Function _generate_posix_vars

Lib/sysconfig/__main__.py:176–248

Generate the Python module containing build-time variables.

()

def _generate_posix_vars():
    """Generate the Python module containing build-time variables."""
    vars = {}
    # load the installed Makefile:
    makefile = get_makefile_filename()
    try:
        _parse_makefile(makefile, vars)
    except OSError as e:
        msg = f"invalid Python installation: unable to open {makefile}"
        if hasattr(e, "strerror"):
            msg = f"{msg} ({e.strerror})"
        raise OSError(msg)
    # load the installed pyconfig.h:
    config_h = get_config_h_filename()
    try:
        with open(config_h, encoding="utf-8") as f:
            parse_config_h(f, vars)
    except OSError as e:
        msg = f"invalid Python installation: unable to open {config_h}"
        if hasattr(e, "strerror"):
            msg = f"{msg} ({e.strerror})"
        raise OSError(msg)
    # On AIX, there are wrong paths to the linker scripts in the Makefile
    # -- these paths are relative to the Python source, but when installed
    # the scripts are in another directory.
    if _PYTHON_BUILD:
        vars['BLDSHARED'] = vars['LDSHARED']

    name = _get_sysconfigdata_name()

    # There's a chicken-and-egg situation on OS X with regards to the
    # _sysconfigdata module after the changes introduced by #15298:
    # get_config_vars() is called by get_platform() as part of the
    # `make pybuilddir.txt` target -- which is a precursor to the
    # _sysconfigdata.py module being constructed.  Unfortunately,
    # get_config_vars() eventually calls _init_posix(), which attempts
    # to import _sysconfigdata, which we won't have built yet.  In order
    # for _init_posix() to work, if we're on Darwin, just mock up the
    # _sysconfigdata module manually and populate it with the build vars.
    # This is more than sufficient for ensuring the subsequent call to
    # get_platform() succeeds.
    # GH-127178: Since we started generating a .json file, we also need this to
    #            be able to run sysconfig.get_config_vars().
    module = types.ModuleType(name)
    module.build_time_vars = vars
    sys.modules[name] = module

    pybuilddir = _get_pybuilddir()
    os.makedirs(pybuilddir, exist_ok=True)
    destfile = os.path.join(pybuilddir, name + '.py')

    with open(destfile, 'w', encoding='utf8') as f:
        f.write('# system configuration generated and used by'
                ' the sysconfig module\n')
        f.write('build_time_vars = ')
        _print_config_dict(vars, stream=f)

    print(f'Written {destfile}')