| """ |
| Ensure that the local copy of distutils is preferred over stdlib. |
| |
| See https://github.com/pypa/setuptools/issues/417#issuecomment-392298401 |
| for more motivation. |
| """ |
| |
| import sys |
| import re |
| import os |
| import importlib |
| import warnings |
| |
| |
| is_pypy = '__pypy__' in sys.builtin_module_names |
| |
| |
| def warn_distutils_present(): |
| if 'distutils' not in sys.modules: |
| return |
| if is_pypy and sys.version_info < (3, 7): |
| # PyPy for 3.6 unconditionally imports distutils, so bypass the warning |
| # https://foss.heptapod.net/pypy/pypy/-/blob/be829135bc0d758997b3566062999ee8b23872b4/lib-python/3/site.py#L250 |
| return |
| warnings.warn( |
| "Distutils was imported before Setuptools. This usage is discouraged " |
| "and may exhibit undesirable behaviors or errors. Please use " |
| "Setuptools' objects directly or at least import Setuptools first.") |
| |
| |
| def clear_distutils(): |
| if 'distutils' not in sys.modules: |
| return |
| warnings.warn("Setuptools is replacing distutils.") |
| mods = [name for name in sys.modules if re.match(r'distutils\b', name)] |
| for name in mods: |
| del sys.modules[name] |
| |
| |
| def enabled(): |
| """ |
| Allow selection of distutils by environment variable. |
| """ |
| which = os.environ.get('SETUPTOOLS_USE_DISTUTILS', 'stdlib') |
| return which == 'local' |
| |
| |
| def ensure_local_distutils(): |
| clear_distutils() |
| distutils = importlib.import_module('setuptools._distutils') |
| distutils.__name__ = 'distutils' |
| sys.modules['distutils'] = distutils |
| |
| # sanity check that submodules load as expected |
| core = importlib.import_module('distutils.core') |
| assert '_distutils' in core.__file__, core.__file__ |
| |
| |
| warn_distutils_present() |
| if enabled(): |
| ensure_local_distutils() |
