix environments with a name change, I doubt anyone would complain
about standard PYTHONPATH being gone.

> If we’re feeling lucky we could even introduce GUIX_PYTHON2_PATH and
> GUIX_PYTHON3_PATH to solve the other half of the problem, namely that
> Python 2 applications will load Python 3 libraries (and vice versa).

Definitely. It solves one more problem at no extra cost.

Konrad.