Re: master 7f0a252f216 1/2: Prefer python3 for python-interpreter

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Kangas <stefankangas@gmail.com>
> Date: Sun, 29 Sep 2024 09:05:29 -0700
> Cc: emacs-devel@gnu.org
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> There is no "python" binary or symlink by default on Debian, Ubuntu,
> >> Fedora, etc.
> >
> > There is a "python" (a symlink) on Trisquel, and I think someone else
> > said here the same about another variety (Arch?).
> 
> > And I see at least one Fedora system, where "python" _is_ available
> > (and is a symlink).
> 
> Maybe I confused Fedora with CentOS.  In any case, systems where
> "python" is a symlink should have no problem with this change.

Yes, they will: we now force them to use Python 3.x, even if they
point the 'python' symlink to Python 2.x.

> (Arch removed Python 2 from their archive in 2022, FWIW.  It's possible
> that they symlink "python" to "python3"; I don't know.)

What happens when there's Python 4.x? will we change the value again?

> >> the commands `python-sort-imports', `python-add-import',
> >> `python-remove-import', and `python-fix-imports' have been broken by
> >> default.  That is now fixed.
> >
> > We had the previous value for a long time, and I don't recollect any
> > complaints.  So calling this "broken" is too far-reaching.
> 
> Well, I'm telling you that it doesn't work.  For example, `M-x
> python-sort-imports' on Ubuntu 22 gives:
> 
>     Debugger entered--Lisp error: (file-missing "Searching for program"
>     "No such file or directory" "python")

I'm not saying we should necessarily go back to a single fixed value.
But we could, for example, test "python" before "python3".  That
should solve the above case.

> > Can we be a bit more friendly to systems where the previous default
> > was better?
> 
> Which systems are those, and what is the problem?

I think I already answered that.