More reliable than regular expressions.
* guix/build-system/pyproject.scm (%pyproject-build-system-modules): Add (guix build toml).
(pyproject-build): Add argument #:backend-path.
* guix/build/pyproject-build-system.scm (build): Add support for
auto-detected and override backend-path.
* gnu/packages/python-build.scm (python-tomli)[arguments]: Remove
'add-self-to-path, because it is not necessary any more.
(python-poetry-core): Same.
(python-hatchling): Same.
(python-pdm-backend): Same.
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>
