Poetry cannot be installed on Github Actions runner using latest installer and Python 3.8.

• I am on the latest Poetry version.
• I have searched the issues of this repo and believe that this is not a duplicate.
• [N/A] If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: Windows
• Poetry version: Latest
• Link of a Gist with the contents of your pyproject.toml file: N/A

Issue

After changing from the old installer process, i.e. curl -L https://raw.githubusercontent.com/sdispater/poetry/master/get-poetry.py -o get-poetry.py to the new installer process, i.e. curl -sSL https://install.python-poetry.org/ | POETRY_HOME=$HOME/.poetry python3 -, my builds are failing on Github Actions and Python 3.8: Poetry cannot be installed:

022-09-17T01:37:56.7561313Z ##[group]Run curl -sSL https://install.python-poetry.org | python3 -
2022-09-17T01:37:56.7561741Z curl -sSL https://install.python-poetry.org | python3 -
2022-09-17T01:37:56.7572615Z shell: C:\Program Files\Git\bin\bash.EXE --noprofile --norc -e -o pipefail {0}
2022-09-17T01:37:56.7572971Z env:
2022-09-17T01:37:56.7573137Z   CI_PYTHON_VERSION: 3.8
2022-09-17T01:37:56.7573406Z   pythonLocation: C:\hostedtoolcache\windows\Python\3.8.10\x64
2022-09-17T01:37:56.7573650Z ##[endgroup]
2022-09-17T01:37:59.4702925Z Retrieving Poetry metadata
2022-09-17T01:37:59.4703126Z 
2022-09-17T01:37:59.4703425Z # Welcome to Poetry!
2022-09-17T01:37:59.4703691Z 
2022-09-17T01:37:59.4703874Z This will download and install the latest version of Poetry,
2022-09-17T01:37:59.4704250Z a dependency and package manager for Python.
2022-09-17T01:37:59.4704413Z 
2022-09-17T01:37:59.4704801Z It will add the `poetry` command to Poetry's bin directory, located at:
2022-09-17T01:37:59.4705053Z 
2022-09-17T01:37:59.4705200Z C:\Users\runneradmin\AppData\Roaming\Python\Scripts
2022-09-17T01:37:59.4705368Z 
2022-09-17T01:37:59.4705644Z You can uninstall at any time by executing this script with the --uninstall option,
2022-09-17T01:37:59.4705956Z and these changes will be reverted.
2022-09-17T01:37:59.4706100Z 
2022-09-17T01:37:59.4706188Z Installing Poetry (1.2.1)
2022-09-17T01:37:59.4706429Z Installing Poetry (1.2.1): Creating environment
2022-09-17T01:37:59.4706740Z Installing Poetry (1.2.1): An error occurred. Removing partial environment.
2022-09-17T01:37:59.4963567Z Traceback (most recent call last):
2022-09-17T01:37:59.4970320Z   File "<stdin>", line 935, in <module>
2022-09-17T01:37:59.4970900Z   File "<stdin>", line 914, in main
2022-09-17T01:37:59.4971289Z   File "<stdin>", line 545, in run
2022-09-17T01:37:59.4971657Z   File "<stdin>", line 566, in install
2022-09-17T01:37:59.4972175Z   File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\contextlib.py", line 113, in __enter__
2022-09-17T01:37:59.4972602Z     return next(self.gen)
2022-09-17T01:37:59.4972971Z   File "<stdin>", line 638, in make_env
2022-09-17T01:37:59.4973331Z   File "<stdin>", line 624, in make_env
2022-09-17T01:37:59.4973679Z   File "<stdin>", line 314, in make
2022-09-17T01:37:59.4974144Z   File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\venv\__init__.py", line 68, in create
2022-09-17T01:37:59.4974571Z     self._setup_pip(context)
2022-09-17T01:37:59.4975025Z   File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\venv\__init__.py", line 289, in _setup_pip
2022-09-17T01:37:59.4975508Z     subprocess.check_output(cmd, stderr=subprocess.STDOUT)
2022-09-17T01:37:59.4976022Z   File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\subprocess.py", line 415, in check_output
2022-09-17T01:37:59.4976513Z     return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
2022-09-17T01:37:59.4977012Z   File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\subprocess.py", line 493, in run
2022-09-17T01:37:59.4977453Z     with Popen(*popenargs, **kwargs) as process:
2022-09-17T01:37:59.4977935Z   File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\subprocess.py", line 858, in __init__
2022-09-17T01:37:59.4978405Z     self._execute_child(args, executable, preexec_fn, close_fds,
2022-09-17T01:37:59.4978916Z   File "C:\hostedtoolcache\windows\Python\3.8.10\x64\lib\subprocess.py", line 1311, in _execute_child
2022-09-17T01:37:59.4979397Z     hp, ht, pid, tid = _winapi.CreateProcess(executable, args,
2022-09-17T01:37:59.4979834Z FileNotFoundError: [WinError 2] The system cannot find the file specified
2022-09-17T01:37:59.5142470Z ##[error]Process completed with exit code 1.
2022-09-17T01:37:59.5272597Z Cleaning up orphan processes

An exception is raised in the new installer make definition:

    @classmethod
    def make(cls, target: Path) -> "VirtualEnvironment":
        try:
            # on some linux distributions (eg: debian), the distribution provided python
            # installation might not include ensurepip, causing the venv module to
            # fail when attempting to create a virtual environment
            # we import ensurepip but do not use it explicitly here
            import ensurepip  # noqa: F401
            import venv

            builder = venv.EnvBuilder(clear=True, with_pip=True, symlinks=False)
            context = builder.ensure_directories(target)

            if (
                WINDOWS
                and hasattr(context, "env_exec_cmd")
                and context.env_exe != context.env_exec_cmd
            ):
                target = target.resolve()

            builder.create(target)
        except ImportError:
            # fallback to using virtualenv package if venv is not available, eg: ubuntu
            python_version = f"{sys.version_info.major}.{sys.version_info.minor}"
            virtualenv_bootstrap_url = (
                f"https://bootstrap.pypa.io/virtualenv/{python_version}/virtualenv.pyz"
            )

            with tempfile.TemporaryDirectory(prefix="poetry-installer") as temp_dir:
                virtualenv_pyz = Path(temp_dir) / "virtualenv.pyz"
                request = Request(
                    virtualenv_bootstrap_url, headers={"User-Agent": "Python Poetry"}
                )
                virtualenv_pyz.write_bytes(urlopen(request).read())
                cls.run(
                    sys.executable, virtualenv_pyz, "--clear", "--always-copy", target
                )

        # We add a special file so that Poetry can detect
        # its own virtual environment
        target.joinpath("poetry_env").touch()

        env = cls(target)

        # we do this here to ensure that outdated system default pip does not trigger older bugs
        env.pip("install", "--disable-pip-version-check", "--upgrade", "pip")

        return env

Specifically, the venv._setup_pip definition seems to not find the Python interpreter for the Poetry environment:

    def _setup_pip(self, context):
        """Installs or upgrades pip in a virtual environment"""
        # We run ensurepip in isolated mode to avoid side effects from
        # environment vars, the current directory and anything else
        # intended for the global Python environment
        cmd = [context.env_exec_cmd, '-Im', 'ensurepip', '--upgrade',
                                                         '--default-pip']
        subprocess.check_output(cmd, stderr=subprocess.STDOUT)

I have a repo with a small repro case here: https://github.com/KelSolaar/ActionsRamblings/actions/runs/3071692472/jobs/4962601087

Comienza con la definición de VirtualEnvironment.make del instalador y reproduce el fallo de Windows GitHub Actions usando Python 3.8 y el instalador más reciente. Compara la ruta de creación de venv y el comando venv._setup_pip informado; la tarea estará terminada cuando Poetry se instale correctamente en ese entorno sin WinError 2.