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