pyproject-rpm-macros/pyproject_buildrequires.py

import sys
import importlib

try:
    import pytoml
    from packaging.requirements import Requirement, InvalidRequirement
    from packaging.utils import canonicalize_name, canonicalize_version
except ImportError:
    # already echoed by the %pyproject_buildrequires macro
    sys.exit(0)


try:
    f = open("pyproject.toml") as f
except FileNotFoundError:
    pyproject_data = {}
else:
    with f:
        pyproject_data = pytoml.load(f)

    try:
        backend_name = pyproject_data["build-system"]["build-backend"]
    except KeyError:
        try:
            import setuptools.build_meta
        except ImportError:
            print("python3dist(setuptools) >= 40.8")
            print("python3dist(wheel)")
            sys.exit(0)

        backend = setuptools.build_meta
    else:
        try:
            backend = importlib.import_module(backend_name)
        except ImportError:
            backend = None


requirements = set()
rpm_requirements = set()


def add_requirement(requirement):
    try:
        requirements.add(Requirement(requirement))
    except InvalidRequirement as e:
        print(
            f"WARNING: Skipping invalid requirement: {requirement}\n         {e}",
            file=sys.stderr,
        )


if "requires" in pyproject_data.get("build-system", {}):
    for requirement in pyproject_data["build-system"]["requires"]:
        add_requirement(requirement)


get_requires = getattr(backend, "get_requires_for_build_wheel", None)
if get_requires:
    for requirement in get_requires():
        add_requirement(requirement)

for requirement in requirements:
    name = canonicalize_name(requirement.name)
    if requirement.marker is not None and not requirement.marker.evaluate():
        continue
    together = []
    for specifier in requirement.specifier:
        version = canonicalize_version(specifier.version)
        if specifier.operator == "!=":
            together.append(
                f"(python3dist({name}) < {version} or python3dist({name}) >= {version}.0)"
            )
        else:
            together.append(f"python3dist({name}) {specifier.operator} {version}")
    if len(together) == 0:
        rpm_requirements.add(f"python3dist({name})")
    if len(together) == 1:
        rpm_requirements.add(together[0])
    elif len(together) > 1:
        rpm_requirements.add(f"({' and '.join(together)})")


print(*sorted(rpm_requirements), sep="\n")