Bug 1935621 - Fix virtual environment sysconfig path calculation...

import sys

import sysconfig

import tempfile

import warnings

from contextlib import contextmanager

from pathlib import Path

from typing import Callable, Optional

    """Calculates paths of interest for general python virtual environments"""

    def __init__(self, prefix):

        if _is_windows:

            self.bin_path = os.path.join(prefix, "Scripts")

            self.python_path = os.path.join(self.bin_path, "python.exe")

        else:

            self.bin_path = os.path.join(prefix, "bin")

            self.python_path = os.path.join(self.bin_path, "python")

        self.prefix = os.path.realpath(prefix)

        self.paths = self._get_sysconfig_paths(self.prefix)

    @functools.lru_cache(maxsize=None)

    def resolve_sysconfig_packages_path(self, sysconfig_path):

        # macOS uses a different default sysconfig scheme based on whether it's using the

        # system Python or running in a virtualenv.

        # Manually define the scheme (following the implementation in

        # "sysconfig._get_default_scheme()") so that we're always following the

        # code path for a virtualenv directory structure.

        if os.name == "posix":

            scheme = "posix_prefix"

        else:

            scheme = os.name

        # Name of the Python executable to use in virtual environments.

        # An executable with the same name as sys.executable might not exist in

        # virtual environments. An executable with 'python' as the steam —

        # without version numbers or ABI flags — will always be present in

        # virtual environments, so we use that.

        python_exe_name = "python" + sysconfig.get_config_var("EXE")

        sysconfig_paths = sysconfig.get_paths(scheme)

        data_path = Path(sysconfig_paths["data"])

        path = Path(sysconfig_paths[sysconfig_path])

        relative_path = path.relative_to(data_path)

        self.bin_path = self.paths["scripts"]

        self.python_path = os.path.join(self.bin_path, python_exe_name)

        # Path to virtualenv's "site-packages" directory for provided sysconfig path

        return os.path.normpath(os.path.normcase(Path(self.prefix) / relative_path))

    @staticmethod

    def _get_sysconfig_paths(prefix):

        """Calculate the sysconfig paths of a virtual environment in the given prefix.

        The virtual environment MUST be using the same Python distribution as us.

        """

        # Determine the sysconfig scheme used in virtual environments

        if "venv" in sysconfig.get_scheme_names():

            # A 'venv' scheme was added in Python 3.11 to allow users to

            # calculate the paths for a virtual environment, since the default

            # scheme may not always be the same as used on virtual environments.

            # Some common examples are the system Python distributed by macOS,

            # Debian, and Fedora.

            # For more information, see https://github.com/python/cpython/issues/89576

            venv_scheme = "venv"

        elif os.name == "nt":

            # We know that before the 'venv' scheme was added, on Windows,

            # the 'nt' scheme was used in virtual environments.

            venv_scheme = "nt"

        elif os.name == "posix":

            # We know that before the 'venv' scheme was added, on POSIX,

            # the 'posix_prefix' scheme was used in virtual environments.

            venv_scheme = "posix_prefix"

        else:

            # This should never happen with upstream Python, as the 'venv'

            # scheme should always be available on >=3.11, and no other

            # platforms are supported by the upstream on older Python versions.

            #

            # Since the 'venv' scheme isn't available, and we have no knowledge

            # of this platform/distribution, fallback to the default scheme.

            #

            # Hitting this will likely be the result of running a custom Python

            # distribution targetting a platform that is not supported by the

            # upstream.

            # In this case, unless the Python vendor patched the Python

            # distribution in such a way as the default scheme may not always be

            # the same scheme, using the default scheme should be correct.

            # If the vendor did patch Python as such, to work around this issue,

            # I would recommend them to define a 'venv' scheme that matches

            # the layout used on virtual environments in their Python distribution.

            # (rec. signed Filipe Laíns — upstream sysconfig maintainer)

            venv_scheme = sysconfig.get_default_scheme()

            warnings.warn(

                f"Unknown platform '{os.name}', using the default install scheme '{venv_scheme}'. "

                "If this is incorrect, please ask your Python vendor to add a 'venv' sysconfig scheme "

                "(see https://github.com/python/cpython/issues/89576, or check the code comment).",

                stacklevel=2,

            )

        # Build the sysconfig config_vars dictionary for the virtual environment.

        venv_vars = sysconfig.get_config_vars().copy()

        venv_vars["base"] = venv_vars["platbase"] = prefix

        # Get sysconfig paths for the virtual environment.

        return sysconfig.get_paths(venv_scheme, vars=venv_vars)

    def resolve_sysconfig_packages_path(self, sysconfig_path):

        return self.paths[sysconfig_path]

    def site_packages_dirs(self):

        dirs = []