Re: [PATCH] meson: port python bindings to build natively via meson and meson-python

On Sun, Mar 16, 2025 at 7:42 PM Eli Schwartz <[email protected]> wrote:
>
> We get full build parallelism and fewer confusing ancient distutils
> paths. The python wheels build fully standalone, including linking
> libfdt as a static library.
>
> For convenience, when running pip install a meson option is passed that g
> prevents building tools or installing headers/pkgconfig files.
> meson-python would otherwise include them in the wheel itself, in case
> they are needed, but this is essentially a bit useless so don't bother.

This is great as building a sdist that can be uploaded to pypi works.
I've been maintaining a separate repo solely for that purpose.

>
> Signed-off-by: Eli Schwartz <[email protected]>
> ---
>  MANIFEST.in          | 12 ------
>  libfdt/meson.build   | 32 ++++++++-------
>  meson.build          |  3 +-
>  meson_options.txt    |  2 +
>  pylibfdt/meson.build | 28 ++++++++-----
>  pyproject.toml       | 25 ++++++++++++
>  setup.py             | 97 --------------------------------------------

Isn't removing this going to break make based builds as that calls
setup.py directly? Personally, I think that's fine because I think
python things should be built "the Python way", rather than trying to
wrap them in make or meson. David didn't agree though. I think the
only somewhat sane path is making the make support purely a wrapper to
call meson so we're not maintaining 2 parallel build systems.

>  7 files changed, 64 insertions(+), 135 deletions(-)
>  delete mode 100644 MANIFEST.in
>  create mode 100644 pyproject.toml
>  delete mode 100755 setup.py
>
> diff --git a/MANIFEST.in b/MANIFEST.in
> deleted file mode 100644
> index 904d124..0000000
> --- a/MANIFEST.in
> +++ /dev/null
> @@ -1,12 +0,0 @@
> -# SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
> -
> -global-exclude *
> -include README.md
> -include GPL
> -include BSD-2-Clause
> -include setup.py
> -include pylibfdt/libfdt.i
> -include libfdt/libfdt.h
> -include libfdt/fdt.h
> -include libfdt/libfdt_env.h
> -include VERSION.txt
> diff --git a/libfdt/meson.build b/libfdt/meson.build
> index c2f4bd6..9c6ef54 100644
> --- a/libfdt/meson.build
> +++ b/libfdt/meson.build
> @@ -31,7 +31,7 @@ libfdt = library(
>    version: meson.project_version(),
>    link_args: link_args,
>    link_depends: 'version.lds',
> -  install: true,
> +  install: get_option('default_library') != 'static' or not wheel_only,
>  )
>
>  libfdt_inc = include_directories('.')
> @@ -41,20 +41,22 @@ libfdt_dep = declare_dependency(
>    link_with: libfdt,
>  )
>
> -install_headers(
> -  files(
> -    'fdt.h',
> -    'libfdt.h',
> -    'libfdt_env.h',
> +if not wheel_only
> +  install_headers(
> +    files(
> +      'fdt.h',
> +      'libfdt.h',
> +      'libfdt_env.h',
> +    )
>    )
> -)
>
> -pkgconfig = import('pkgconfig')
> +  pkgconfig = import('pkgconfig')
>
> -pkgconfig.generate(
> -  libraries: libfdt,
> -  version: meson.project_version(),
> -  filebase: 'libfdt',
> -  name: 'libfdt',
> -  description: 'Flat Device Tree manipulation',
> -)
> +  pkgconfig.generate(
> +    libraries: libfdt,
> +    version: meson.project_version(),
> +    filebase: 'libfdt',
> +    name: 'libfdt',
> +    description: 'Flat Device Tree manipulation',
> +  )
> +endif
> diff --git a/meson.build b/meson.build
> index 3026f88..ed4a39d 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -43,6 +43,7 @@ py = import('python')
>  py = py.find_installation(required: get_option('python'))
>  swig = find_program('swig', required: get_option('python'))
>  pylibfdt_enabled = not meson.is_cross_build() and py.found() and swig.found() ? true : false
> +wheel_only = get_option('wheel-only')
>
>  version_gen_h = vcs_tag(
>    command: ['git', 'describe', '--dirty=+'],
> @@ -59,7 +60,7 @@ util_dep = declare_dependency(
>    dependencies: libfdt_dep
>  )
>
> -if get_option('tools')
> +if get_option('tools') and not wheel_only
>    flex = find_program('flex', required: true)
>    bison = find_program('bison', required: true)
>
> diff --git a/meson_options.txt b/meson_options.txt
> index 62b31b3..a866b17 100644
> --- a/meson_options.txt
> +++ b/meson_options.txt
> @@ -10,3 +10,5 @@ option('python', type: 'feature', value: 'auto',
>         description: 'Build pylibfdt Python library')
>  option('tests', type: 'boolean', value: true,
>         description: 'Build tests')
> +option('wheel-only', type: 'boolean', value: false,
> +       description: 'building from meson-python')
> diff --git a/pylibfdt/meson.build b/pylibfdt/meson.build
> index 6157f8d..b13d802 100644
> --- a/pylibfdt/meson.build
> +++ b/pylibfdt/meson.build
> @@ -1,13 +1,21 @@
> -setup_py = find_program('../setup.py')
> -setup_py = [setup_py, '--quiet', '--top-builddir', meson.project_build_root()]
> -
> -pylibfdt = custom_target(
> -  'pylibfdt',
> +libfdt_c = custom_target(
> +  'swig',
>    input: 'libfdt.i',
> -  depends: libfdt,
> -  output: '_libfdt.so',
> -  command: [setup_py, 'build_ext'],
> -  build_by_default: true,
> +  output: ['libfdt.c', 'libfdt.py'],
> +  install: true,
> +  install_dir: [false, py.get_install_dir(pure: false)],
> +  command: [swig, '-python', '-I'+meson.current_source_dir() / '../libfdt', '-o', '@OUTPUT0@', '@INPUT@']
>  )
>
> -meson.add_install_script(setup_py, 'install', '--prefix=' + get_option('prefix'), '--root=$DESTDIR')
> +nowarn_gen = cc.get_supported_arguments(
> +  '-Wno-cast-qual',
> +  '-Wno-missing-prototypes',
> +  '-Wno-redundant-decls',
> +)
> +pylibfdt = py.extension_module(
> +  '_libfdt',
> +  libfdt_c,
> +  c_args: ['-DPY_SSIZE_T_CLEAN'] + nowarn_gen,
> +  dependencies: [libfdt_dep, py.dependency()],
> +  install: true,
> +)
> diff --git a/pyproject.toml b/pyproject.toml
> new file mode 100644
> index 0000000..0929bd0
> --- /dev/null
> +++ b/pyproject.toml
> @@ -0,0 +1,25 @@
> +[build-system]
> +build-backend = 'mesonpy'
> +requires = ['meson-python']
> +
> +[project]
> +name = 'libfdt'
> +authors = [
> +    {name = 'Simon Glass', email = '[email protected]'},
> +]
> +classifiers = [
> +    'Programming Language :: Python :: 3',
> +    'License :: OSI Approved :: BSD License',
> +    'License :: OSI Approved :: GNU General Public License v2 or later (GPLv2+)',
> +    'Operating System :: OS Independent',
> +]
> +description = 'Pthon binding for libfdt'

typo