[PATCH] Convert all Python scripts to Python 3

[Zack Weinberg]

On Fri, Jan 31, 2020 at 6:51 PM Alistair Francis <alistair23@gmail.com> wrote:
> On Fri, Jan 31, 2020 at 9:29 AM Zack Weinberg <zackw@panix.com> wrote:
> > I think this change needs manual explicit testing that all of the
> > scripts do in fact work with Python 3 (and not just any Python 3, but
> > specifically version 3.4, since that's the oldest version that
>
> I don't have a way to test all of the scripts, especially with Python 3.4.
>
> My original patch just updated math/gen-libm-test.py as I have tested
> that with Python 3 (although not 3.4). I don't know if I will be able
> to explicitly test all of the scripts with Python3 (definitely not
> with 3.4, where do you even get that?). The painful part with Python
> testing is you actually need to run the code, not just run the script
> once.
>
> With Python2 EOL and the assumption that everyone is already using
> Python3 anyway (and calling this scripts with $(PYTHON)) I was hoping
> this would be enough.

I may have misunderstood the situation.  I thought we were allowing
use of either Python 2 or 3 for these scripts, but on further
investigation, it looks more like we were already requiring them to be
run with v3.  If so, your proposed change does not need testing,
because they must already work with v3.  Joseph, you've been
spearheading a lot of the use of Python - can you confirm that Python
3 is already being used for all these scripts?

> I also have no way to test a setup with Python 2.

The simplest way to test with a Python 2-only environment (or a
3.4-only environment) would probably be to use 'schroot'
(https://wiki.debian.org/Schroot) together with appropriately old
versions of Debian.  I don't know off the top of my head what those
versions are.

> On Arch "python" is Python3

That is a bug in Arch.  The bare command name "python" and the #! path
/usr/bin/python need to be permanently reserved for Python 2.  As long
as "python3" is also available, we don't actually care, but we should
actively refuse to support an environment where there is no "python3"
command.

zw