Function interpreter_requires_environment

Lib/test/support/script_helper.py:21–58

Returns True if our sys.executable interpreter requires environment variables in order to be able to run at all. This is designed to be used with @unittest.skipIf() to annotate tests that need to use an assert_python*() function to launch an isolated mode (-I) or no environment

()

def interpreter_requires_environment():
    """
    Returns True if our sys.executable interpreter requires environment
    variables in order to be able to run at all.

    This is designed to be used with @unittest.skipIf() to annotate tests
    that need to use an assert_python*() function to launch an isolated
    mode (-I) or no environment mode (-E) sub-interpreter process.

    A normal build & test does not run into this situation but it can happen
    when trying to run the standard library test suite from an interpreter that
    doesn't have an obvious home with Python's current home finding logic.

    Setting PYTHONHOME is one way to get most of the testsuite to run in that
    situation.  PYTHONPATH or PYTHONUSERSITE are other common environment
    variables that might impact whether or not the interpreter can start.
    """
    global __cached_interp_requires_environment
    if __cached_interp_requires_environment is None:
        # If PYTHONHOME is set, assume that we need it
        if 'PYTHONHOME' in os.environ:
            __cached_interp_requires_environment = True
            return True
        # cannot run subprocess, assume we don't need it
        if not support.has_subprocess_support:
            __cached_interp_requires_environment = False
            return False

        # Try running an interpreter with -E to see if it works or not.
        try:
            subprocess.check_call([sys.executable, '-E',
                                   '-c', 'import sys; sys.exit(0)'])
        except subprocess.CalledProcessError:
            __cached_interp_requires_environment = True
        else:
            __cached_interp_requires_environment = False

    return __cached_interp_requires_environment


class _PythonRunResult(collections.namedtuple("_PythonRunResult",