105 lines
3.4 KiB
Python
105 lines
3.4 KiB
Python
import logging
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import os
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import re
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import site
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import sys
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from typing import List, Optional
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logger = logging.getLogger(__name__)
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_INCLUDE_SYSTEM_SITE_PACKAGES_REGEX = re.compile(
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r"include-system-site-packages\s*=\s*(?P<value>true|false)"
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)
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def _running_under_venv() -> bool:
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"""Checks if sys.base_prefix and sys.prefix match.
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This handles PEP 405 compliant virtual environments.
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"""
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return sys.prefix != getattr(sys, "base_prefix", sys.prefix)
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def _running_under_legacy_virtualenv() -> bool:
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"""Checks if sys.real_prefix is set.
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This handles virtual environments created with pypa's virtualenv.
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"""
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# pypa/virtualenv case
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return hasattr(sys, "real_prefix")
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def running_under_virtualenv() -> bool:
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"""True if we're running inside a virtual environment, False otherwise."""
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return _running_under_venv() or _running_under_legacy_virtualenv()
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def _get_pyvenv_cfg_lines() -> Optional[List[str]]:
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"""Reads {sys.prefix}/pyvenv.cfg and returns its contents as list of lines
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Returns None, if it could not read/access the file.
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"""
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pyvenv_cfg_file = os.path.join(sys.prefix, "pyvenv.cfg")
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try:
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# Although PEP 405 does not specify, the built-in venv module always
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# writes with UTF-8. (pypa/pip#8717)
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with open(pyvenv_cfg_file, encoding="utf-8") as f:
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return f.read().splitlines() # avoids trailing newlines
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except OSError:
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return None
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def _no_global_under_venv() -> bool:
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"""Check `{sys.prefix}/pyvenv.cfg` for system site-packages inclusion
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PEP 405 specifies that when system site-packages are not supposed to be
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visible from a virtual environment, `pyvenv.cfg` must contain the following
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line:
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include-system-site-packages = false
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Additionally, log a warning if accessing the file fails.
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"""
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cfg_lines = _get_pyvenv_cfg_lines()
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if cfg_lines is None:
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# We're not in a "sane" venv, so assume there is no system
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# site-packages access (since that's PEP 405's default state).
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logger.warning(
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"Could not access 'pyvenv.cfg' despite a virtual environment "
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"being active. Assuming global site-packages is not accessible "
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"in this environment."
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)
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return True
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for line in cfg_lines:
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match = _INCLUDE_SYSTEM_SITE_PACKAGES_REGEX.match(line)
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if match is not None and match.group("value") == "false":
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return True
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return False
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def _no_global_under_legacy_virtualenv() -> bool:
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"""Check if "no-global-site-packages.txt" exists beside site.py
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This mirrors logic in pypa/virtualenv for determining whether system
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site-packages are visible in the virtual environment.
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"""
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site_mod_dir = os.path.dirname(os.path.abspath(site.__file__))
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no_global_site_packages_file = os.path.join(
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site_mod_dir,
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"no-global-site-packages.txt",
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)
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return os.path.exists(no_global_site_packages_file)
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def virtualenv_no_global() -> bool:
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"""Returns a boolean, whether running in venv with no system site-packages."""
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# PEP 405 compliance needs to be checked first since virtualenv >=20 would
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# return True for both checks, but is only able to use the PEP 405 config.
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if _running_under_venv():
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return _no_global_under_venv()
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if _running_under_legacy_virtualenv():
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return _no_global_under_legacy_virtualenv()
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return False
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