def parse_args()

in build/fbcode_builder/getdeps.py [0:0]
78 lines of code
7 McCabe index (conditional complexity)

def parse_args():
    # We want to allow common arguments to be specified either before or after
    # the subcommand name.  In order to do this we add them to the main parser
    # and to subcommand parsers.  In order for this to work, we need to tell
    # argparse that the default value is SUPPRESS, so that the default values
    # from the subparser arguments won't override values set by the user from
    # the main parser.  We maintain our own list of desired defaults in the
    # common_defaults dictionary, and manually set those if the argument wasn't
    # present at all.
    common_args = argparse.ArgumentParser(add_help=False)
    common_defaults = {}

    def add_common_arg(*args, **kwargs):
        var_name = get_arg_var_name(args)
        default_value = kwargs.pop("default", None)
        common_defaults[var_name] = default_value
        kwargs["default"] = argparse.SUPPRESS
        common_args.add_argument(*args, **kwargs)

    add_common_arg("--scratch-path", help="Where to maintain checkouts and build dirs")
    add_common_arg(
        "--vcvars-path", default=None, help="Path to the vcvarsall.bat on Windows."
    )
    add_common_arg(
        "--install-prefix",
        help=(
            "Where the final build products will be installed "
            "(default is [scratch-path]/installed)"
        ),
    )
    add_common_arg(
        "--num-jobs",
        type=int,
        help=(
            "Number of concurrent jobs to use while building. "
            "(default=number of cpu cores)"
        ),
    )
    add_common_arg(
        "--use-shipit",
        help="use the real ShipIt instead of the simple shipit transformer",
        action="store_true",
        default=False,
    )
    add_common_arg(
        "--facebook-internal",
        help="Setup the build context as an FB internal build",
        action="store_true",
        default=None,
    )
    add_common_arg(
        "--no-facebook-internal",
        help="Perform a non-FB internal build, even when in an fbsource repository",
        action="store_false",
        dest="facebook_internal",
    )
    add_common_arg(
        "--allow-system-packages",
        help="Allow satisfying third party deps from installed system packages",
        action="store_true",
        default=False,
    )
    add_common_arg(
        "-v",
        "--verbose",
        help="Print more output",
        action="store_true",
        default=False,
    )
    add_common_arg(
        "--lfs-path",
        help="Provide a parent directory for lfs when fbsource is unavailable",
        default=None,
    )

    ap = argparse.ArgumentParser(
        description="Get and build dependencies and projects", parents=[common_args]
    )
    sub = ap.add_subparsers(
        # metavar suppresses the long and ugly default list of subcommands on a
        # single line.  We still render the nicer list below where we would
        # have shown the nasty one.
        metavar="",
        title="Available commands",
        help="",
    )

    add_subcommands(sub, common_args)

    args = ap.parse_args()
    for var_name, default_value in common_defaults.items():
        if not hasattr(args, var_name):
            setattr(args, var_name, default_value)

    return ap, args