Re: Removal of Python 2?

[Ludovic Courtès]

Hi,

Konrad Hinsen <konrad.hinsen@fastmail.net> skribis:

>> Python 2 is dead, dead, dead like the parrot and end-of-prolonged life 
>> as of more than 1 1/2 years. Anyhow, there might still be quite some 
>> software not ported to Python 3 after 10 years. So I'm afraid we need to 
>> keep Python 2.
>
> At this time, more than 2500 packages still depend on Python 2, and
> that's not just Python libraries. The list includes packages such as
> TeXlive, LLVM, Rust, OpenJDK, Calibre, OCaml, qemu, etc.
>
> For many of these packages, Python 2 is used only as part of the build
> procedure. Which is run in a highly protective sandbox. So I don't think
> we need to worry much about having Python 2 in Guix. To discourage
> people from installing it by accident, we could make it a hidden
> package.

I agree.

What we could do is start removing ‘python2-’ packages, especially those
with a non-negligible maintenance cost (numpy, scipy, matplotlib, etc.).
We can move them to the Guix-Past channel if there’s interest.

The attached script lists unused ‘python2-’ leaf packages:

--8<---------------cut here---------------start------------->8---
$ guix repl -- unused-python2-packages.scm | wc -l
288
--8<---------------cut here---------------end--------------->8---

Are these good candidates for removal?

Thoughts?

Ludo’.

(use-modules (gnu packages)
             (guix)
             (guix graph)
             (guix scripts graph))

(define all
  (fold-packages cons '() #:select? (const #t)))

(with-store store
  (let ((back-edges (run-with-store store
                      (node-back-edges %bag-node-type all))))
    (define (unused-python2? package)
      (and (string-prefix? "python2-" (package-name package))
           (zero? (node-reachable-count (list package)
                                        back-edges))))
    (for-each (lambda (package)
                (when (unused-python2? package)
                  (format #t "~a~%" (package-name package))))
              all)))