Function process_options

mypy/main.py:1408–1629

Parse command line arguments. If a FileSystemCache is passed in, and package_root options are given, call fscache.set_package_root() to set the cache's package root. Returns a tuple of: a list of source files, an Options collected from flags.

(
    args: list[str],
    stdout: TextIO | None = None,
    stderr: TextIO | None = None,
    require_targets: bool = True,
    server_options: bool = False,
    fscache: FileSystemCache | None = None,
    program: str = "mypy",
    header: str = HEADER,
    mypyc: bool = False,
)

def process_options(
    args: list[str],
    stdout: TextIO | None = None,
    stderr: TextIO | None = None,
    require_targets: bool = True,
    server_options: bool = False,
    fscache: FileSystemCache | None = None,
    program: str = "mypy",
    header: str = HEADER,
    mypyc: bool = False,
) -> tuple[list[BuildSource], Options]:
    """Parse command line arguments.

    If a FileSystemCache is passed in, and package_root options are given,
    call fscache.set_package_root() to set the cache's package root.

    Returns a tuple of: a list of source files, an Options collected from flags.
    """
    stdout = stdout if stdout is not None else sys.stdout
    stderr = stderr if stderr is not None else sys.stderr

    parser, _, strict_flag_assignments = define_options(
        program, header, stdout, stderr, server_options
    )

    # Parse arguments once into a dummy namespace so we can get the
    # filename for the config file and know if the user requested all strict options.
    dummy = argparse.Namespace()
    parser.parse_args(args, dummy)
    config_file = dummy.config_file
    # Don't explicitly test if "config_file is not None" for this check.
    # This lets `--config-file=` (an empty string) be used to disable all config files.
    if config_file and not os.path.exists(config_file):
        parser.error(f"Cannot find config file '{config_file}'")

    options = Options()
    strict_option_set = False
    if mypyc:
        # Mypyc has strict_bytes enabled by default
        options.strict_bytes = True

    def set_strict_flags() -> None:
        nonlocal strict_option_set
        strict_option_set = True
        for dest, value in strict_flag_assignments:
            setattr(options, dest, value)

    # Parse config file first, so command line can override.
    parse_config_file(options, set_strict_flags, config_file, stdout, stderr)

    # Set strict flags before parsing (if strict mode enabled), so other command
    # line options can override.
    if getattr(dummy, "special-opts:strict"):
        set_strict_flags()

    # Override cache_dir if provided in the environment
    environ_cache_dir = os.getenv("MYPY_CACHE_DIR", "")
    if environ_cache_dir.strip():