[bug#45158] [PATCH] gnu: Add python-3.9.

[Tanguy LE CARROUR <tanguy@bioneland.org>]

Hi Ludo’.

Excerpts from Ludovic Courtès's message of December 12, 2020 7:00 pm:
> Tanguy Le Carrour <tanguy@bioneland.org> skribis:
> 
>> * gnu/packages/python.scm (python-3.9): New variable.
>> * gnu/packages/patches/python-3.9-fix-tests.patch: New file.
> 
> Nitpick: the patch should be added to gnu/local.mk as well.

Sorry for the omission! Done.


> It LGTM but I have one concern: someone adding ‘python’ and (say)
> ‘python-itsdangerous’ to the same profile would get Python 3.9 together
> with a Python 3.8 package.  Thus ‘PYTHONPATH’ would remain unset and the
> user might become upset.  :-)
> 
> One way to work around that would be to rename 3.9 from ‘python’ to
> ‘python-next’.  That way, someone would have to explicitly install
> ‘python-next’ to get 3.9, and there wouldn’t be any bad surprises for
> the rest of us.
> 
> WDYT?

Makes total sense! I was still in the "inputs" mindset, where one has to
provide the variable name on top of the package name. But you're right,
added to a profile, it would be a mess for the `PYTHONPATH` contains a
reference to Python minor version.

As it is, the patch only applies to the `core-updates` branch, because the
file `python-3-hurd-configure.patch` only exists there. But I guess,
with the change you suggested, it can go to master. I'll also change
this in my V2.

Thanks,


-- 
Tanguy