diff options
Diffstat (limited to 'third_party/python/setuptools/_distutils_hack/__init__.py')
-rw-r--r-- | third_party/python/setuptools/_distutils_hack/__init__.py | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/third_party/python/setuptools/_distutils_hack/__init__.py b/third_party/python/setuptools/_distutils_hack/__init__.py new file mode 100644 index 0000000000..c31edfed17 --- /dev/null +++ b/third_party/python/setuptools/_distutils_hack/__init__.py @@ -0,0 +1,123 @@ +import sys +import os +import re +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, but importing Setuptools " + "also replaces the `distutils` module in `sys.modules`. This may lead " + "to undesirable behaviors or errors. To avoid these issues, avoid " + "using distutils directly, ensure that setuptools is installed in the " + "traditional way (e.g. not an editable install), and/or make sure " + "that setuptools is always imported before distutils.") + + +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__ + + +def do_override(): + """ + Ensure that the local copy of distutils is preferred over stdlib. + + See https://github.com/pypa/setuptools/issues/417#issuecomment-392298401 + for more motivation. + """ + if enabled(): + warn_distutils_present() + ensure_local_distutils() + + +class DistutilsMetaFinder: + def find_spec(self, fullname, path, target=None): + if path is not None: + return + + method_name = 'spec_for_{fullname}'.format(**locals()) + method = getattr(self, method_name, lambda: None) + return method() + + def spec_for_distutils(self): + import importlib.abc + import importlib.util + + class DistutilsLoader(importlib.abc.Loader): + + def create_module(self, spec): + return importlib.import_module('setuptools._distutils') + + def exec_module(self, module): + pass + + return importlib.util.spec_from_loader('distutils', DistutilsLoader()) + + def spec_for_pip(self): + """ + Ensure stdlib distutils when running under pip. + See pypa/pip#8761 for rationale. + """ + if self.pip_imported_during_build(): + return + clear_distutils() + self.spec_for_distutils = lambda: None + + @staticmethod + def pip_imported_during_build(): + """ + Detect if pip is being imported in a build script. Ref #2355. + """ + import traceback + return any( + frame.f_globals['__file__'].endswith('setup.py') + for frame, line in traceback.walk_stack(None) + ) + + +DISTUTILS_FINDER = DistutilsMetaFinder() + + +def add_shim(): + sys.meta_path.insert(0, DISTUTILS_FINDER) + + +def remove_shim(): + try: + sys.meta_path.remove(DISTUTILS_FINDER) + except ValueError: + pass |