venv/lib/python3.11/site-packages/pip/_internal/utils/virtualenv.py

   1 import logging
   2 import os
   3 import re
   4 import site
   5 import sys
   6 from typing import List, Optional
   7
   8 logger = logging.getLogger(__name__)
   9 _INCLUDE_SYSTEM_SITE_PACKAGES_REGEX = re.compile(
  10     r"include-system-site-packages\s*=\s*(?P<value>true|false)"
  11 )
  12
  13
  14 def _running_under_venv() -> bool:
  15     """Checks if sys.base_prefix and sys.prefix match.
  16
  17     This handles PEP 405 compliant virtual environments.
  18     """
  19     return sys.prefix != getattr(sys, "base_prefix", sys.prefix)
  20
  21
  22 def _running_under_legacy_virtualenv() -> bool:
  23     """Checks if sys.real_prefix is set.
  24
  25     This handles virtual environments created with pypa's virtualenv.
  26     """
  27     # pypa/virtualenv case
  28     return hasattr(sys, "real_prefix")
  29
  30
  31 def running_under_virtualenv() -> bool:
  32     """True if we're running inside a virtual environment, False otherwise."""
  33     return _running_under_venv() or _running_under_legacy_virtualenv()
  34
  35
  36 def _get_pyvenv_cfg_lines() -> Optional[List[str]]:
  37     """Reads {sys.prefix}/pyvenv.cfg and returns its contents as list of lines
  38
  39     Returns None, if it could not read/access the file.
  40     """
  41     pyvenv_cfg_file = os.path.join(sys.prefix, "pyvenv.cfg")
  42     try:
  43         # Although PEP 405 does not specify, the built-in venv module always
  44         # writes with UTF-8. (pypa/pip#8717)
  45         with open(pyvenv_cfg_file, encoding="utf-8") as f:
  46             return f.read().splitlines()  # avoids trailing newlines
  47     except OSError:
  48         return None
  49
  50
  51 def _no_global_under_venv() -> bool:
  52     """Check `{sys.prefix}/pyvenv.cfg` for system site-packages inclusion
  53
  54     PEP 405 specifies that when system site-packages are not supposed to be
  55     visible from a virtual environment, `pyvenv.cfg` must contain the following
  56     line:
  57
  58         include-system-site-packages = false
  59
  60     Additionally, log a warning if accessing the file fails.
  61     """
  62     cfg_lines = _get_pyvenv_cfg_lines()
  63     if cfg_lines is None:
  64         # We're not in a "sane" venv, so assume there is no system
  65         # site-packages access (since that's PEP 405's default state).
  66         logger.warning(
  67             "Could not access 'pyvenv.cfg' despite a virtual environment "
  68             "being active. Assuming global site-packages is not accessible "
  69             "in this environment."
  70         )
  71         return True
  72
  73     for line in cfg_lines:
  74         match = _INCLUDE_SYSTEM_SITE_PACKAGES_REGEX.match(line)
  75         if match is not None and match.group("value") == "false":
  76             return True
  77     return False
  78
  79
  80 def _no_global_under_legacy_virtualenv() -> bool:
  81     """Check if "no-global-site-packages.txt" exists beside site.py
  82
  83     This mirrors logic in pypa/virtualenv for determining whether system
  84     site-packages are visible in the virtual environment.
  85     """
  86     site_mod_dir = os.path.dirname(os.path.abspath(site.__file__))
  87     no_global_site_packages_file = os.path.join(
  88         site_mod_dir,
  89         "no-global-site-packages.txt",
  90     )
  91     return os.path.exists(no_global_site_packages_file)
  92
  93
  94 def virtualenv_no_global() -> bool:
  95     """Returns a boolean, whether running in venv with no system site-packages."""
  96     # PEP 405 compliance needs to be checked first since virtualenv >=20 would
  97     # return True for both checks, but is only able to use the PEP 405 config.
  98     if _running_under_venv():
  99         return _no_global_under_venv()
 100
 101     if _running_under_legacy_virtualenv():
 102         return _no_global_under_legacy_virtualenv()
 103
 104     return False