build-system: Add pyproject-build-system.

This is an experimental build system based on python-build-system
that implements PEP 517-compliant builds.

* doc/guix.texi (Build Systems): Add pyproject-build-system section.
* doc/contributing.texi (Python Modules): Mention pyproject.toml and the
PYTHON-TOOLCHAIN package, as well as differences to python-build-system.
* guix/build-system/pyproject.scm,
guix/build/pyproject-build-system.scm,
gnu/packages/aux-files/python/sanity-check-next.py,
gnu/packages/python-commencement.scm: New files.
* Makefile.am (MODULES): Register the new build systems.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add python-commencement.scm.
* gnu/packages/python.scm (python-sans-pip, python-sans-pip-wrapper): New
variables.

Co-authored-by: Marius Bakke <marius@gnu.org>

1 files changed, 34 insertions, 1 deletions

diff --git a/gnu/packages/python.scm b/gnu/packages/python.scm
index 00c3eb7774..0c164d7991 100644
--- a/gnu/packages/python.scm
+++ b/gnu/packages/python.scm
@@ -26,7 +26,7 @@
 ;;; Copyright © 2016, 2017 Nikita <nikita@n0.is>
 ;;; Copyright © 2016 Dylan Jeffers <sapientech@sapientech@openmailbox.org>
 ;;; Copyright © 2016 David Craven <david@craven.ch>
-;;; Copyright © 2016, 2017, 2018, 2019, 2020, 2021 Marius Bakke <marius@gnu.org>
+;;; Copyright © 2016-2022 Marius Bakke <marius@gnu.org>
 ;;; Copyright © 2016, 2017 Stefan Reichör <stefan@xsteve.at>
 ;;; Copyright © 2016, 2017 Alex Vong <alexvong1995@gmail.com>
 ;;; Copyright © 2016, 2017, 2018 Arun Isaac <arunisaac@systemreboot.net>
@@ -60,6 +60,7 @@
 ;;; Copyright © 2020, 2021 Greg Hogan <code@greghogan.com>
 ;;; Copyright © 2022 Philip McGrath <philip@philipmcgrath.com>
 ;;; Copyright © 2022 jgart <jgart@dismail.de>
+;;; Copyright © 2021 Lars-Dominik Braun <lars@6xq.net>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -87,6 +88,7 @@
   #:use-module (gnu packages hurd)
   #:use-module (gnu packages libffi)
   #:use-module (gnu packages pkg-config)
+  #:use-module (gnu packages python-build)
   #:use-module (gnu packages readline)
   #:use-module (gnu packages sqlite)
   #:use-module (gnu packages tcl)
@@ -674,6 +676,37 @@ and the unversioned commands available.")))
 (define-public python-wrapper (wrap-python3 python))
 (define-public python-minimal-wrapper (wrap-python3 python-minimal))
 
+;; The Python used in pyproject-build-system.
+(define-public python-sans-pip
+  (hidden-package
+   (package/inherit python
+     (arguments
+      (substitute-keyword-arguments (package-arguments python)
+        ((#:configure-flags flags #~())
+         #~(append '("--with-ensurepip=no")
+                   (delete "--with-ensurepip=install" #$flags))))))))
+
+(define-public python-sans-pip-wrapper
+  (wrap-python3 python-sans-pip))
+
+(define-public python-toolchain
+  (let ((base (package/inherit python-sans-pip-wrapper)))
+    (package
+      (inherit base)
+      (properties '())
+      (name "python-toolchain")
+      (propagated-inputs
+       (modify-inputs (package-propagated-inputs base)
+         (append python-pip
+                 python-pypa-build
+                 python-setuptools
+                 python-wheel)))
+      (synopsis "Python toolchain")
+      (description
+       "Python toolchain including Python itself, setuptools and pip.
+Use this package if you need a minimal Python toolchain instead of just
+the interpreter."))))
+
 (define-public micropython
   (package
     (name "micropython")