typing.py

"""
    sphinx.util.typing
    ~~~~~~~~~~~~~~~~~~

    The composit types for Sphinx.

    :copyright: Copyright 2007-2020 by the Sphinx team, see AUTHORS.
    :license: BSD, see LICENSE for details.
"""

import sys
import typing
from typing import Any, Callable, Dict, Generator, List, Optional, Tuple, TypeVar, Union

from docutils import nodes
from docutils.parsers.rst.states import Inliner

if sys.version_info > (3, 7):
    from typing import ForwardRef
else:
    from typing import _ForwardRef  # type: ignore

    class ForwardRef:
        """A pseudo ForwardRef class for py35 and py36."""
        def __init__(self, arg: Any, is_argument: bool = True) -> None:
            self.arg = arg

        def _evaluate(self, globalns: Dict, localns: Dict) -> Any:
            ref = _ForwardRef(self.arg)
            return ref._eval_type(globalns, localns)

if False:
    # For type annotation
    from typing import Type  # NOQA # for python3.5.1


# An entry of Directive.option_spec
DirectiveOption = Callable[[str], Any]

# Text like nodes which are initialized with text and rawsource
TextlikeNode = Union[nodes.Text, nodes.TextElement]

# type of None
NoneType = type(None)

# path matcher
PathMatcher = Callable[[str], bool]

# common role functions
RoleFunction = Callable[[str, str, str, int, Inliner, Dict[str, Any], List[str]],
                        Tuple[List[nodes.Node], List[nodes.system_message]]]

# title getter functions for enumerable nodes (see sphinx.domains.std)
TitleGetter = Callable[[nodes.Node], str]

# inventory data on memory
Inventory = Dict[str, Dict[str, Tuple[str, str, str, str]]]


def get_type_hints(obj: Any, globalns: Dict = None, localns: Dict = None) -> Dict[str, Any]:
    """Return a dictionary containing type hints for a function, method, module or class object.

    This is a simple wrapper of `typing.get_type_hints()` that does not raise an error on
    runtime.
    """
    from sphinx.util.inspect import safe_getattr  # lazy loading

    try:
        return typing.get_type_hints(obj, globalns, localns)
    except NameError:
        # Failed to evaluate ForwardRef (maybe TYPE_CHECKING)
        return safe_getattr(obj, '__annotations__', {})
    except TypeError:
        return {}
    except KeyError:
        # a broken class found (refs: https://github.com/sphinx-doc/sphinx/issues/8084)
        return {}
    except AttributeError:
        # AttributeError is raised on 3.5.2 (fixed by 3.5.3)
        return {}


def is_system_TypeVar(typ: Any) -> bool:
    """Check *typ* is system defined TypeVar."""
    modname = getattr(typ, '__module__', '')
    return modname == 'typing' and isinstance(typ, TypeVar)


def restify(cls: Optional["Type"]) -> str:
    """Convert python class to a reST reference."""
    from sphinx.util import inspect  # lazy loading

    if cls is None or cls is NoneType:
        return ':obj:`None`'
    elif cls is Ellipsis:
        return '...'
    elif inspect.isNewType(cls):
        return ':class:`%s`' % cls.__name__
    elif cls.__module__ in ('__builtin__', 'builtins'):
        return ':class:`%s`' % cls.__name__
    else:
        if sys.version_info >= (3, 7):  # py37+
            return _restify_py37(cls)
        else:
            return _restify_py36(cls)


def _restify_py37(cls: Optional["Type"]) -> str:
    """Convert python class to a reST reference."""
    from sphinx.util import inspect  # lazy loading

    if (inspect.isgenericalias(cls) and
            cls.__module__ == 'typing' and cls.__origin__ is Union):
        # Union
        if len(cls.__args__) > 1 and cls.__args__[-1] is NoneType:
            if len(cls.__args__) > 2:
                args = ', '.join(restify(a) for a in cls.__args__[:-1])
                return ':obj:`Optional`\\ [:obj:`Union`\\ [%s]]' % args
            else:
                return ':obj:`Optional`\\ [%s]' % restify(cls.__args__[0])
        else:
            args = ', '.join(restify(a) for a in cls.__args__)
            return ':obj:`Union`\\ [%s]' % args
    elif inspect.isgenericalias(cls):
        if getattr(cls, '_name', None):
            if cls.__module__ == 'typing':
                text = ':class:`%s`' % cls._name
            else:
                text = ':class:`%s.%s`' % (cls.__module__, cls._name)
        else:
            text = restify(cls.__origin__)

        if not hasattr(cls, '__args__'):
            pass
        elif all(is_system_TypeVar(a) for a in cls.__args__):
            # Suppress arguments if all system defined TypeVars (ex. Dict[KT, VT])
            pass
        elif cls.__module__ == 'typing' and cls._name == 'Callable':
            args = ', '.join(restify(a) for a in cls.__args__[:-1])
            text += r"\ [[%s], %s]" % (args, restify(cls.__args__[-1]))
        elif cls.__args__:
            text += r"\ [%s]" % ", ".join(restify(a) for a in cls.__args__)

        return text
    elif hasattr(cls, '__qualname__'):
        if cls.__module__ == 'typing':
            return ':class:`%s`' % cls.__qualname__
        else:
            return ':class:`%s.%s`' % (cls.__module__, cls.__qualname__)
    elif hasattr(cls, '_name'):
        # SpecialForm
        if cls.__module__ == 'typing':
            return ':obj:`%s`' % cls._name
        else:
            return ':obj:`%s.%s`' % (cls.__module__, cls._name)
    elif isinstance(cls, ForwardRef):
        return ':class:`%s`' % cls.__forward_arg__
    else:
        # not a class (ex. TypeVar)
        return ':obj:`%s.%s`' % (cls.__module__, cls.__name__)


def _restify_py36(cls: Optional["Type"]) -> str:
    module = getattr(cls, '__module__', None)
    if module == 'typing':
        if getattr(cls, '_name', None):
            qualname = cls._name
        elif getattr(cls, '__qualname__', None):
            qualname = cls.__qualname__
        elif getattr(cls, '__forward_arg__', None):
            qualname = cls.__forward_arg__
        elif getattr(cls, '__origin__', None):
            qualname = stringify(cls.__origin__)  # ex. Union
        else:
            qualname = repr(cls).replace('typing.', '')
    elif hasattr(cls, '__qualname__'):
        qualname = '%s.%s' % (module, cls.__qualname__)
    else:
        qualname = repr(cls)

    if (isinstance(cls, typing.TupleMeta) and  # type: ignore
            not hasattr(cls, '__tuple_params__')):  # for Python 3.6
        params = cls.__args__
        if params:
            param_str = ', '.join(restify(p) for p in params)
            return ':class:`%s`\\ [%s]' % (qualname, param_str)
        else:
            return ':class:`%s`' % qualname
    elif isinstance(cls, typing.GenericMeta):
        params = None
        if hasattr(cls, '__args__'):
            # for Python 3.5.2+
            if cls.__args__ is None or len(cls.__args__) <= 2:  # type: ignore  # NOQA
                params = cls.__args__  # type: ignore
            elif cls.__origin__ == Generator:  # type: ignore
                params = cls.__args__  # type: ignore
            else:  # typing.Callable
                args = ', '.join(restify(arg) for arg in cls.__args__[:-1])  # type: ignore
                result = restify(cls.__args__[-1])  # type: ignore
                return ':class:`%s`\\ [[%s], %s]' % (qualname, args, result)
        elif hasattr(cls, '__parameters__'):
            # for Python 3.5.0 and 3.5.1
            params = cls.__parameters__  # type: ignore

        if params:
            param_str = ', '.join(restify(p) for p in params)
            return ':class:`%s`\\ [%s]' % (qualname, param_str)
        else:
            return ':class:`%s`' % qualname
    elif (hasattr(typing, 'UnionMeta') and
            isinstance(cls, typing.UnionMeta) and  # type: ignore
            hasattr(cls, '__union_params__')):  # for Python 3.5
        params = cls.__union_params__
        if params is not None:
            if len(params) == 2 and params[1] is NoneType:
                return ':obj:`Optional`\\ [%s]' % restify(params[0])
            else:
                param_str = ', '.join(restify(p) for p in params)
                return ':obj:`%s`\\ [%s]' % (qualname, param_str)
        else:
            return ':obj:`%s`' % qualname
    elif (hasattr(cls, '__origin__') and
          cls.__origin__ is typing.Union):  # for Python 3.5.2+
        params = cls.__args__
        if params is not None:
            if len(params) > 1 and params[-1] is NoneType:
                if len(params) > 2:
                    param_str = ", ".join(restify(p) for p in params[:-1])
                    return ':obj:`Optional`\\ [:obj:`Union`\\ [%s]]' % param_str
                else:
                    return ':obj:`Optional`\\ [%s]' % restify(params[0])
            else:
                param_str = ', '.join(restify(p) for p in params)
                return ':obj:`Union`\\ [%s]' % param_str
        else:
            return ':obj:`Union`'
    elif (isinstance(cls, typing.CallableMeta) and  # type: ignore
          getattr(cls, '__args__', None) is not None and
          hasattr(cls, '__result__')):  # for Python 3.5
        # Skipped in the case of plain typing.Callable
        args = cls.__args__
        if args is None:
            return qualname
        elif args is Ellipsis:
            args_str = '...'
        else:
            formatted_args = (restify(a) for a in args)  # type: ignore
            args_str = '[%s]' % ', '.join(formatted_args)

        return ':class:`%s`\\ [%s, %s]' % (qualname, args_str, stringify(cls.__result__))
    elif (isinstance(cls, typing.TupleMeta) and  # type: ignore
          hasattr(cls, '__tuple_params__') and
          hasattr(cls, '__tuple_use_ellipsis__')):  # for Python 3.5
        params = cls.__tuple_params__
        if params is not None:
            param_strings = [restify(p) for p in params]
            if cls.__tuple_use_ellipsis__:
                param_strings.append('...')
            return ':class:`%s`\\ [%s]' % (qualname, ', '.join(param_strings))
        else:
            return ':class:`%s`' % qualname
    elif hasattr(cls, '__qualname__'):
        if cls.__module__ == 'typing':
            return ':class:`%s`' % cls.__qualname__
        else:
            return ':class:`%s.%s`' % (cls.__module__, cls.__qualname__)
    elif hasattr(cls, '_name'):
        # SpecialForm
        if cls.__module__ == 'typing':
            return ':obj:`%s`' % cls._name
        else:
            return ':obj:`%s.%s`' % (cls.__module__, cls._name)
    elif hasattr(cls, '__name__'):
        # not a class (ex. TypeVar)
        return ':obj:`%s.%s`' % (cls.__module__, cls.__name__)
    else:
        # others (ex. Any)
        if cls.__module__ == 'typing':
            return ':obj:`%s`' % qualname
        else:
            return ':obj:`%s.%s`' % (cls.__module__, qualname)


def stringify(annotation: Any) -> str:
    """Stringify type annotation object."""
    from sphinx.util import inspect  # lazy loading

    if isinstance(annotation, str):
        if annotation.startswith("'") and annotation.endswith("'"):
            # might be a double Forward-ref'ed type.  Go unquoting.
            return annotation[1:-1]
        else:
            return annotation
    elif isinstance(annotation, TypeVar):
        return annotation.__name__
    elif inspect.isNewType(annotation):
        # Could not get the module where it defiend
        return annotation.__name__
    elif not annotation:
        return repr(annotation)
    elif annotation is NoneType:
        return 'None'
    elif (getattr(annotation, '__module__', None) == 'builtins' and
          hasattr(annotation, '__qualname__')):
        return annotation.__qualname__
    elif annotation is Ellipsis:
        return '...'

    if sys.version_info >= (3, 7):  # py37+
        return _stringify_py37(annotation)
    else:
        return _stringify_py36(annotation)


def _stringify_py37(annotation: Any) -> str:
    """stringify() for py37+."""
    module = getattr(annotation, '__module__', None)
    if module == 'typing':
        if getattr(annotation, '_name', None):
            qualname = annotation._name
        elif getattr(annotation, '__qualname__', None):
            qualname = annotation.__qualname__
        elif getattr(annotation, '__forward_arg__', None):
            qualname = annotation.__forward_arg__
        else:
            qualname = stringify(annotation.__origin__)  # ex. Union
    elif hasattr(annotation, '__qualname__'):
        qualname = '%s.%s' % (module, annotation.__qualname__)
    elif hasattr(annotation, '__origin__'):
        # instantiated generic provided by a user
        qualname = stringify(annotation.__origin__)
    else:
        # we weren't able to extract the base type, appending arguments would
        # only make them appear twice
        return repr(annotation)

    if getattr(annotation, '__args__', None):
        if not isinstance(annotation.__args__, (list, tuple)):
            # broken __args__ found
            pass
        elif qualname == 'Union':
            if len(annotation.__args__) > 1 and annotation.__args__[-1] is NoneType:
                if len(annotation.__args__) > 2:
                    args = ', '.join(stringify(a) for a in annotation.__args__[:-1])
                    return 'Optional[Union[%s]]' % args
                else:
                    return 'Optional[%s]' % stringify(annotation.__args__[0])
            else:
                args = ', '.join(stringify(a) for a in annotation.__args__)
                return 'Union[%s]' % args
        elif qualname == 'Callable':
            args = ', '.join(stringify(a) for a in annotation.__args__[:-1])
            returns = stringify(annotation.__args__[-1])
            return '%s[[%s], %s]' % (qualname, args, returns)
        elif str(annotation).startswith('typing.Annotated'):  # for py39+
            return stringify(annotation.__args__[0])
        elif all(is_system_TypeVar(a) for a in annotation.__args__):
            # Suppress arguments if all system defined TypeVars (ex. Dict[KT, VT])
            return qualname
        else:
            args = ', '.join(stringify(a) for a in annotation.__args__)
            return '%s[%s]' % (qualname, args)

    return qualname


def _stringify_py36(annotation: Any) -> str:
    """stringify() for py35 and py36."""
    module = getattr(annotation, '__module__', None)
    if module == 'typing':
        if getattr(annotation, '_name', None):
            qualname = annotation._name
        elif getattr(annotation, '__qualname__', None):
            qualname = annotation.__qualname__
        elif getattr(annotation, '__forward_arg__', None):
            qualname = annotation.__forward_arg__
        elif getattr(annotation, '__origin__', None):
            qualname = stringify(annotation.__origin__)  # ex. Union
        else:
            qualname = repr(annotation).replace('typing.', '')
    elif hasattr(annotation, '__qualname__'):
        qualname = '%s.%s' % (module, annotation.__qualname__)
    else:
        qualname = repr(annotation)

    if (isinstance(annotation, typing.TupleMeta) and  # type: ignore
            not hasattr(annotation, '__tuple_params__')):  # for Python 3.6
        params = annotation.__args__
        if params:
            param_str = ', '.join(stringify(p) for p in params)
            return '%s[%s]' % (qualname, param_str)
        else:
            return qualname
    elif isinstance(annotation, typing.GenericMeta):
        params = None
        if hasattr(annotation, '__args__'):
            # for Python 3.5.2+
            if annotation.__args__ is None or len(annotation.__args__) <= 2:  # type: ignore  # NOQA
                params = annotation.__args__  # type: ignore
            elif annotation.__origin__ == Generator:  # type: ignore
                params = annotation.__args__  # type: ignore
            else:  # typing.Callable
                args = ', '.join(stringify(arg) for arg
                                 in annotation.__args__[:-1])  # type: ignore
                result = stringify(annotation.__args__[-1])  # type: ignore
                return '%s[[%s], %s]' % (qualname, args, result)
        elif hasattr(annotation, '__parameters__'):
            # for Python 3.5.0 and 3.5.1
            params = annotation.__parameters__  # type: ignore
        if params is not None:
            param_str = ', '.join(stringify(p) for p in params)
            return '%s[%s]' % (qualname, param_str)
    elif (hasattr(typing, 'UnionMeta') and
          isinstance(annotation, typing.UnionMeta) and  # type: ignore
          hasattr(annotation, '__union_params__')):  # for Python 3.5
        params = annotation.__union_params__
        if params is not None:
            if len(params) == 2 and params[1] is NoneType:
                return 'Optional[%s]' % stringify(params[0])
            else:
                param_str = ', '.join(stringify(p) for p in params)
                return '%s[%s]' % (qualname, param_str)
    elif (hasattr(annotation, '__origin__') and
          annotation.__origin__ is typing.Union):  # for Python 3.5.2+
        params = annotation.__args__
        if params is not None:
            if len(params) > 1 and params[-1] is NoneType:
                if len(params) > 2:
                    param_str = ", ".join(stringify(p) for p in params[:-1])
                    return 'Optional[Union[%s]]' % param_str
                else:
                    return 'Optional[%s]' % stringify(params[0])
            else:
                param_str = ', '.join(stringify(p) for p in params)
                return 'Union[%s]' % param_str
    elif (isinstance(annotation, typing.CallableMeta) and  # type: ignore
          getattr(annotation, '__args__', None) is not None and
          hasattr(annotation, '__result__')):  # for Python 3.5
        # Skipped in the case of plain typing.Callable
        args = annotation.__args__
        if args is None:
            return qualname
        elif args is Ellipsis:
            args_str = '...'
        else:
            formatted_args = (stringify(a) for a in args)
            args_str = '[%s]' % ', '.join(formatted_args)
        return '%s[%s, %s]' % (qualname,
                               args_str,
                               stringify(annotation.__result__))
    elif (isinstance(annotation, typing.TupleMeta) and  # type: ignore
          hasattr(annotation, '__tuple_params__') and
          hasattr(annotation, '__tuple_use_ellipsis__')):  # for Python 3.5
        params = annotation.__tuple_params__
        if params is not None:
            param_strings = [stringify(p) for p in params]
            if annotation.__tuple_use_ellipsis__:
                param_strings.append('...')
            return '%s[%s]' % (qualname,
                               ', '.join(param_strings))

    return qualname