Ejemplo n.º 1
0
 def __init__(self, options: Options) -> None:
     super().__init__(options)
     django_settings_module = extract_django_settings_module(options.config_file)
     # Add paths from MYPYPATH env var
     sys.path.extend(mypy_path())
     # Add paths from mypy_path config option
     sys.path.extend(options.mypy_path)
     self.django_context = DjangoContext(django_settings_module)
Ejemplo n.º 2
0
def get_explicit_package_bases(options: Options) -> Optional[List[str]]:
    """Returns explicit package bases to use if the option is enabled, or None if disabled.

    We currently use MYPYPATH and the current directory as the package bases. In the future,
    when --namespace-packages is the default could also use the values passed with the
    --package-root flag, see #9632.

    Values returned are normalised so we can use simple string comparisons in
    SourceFinder.is_explicit_package_base
    """
    if not options.explicit_package_bases:
        return None
    roots = mypy_path() + options.mypy_path + [os.getcwd()]
    return [normalise_package_base(root) for root in roots]
Ejemplo n.º 3
0
def process_options(
    args: List[str],
    stdout: Optional[TextIO] = None,
    stderr: Optional[TextIO] = None,
    require_targets: bool = True,
    server_options: bool = False,
    fscache: Optional[FileSystemCache] = None,
    program: str = 'mypy',
    header: str = HEADER,
) -> 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.
    """
    stdout = stdout or sys.stdout
    stderr = stderr or sys.stderr

    parser = argparse.ArgumentParser(prog=program,
                                     usage=header,
                                     description=DESCRIPTION,
                                     epilog=FOOTER,
                                     fromfile_prefix_chars='@',
                                     formatter_class=AugmentedHelpFormatter,
                                     add_help=False)

    strict_flag_names = []  # type: List[str]
    strict_flag_assignments = []  # type: List[Tuple[str, bool]]

    def add_invertible_flag(
            flag: str,
            *,
            inverse: Optional[str] = None,
            default: bool,
            dest: Optional[str] = None,
            help: str,
            strict_flag: bool = False,
            group: Optional[argparse._ActionsContainer] = None) -> None:
        if inverse is None:
            inverse = invert_flag_name(flag)
        if group is None:
            group = parser

        if help is not argparse.SUPPRESS:
            help += " (inverse: {})".format(inverse)

        arg = group.add_argument(
            flag,
            action='store_false' if default else 'store_true',
            dest=dest,
            help=help)
        dest = arg.dest
        arg = group.add_argument(
            inverse,
            action='store_true' if default else 'store_false',
            dest=dest,
            help=argparse.SUPPRESS)
        if strict_flag:
            assert dest is not None
            strict_flag_names.append(flag)
            strict_flag_assignments.append((dest, not default))

    # Unless otherwise specified, arguments will be parsed directly onto an
    # Options object.  Options that require further processing should have
    # their `dest` prefixed with `special-opts:`, which will cause them to be
    # parsed into the separate special_opts namespace object.

    # Note: we have a style guide for formatting the mypy --help text. See
    # https://github.com/python/mypy/wiki/Documentation-Conventions

    general_group = parser.add_argument_group(title='Optional arguments')
    general_group.add_argument('-h',
                               '--help',
                               action='help',
                               help="Show this help message and exit")
    general_group.add_argument('-v',
                               '--verbose',
                               action='count',
                               dest='verbosity',
                               help="More verbose messages")
    general_group.add_argument('-V',
                               '--version',
                               action='version',
                               version='%(prog)s ' + __version__,
                               help="Show program's version number and exit")

    config_group = parser.add_argument_group(
        title='Config file',
        description="Use a config file instead of command line arguments. "
        "This is useful if you are using many flags or want "
        "to set different options per each module.")
    config_group.add_argument(
        '--config-file',
        help="Configuration file, must have a [mypy] section "
        "(defaults to {})".format(', '.join(defaults.CONFIG_FILES)))
    add_invertible_flag(
        '--warn-unused-configs',
        default=False,
        strict_flag=True,
        help="Warn about unused '[mypy-<pattern>]' config sections",
        group=config_group)

    imports_group = parser.add_argument_group(
        title='Import discovery',
        description="Configure how imports are discovered and followed.")
    imports_group.add_argument(
        '--ignore-missing-imports',
        action='store_true',
        help="Silently ignore imports of missing modules")
    imports_group.add_argument('--follow-imports',
                               choices=['normal', 'silent', 'skip', 'error'],
                               default='normal',
                               help="How to treat imports (default normal)")
    imports_group.add_argument(
        '--python-executable',
        action='store',
        metavar='EXECUTABLE',
        help="Python executable used for finding PEP 561 compliant installed"
        " packages and stubs",
        dest='special-opts:python_executable')
    imports_group.add_argument(
        '--no-site-packages',
        action='store_true',
        dest='special-opts:no_executable',
        help="Do not search for installed PEP 561 compliant packages")
    imports_group.add_argument(
        '--no-silence-site-packages',
        action='store_true',
        help="Do not silence errors in PEP 561 compliant installed packages")
    add_invertible_flag(
        '--namespace-packages',
        default=False,
        help="Support namespace packages (PEP 420, __init__.py-less)",
        group=imports_group)

    platform_group = parser.add_argument_group(
        title='Platform configuration',
        description="Type check code assuming it will be run under certain "
        "runtime conditions. By default, mypy assumes your code "
        "will be run using the same operating system and Python "
        "version you are using to run mypy itself.")
    platform_group.add_argument(
        '--python-version',
        type=parse_version,
        metavar='x.y',
        help='Type check code assuming it will be running on Python x.y',
        dest='special-opts:python_version')
    platform_group.add_argument(
        '-2',
        '--py2',
        dest='special-opts:python_version',
        action='store_const',
        const=defaults.PYTHON2_VERSION,
        help="Use Python 2 mode (same as --python-version 2.7)")
    platform_group.add_argument(
        '--platform',
        action='store',
        metavar='PLATFORM',
        help="Type check special-cased code for the given OS platform "
        "(defaults to sys.platform)")
    platform_group.add_argument(
        '--always-true',
        metavar='NAME',
        action='append',
        default=[],
        help="Additional variable to be considered True (may be repeated)")
    platform_group.add_argument(
        '--always-false',
        metavar='NAME',
        action='append',
        default=[],
        help="Additional variable to be considered False (may be repeated)")

    disallow_any_group = parser.add_argument_group(
        title='Dynamic typing',
        description=
        "Disallow the use of the dynamic 'Any' type under certain conditions.")
    disallow_any_group.add_argument(
        '--disallow-any-unimported',
        default=False,
        action='store_true',
        help="Disallow Any types resulting from unfollowed imports")
    add_invertible_flag(
        '--disallow-subclassing-any',
        default=False,
        strict_flag=True,
        help="Disallow subclassing values of type 'Any' when defining classes",
        group=disallow_any_group)
    disallow_any_group.add_argument(
        '--disallow-any-expr',
        default=False,
        action='store_true',
        help='Disallow all expressions that have type Any')
    disallow_any_group.add_argument(
        '--disallow-any-decorated',
        default=False,
        action='store_true',
        help='Disallow functions that have Any in their signature '
        'after decorator transformation')
    disallow_any_group.add_argument(
        '--disallow-any-explicit',
        default=False,
        action='store_true',
        help='Disallow explicit Any in type positions')
    add_invertible_flag(
        '--disallow-any-generics',
        default=False,
        strict_flag=True,
        help='Disallow usage of generic types that do not specify explicit type '
        'parameters',
        group=disallow_any_group)

    untyped_group = parser.add_argument_group(
        title='Untyped definitions and calls',
        description="Configure how untyped definitions and calls are handled. "
        "Note: by default, mypy ignores any untyped function definitions "
        "and assumes any calls to such functions have a return "
        "type of 'Any'.")
    add_invertible_flag(
        '--disallow-untyped-calls',
        default=False,
        strict_flag=True,
        help="Disallow calling functions without type annotations"
        " from functions with type annotations",
        group=untyped_group)
    add_invertible_flag(
        '--disallow-untyped-defs',
        default=False,
        strict_flag=True,
        help="Disallow defining functions without type annotations"
        " or with incomplete type annotations",
        group=untyped_group)
    add_invertible_flag(
        '--disallow-incomplete-defs',
        default=False,
        strict_flag=True,
        help="Disallow defining functions with incomplete type annotations",
        group=untyped_group)
    add_invertible_flag(
        '--check-untyped-defs',
        default=False,
        strict_flag=True,
        help="Type check the interior of functions without type annotations",
        group=untyped_group)
    add_invertible_flag(
        '--disallow-untyped-decorators',
        default=False,
        strict_flag=True,
        help="Disallow decorating typed functions with untyped decorators",
        group=untyped_group)

    none_group = parser.add_argument_group(
        title='None and Optional handling',
        description=
        "Adjust how values of type 'None' are handled. For more context on "
        "how mypy handles values of type 'None', see: "
        "mypy.readthedocs.io/en/latest/kinds_of_types.html#no-strict-optional")
    add_invertible_flag(
        '--no-implicit-optional',
        default=False,
        strict_flag=True,
        help="Don't assume arguments with default values of None are Optional",
        group=none_group)
    none_group.add_argument('--strict-optional',
                            action='store_true',
                            help=argparse.SUPPRESS)
    none_group.add_argument(
        '--no-strict-optional',
        action='store_false',
        dest='strict_optional',
        help="Disable strict Optional checks (inverse: --strict-optional)")
    none_group.add_argument(
        '--strict-optional-whitelist',
        metavar='GLOB',
        nargs='*',
        help="Suppress strict Optional errors in all but the provided files; "
        "implies --strict-optional (may suppress certain other errors "
        "in non-whitelisted files)")

    lint_group = parser.add_argument_group(
        title='Warnings',
        description="Detect code that is sound but redundant or problematic.")
    add_invertible_flag(
        '--warn-redundant-casts',
        default=False,
        strict_flag=True,
        help="Warn about casting an expression to its inferred type",
        group=lint_group)
    add_invertible_flag('--warn-unused-ignores',
                        default=False,
                        strict_flag=True,
                        help="Warn about unneeded '# type: ignore' comments",
                        group=lint_group)
    add_invertible_flag(
        '--no-warn-no-return',
        dest='warn_no_return',
        default=True,
        help="Do not warn about functions that end without returning",
        group=lint_group)
    add_invertible_flag('--warn-return-any',
                        default=False,
                        strict_flag=True,
                        help="Warn about returning values of type Any"
                        " from non-Any typed functions",
                        group=lint_group)

    # Note: this group is intentionally added here even though we don't add
    # --strict to this group near the end.
    #
    # That way, this group will appear after the various strictness groups
    # but before the remaining flags.
    # We add `--strict` near the end so we don't accidentally miss any strictness
    # flags that are added after this group.
    strictness_group = parser.add_argument_group(
        title='Other strictness checks')

    add_invertible_flag(
        '--allow-untyped-globals',
        default=False,
        strict_flag=False,
        help="Suppress toplevel errors caused by missing annotations",
        group=strictness_group)

    add_invertible_flag(
        '--allow-redefinition',
        default=False,
        strict_flag=False,
        help="Allow unconditional variable redefinition with a new type",
        group=strictness_group)

    add_invertible_flag(
        '--strict-equality',
        default=False,
        strict_flag=False,
        help="Prohibit equality, identity, and container checks for"
        " non-overlapping types",
        group=strictness_group)

    incremental_group = parser.add_argument_group(
        title='Incremental mode',
        description=
        "Adjust how mypy incrementally type checks and caches modules. "
        "Mypy caches type information about modules into a cache to "
        "let you speed up future invocations of mypy. Also see "
        "mypy's daemon mode: "
        "mypy.readthedocs.io/en/latest/mypy_daemon.html#mypy-daemon")
    incremental_group.add_argument('-i',
                                   '--incremental',
                                   action='store_true',
                                   help=argparse.SUPPRESS)
    incremental_group.add_argument(
        '--no-incremental',
        action='store_false',
        dest='incremental',
        help="Disable module cache (inverse: --incremental)")
    incremental_group.add_argument(
        '--cache-dir',
        action='store',
        metavar='DIR',
        help="Store module cache info in the given folder in incremental mode "
        "(defaults to '{}')".format(defaults.CACHE_DIR))
    add_invertible_flag('--sqlite-cache',
                        default=False,
                        help="Use a sqlite database to store the cache",
                        group=incremental_group)
    incremental_group.add_argument(
        '--cache-fine-grained',
        action='store_true',
        help=
        "Include fine-grained dependency information in the cache for the mypy daemon"
    )
    incremental_group.add_argument(
        '--skip-version-check',
        action='store_true',
        help="Allow using cache written by older mypy version")
    incremental_group.add_argument(
        '--skip-cache-mtime-checks',
        action='store_true',
        help="Skip cache internal consistency checks based on mtime")

    internals_group = parser.add_argument_group(
        title='Mypy internals',
        description="Debug and customize mypy internals.")
    internals_group.add_argument('--pdb',
                                 action='store_true',
                                 help="Invoke pdb on fatal error")
    internals_group.add_argument('--show-traceback',
                                 '--tb',
                                 action='store_true',
                                 help="Show traceback on fatal error")
    internals_group.add_argument('--raise-exceptions',
                                 action='store_true',
                                 help="Raise exception on fatal error")
    internals_group.add_argument('--custom-typing',
                                 metavar='MODULE',
                                 dest='custom_typing_module',
                                 help="Use a custom typing module")
    internals_group.add_argument('--custom-typeshed-dir',
                                 metavar='DIR',
                                 help="Use the custom typeshed in DIR")
    add_invertible_flag(
        '--warn-incomplete-stub',
        default=False,
        help="Warn if missing type annotation in typeshed, only relevant with"
        " --disallow-untyped-defs or --disallow-incomplete-defs enabled",
        group=internals_group)
    internals_group.add_argument(
        '--shadow-file',
        nargs=2,
        metavar=('SOURCE_FILE', 'SHADOW_FILE'),
        dest='shadow_file',
        action='append',
        help="When encountering SOURCE_FILE, read and type check "
        "the contents of SHADOW_FILE instead.")
    add_invertible_flag('--fast-exit',
                        default=False,
                        help=argparse.SUPPRESS,
                        group=internals_group)
    add_invertible_flag('--new-semantic-analyzer',
                        default=False,
                        help=argparse.SUPPRESS,
                        group=internals_group)

    error_group = parser.add_argument_group(
        title='Error reporting',
        description="Adjust the amount of detail shown in error messages.")
    add_invertible_flag(
        '--show-error-context',
        default=False,
        dest='show_error_context',
        help='Precede errors with "note:" messages explaining context',
        group=error_group)
    add_invertible_flag('--show-column-numbers',
                        default=False,
                        help="Show column numbers in error messages",
                        group=error_group)

    strict_help = "Strict mode; enables the following flags: {}".format(
        ", ".join(strict_flag_names))
    strictness_group.add_argument('--strict',
                                  action='store_true',
                                  dest='special-opts:strict',
                                  help=strict_help)

    report_group = parser.add_argument_group(
        title='Report generation',
        description='Generate a report in the specified format.')
    for report_type in sorted(defaults.REPORTER_NAMES):
        report_group.add_argument('--%s-report' %
                                  report_type.replace('_', '-'),
                                  metavar='DIR',
                                  dest='special-opts:%s_report' % report_type)

    other_group = parser.add_argument_group(title='Miscellaneous')
    other_group.add_argument('--quickstart-file', help=argparse.SUPPRESS)
    other_group.add_argument('--junit-xml',
                             help="Write junit.xml to the given file")
    other_group.add_argument(
        '--scripts-are-modules',
        action='store_true',
        help="Script x becomes module x instead of __main__")
    other_group.add_argument(
        '--find-occurrences',
        metavar='CLASS.MEMBER',
        dest='special-opts:find_occurrences',
        help="Print out all usages of a class member (experimental)")

    if server_options:
        # TODO: This flag is superfluous; remove after a short transition (2018-03-16)
        other_group.add_argument('--experimental',
                                 action='store_true',
                                 dest='fine_grained_incremental',
                                 help="Enable fine-grained incremental mode")
        other_group.add_argument(
            '--use-fine-grained-cache',
            action='store_true',
            help="Use the cache in fine-grained incremental mode")

    # hidden options
    parser.add_argument('--stats',
                        action='store_true',
                        dest='dump_type_stats',
                        help=argparse.SUPPRESS)
    parser.add_argument('--inferstats',
                        action='store_true',
                        dest='dump_inference_stats',
                        help=argparse.SUPPRESS)
    # --debug-cache will disable any cache-related compressions/optimizations,
    # which will make the cache writing process output pretty-printed JSON (which
    # is easier to debug).
    parser.add_argument('--debug-cache',
                        action='store_true',
                        help=argparse.SUPPRESS)
    # --dump-deps will dump all fine-grained dependencies to stdout
    parser.add_argument('--dump-deps',
                        action='store_true',
                        help=argparse.SUPPRESS)
    # --dump-graph will dump the contents of the graph of SCCs and exit.
    parser.add_argument('--dump-graph',
                        action='store_true',
                        help=argparse.SUPPRESS)
    # --semantic-analysis-only does exactly that.
    parser.add_argument('--semantic-analysis-only',
                        action='store_true',
                        help=argparse.SUPPRESS)
    # --local-partial-types disallows partial types spanning module top level and a function
    # (implicitly defined in fine-grained incremental mode)
    parser.add_argument('--local-partial-types',
                        action='store_true',
                        help=argparse.SUPPRESS)
    # --logical-deps adds some more dependencies that are not semantically needed, but
    # may be helpful to determine relative importance of classes and functions for overall
    # type precision in a code base. It also _removes_ some deps, so this flag should be never
    # used except for generating code stats. This also automatically enables --cache-fine-grained.
    # NOTE: This is an experimental option that may be modified or removed at any time.
    parser.add_argument('--logical-deps',
                        action='store_true',
                        help=argparse.SUPPRESS)
    # --bazel changes some behaviors for use with Bazel (https://bazel.build).
    parser.add_argument('--bazel', action='store_true', help=argparse.SUPPRESS)
    # --package-root adds a directory below which directories are considered
    # packages even without __init__.py.  May be repeated.
    parser.add_argument('--package-root',
                        metavar='ROOT',
                        action='append',
                        default=[],
                        help=argparse.SUPPRESS)
    # --cache-map FILE ... gives a mapping from source files to cache files.
    # Each triple of arguments is a source file, a cache meta file, and a cache data file.
    # Modules not mentioned in the file will go through cache_dir.
    # Must be followed by another flag or by '--' (and then only file args may follow).
    parser.add_argument('--cache-map',
                        nargs='+',
                        dest='special-opts:cache_map',
                        help=argparse.SUPPRESS)

    # options specifying code to check
    code_group = parser.add_argument_group(
        title="Running code",
        description=
        "Specify the code you want to type check. For more details, see "
        "mypy.readthedocs.io/en/latest/running_mypy.html#running-mypy")
    code_group.add_argument(
        '-m',
        '--module',
        action='append',
        metavar='MODULE',
        default=[],
        dest='special-opts:modules',
        help="Type-check module; can repeat for more modules")
    code_group.add_argument(
        '-p',
        '--package',
        action='append',
        metavar='PACKAGE',
        default=[],
        dest='special-opts:packages',
        help="Type-check package recursively; can be repeated")
    code_group.add_argument('-c',
                            '--command',
                            action='append',
                            metavar='PROGRAM_TEXT',
                            dest='special-opts:command',
                            help="Type-check program passed in as string")
    code_group.add_argument(metavar='files',
                            nargs='*',
                            dest='special-opts:files',
                            help="Type-check given files or directories")

    # 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("Cannot find config file '%s'" % config_file)

    # Parse config file first, so command line can override.
    options = Options()
    parse_config_file(options, 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'):  # noqa
        for dest, value in strict_flag_assignments:
            setattr(options, dest, value)

    # Parse command line for real, using a split namespace.
    special_opts = argparse.Namespace()
    parser.parse_args(args,
                      SplitNamespace(options, special_opts, 'special-opts:'))

    # The python_version is either the default, which can be overridden via a config file,
    # or stored in special_opts and is passed via the command line.
    options.python_version = special_opts.python_version or options.python_version
    try:
        infer_python_executable(options, special_opts)
    except PythonExecutableInferenceError as e:
        parser.error(str(e))

    if special_opts.no_executable:
        options.python_executable = None

    # Paths listed in the config file will be ignored if any paths are passed on
    # the command line.
    if options.files and not special_opts.files:
        special_opts.files = options.files

    # Check for invalid argument combinations.
    if require_targets:
        code_methods = sum(
            bool(c) for c in [
                special_opts.modules +
                special_opts.packages, special_opts.command, special_opts.files
            ])
        if code_methods == 0:
            parser.error("Missing target module, package, files, or command.")
        elif code_methods > 1:
            parser.error(
                "May only specify one of: module/package, files, or command.")

    # Check for overlapping `--always-true` and `--always-false` flags.
    overlap = set(options.always_true) & set(options.always_false)
    if overlap:
        parser.error(
            "You can't make a variable always true and always false (%s)" %
            ', '.join(sorted(overlap)))

    # Set build flags.
    if options.strict_optional_whitelist is not None:
        # TODO: Deprecate, then kill this flag
        options.strict_optional = True
    if special_opts.find_occurrences:
        state.find_occurrences = special_opts.find_occurrences.split('.')
        assert state.find_occurrences is not None
        if len(state.find_occurrences) < 2:
            parser.error("Can only find occurrences of class members.")
        if len(state.find_occurrences) != 2:
            parser.error(
                "Can only find occurrences of non-nested class members.")

    # Set reports.
    for flag, val in vars(special_opts).items():
        if flag.endswith('_report') and val is not None:
            report_type = flag[:-7].replace('_', '-')
            report_dir = val
            options.report_dirs[report_type] = report_dir

    # Process --package-root.
    if options.package_root:
        process_package_roots(fscache, parser, options)

    # Process --cache-map.
    if special_opts.cache_map:
        if options.sqlite_cache:
            parser.error("--cache-map is incompatible with --sqlite-cache")

        process_cache_map(parser, special_opts, options)

    # Let logical_deps imply cache_fine_grained (otherwise the former is useless).
    if options.logical_deps:
        options.cache_fine_grained = True

    # Set target.
    if special_opts.modules + special_opts.packages:
        options.build_type = BuildType.MODULE
        search_paths = SearchPaths((os.getcwd(), ), tuple(mypy_path()), (), ())
        targets = []
        # TODO: use the same cache that the BuildManager will
        cache = FindModuleCache(search_paths, fscache)
        for p in special_opts.packages:
            if os.sep in p or os.altsep and os.altsep in p:
                fail("Package name '{}' cannot have a slash in it.".format(p),
                     stderr)
            p_targets = cache.find_modules_recursive(p)
            if not p_targets:
                fail("Can't find package '{}'".format(p), stderr)
            targets.extend(p_targets)
        for m in special_opts.modules:
            targets.append(BuildSource(None, m, None))
        return targets, options
    elif special_opts.command:
        options.build_type = BuildType.PROGRAM_TEXT
        targets = [BuildSource(None, None, '\n'.join(special_opts.command))]
        return targets, options
    else:
        try:
            targets = create_source_list(special_opts.files, options, fscache)
        # Variable named e2 instead of e to work around mypyc bug #620
        # which causes issues when using the same variable to catch
        # exceptions of different types.
        except InvalidSourceList as e2:
            fail(str(e2), stderr)
        return targets, options
Ejemplo n.º 4
0
Archivo: main.py Proyecto: python/mypy
def process_options(args: List[str],
                    require_targets: bool = True,
                    server_options: bool = False,
                    fscache: Optional[FileSystemCache] = None,
                    program: str = 'mypy',
                    header: str = HEADER,
                    ) -> 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.
    """

    parser = argparse.ArgumentParser(prog=program,
                                     usage=header,
                                     description=DESCRIPTION,
                                     epilog=FOOTER,
                                     fromfile_prefix_chars='@',
                                     formatter_class=AugmentedHelpFormatter,
                                     add_help=False)

    strict_flag_names = []  # type: List[str]
    strict_flag_assignments = []  # type: List[Tuple[str, bool]]

    def add_invertible_flag(flag: str,
                            *,
                            inverse: Optional[str] = None,
                            default: bool,
                            dest: Optional[str] = None,
                            help: str,
                            strict_flag: bool = False,
                            group: Optional[argparse._ActionsContainer] = None
                            ) -> None:
        if inverse is None:
            inverse = invert_flag_name(flag)
        if group is None:
            group = parser

        if help is not argparse.SUPPRESS:
            help += " (inverse: {})".format(inverse)

        arg = group.add_argument(flag,
                                 action='store_false' if default else 'store_true',
                                 dest=dest,
                                 help=help)
        dest = arg.dest
        arg = group.add_argument(inverse,
                                 action='store_true' if default else 'store_false',
                                 dest=dest,
                                 help=argparse.SUPPRESS)
        if strict_flag:
            assert dest is not None
            strict_flag_names.append(flag)
            strict_flag_assignments.append((dest, not default))

    # Unless otherwise specified, arguments will be parsed directly onto an
    # Options object.  Options that require further processing should have
    # their `dest` prefixed with `special-opts:`, which will cause them to be
    # parsed into the separate special_opts namespace object.

    # Note: we have a style guide for formatting the mypy --help text. See
    # https://github.com/python/mypy/wiki/Documentation-Conventions

    general_group = parser.add_argument_group(
        title='Optional arguments')
    general_group.add_argument(
        '-h', '--help', action='help',
        help="Show this help message and exit")
    general_group.add_argument(
        '-v', '--verbose', action='count', dest='verbosity',
        help="More verbose messages")
    general_group.add_argument(
        '-V', '--version', action='version',
        version='%(prog)s ' + __version__,
        help="Show program's version number and exit")

    config_group = parser.add_argument_group(
        title='Config file',
        description="Use a config file instead of command line arguments. "
                    "This is useful if you are using many flags or want "
                    "to set different options per each module.")
    config_group.add_argument(
        '--config-file',
        help="Configuration file, must have a [mypy] section "
             "(defaults to {})".format(', '.join(defaults.CONFIG_FILES)))
    add_invertible_flag('--warn-unused-configs', default=False, strict_flag=True,
                        help="Warn about unused '[mypy-<pattern>]' config sections",
                        group=config_group)

    imports_group = parser.add_argument_group(
        title='Import discovery',
        description="Configure how imports are discovered and followed.")
    imports_group.add_argument(
        '--ignore-missing-imports', action='store_true',
        help="Silently ignore imports of missing modules")
    imports_group.add_argument(
        '--follow-imports', choices=['normal', 'silent', 'skip', 'error'],
        default='normal', help="How to treat imports (default normal)")
    imports_group.add_argument(
        '--python-executable', action='store', metavar='EXECUTABLE',
        help="Python executable used for finding PEP 561 compliant installed"
             " packages and stubs",
        dest='special-opts:python_executable')
    imports_group.add_argument(
        '--no-site-packages', action='store_true',
        dest='special-opts:no_executable',
        help="Do not search for installed PEP 561 compliant packages")
    imports_group.add_argument(
        '--no-silence-site-packages', action='store_true',
        help="Do not silence errors in PEP 561 compliant installed packages")
    add_invertible_flag(
        '--namespace-packages', default=False,
        help="Support namespace packages (PEP 420, __init__.py-less)",
        group=imports_group)

    platform_group = parser.add_argument_group(
        title='Platform configuration',
        description="Type check code assuming it will be run under certain "
                    "runtime conditions. By default, mypy assumes your code "
                    "will be run using the same operating system and Python "
                    "version you are using to run mypy itself.")
    platform_group.add_argument(
        '--python-version', type=parse_version, metavar='x.y',
        help='Type check code assuming it will be running on Python x.y',
        dest='special-opts:python_version')
    platform_group.add_argument(
        '-2', '--py2', dest='special-opts:python_version', action='store_const',
        const=defaults.PYTHON2_VERSION,
        help="Use Python 2 mode (same as --python-version 2.7)")
    platform_group.add_argument(
        '--platform', action='store', metavar='PLATFORM',
        help="Type check special-cased code for the given OS platform "
             "(defaults to sys.platform)")
    platform_group.add_argument(
        '--always-true', metavar='NAME', action='append', default=[],
        help="Additional variable to be considered True (may be repeated)")
    platform_group.add_argument(
        '--always-false', metavar='NAME', action='append', default=[],
        help="Additional variable to be considered False (may be repeated)")

    disallow_any_group = parser.add_argument_group(
        title='Dynamic typing',
        description="Disallow the use of the dynamic 'Any' type under certain conditions.")
    disallow_any_group.add_argument(
        '--disallow-any-unimported', default=False, action='store_true',
        help="Disallow Any types resulting from unfollowed imports")
    add_invertible_flag('--disallow-subclassing-any', default=False, strict_flag=True,
                        help="Disallow subclassing values of type 'Any' when defining classes",
                        group=disallow_any_group)
    disallow_any_group.add_argument(
        '--disallow-any-expr', default=False, action='store_true',
        help='Disallow all expressions that have type Any')
    disallow_any_group.add_argument(
        '--disallow-any-decorated', default=False, action='store_true',
        help='Disallow functions that have Any in their signature '
             'after decorator transformation')
    disallow_any_group.add_argument(
        '--disallow-any-explicit', default=False, action='store_true',
        help='Disallow explicit Any in type positions')
    add_invertible_flag('--disallow-any-generics', default=False, strict_flag=True,
                        help='Disallow usage of generic types that do not specify explicit type '
                        'parameters', group=disallow_any_group)

    untyped_group = parser.add_argument_group(
        title='Untyped definitions and calls',
        description="Configure how untyped definitions and calls are handled. "
                    "Note: by default, mypy ignores any untyped function definitions "
                    "and assumes any calls to such functions have a return "
                    "type of 'Any'.")
    add_invertible_flag('--disallow-untyped-calls', default=False, strict_flag=True,
                        help="Disallow calling functions without type annotations"
                        " from functions with type annotations",
                        group=untyped_group)
    add_invertible_flag('--disallow-untyped-defs', default=False, strict_flag=True,
                        help="Disallow defining functions without type annotations"
                        " or with incomplete type annotations",
                        group=untyped_group)
    add_invertible_flag('--disallow-incomplete-defs', default=False, strict_flag=True,
                        help="Disallow defining functions with incomplete type annotations",
                        group=untyped_group)
    add_invertible_flag('--check-untyped-defs', default=False, strict_flag=True,
                        help="Type check the interior of functions without type annotations",
                        group=untyped_group)
    add_invertible_flag('--disallow-untyped-decorators', default=False, strict_flag=True,
                        help="Disallow decorating typed functions with untyped decorators",
                        group=untyped_group)

    none_group = parser.add_argument_group(
        title='None and Optional handling',
        description="Adjust how values of type 'None' are handled. For more context on "
                    "how mypy handles values of type 'None', see: "
                    "mypy.readthedocs.io/en/latest/kinds_of_types.html#no-strict-optional")
    add_invertible_flag('--no-implicit-optional', default=False, strict_flag=True,
                        help="Don't assume arguments with default values of None are Optional",
                        group=none_group)
    none_group.add_argument(
        '--strict-optional', action='store_true',
        help=argparse.SUPPRESS)
    none_group.add_argument(
        '--no-strict-optional', action='store_false', dest='strict_optional',
        help="Disable strict Optional checks (inverse: --strict-optional)")
    none_group.add_argument(
        '--strict-optional-whitelist', metavar='GLOB', nargs='*',
        help="Suppress strict Optional errors in all but the provided files; "
             "implies --strict-optional (may suppress certain other errors "
             "in non-whitelisted files)")

    lint_group = parser.add_argument_group(
        title='Warnings',
        description="Detect code that is sound but redundant or problematic.")
    add_invertible_flag('--warn-redundant-casts', default=False, strict_flag=True,
                        help="Warn about casting an expression to its inferred type",
                        group=lint_group)
    add_invertible_flag('--warn-unused-ignores', default=False, strict_flag=True,
                        help="Warn about unneeded '# type: ignore' comments",
                        group=lint_group)
    add_invertible_flag('--no-warn-no-return', dest='warn_no_return', default=True,
                        help="Do not warn about functions that end without returning",
                        group=lint_group)
    add_invertible_flag('--warn-return-any', default=False, strict_flag=True,
                        help="Warn about returning values of type Any"
                             " from non-Any typed functions",
                        group=lint_group)

    # Note: this group is intentionally added here even though we don't add
    # --strict to this group near the end.
    #
    # That way, this group will appear after the various strictness groups
    # but before the remaining flags.
    # We add `--strict` near the end so we don't accidentally miss any strictness
    # flags that are added after this group.
    strictness_group = parser.add_argument_group(
        title='Other strictness checks')

    add_invertible_flag('--allow-untyped-globals', default=False, strict_flag=False,
                        help="Suppress toplevel errors caused by missing annotations",
                        group=strictness_group)

    add_invertible_flag('--allow-redefinition', default=False, strict_flag=False,
                        help="Allow unconditional variable redefinition with a new type",
                        group=strictness_group)

    add_invertible_flag('--strict-equality', default=False, strict_flag=False,
                        help="Prohibit equality, identity, and container checks for"
                             " non-overlapping types",
                        group=strictness_group)

    incremental_group = parser.add_argument_group(
        title='Incremental mode',
        description="Adjust how mypy incrementally type checks and caches modules. "
                    "Mypy caches type information about modules into a cache to "
                    "let you speed up future invocations of mypy. Also see "
                    "mypy's daemon mode: "
                    "mypy.readthedocs.io/en/latest/mypy_daemon.html#mypy-daemon")
    incremental_group.add_argument(
        '-i', '--incremental', action='store_true',
        help=argparse.SUPPRESS)
    incremental_group.add_argument(
        '--no-incremental', action='store_false', dest='incremental',
        help="Disable module cache (inverse: --incremental)")
    incremental_group.add_argument(
        '--cache-dir', action='store', metavar='DIR',
        help="Store module cache info in the given folder in incremental mode "
             "(defaults to '{}')".format(defaults.CACHE_DIR))
    add_invertible_flag('--sqlite-cache', default=False,
                        help="Use a sqlite database to store the cache",
                        group=incremental_group)
    incremental_group.add_argument(
        '--cache-fine-grained', action='store_true',
        help="Include fine-grained dependency information in the cache for the mypy daemon")
    incremental_group.add_argument(
        '--skip-version-check', action='store_true',
        help="Allow using cache written by older mypy version")
    incremental_group.add_argument(
        '--skip-cache-mtime-checks', action='store_true',
        help="Skip cache internal consistency checks based on mtime")

    internals_group = parser.add_argument_group(
        title='Mypy internals',
        description="Debug and customize mypy internals.")
    internals_group.add_argument(
        '--pdb', action='store_true', help="Invoke pdb on fatal error")
    internals_group.add_argument(
        '--show-traceback', '--tb', action='store_true',
        help="Show traceback on fatal error")
    internals_group.add_argument(
        '--raise-exceptions', action='store_true', help="Raise exception on fatal error"
    )
    internals_group.add_argument(
        '--custom-typing', metavar='MODULE', dest='custom_typing_module',
        help="Use a custom typing module")
    internals_group.add_argument(
        '--custom-typeshed-dir', metavar='DIR',
        help="Use the custom typeshed in DIR")
    add_invertible_flag('--warn-incomplete-stub', default=False,
                        help="Warn if missing type annotation in typeshed, only relevant with"
                             " --disallow-untyped-defs or --disallow-incomplete-defs enabled",
                        group=internals_group)
    internals_group.add_argument(
        '--shadow-file', nargs=2, metavar=('SOURCE_FILE', 'SHADOW_FILE'),
        dest='shadow_file', action='append',
        help="When encountering SOURCE_FILE, read and type check "
             "the contents of SHADOW_FILE instead.")
    add_invertible_flag('--fast-exit', default=False, help=argparse.SUPPRESS,
                        group=internals_group)
    add_invertible_flag('--new-semantic-analyzer', default=False, help=argparse.SUPPRESS,
                        group=internals_group)

    error_group = parser.add_argument_group(
        title='Error reporting',
        description="Adjust the amount of detail shown in error messages.")
    add_invertible_flag('--show-error-context', default=False,
                        dest='show_error_context',
                        help='Precede errors with "note:" messages explaining context',
                        group=error_group)
    add_invertible_flag('--show-column-numbers', default=False,
                        help="Show column numbers in error messages",
                        group=error_group)

    strict_help = "Strict mode; enables the following flags: {}".format(
        ", ".join(strict_flag_names))
    strictness_group.add_argument(
        '--strict', action='store_true', dest='special-opts:strict',
        help=strict_help)

    report_group = parser.add_argument_group(
        title='Report generation',
        description='Generate a report in the specified format.')
    for report_type in sorted(defaults.REPORTER_NAMES):
        report_group.add_argument('--%s-report' % report_type.replace('_', '-'),
                                  metavar='DIR',
                                  dest='special-opts:%s_report' % report_type)

    other_group = parser.add_argument_group(
        title='Miscellaneous')
    other_group.add_argument(
        '--quickstart-file', help=argparse.SUPPRESS)
    other_group.add_argument(
        '--junit-xml', help="Write junit.xml to the given file")
    other_group.add_argument(
        '--scripts-are-modules', action='store_true',
        help="Script x becomes module x instead of __main__")
    other_group.add_argument(
        '--find-occurrences', metavar='CLASS.MEMBER',
        dest='special-opts:find_occurrences',
        help="Print out all usages of a class member (experimental)")

    if server_options:
        # TODO: This flag is superfluous; remove after a short transition (2018-03-16)
        other_group.add_argument(
            '--experimental', action='store_true', dest='fine_grained_incremental',
            help="Enable fine-grained incremental mode")
        other_group.add_argument(
            '--use-fine-grained-cache', action='store_true',
            help="Use the cache in fine-grained incremental mode")

    # hidden options
    parser.add_argument(
        '--stats', action='store_true', dest='dump_type_stats', help=argparse.SUPPRESS)
    parser.add_argument(
        '--inferstats', action='store_true', dest='dump_inference_stats',
        help=argparse.SUPPRESS)
    # --debug-cache will disable any cache-related compressions/optimizations,
    # which will make the cache writing process output pretty-printed JSON (which
    # is easier to debug).
    parser.add_argument('--debug-cache', action='store_true', help=argparse.SUPPRESS)
    # --dump-deps will dump all fine-grained dependencies to stdout
    parser.add_argument('--dump-deps', action='store_true', help=argparse.SUPPRESS)
    # --dump-graph will dump the contents of the graph of SCCs and exit.
    parser.add_argument('--dump-graph', action='store_true', help=argparse.SUPPRESS)
    # --semantic-analysis-only does exactly that.
    parser.add_argument('--semantic-analysis-only', action='store_true', help=argparse.SUPPRESS)
    # --local-partial-types disallows partial types spanning module top level and a function
    # (implicitly defined in fine-grained incremental mode)
    parser.add_argument('--local-partial-types', action='store_true', help=argparse.SUPPRESS)
    # --logical-deps adds some more dependencies that are not semantically needed, but
    # may be helpful to determine relative importance of classes and functions for overall
    # type precision in a code base. It also _removes_ some deps, so this flag should be never
    # used except for generating code stats. This also automatically enables --cache-fine-grained.
    # NOTE: This is an experimental option that may be modified or removed at any time.
    parser.add_argument('--logical-deps', action='store_true', help=argparse.SUPPRESS)
    # --bazel changes some behaviors for use with Bazel (https://bazel.build).
    parser.add_argument('--bazel', action='store_true', help=argparse.SUPPRESS)
    # --package-root adds a directory below which directories are considered
    # packages even without __init__.py.  May be repeated.
    parser.add_argument('--package-root', metavar='ROOT', action='append', default=[],
                        help=argparse.SUPPRESS)
    # --cache-map FILE ... gives a mapping from source files to cache files.
    # Each triple of arguments is a source file, a cache meta file, and a cache data file.
    # Modules not mentioned in the file will go through cache_dir.
    # Must be followed by another flag or by '--' (and then only file args may follow).
    parser.add_argument('--cache-map', nargs='+', dest='special-opts:cache_map',
                        help=argparse.SUPPRESS)

    # options specifying code to check
    code_group = parser.add_argument_group(
        title="Running code",
        description="Specify the code you want to type check. For more details, see "
                    "mypy.readthedocs.io/en/latest/running_mypy.html#running-mypy")
    code_group.add_argument(
        '-m', '--module', action='append', metavar='MODULE',
        default=[],
        dest='special-opts:modules',
        help="Type-check module; can repeat for more modules")
    code_group.add_argument(
        '-p', '--package', action='append', metavar='PACKAGE',
        default=[],
        dest='special-opts:packages',
        help="Type-check package recursively; can be repeated")
    code_group.add_argument(
        '-c', '--command', action='append', metavar='PROGRAM_TEXT',
        dest='special-opts:command',
        help="Type-check program passed in as string")
    code_group.add_argument(
        metavar='files', nargs='*', dest='special-opts:files',
        help="Type-check given files or directories")

    # 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("Cannot find config file '%s'" % config_file)

    # Parse config file first, so command line can override.
    options = Options()
    parse_config_file(options, config_file)

    # Set strict flags before parsing (if strict mode enabled), so other command
    # line options can override.
    if getattr(dummy, 'special-opts:strict'):
        for dest, value in strict_flag_assignments:
            setattr(options, dest, value)

    # Parse command line for real, using a split namespace.
    special_opts = argparse.Namespace()
    parser.parse_args(args, SplitNamespace(options, special_opts, 'special-opts:'))

    # The python_version is either the default, which can be overridden via a config file,
    # or stored in special_opts and is passed via the command line.
    options.python_version = special_opts.python_version or options.python_version
    try:
        infer_python_executable(options, special_opts)
    except PythonExecutableInferenceError as e:
        parser.error(str(e))

    if special_opts.no_executable:
        options.python_executable = None

    # Paths listed in the config file will be ignored if any paths are passed on
    # the command line.
    if options.files and not special_opts.files:
        special_opts.files = options.files

    # Check for invalid argument combinations.
    if require_targets:
        code_methods = sum(bool(c) for c in [special_opts.modules + special_opts.packages,
                                             special_opts.command,
                                             special_opts.files])
        if code_methods == 0:
            parser.error("Missing target module, package, files, or command.")
        elif code_methods > 1:
            parser.error("May only specify one of: module/package, files, or command.")

    # Check for overlapping `--always-true` and `--always-false` flags.
    overlap = set(options.always_true) & set(options.always_false)
    if overlap:
        parser.error("You can't make a variable always true and always false (%s)" %
                     ', '.join(sorted(overlap)))

    # Set build flags.
    if options.strict_optional_whitelist is not None:
        # TODO: Deprecate, then kill this flag
        options.strict_optional = True
    if special_opts.find_occurrences:
        state.find_occurrences = special_opts.find_occurrences.split('.')
        assert state.find_occurrences is not None
        if len(state.find_occurrences) < 2:
            parser.error("Can only find occurrences of class members.")
        if len(state.find_occurrences) != 2:
            parser.error("Can only find occurrences of non-nested class members.")

    # Set reports.
    for flag, val in vars(special_opts).items():
        if flag.endswith('_report') and val is not None:
            report_type = flag[:-7].replace('_', '-')
            report_dir = val
            options.report_dirs[report_type] = report_dir

    # Process --package-root.
    if options.package_root:
        process_package_roots(fscache, parser, options)

    # Process --cache-map.
    if special_opts.cache_map:
        if options.sqlite_cache:
            parser.error("--cache-map is incompatible with --sqlite-cache")

        process_cache_map(parser, special_opts, options)

    # Let logical_deps imply cache_fine_grained (otherwise the former is useless).
    if options.logical_deps:
        options.cache_fine_grained = True

    # Set target.
    if special_opts.modules + special_opts.packages:
        options.build_type = BuildType.MODULE
        search_paths = SearchPaths((os.getcwd(),), tuple(mypy_path()), (), ())
        targets = []
        # TODO: use the same cache that the BuildManager will
        cache = FindModuleCache(search_paths, fscache)
        for p in special_opts.packages:
            if os.sep in p or os.altsep and os.altsep in p:
                fail("Package name '{}' cannot have a slash in it.".format(p))
            p_targets = cache.find_modules_recursive(p)
            if not p_targets:
                fail("Can't find package '{}'".format(p))
            targets.extend(p_targets)
        for m in special_opts.modules:
            targets.append(BuildSource(None, m, None))
        return targets, options
    elif special_opts.command:
        options.build_type = BuildType.PROGRAM_TEXT
        targets = [BuildSource(None, None, '\n'.join(special_opts.command))]
        return targets, options
    else:
        try:
            targets = create_source_list(special_opts.files, options, fscache)
        except InvalidSourceList as e:
            fail(str(e))
        return targets, options