Extract deps from pyproject 'project' section, PEP 621 (https://peps.python.org/pep-0621/)

extractdep.py

#!/usr/bin/env python

r"""Extract dependencies from Pyproject PEP 621 "project" section.

Specificiation: https://peps.python.org/pep-0621/
"""

import sys
from argparse import ArgumentParser
from enum import IntEnum
from pathlib import Path
from typing import NoReturn


class ErrorCode(IntEnum):
    OTHER = 1
    USAGE = 2

    
def warn(message: str) -> None:
    print(message, file=sys.stderr)


def die(status: int, message: str) -> NoReturn:
    warn(message)
    sys.exit(status)


if sys.version_info >= (3, 11):
    # `tomllib` will be part of the standard library in Python 3.11+.
    import tomllib
else:
    try:
        import tomli as tomllib
    except ImportError:
        die(ErrorCode.OTHER, "The 'tomli' package is required for this script when using Python < 3.11.")


arg_parser = ArgumentParser()
arg_parser.add_argument('optional_dependency_groups', nargs='*')
arg_parser.add_argument('--file', '-f', nargs=1, default='pyproject.toml')
arg_parser.add_argument('--all', '-a', dest='use_all_categories', action='store_true')


def main():
    cli_args = arg_parser.parse_args()
    pyproject_file = Path(cli_args.file)
    use_all_categories = cli_args.use_all_categories
    opt_dep_groups = cli_args.optional_dependency_groups

    with pyproject_file.open('rb') as fp:
        pyproject = tomllib.load(fp)
    project_data = pyproject.get('project', {})
    deps: list[str] = project_data.get('dependencies', [])
    opt_deps: dict[str, list[str]] = project_data.get('optional-dependencies', {})

    if use_all_categories:
        if opt_dep_groups:
            warn('Warning: ignoring positional arguments, because -a/--all is set.')
        opt_dep_groups = list(opt_deps.keys())

    for categ in opt_dep_groups:
        try:
            deps.extend(opt_deps[categ])
        except KeyError:
            die(ErrorCode.OTHER, f'Unknown optional dependency group: {categ!r}')

    sys.stdout.writelines(f'{dep}\n' for dep in deps)


if __name__ == '__main__':
    main()

requirements.in

tomli >= 1.1.0 ; python_version < "3.11"