Source code for pyscaffold.dependencies

"""Internal library for manipulating package dependencies and requirements."""

import re
from itertools import chain
from typing import Iterable, List

from packaging.requirements import Requirement
from packaging.version import parse as parse_version
from setuptools_scm.version import VERSION_CLASS

from .exceptions import OldSetuptools

try:
    from setuptools import __version__ as setuptools_ver
except ImportError:
    raise OldSetuptools


SETUPTOOLS_VERSION = parse_version("40.1")  # required for find_namespace
BUILD = ("setuptools_scm>=5", "wheel")
"""Dependencies that will be required to build the created project"""
RUNTIME = ('importlib-metadata; python_version<"3.8"',)
# TODO: Remove `importlib-metadata` when `python_requires = >= 3.8`
"""Dependencies that will be required at runtime by the created project"""
ISOLATED = ("setuptools>=46.1.0", "setuptools_scm[toml]>=5", *BUILD[1:])
"""Dependencies for isolated builds (PEP517/518).
- setuptools min version might be slightly higher then the version required at runtime.
- setuptools_scm requires an optional dependency to work with pyproject.toml
"""
# Although version 36.6.0 introduces PEP517 implementation,
# version 46.1.0 fix a bug with setuptools.finalize_distribution_options,
# which is a hook used by setuptools_scm (better safe then sorry).

# TODO: Maybe specify a min version for wheel?
#       For the time being, there is an issue preventing us to do that:
#       https://github.com/pypa/pep517/issues/86

REQ_SPLITTER = re.compile(r";(?!\s*(python|platform|implementation|os|sys)_)", re.M)
"""Regex to split requirements that considers both `setup.cfg specs`_ and `PEP 508`_
(in a *good enough* simplified fashion).

.. _setup.cfg specs: https://setuptools.readthedocs.io/en/latest/setuptools.html#options
.. _PEP 508: https://www.python.org/dev/peps/pep-0508/
"""


def check_setuptools_version():
    """Check minimum required version of setuptools

    Check that setuptools has all necessary capabilities for setuptools_scm
    as well as support for configuration with the help of ``setup.cfg``.

    Raises:
          :obj:`OldSetuptools` : raised if necessary capabilities are not met
    """
    setuptools_too_old = parse_version(setuptools_ver) < SETUPTOOLS_VERSION
    setuptools_scm_check_failed = VERSION_CLASS is None
    if setuptools_too_old or setuptools_scm_check_failed:
        raise OldSetuptools


def split(requirements: str) -> List[str]:
    """Split a combined requirement string (such as the values for ``setup_requires``
    and ``install_requires`` in ``setup.cfg``) into a list of individual requirement
    strings, that can be used in :obj:`is_included`, :obj:`get_requirements_str`,
    :obj:`remove`, etc...
    """
    lines = requirements.splitlines()
    deps = (dep.strip() for line in lines for dep in REQ_SPLITTER.split(line) if dep)
    return [dep for dep in deps if dep]  # Remove empty deps


def deduplicate(requirements: Iterable[str]) -> List[str]:
    """Given a sequence of individual requirement strings, e.g. ``["appdirs>=1.4.4",
    "packaging>20.0"]``, remove the duplicated packages.
    If a package is duplicated, the last occurrence stays.
    """
    return list({Requirement(r).name: r for r in requirements}.values())


def remove(requirements: Iterable[str], to_remove: Iterable[str]) -> List[str]:
    """Given a list of individual requirement strings, e.g.  ``["appdirs>=1.4.4",
    "packaging>20.0"]``, remove the requirements in ``to_remove``.
    """
    removable = {Requirement(r).name for r in to_remove}
    return [r for r in requirements if Requirement(r).name not in removable]


def add(requirements: Iterable[str], to_add: Iterable[str] = BUILD) -> List[str]:
    """Given a sequence of individual requirement strings, add ``to_add`` to it.
    By default adds :obj:`BUILD` if ``to_add`` is not given."""
    return deduplicate(chain(requirements, to_add))