# wrap setuptools.build_meta with an in-tree build backend

# This is the recommended way to implement dynamic build requirements that

# cannot be expressed via environment markers

# https://setuptools.pypa.io/en/latest/build_meta.html#dynamic-build-dependencies-and-other-build-meta-tweaks

import os

from setuptools import build_meta as _orig

from setuptools.build_meta import *

def get_requires_for_build_wheel(config_settings=None):

# return is a list of packages needed to build h5py

# (in addition to static list in pyproject.toml)

# For mpi4py, we build against the oldest supported version;

# h5py wheels should then work with newer versions of these.

# Downstream packagers - e.g. Linux distros - can safely build with newer

# versions.

requires = _orig.get_requires_for_build_wheel(config_settings)

# Set the environment variable H5PY_SETUP_REQUIRES=0 if we need to skip

# these build requirements for any reason.

if os.getenv('HDF5_MPI') == 'ON' and os.getenv('H5PY_SETUP_REQUIRES') != '0':

requires.extend([

# mpi4py 3.x fails to build with setuptools >= 81, so we'll use 4.0

# to keep things simple. If you need to build with older mpi4py, it

# may well work, but it's up to you to figure out.

"mpi4py ==4.0.0; python_version<'3.13'",

"mpi4py ==4.0.1; python_version=='3.13.*'",

"mpi4py ==4.1.0; python_version=='3.14.*'",

# leave dependency unpinned for unstable Python versions

"mpi4py",

])

return requires