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import abc | |
import collections | |
import collections.abc | |
import functools | |
import operator | |
import sys | |
import types as _types | |
import typing | |
__all__ = [ | |
# Super-special typing primitives. | |
'Any', | |
'ClassVar', | |
'Concatenate', | |
'Final', | |
'LiteralString', | |
'ParamSpec', | |
'ParamSpecArgs', | |
'ParamSpecKwargs', | |
'Self', | |
'Type', | |
'TypeVar', | |
'TypeVarTuple', | |
'Unpack', | |
# ABCs (from collections.abc). | |
'Awaitable', | |
'AsyncIterator', | |
'AsyncIterable', | |
'Coroutine', | |
'AsyncGenerator', | |
'AsyncContextManager', | |
'ChainMap', | |
# Concrete collection types. | |
'ContextManager', | |
'Counter', | |
'Deque', | |
'DefaultDict', | |
'NamedTuple', | |
'OrderedDict', | |
'TypedDict', | |
# Structural checks, a.k.a. protocols. | |
'SupportsIndex', | |
# One-off things. | |
'Annotated', | |
'assert_never', | |
'assert_type', | |
'clear_overloads', | |
'dataclass_transform', | |
'get_overloads', | |
'final', | |
'get_args', | |
'get_origin', | |
'get_type_hints', | |
'IntVar', | |
'is_typeddict', | |
'Literal', | |
'NewType', | |
'overload', | |
'override', | |
'Protocol', | |
'reveal_type', | |
'runtime', | |
'runtime_checkable', | |
'Text', | |
'TypeAlias', | |
'TypeGuard', | |
'TYPE_CHECKING', | |
'Never', | |
'NoReturn', | |
'Required', | |
'NotRequired', | |
] | |
# for backward compatibility | |
PEP_560 = True | |
GenericMeta = type | |
# The functions below are modified copies of typing internal helpers. | |
# They are needed by _ProtocolMeta and they provide support for PEP 646. | |
_marker = object() | |
def _check_generic(cls, parameters, elen=_marker): | |
"""Check correct count for parameters of a generic cls (internal helper). | |
This gives a nice error message in case of count mismatch. | |
""" | |
if not elen: | |
raise TypeError(f"{cls} is not a generic class") | |
if elen is _marker: | |
if not hasattr(cls, "__parameters__") or not cls.__parameters__: | |
raise TypeError(f"{cls} is not a generic class") | |
elen = len(cls.__parameters__) | |
alen = len(parameters) | |
if alen != elen: | |
if hasattr(cls, "__parameters__"): | |
parameters = [p for p in cls.__parameters__ if not _is_unpack(p)] | |
num_tv_tuples = sum(isinstance(p, TypeVarTuple) for p in parameters) | |
if (num_tv_tuples > 0) and (alen >= elen - num_tv_tuples): | |
return | |
raise TypeError(f"Too {'many' if alen > elen else 'few'} parameters for {cls};" | |
f" actual {alen}, expected {elen}") | |
if sys.version_info >= (3, 10): | |
def _should_collect_from_parameters(t): | |
return isinstance( | |
t, (typing._GenericAlias, _types.GenericAlias, _types.UnionType) | |
) | |
elif sys.version_info >= (3, 9): | |
def _should_collect_from_parameters(t): | |
return isinstance(t, (typing._GenericAlias, _types.GenericAlias)) | |
else: | |
def _should_collect_from_parameters(t): | |
return isinstance(t, typing._GenericAlias) and not t._special | |
def _collect_type_vars(types, typevar_types=None): | |
"""Collect all type variable contained in types in order of | |
first appearance (lexicographic order). For example:: | |
_collect_type_vars((T, List[S, T])) == (T, S) | |
""" | |
if typevar_types is None: | |
typevar_types = typing.TypeVar | |
tvars = [] | |
for t in types: | |
if ( | |
isinstance(t, typevar_types) and | |
t not in tvars and | |
not _is_unpack(t) | |
): | |
tvars.append(t) | |
if _should_collect_from_parameters(t): | |
tvars.extend([t for t in t.__parameters__ if t not in tvars]) | |
return tuple(tvars) | |
NoReturn = typing.NoReturn | |
# Some unconstrained type variables. These are used by the container types. | |
# (These are not for export.) | |
T = typing.TypeVar('T') # Any type. | |
KT = typing.TypeVar('KT') # Key type. | |
VT = typing.TypeVar('VT') # Value type. | |
T_co = typing.TypeVar('T_co', covariant=True) # Any type covariant containers. | |
T_contra = typing.TypeVar('T_contra', contravariant=True) # Ditto contravariant. | |
if sys.version_info >= (3, 11): | |
from typing import Any | |
else: | |
class _AnyMeta(type): | |
def __instancecheck__(self, obj): | |
if self is Any: | |
raise TypeError("typing_extensions.Any cannot be used with isinstance()") | |
return super().__instancecheck__(obj) | |
def __repr__(self): | |
if self is Any: | |
return "typing_extensions.Any" | |
return super().__repr__() | |
class Any(metaclass=_AnyMeta): | |
"""Special type indicating an unconstrained type. | |
- Any is compatible with every type. | |
- Any assumed to have all methods. | |
- All values assumed to be instances of Any. | |
Note that all the above statements are true from the point of view of | |
static type checkers. At runtime, Any should not be used with instance | |
checks. | |
""" | |
def __new__(cls, *args, **kwargs): | |
if cls is Any: | |
raise TypeError("Any cannot be instantiated") | |
return super().__new__(cls, *args, **kwargs) | |
ClassVar = typing.ClassVar | |
# On older versions of typing there is an internal class named "Final". | |
# 3.8+ | |
if hasattr(typing, 'Final') and sys.version_info[:2] >= (3, 7): | |
Final = typing.Final | |
# 3.7 | |
else: | |
class _FinalForm(typing._SpecialForm, _root=True): | |
def __repr__(self): | |
return 'typing_extensions.' + self._name | |
def __getitem__(self, parameters): | |
item = typing._type_check(parameters, | |
f'{self._name} accepts only a single type.') | |
return typing._GenericAlias(self, (item,)) | |
Final = _FinalForm('Final', | |
doc="""A special typing construct to indicate that a name | |
cannot be re-assigned or overridden in a subclass. | |
For example: | |
MAX_SIZE: Final = 9000 | |
MAX_SIZE += 1 # Error reported by type checker | |
class Connection: | |
TIMEOUT: Final[int] = 10 | |
class FastConnector(Connection): | |
TIMEOUT = 1 # Error reported by type checker | |
There is no runtime checking of these properties.""") | |
if sys.version_info >= (3, 11): | |
final = typing.final | |
else: | |
# @final exists in 3.8+, but we backport it for all versions | |
# before 3.11 to keep support for the __final__ attribute. | |
# See https://bugs.python.org/issue46342 | |
def final(f): | |
"""This decorator can be used to indicate to type checkers that | |
the decorated method cannot be overridden, and decorated class | |
cannot be subclassed. For example: | |
class Base: | |
@final | |
def done(self) -> None: | |
... | |
class Sub(Base): | |
def done(self) -> None: # Error reported by type checker | |
... | |
@final | |
class Leaf: | |
... | |
class Other(Leaf): # Error reported by type checker | |
... | |
There is no runtime checking of these properties. The decorator | |
sets the ``__final__`` attribute to ``True`` on the decorated object | |
to allow runtime introspection. | |
""" | |
try: | |
f.__final__ = True | |
except (AttributeError, TypeError): | |
# Skip the attribute silently if it is not writable. | |
# AttributeError happens if the object has __slots__ or a | |
# read-only property, TypeError if it's a builtin class. | |
pass | |
return f | |
def IntVar(name): | |
return typing.TypeVar(name) | |
# 3.8+: | |
if hasattr(typing, 'Literal'): | |
Literal = typing.Literal | |
# 3.7: | |
else: | |
class _LiteralForm(typing._SpecialForm, _root=True): | |
def __repr__(self): | |
return 'typing_extensions.' + self._name | |
def __getitem__(self, parameters): | |
return typing._GenericAlias(self, parameters) | |
Literal = _LiteralForm('Literal', | |
doc="""A type that can be used to indicate to type checkers | |
that the corresponding value has a value literally equivalent | |
to the provided parameter. For example: | |
var: Literal[4] = 4 | |
The type checker understands that 'var' is literally equal to | |
the value 4 and no other value. | |
Literal[...] cannot be subclassed. There is no runtime | |
checking verifying that the parameter is actually a value | |
instead of a type.""") | |
_overload_dummy = typing._overload_dummy # noqa | |
if hasattr(typing, "get_overloads"): # 3.11+ | |
overload = typing.overload | |
get_overloads = typing.get_overloads | |
clear_overloads = typing.clear_overloads | |
else: | |
# {module: {qualname: {firstlineno: func}}} | |
_overload_registry = collections.defaultdict( | |
functools.partial(collections.defaultdict, dict) | |
) | |
def overload(func): | |
"""Decorator for overloaded functions/methods. | |
In a stub file, place two or more stub definitions for the same | |
function in a row, each decorated with @overload. For example: | |
@overload | |
def utf8(value: None) -> None: ... | |
@overload | |
def utf8(value: bytes) -> bytes: ... | |
@overload | |
def utf8(value: str) -> bytes: ... | |
In a non-stub file (i.e. a regular .py file), do the same but | |
follow it with an implementation. The implementation should *not* | |
be decorated with @overload. For example: | |
@overload | |
def utf8(value: None) -> None: ... | |
@overload | |
def utf8(value: bytes) -> bytes: ... | |
@overload | |
def utf8(value: str) -> bytes: ... | |
def utf8(value): | |
# implementation goes here | |
The overloads for a function can be retrieved at runtime using the | |
get_overloads() function. | |
""" | |
# classmethod and staticmethod | |
f = getattr(func, "__func__", func) | |
try: | |
_overload_registry[f.__module__][f.__qualname__][ | |
f.__code__.co_firstlineno | |
] = func | |
except AttributeError: | |
# Not a normal function; ignore. | |
pass | |
return _overload_dummy | |
def get_overloads(func): | |
"""Return all defined overloads for *func* as a sequence.""" | |
# classmethod and staticmethod | |
f = getattr(func, "__func__", func) | |
if f.__module__ not in _overload_registry: | |
return [] | |
mod_dict = _overload_registry[f.__module__] | |
if f.__qualname__ not in mod_dict: | |
return [] | |
return list(mod_dict[f.__qualname__].values()) | |
def clear_overloads(): | |
"""Clear all overloads in the registry.""" | |
_overload_registry.clear() | |
# This is not a real generic class. Don't use outside annotations. | |
Type = typing.Type | |
# Various ABCs mimicking those in collections.abc. | |
# A few are simply re-exported for completeness. | |
Awaitable = typing.Awaitable | |
Coroutine = typing.Coroutine | |
AsyncIterable = typing.AsyncIterable | |
AsyncIterator = typing.AsyncIterator | |
Deque = typing.Deque | |
ContextManager = typing.ContextManager | |
AsyncContextManager = typing.AsyncContextManager | |
DefaultDict = typing.DefaultDict | |
# 3.7.2+ | |
if hasattr(typing, 'OrderedDict'): | |
OrderedDict = typing.OrderedDict | |
# 3.7.0-3.7.2 | |
else: | |
OrderedDict = typing._alias(collections.OrderedDict, (KT, VT)) | |
Counter = typing.Counter | |
ChainMap = typing.ChainMap | |
AsyncGenerator = typing.AsyncGenerator | |
NewType = typing.NewType | |
Text = typing.Text | |
TYPE_CHECKING = typing.TYPE_CHECKING | |
_PROTO_WHITELIST = ['Callable', 'Awaitable', | |
'Iterable', 'Iterator', 'AsyncIterable', 'AsyncIterator', | |
'Hashable', 'Sized', 'Container', 'Collection', 'Reversible', | |
'ContextManager', 'AsyncContextManager'] | |
def _get_protocol_attrs(cls): | |
attrs = set() | |
for base in cls.__mro__[:-1]: # without object | |
if base.__name__ in ('Protocol', 'Generic'): | |
continue | |
annotations = getattr(base, '__annotations__', {}) | |
for attr in list(base.__dict__.keys()) + list(annotations.keys()): | |
if (not attr.startswith('_abc_') and attr not in ( | |
'__abstractmethods__', '__annotations__', '__weakref__', | |
'_is_protocol', '_is_runtime_protocol', '__dict__', | |
'__args__', '__slots__', | |
'__next_in_mro__', '__parameters__', '__origin__', | |
'__orig_bases__', '__extra__', '__tree_hash__', | |
'__doc__', '__subclasshook__', '__init__', '__new__', | |
'__module__', '_MutableMapping__marker', '_gorg')): | |
attrs.add(attr) | |
return attrs | |
def _is_callable_members_only(cls): | |
return all(callable(getattr(cls, attr, None)) for attr in _get_protocol_attrs(cls)) | |
def _maybe_adjust_parameters(cls): | |
"""Helper function used in Protocol.__init_subclass__ and _TypedDictMeta.__new__. | |
The contents of this function are very similar | |
to logic found in typing.Generic.__init_subclass__ | |
on the CPython main branch. | |
""" | |
tvars = [] | |
if '__orig_bases__' in cls.__dict__: | |
tvars = typing._collect_type_vars(cls.__orig_bases__) | |
# Look for Generic[T1, ..., Tn] or Protocol[T1, ..., Tn]. | |
# If found, tvars must be a subset of it. | |
# If not found, tvars is it. | |
# Also check for and reject plain Generic, | |
# and reject multiple Generic[...] and/or Protocol[...]. | |
gvars = None | |
for base in cls.__orig_bases__: | |
if (isinstance(base, typing._GenericAlias) and | |
base.__origin__ in (typing.Generic, Protocol)): | |
# for error messages | |
the_base = base.__origin__.__name__ | |
if gvars is not None: | |
raise TypeError( | |
"Cannot inherit from Generic[...]" | |
" and/or Protocol[...] multiple types.") | |
gvars = base.__parameters__ | |
if gvars is None: | |
gvars = tvars | |
else: | |
tvarset = set(tvars) | |
gvarset = set(gvars) | |
if not tvarset <= gvarset: | |
s_vars = ', '.join(str(t) for t in tvars if t not in gvarset) | |
s_args = ', '.join(str(g) for g in gvars) | |
raise TypeError(f"Some type variables ({s_vars}) are" | |
f" not listed in {the_base}[{s_args}]") | |
tvars = gvars | |
cls.__parameters__ = tuple(tvars) | |
# 3.8+ | |
if hasattr(typing, 'Protocol'): | |
Protocol = typing.Protocol | |
# 3.7 | |
else: | |
def _no_init(self, *args, **kwargs): | |
if type(self)._is_protocol: | |
raise TypeError('Protocols cannot be instantiated') | |
class _ProtocolMeta(abc.ABCMeta): # noqa: B024 | |
# This metaclass is a bit unfortunate and exists only because of the lack | |
# of __instancehook__. | |
def __instancecheck__(cls, instance): | |
# We need this method for situations where attributes are | |
# assigned in __init__. | |
if ((not getattr(cls, '_is_protocol', False) or | |
_is_callable_members_only(cls)) and | |
issubclass(instance.__class__, cls)): | |
return True | |
if cls._is_protocol: | |
if all(hasattr(instance, attr) and | |
(not callable(getattr(cls, attr, None)) or | |
getattr(instance, attr) is not None) | |
for attr in _get_protocol_attrs(cls)): | |
return True | |
return super().__instancecheck__(instance) | |
class Protocol(metaclass=_ProtocolMeta): | |
# There is quite a lot of overlapping code with typing.Generic. | |
# Unfortunately it is hard to avoid this while these live in two different | |
# modules. The duplicated code will be removed when Protocol is moved to typing. | |
"""Base class for protocol classes. Protocol classes are defined as:: | |
class Proto(Protocol): | |
def meth(self) -> int: | |
... | |
Such classes are primarily used with static type checkers that recognize | |
structural subtyping (static duck-typing), for example:: | |
class C: | |
def meth(self) -> int: | |
return 0 | |
def func(x: Proto) -> int: | |
return x.meth() | |
func(C()) # Passes static type check | |
See PEP 544 for details. Protocol classes decorated with | |
@typing_extensions.runtime act as simple-minded runtime protocol that checks | |
only the presence of given attributes, ignoring their type signatures. | |
Protocol classes can be generic, they are defined as:: | |
class GenProto(Protocol[T]): | |
def meth(self) -> T: | |
... | |
""" | |
__slots__ = () | |
_is_protocol = True | |
def __new__(cls, *args, **kwds): | |
if cls is Protocol: | |
raise TypeError("Type Protocol cannot be instantiated; " | |
"it can only be used as a base class") | |
return super().__new__(cls) | |
def __class_getitem__(cls, params): | |
if not isinstance(params, tuple): | |
params = (params,) | |
if not params and cls is not typing.Tuple: | |
raise TypeError( | |
f"Parameter list to {cls.__qualname__}[...] cannot be empty") | |
msg = "Parameters to generic types must be types." | |
params = tuple(typing._type_check(p, msg) for p in params) # noqa | |
if cls is Protocol: | |
# Generic can only be subscripted with unique type variables. | |
if not all(isinstance(p, typing.TypeVar) for p in params): | |
i = 0 | |
while isinstance(params[i], typing.TypeVar): | |
i += 1 | |
raise TypeError( | |
"Parameters to Protocol[...] must all be type variables." | |
f" Parameter {i + 1} is {params[i]}") | |
if len(set(params)) != len(params): | |
raise TypeError( | |
"Parameters to Protocol[...] must all be unique") | |
else: | |
# Subscripting a regular Generic subclass. | |
_check_generic(cls, params, len(cls.__parameters__)) | |
return typing._GenericAlias(cls, params) | |
def __init_subclass__(cls, *args, **kwargs): | |
if '__orig_bases__' in cls.__dict__: | |
error = typing.Generic in cls.__orig_bases__ | |
else: | |
error = typing.Generic in cls.__bases__ | |
if error: | |
raise TypeError("Cannot inherit from plain Generic") | |
_maybe_adjust_parameters(cls) | |
# Determine if this is a protocol or a concrete subclass. | |
if not cls.__dict__.get('_is_protocol', None): | |
cls._is_protocol = any(b is Protocol for b in cls.__bases__) | |
# Set (or override) the protocol subclass hook. | |
def _proto_hook(other): | |
if not cls.__dict__.get('_is_protocol', None): | |
return NotImplemented | |
if not getattr(cls, '_is_runtime_protocol', False): | |
if sys._getframe(2).f_globals['__name__'] in ['abc', 'functools']: | |
return NotImplemented | |
raise TypeError("Instance and class checks can only be used with" | |
" @runtime protocols") | |
if not _is_callable_members_only(cls): | |
if sys._getframe(2).f_globals['__name__'] in ['abc', 'functools']: | |
return NotImplemented | |
raise TypeError("Protocols with non-method members" | |
" don't support issubclass()") | |
if not isinstance(other, type): | |
# Same error as for issubclass(1, int) | |
raise TypeError('issubclass() arg 1 must be a class') | |
for attr in _get_protocol_attrs(cls): | |
for base in other.__mro__: | |
if attr in base.__dict__: | |
if base.__dict__[attr] is None: | |
return NotImplemented | |
break | |
annotations = getattr(base, '__annotations__', {}) | |
if (isinstance(annotations, typing.Mapping) and | |
attr in annotations and | |
isinstance(other, _ProtocolMeta) and | |
other._is_protocol): | |
break | |
else: | |
return NotImplemented | |
return True | |
if '__subclasshook__' not in cls.__dict__: | |
cls.__subclasshook__ = _proto_hook | |
# We have nothing more to do for non-protocols. | |
if not cls._is_protocol: | |
return | |
# Check consistency of bases. | |
for base in cls.__bases__: | |
if not (base in (object, typing.Generic) or | |
base.__module__ == 'collections.abc' and | |
base.__name__ in _PROTO_WHITELIST or | |
isinstance(base, _ProtocolMeta) and base._is_protocol): | |
raise TypeError('Protocols can only inherit from other' | |
f' protocols, got {repr(base)}') | |
cls.__init__ = _no_init | |
# 3.8+ | |
if hasattr(typing, 'runtime_checkable'): | |
runtime_checkable = typing.runtime_checkable | |
# 3.7 | |
else: | |
def runtime_checkable(cls): | |
"""Mark a protocol class as a runtime protocol, so that it | |
can be used with isinstance() and issubclass(). Raise TypeError | |
if applied to a non-protocol class. | |
This allows a simple-minded structural check very similar to the | |
one-offs in collections.abc such as Hashable. | |
""" | |
if not isinstance(cls, _ProtocolMeta) or not cls._is_protocol: | |
raise TypeError('@runtime_checkable can be only applied to protocol classes,' | |
f' got {cls!r}') | |
cls._is_runtime_protocol = True | |
return cls | |
# Exists for backwards compatibility. | |
runtime = runtime_checkable | |
# 3.8+ | |
if hasattr(typing, 'SupportsIndex'): | |
SupportsIndex = typing.SupportsIndex | |
# 3.7 | |
else: | |
class SupportsIndex(Protocol): | |
__slots__ = () | |
def __index__(self) -> int: | |
pass | |
if hasattr(typing, "Required"): | |
# The standard library TypedDict in Python 3.8 does not store runtime information | |
# about which (if any) keys are optional. See https://bugs.python.org/issue38834 | |
# The standard library TypedDict in Python 3.9.0/1 does not honour the "total" | |
# keyword with old-style TypedDict(). See https://bugs.python.org/issue42059 | |
# The standard library TypedDict below Python 3.11 does not store runtime | |
# information about optional and required keys when using Required or NotRequired. | |
# Generic TypedDicts are also impossible using typing.TypedDict on Python <3.11. | |
TypedDict = typing.TypedDict | |
_TypedDictMeta = typing._TypedDictMeta | |
is_typeddict = typing.is_typeddict | |
else: | |
def _check_fails(cls, other): | |
try: | |
if sys._getframe(1).f_globals['__name__'] not in ['abc', | |
'functools', | |
'typing']: | |
# Typed dicts are only for static structural subtyping. | |
raise TypeError('TypedDict does not support instance and class checks') | |
except (AttributeError, ValueError): | |
pass | |
return False | |
def _dict_new(*args, **kwargs): | |
if not args: | |
raise TypeError('TypedDict.__new__(): not enough arguments') | |
_, args = args[0], args[1:] # allow the "cls" keyword be passed | |
return dict(*args, **kwargs) | |
_dict_new.__text_signature__ = '($cls, _typename, _fields=None, /, **kwargs)' | |
def _typeddict_new(*args, total=True, **kwargs): | |
if not args: | |
raise TypeError('TypedDict.__new__(): not enough arguments') | |
_, args = args[0], args[1:] # allow the "cls" keyword be passed | |
if args: | |
typename, args = args[0], args[1:] # allow the "_typename" keyword be passed | |
elif '_typename' in kwargs: | |
typename = kwargs.pop('_typename') | |
import warnings | |
warnings.warn("Passing '_typename' as keyword argument is deprecated", | |
DeprecationWarning, stacklevel=2) | |
else: | |
raise TypeError("TypedDict.__new__() missing 1 required positional " | |
"argument: '_typename'") | |
if args: | |
try: | |
fields, = args # allow the "_fields" keyword be passed | |
except ValueError: | |
raise TypeError('TypedDict.__new__() takes from 2 to 3 ' | |
f'positional arguments but {len(args) + 2} ' | |
'were given') | |
elif '_fields' in kwargs and len(kwargs) == 1: | |
fields = kwargs.pop('_fields') | |
import warnings | |
warnings.warn("Passing '_fields' as keyword argument is deprecated", | |
DeprecationWarning, stacklevel=2) | |
else: | |
fields = None | |
if fields is None: | |
fields = kwargs | |
elif kwargs: | |
raise TypeError("TypedDict takes either a dict or keyword arguments," | |
" but not both") | |
ns = {'__annotations__': dict(fields)} | |
try: | |
# Setting correct module is necessary to make typed dict classes pickleable. | |
ns['__module__'] = sys._getframe(1).f_globals.get('__name__', '__main__') | |
except (AttributeError, ValueError): | |
pass | |
return _TypedDictMeta(typename, (), ns, total=total) | |
_typeddict_new.__text_signature__ = ('($cls, _typename, _fields=None,' | |
' /, *, total=True, **kwargs)') | |
class _TypedDictMeta(type): | |
def __init__(cls, name, bases, ns, total=True): | |
super().__init__(name, bases, ns) | |
def __new__(cls, name, bases, ns, total=True): | |
# Create new typed dict class object. | |
# This method is called directly when TypedDict is subclassed, | |
# or via _typeddict_new when TypedDict is instantiated. This way | |
# TypedDict supports all three syntaxes described in its docstring. | |
# Subclasses and instances of TypedDict return actual dictionaries | |
# via _dict_new. | |
ns['__new__'] = _typeddict_new if name == 'TypedDict' else _dict_new | |
# Don't insert typing.Generic into __bases__ here, | |
# or Generic.__init_subclass__ will raise TypeError | |
# in the super().__new__() call. | |
# Instead, monkey-patch __bases__ onto the class after it's been created. | |
tp_dict = super().__new__(cls, name, (dict,), ns) | |
if any(issubclass(base, typing.Generic) for base in bases): | |
tp_dict.__bases__ = (typing.Generic, dict) | |
_maybe_adjust_parameters(tp_dict) | |
annotations = {} | |
own_annotations = ns.get('__annotations__', {}) | |
msg = "TypedDict('Name', {f0: t0, f1: t1, ...}); each t must be a type" | |
own_annotations = { | |
n: typing._type_check(tp, msg) for n, tp in own_annotations.items() | |
} | |
required_keys = set() | |
optional_keys = set() | |
for base in bases: | |
annotations.update(base.__dict__.get('__annotations__', {})) | |
required_keys.update(base.__dict__.get('__required_keys__', ())) | |
optional_keys.update(base.__dict__.get('__optional_keys__', ())) | |
annotations.update(own_annotations) | |
for annotation_key, annotation_type in own_annotations.items(): | |
annotation_origin = get_origin(annotation_type) | |
if annotation_origin is Annotated: | |
annotation_args = get_args(annotation_type) | |
if annotation_args: | |
annotation_type = annotation_args[0] | |
annotation_origin = get_origin(annotation_type) | |
if annotation_origin is Required: | |
required_keys.add(annotation_key) | |
elif annotation_origin is NotRequired: | |
optional_keys.add(annotation_key) | |
elif total: | |
required_keys.add(annotation_key) | |
else: | |
optional_keys.add(annotation_key) | |
tp_dict.__annotations__ = annotations | |
tp_dict.__required_keys__ = frozenset(required_keys) | |
tp_dict.__optional_keys__ = frozenset(optional_keys) | |
if not hasattr(tp_dict, '__total__'): | |
tp_dict.__total__ = total | |
return tp_dict | |
__instancecheck__ = __subclasscheck__ = _check_fails | |
TypedDict = _TypedDictMeta('TypedDict', (dict,), {}) | |
TypedDict.__module__ = __name__ | |
TypedDict.__doc__ = \ | |
"""A simple typed name space. At runtime it is equivalent to a plain dict. | |
TypedDict creates a dictionary type that expects all of its | |
instances to have a certain set of keys, with each key | |
associated with a value of a consistent type. This expectation | |
is not checked at runtime but is only enforced by type checkers. | |
Usage:: | |
class Point2D(TypedDict): | |
x: int | |
y: int | |
label: str | |
a: Point2D = {'x': 1, 'y': 2, 'label': 'good'} # OK | |
b: Point2D = {'z': 3, 'label': 'bad'} # Fails type check | |
assert Point2D(x=1, y=2, label='first') == dict(x=1, y=2, label='first') | |
The type info can be accessed via the Point2D.__annotations__ dict, and | |
the Point2D.__required_keys__ and Point2D.__optional_keys__ frozensets. | |
TypedDict supports two additional equivalent forms:: | |
Point2D = TypedDict('Point2D', x=int, y=int, label=str) | |
Point2D = TypedDict('Point2D', {'x': int, 'y': int, 'label': str}) | |
The class syntax is only supported in Python 3.6+, while two other | |
syntax forms work for Python 2.7 and 3.2+ | |
""" | |
if hasattr(typing, "_TypedDictMeta"): | |
_TYPEDDICT_TYPES = (typing._TypedDictMeta, _TypedDictMeta) | |
else: | |
_TYPEDDICT_TYPES = (_TypedDictMeta,) | |
def is_typeddict(tp): | |
"""Check if an annotation is a TypedDict class | |
For example:: | |
class Film(TypedDict): | |
title: str | |
year: int | |
is_typeddict(Film) # => True | |
is_typeddict(Union[list, str]) # => False | |
""" | |
return isinstance(tp, tuple(_TYPEDDICT_TYPES)) | |
if hasattr(typing, "assert_type"): | |
assert_type = typing.assert_type | |
else: | |
def assert_type(__val, __typ): | |
"""Assert (to the type checker) that the value is of the given type. | |
When the type checker encounters a call to assert_type(), it | |
emits an error if the value is not of the specified type:: | |
def greet(name: str) -> None: | |
assert_type(name, str) # ok | |
assert_type(name, int) # type checker error | |
At runtime this returns the first argument unchanged and otherwise | |
does nothing. | |
""" | |
return __val | |
if hasattr(typing, "Required"): | |
get_type_hints = typing.get_type_hints | |
else: | |
import functools | |
import types | |
# replaces _strip_annotations() | |
def _strip_extras(t): | |
"""Strips Annotated, Required and NotRequired from a given type.""" | |
if isinstance(t, _AnnotatedAlias): | |
return _strip_extras(t.__origin__) | |
if hasattr(t, "__origin__") and t.__origin__ in (Required, NotRequired): | |
return _strip_extras(t.__args__[0]) | |
if isinstance(t, typing._GenericAlias): | |
stripped_args = tuple(_strip_extras(a) for a in t.__args__) | |
if stripped_args == t.__args__: | |
return t | |
return t.copy_with(stripped_args) | |
if hasattr(types, "GenericAlias") and isinstance(t, types.GenericAlias): | |
stripped_args = tuple(_strip_extras(a) for a in t.__args__) | |
if stripped_args == t.__args__: | |
return t | |
return types.GenericAlias(t.__origin__, stripped_args) | |
if hasattr(types, "UnionType") and isinstance(t, types.UnionType): | |
stripped_args = tuple(_strip_extras(a) for a in t.__args__) | |
if stripped_args == t.__args__: | |
return t | |
return functools.reduce(operator.or_, stripped_args) | |
return t | |
def get_type_hints(obj, globalns=None, localns=None, include_extras=False): | |
"""Return type hints for an object. | |
This is often the same as obj.__annotations__, but it handles | |
forward references encoded as string literals, adds Optional[t] if a | |
default value equal to None is set and recursively replaces all | |
'Annotated[T, ...]', 'Required[T]' or 'NotRequired[T]' with 'T' | |
(unless 'include_extras=True'). | |
The argument may be a module, class, method, or function. The annotations | |
are returned as a dictionary. For classes, annotations include also | |
inherited members. | |
TypeError is raised if the argument is not of a type that can contain | |
annotations, and an empty dictionary is returned if no annotations are | |
present. | |
BEWARE -- the behavior of globalns and localns is counterintuitive | |
(unless you are familiar with how eval() and exec() work). The | |
search order is locals first, then globals. | |
- If no dict arguments are passed, an attempt is made to use the | |
globals from obj (or the respective module's globals for classes), | |
and these are also used as the locals. If the object does not appear | |
to have globals, an empty dictionary is used. | |
- If one dict argument is passed, it is used for both globals and | |
locals. | |
- If two dict arguments are passed, they specify globals and | |
locals, respectively. | |
""" | |
if hasattr(typing, "Annotated"): | |
hint = typing.get_type_hints( | |
obj, globalns=globalns, localns=localns, include_extras=True | |
) | |
else: | |
hint = typing.get_type_hints(obj, globalns=globalns, localns=localns) | |
if include_extras: | |
return hint | |
return {k: _strip_extras(t) for k, t in hint.items()} | |
# Python 3.9+ has PEP 593 (Annotated) | |
if hasattr(typing, 'Annotated'): | |
Annotated = typing.Annotated | |
# Not exported and not a public API, but needed for get_origin() and get_args() | |
# to work. | |
_AnnotatedAlias = typing._AnnotatedAlias | |
# 3.7-3.8 | |
else: | |
class _AnnotatedAlias(typing._GenericAlias, _root=True): | |
"""Runtime representation of an annotated type. | |
At its core 'Annotated[t, dec1, dec2, ...]' is an alias for the type 't' | |
with extra annotations. The alias behaves like a normal typing alias, | |
instantiating is the same as instantiating the underlying type, binding | |
it to types is also the same. | |
""" | |
def __init__(self, origin, metadata): | |
if isinstance(origin, _AnnotatedAlias): | |
metadata = origin.__metadata__ + metadata | |
origin = origin.__origin__ | |
super().__init__(origin, origin) | |
self.__metadata__ = metadata | |
def copy_with(self, params): | |
assert len(params) == 1 | |
new_type = params[0] | |
return _AnnotatedAlias(new_type, self.__metadata__) | |
def __repr__(self): | |
return (f"typing_extensions.Annotated[{typing._type_repr(self.__origin__)}, " | |
f"{', '.join(repr(a) for a in self.__metadata__)}]") | |
def __reduce__(self): | |
return operator.getitem, ( | |
Annotated, (self.__origin__,) + self.__metadata__ | |
) | |
def __eq__(self, other): | |
if not isinstance(other, _AnnotatedAlias): | |
return NotImplemented | |
if self.__origin__ != other.__origin__: | |
return False | |
return self.__metadata__ == other.__metadata__ | |
def __hash__(self): | |
return hash((self.__origin__, self.__metadata__)) | |
class Annotated: | |
"""Add context specific metadata to a type. | |
Example: Annotated[int, runtime_check.Unsigned] indicates to the | |
hypothetical runtime_check module that this type is an unsigned int. | |
Every other consumer of this type can ignore this metadata and treat | |
this type as int. | |
The first argument to Annotated must be a valid type (and will be in | |
the __origin__ field), the remaining arguments are kept as a tuple in | |
the __extra__ field. | |
Details: | |
- It's an error to call `Annotated` with less than two arguments. | |
- Nested Annotated are flattened:: | |
Annotated[Annotated[T, Ann1, Ann2], Ann3] == Annotated[T, Ann1, Ann2, Ann3] | |
- Instantiating an annotated type is equivalent to instantiating the | |
underlying type:: | |
Annotated[C, Ann1](5) == C(5) | |
- Annotated can be used as a generic type alias:: | |
Optimized = Annotated[T, runtime.Optimize()] | |
Optimized[int] == Annotated[int, runtime.Optimize()] | |
OptimizedList = Annotated[List[T], runtime.Optimize()] | |
OptimizedList[int] == Annotated[List[int], runtime.Optimize()] | |
""" | |
__slots__ = () | |
def __new__(cls, *args, **kwargs): | |
raise TypeError("Type Annotated cannot be instantiated.") | |
def __class_getitem__(cls, params): | |
if not isinstance(params, tuple) or len(params) < 2: | |
raise TypeError("Annotated[...] should be used " | |
"with at least two arguments (a type and an " | |
"annotation).") | |
allowed_special_forms = (ClassVar, Final) | |
if get_origin(params[0]) in allowed_special_forms: | |
origin = params[0] | |
else: | |
msg = "Annotated[t, ...]: t must be a type." | |
origin = typing._type_check(params[0], msg) | |
metadata = tuple(params[1:]) | |
return _AnnotatedAlias(origin, metadata) | |
def __init_subclass__(cls, *args, **kwargs): | |
raise TypeError( | |
f"Cannot subclass {cls.__module__}.Annotated" | |
) | |
# Python 3.8 has get_origin() and get_args() but those implementations aren't | |
# Annotated-aware, so we can't use those. Python 3.9's versions don't support | |
# ParamSpecArgs and ParamSpecKwargs, so only Python 3.10's versions will do. | |
if sys.version_info[:2] >= (3, 10): | |
get_origin = typing.get_origin | |
get_args = typing.get_args | |
# 3.7-3.9 | |
else: | |
try: | |
# 3.9+ | |
from typing import _BaseGenericAlias | |
except ImportError: | |
_BaseGenericAlias = typing._GenericAlias | |
try: | |
# 3.9+ | |
from typing import GenericAlias as _typing_GenericAlias | |
except ImportError: | |
_typing_GenericAlias = typing._GenericAlias | |
def get_origin(tp): | |
"""Get the unsubscripted version of a type. | |
This supports generic types, Callable, Tuple, Union, Literal, Final, ClassVar | |
and Annotated. Return None for unsupported types. Examples:: | |
get_origin(Literal[42]) is Literal | |
get_origin(int) is None | |
get_origin(ClassVar[int]) is ClassVar | |
get_origin(Generic) is Generic | |
get_origin(Generic[T]) is Generic | |
get_origin(Union[T, int]) is Union | |
get_origin(List[Tuple[T, T]][int]) == list | |
get_origin(P.args) is P | |
""" | |
if isinstance(tp, _AnnotatedAlias): | |
return Annotated | |
if isinstance(tp, (typing._GenericAlias, _typing_GenericAlias, _BaseGenericAlias, | |
ParamSpecArgs, ParamSpecKwargs)): | |
return tp.__origin__ | |
if tp is typing.Generic: | |
return typing.Generic | |
return None | |
def get_args(tp): | |
"""Get type arguments with all substitutions performed. | |
For unions, basic simplifications used by Union constructor are performed. | |
Examples:: | |
get_args(Dict[str, int]) == (str, int) | |
get_args(int) == () | |
get_args(Union[int, Union[T, int], str][int]) == (int, str) | |
get_args(Union[int, Tuple[T, int]][str]) == (int, Tuple[str, int]) | |
get_args(Callable[[], T][int]) == ([], int) | |
""" | |
if isinstance(tp, _AnnotatedAlias): | |
return (tp.__origin__,) + tp.__metadata__ | |
if isinstance(tp, (typing._GenericAlias, _typing_GenericAlias)): | |
if getattr(tp, "_special", False): | |
return () | |
res = tp.__args__ | |
if get_origin(tp) is collections.abc.Callable and res[0] is not Ellipsis: | |
res = (list(res[:-1]), res[-1]) | |
return res | |
return () | |
# 3.10+ | |
if hasattr(typing, 'TypeAlias'): | |
TypeAlias = typing.TypeAlias | |
# 3.9 | |
elif sys.version_info[:2] >= (3, 9): | |
class _TypeAliasForm(typing._SpecialForm, _root=True): | |
def __repr__(self): | |
return 'typing_extensions.' + self._name | |
def TypeAlias(self, parameters): | |
"""Special marker indicating that an assignment should | |
be recognized as a proper type alias definition by type | |
checkers. | |
For example:: | |
Predicate: TypeAlias = Callable[..., bool] | |
It's invalid when used anywhere except as in the example above. | |
""" | |
raise TypeError(f"{self} is not subscriptable") | |
# 3.7-3.8 | |
else: | |
class _TypeAliasForm(typing._SpecialForm, _root=True): | |
def __repr__(self): | |
return 'typing_extensions.' + self._name | |
TypeAlias = _TypeAliasForm('TypeAlias', | |
doc="""Special marker indicating that an assignment should | |
be recognized as a proper type alias definition by type | |
checkers. | |
For example:: | |
Predicate: TypeAlias = Callable[..., bool] | |
It's invalid when used anywhere except as in the example | |
above.""") | |
class _DefaultMixin: | |
"""Mixin for TypeVarLike defaults.""" | |
__slots__ = () | |
def __init__(self, default): | |
if isinstance(default, (tuple, list)): | |
self.__default__ = tuple((typing._type_check(d, "Default must be a type") | |
for d in default)) | |
elif default: | |
self.__default__ = typing._type_check(default, "Default must be a type") | |
else: | |
self.__default__ = None | |
# Add default and infer_variance parameters from PEP 696 and 695 | |
class TypeVar(typing.TypeVar, _DefaultMixin, _root=True): | |
"""Type variable.""" | |
__module__ = 'typing' | |
def __init__(self, name, *constraints, bound=None, | |
covariant=False, contravariant=False, | |
default=None, infer_variance=False): | |
super().__init__(name, *constraints, bound=bound, covariant=covariant, | |
contravariant=contravariant) | |
_DefaultMixin.__init__(self, default) | |
self.__infer_variance__ = infer_variance | |
# for pickling: | |
try: | |
def_mod = sys._getframe(1).f_globals.get('__name__', '__main__') | |
except (AttributeError, ValueError): | |
def_mod = None | |
if def_mod != 'typing_extensions': | |
self.__module__ = def_mod | |
# Python 3.10+ has PEP 612 | |
if hasattr(typing, 'ParamSpecArgs'): | |
ParamSpecArgs = typing.ParamSpecArgs | |
ParamSpecKwargs = typing.ParamSpecKwargs | |
# 3.7-3.9 | |
else: | |
class _Immutable: | |
"""Mixin to indicate that object should not be copied.""" | |
__slots__ = () | |
def __copy__(self): | |
return self | |
def __deepcopy__(self, memo): | |
return self | |
class ParamSpecArgs(_Immutable): | |
"""The args for a ParamSpec object. | |
Given a ParamSpec object P, P.args is an instance of ParamSpecArgs. | |
ParamSpecArgs objects have a reference back to their ParamSpec: | |
P.args.__origin__ is P | |
This type is meant for runtime introspection and has no special meaning to | |
static type checkers. | |
""" | |
def __init__(self, origin): | |
self.__origin__ = origin | |
def __repr__(self): | |
return f"{self.__origin__.__name__}.args" | |
def __eq__(self, other): | |
if not isinstance(other, ParamSpecArgs): | |
return NotImplemented | |
return self.__origin__ == other.__origin__ | |
class ParamSpecKwargs(_Immutable): | |
"""The kwargs for a ParamSpec object. | |
Given a ParamSpec object P, P.kwargs is an instance of ParamSpecKwargs. | |
ParamSpecKwargs objects have a reference back to their ParamSpec: | |
P.kwargs.__origin__ is P | |
This type is meant for runtime introspection and has no special meaning to | |
static type checkers. | |
""" | |
def __init__(self, origin): | |
self.__origin__ = origin | |
def __repr__(self): | |
return f"{self.__origin__.__name__}.kwargs" | |
def __eq__(self, other): | |
if not isinstance(other, ParamSpecKwargs): | |
return NotImplemented | |
return self.__origin__ == other.__origin__ | |
# 3.10+ | |
if hasattr(typing, 'ParamSpec'): | |
# Add default Parameter - PEP 696 | |
class ParamSpec(typing.ParamSpec, _DefaultMixin, _root=True): | |
"""Parameter specification variable.""" | |
__module__ = 'typing' | |
def __init__(self, name, *, bound=None, covariant=False, contravariant=False, | |
default=None): | |
super().__init__(name, bound=bound, covariant=covariant, | |
contravariant=contravariant) | |
_DefaultMixin.__init__(self, default) | |
# for pickling: | |
try: | |
def_mod = sys._getframe(1).f_globals.get('__name__', '__main__') | |
except (AttributeError, ValueError): | |
def_mod = None | |
if def_mod != 'typing_extensions': | |
self.__module__ = def_mod | |
# 3.7-3.9 | |
else: | |
# Inherits from list as a workaround for Callable checks in Python < 3.9.2. | |
class ParamSpec(list, _DefaultMixin): | |
"""Parameter specification variable. | |
Usage:: | |
P = ParamSpec('P') | |
Parameter specification variables exist primarily for the benefit of static | |
type checkers. They are used to forward the parameter types of one | |
callable to another callable, a pattern commonly found in higher order | |
functions and decorators. They are only valid when used in ``Concatenate``, | |
or s the first argument to ``Callable``. In Python 3.10 and higher, | |
they are also supported in user-defined Generics at runtime. | |
See class Generic for more information on generic types. An | |
example for annotating a decorator:: | |
T = TypeVar('T') | |
P = ParamSpec('P') | |
def add_logging(f: Callable[P, T]) -> Callable[P, T]: | |
'''A type-safe decorator to add logging to a function.''' | |
def inner(*args: P.args, **kwargs: P.kwargs) -> T: | |
logging.info(f'{f.__name__} was called') | |
return f(*args, **kwargs) | |
return inner | |
@add_logging | |
def add_two(x: float, y: float) -> float: | |
'''Add two numbers together.''' | |
return x + y | |
Parameter specification variables defined with covariant=True or | |
contravariant=True can be used to declare covariant or contravariant | |
generic types. These keyword arguments are valid, but their actual semantics | |
are yet to be decided. See PEP 612 for details. | |
Parameter specification variables can be introspected. e.g.: | |
P.__name__ == 'T' | |
P.__bound__ == None | |
P.__covariant__ == False | |
P.__contravariant__ == False | |
Note that only parameter specification variables defined in global scope can | |
be pickled. | |
""" | |
# Trick Generic __parameters__. | |
__class__ = typing.TypeVar | |
def args(self): | |
return ParamSpecArgs(self) | |
def kwargs(self): | |
return ParamSpecKwargs(self) | |
def __init__(self, name, *, bound=None, covariant=False, contravariant=False, | |
default=None): | |
super().__init__([self]) | |
self.__name__ = name | |
self.__covariant__ = bool(covariant) | |
self.__contravariant__ = bool(contravariant) | |
if bound: | |
self.__bound__ = typing._type_check(bound, 'Bound must be a type.') | |
else: | |
self.__bound__ = None | |
_DefaultMixin.__init__(self, default) | |
# for pickling: | |
try: | |
def_mod = sys._getframe(1).f_globals.get('__name__', '__main__') | |
except (AttributeError, ValueError): | |
def_mod = None | |
if def_mod != 'typing_extensions': | |
self.__module__ = def_mod | |
def __repr__(self): | |
if self.__covariant__: | |
prefix = '+' | |
elif self.__contravariant__: | |
prefix = '-' | |
else: | |
prefix = '~' | |
return prefix + self.__name__ | |
def __hash__(self): | |
return object.__hash__(self) | |
def __eq__(self, other): | |
return self is other | |
def __reduce__(self): | |
return self.__name__ | |
# Hack to get typing._type_check to pass. | |
def __call__(self, *args, **kwargs): | |
pass | |
# 3.7-3.9 | |
if not hasattr(typing, 'Concatenate'): | |
# Inherits from list as a workaround for Callable checks in Python < 3.9.2. | |
class _ConcatenateGenericAlias(list): | |
# Trick Generic into looking into this for __parameters__. | |
__class__ = typing._GenericAlias | |
# Flag in 3.8. | |
_special = False | |
def __init__(self, origin, args): | |
super().__init__(args) | |
self.__origin__ = origin | |
self.__args__ = args | |
def __repr__(self): | |
_type_repr = typing._type_repr | |
return (f'{_type_repr(self.__origin__)}' | |
f'[{", ".join(_type_repr(arg) for arg in self.__args__)}]') | |
def __hash__(self): | |
return hash((self.__origin__, self.__args__)) | |
# Hack to get typing._type_check to pass in Generic. | |
def __call__(self, *args, **kwargs): | |
pass | |
def __parameters__(self): | |
return tuple( | |
tp for tp in self.__args__ if isinstance(tp, (typing.TypeVar, ParamSpec)) | |
) | |
# 3.7-3.9 | |
def _concatenate_getitem(self, parameters): | |
if parameters == (): | |
raise TypeError("Cannot take a Concatenate of no types.") | |
if not isinstance(parameters, tuple): | |
parameters = (parameters,) | |
if not isinstance(parameters[-1], ParamSpec): | |
raise TypeError("The last parameter to Concatenate should be a " | |
"ParamSpec variable.") | |
msg = "Concatenate[arg, ...]: each arg must be a type." | |
parameters = tuple(typing._type_check(p, msg) for p in parameters) | |
return _ConcatenateGenericAlias(self, parameters) | |
# 3.10+ | |
if hasattr(typing, 'Concatenate'): | |
Concatenate = typing.Concatenate | |
_ConcatenateGenericAlias = typing._ConcatenateGenericAlias # noqa | |
# 3.9 | |
elif sys.version_info[:2] >= (3, 9): | |
def Concatenate(self, parameters): | |
"""Used in conjunction with ``ParamSpec`` and ``Callable`` to represent a | |
higher order function which adds, removes or transforms parameters of a | |
callable. | |
For example:: | |
Callable[Concatenate[int, P], int] | |
See PEP 612 for detailed information. | |
""" | |
return _concatenate_getitem(self, parameters) | |
# 3.7-8 | |
else: | |
class _ConcatenateForm(typing._SpecialForm, _root=True): | |
def __repr__(self): | |
return 'typing_extensions.' + self._name | |
def __getitem__(self, parameters): | |
return _concatenate_getitem(self, parameters) | |
Concatenate = _ConcatenateForm( | |
'Concatenate', | |
doc="""Used in conjunction with ``ParamSpec`` and ``Callable`` to represent a | |
higher order function which adds, removes or transforms parameters of a | |
callable. | |
For example:: | |
Callable[Concatenate[int, P], int] | |
See PEP 612 for detailed information. | |
""") | |
# 3.10+ | |
if hasattr(typing, 'TypeGuard'): | |
TypeGuard = typing.TypeGuard | |
# 3.9 | |
elif sys.version_info[:2] >= (3, 9): | |
class _TypeGuardForm(typing._SpecialForm, _root=True): | |
def __repr__(self): | |
return 'typing_extensions.' + self._name | |
def TypeGuard(self, parameters): | |
"""Special typing form used to annotate the return type of a user-defined | |
type guard function. ``TypeGuard`` only accepts a single type argument. | |
At runtime, functions marked this way should return a boolean. | |
``TypeGuard`` aims to benefit *type narrowing* -- a technique used by static | |
type checkers to determine a more precise type of an expression within a | |
program's code flow. Usually type narrowing is done by analyzing | |
conditional code flow and applying the narrowing to a block of code. The | |
conditional expression here is sometimes referred to as a "type guard". | |
Sometimes it would be convenient to use a user-defined boolean function | |
as a type guard. Such a function should use ``TypeGuard[...]`` as its | |
return type to alert static type checkers to this intention. | |
Using ``-> TypeGuard`` tells the static type checker that for a given | |
function: | |
1. The return value is a boolean. | |
2. If the return value is ``True``, the type of its argument | |
is the type inside ``TypeGuard``. | |
For example:: | |
def is_str(val: Union[str, float]): | |
# "isinstance" type guard | |
if isinstance(val, str): | |
# Type of ``val`` is narrowed to ``str`` | |
... | |
else: | |
# Else, type of ``val`` is narrowed to ``float``. | |
... | |
Strict type narrowing is not enforced -- ``TypeB`` need not be a narrower | |
form of ``TypeA`` (it can even be a wider form) and this may lead to | |
type-unsafe results. The main reason is to allow for things like | |
narrowing ``List[object]`` to ``List[str]`` even though the latter is not | |
a subtype of the former, since ``List`` is invariant. The responsibility of | |
writing type-safe type guards is left to the user. | |
``TypeGuard`` also works with type variables. For more information, see | |
PEP 647 (User-Defined Type Guards). | |
""" | |
item = typing._type_check(parameters, f'{self} accepts only a single type.') | |
return typing._GenericAlias(self, (item,)) | |
# 3.7-3.8 | |
else: | |
class _TypeGuardForm(typing._SpecialForm, _root=True): | |
def __repr__(self): | |
return 'typing_extensions.' + self._name | |
def __getitem__(self, parameters): | |
item = typing._type_check(parameters, | |
f'{self._name} accepts only a single type') | |
return typing._GenericAlias(self, (item,)) | |
TypeGuard = _TypeGuardForm( | |
'TypeGuard', | |
doc="""Special typing form used to annotate the return type of a user-defined | |
type guard function. ``TypeGuard`` only accepts a single type argument. | |
At runtime, functions marked this way should return a boolean. | |
``TypeGuard`` aims to benefit *type narrowing* -- a technique used by static | |
type checkers to determine a more precise type of an expression within a | |
program's code flow. Usually type narrowing is done by analyzing | |
conditional code flow and applying the narrowing to a block of code. The | |
conditional expression here is sometimes referred to as a "type guard". | |
Sometimes it would be convenient to use a user-defined boolean function | |
as a type guard. Such a function should use ``TypeGuard[...]`` as its | |
return type to alert static type checkers to this intention. | |
Using ``-> TypeGuard`` tells the static type checker that for a given | |
function: | |
1. The return value is a boolean. | |
2. If the return value is ``True``, the type of its argument | |
is the type inside ``TypeGuard``. | |
For example:: | |
def is_str(val: Union[str, float]): | |
# "isinstance" type guard | |
if isinstance(val, str): | |
# Type of ``val`` is narrowed to ``str`` | |
... | |
else: | |
# Else, type of ``val`` is narrowed to ``float``. | |
... | |
Strict type narrowing is not enforced -- ``TypeB`` need not be a narrower | |
form of ``TypeA`` (it can even be a wider form) and this may lead to | |
type-unsafe results. The main reason is to allow for things like | |
narrowing ``List[object]`` to ``List[str]`` even though the latter is not | |
a subtype of the former, since ``List`` is invariant. The responsibility of | |
writing type-safe type guards is left to the user. | |
``TypeGuard`` also works with type variables. For more information, see | |
PEP 647 (User-Defined Type Guards). | |
""") | |
# Vendored from cpython typing._SpecialFrom | |
class _SpecialForm(typing._Final, _root=True): | |
__slots__ = ('_name', '__doc__', '_getitem') | |
def __init__(self, getitem): | |
self._getitem = getitem | |
self._name = getitem.__name__ | |
self.__doc__ = getitem.__doc__ | |
def __getattr__(self, item): | |
if item in {'__name__', '__qualname__'}: | |
return self._name | |
raise AttributeError(item) | |
def __mro_entries__(self, bases): | |
raise TypeError(f"Cannot subclass {self!r}") | |
def __repr__(self): | |
return f'typing_extensions.{self._name}' | |
def __reduce__(self): | |
return self._name | |
def __call__(self, *args, **kwds): | |
raise TypeError(f"Cannot instantiate {self!r}") | |
def __or__(self, other): | |
return typing.Union[self, other] | |
def __ror__(self, other): | |
return typing.Union[other, self] | |
def __instancecheck__(self, obj): | |
raise TypeError(f"{self} cannot be used with isinstance()") | |
def __subclasscheck__(self, cls): | |
raise TypeError(f"{self} cannot be used with issubclass()") | |
def __getitem__(self, parameters): | |
return self._getitem(self, parameters) | |
if hasattr(typing, "LiteralString"): | |
LiteralString = typing.LiteralString | |
else: | |
def LiteralString(self, params): | |
"""Represents an arbitrary literal string. | |
Example:: | |
from pip._vendor.typing_extensions import LiteralString | |
def query(sql: LiteralString) -> ...: | |
... | |
query("SELECT * FROM table") # ok | |
query(f"SELECT * FROM {input()}") # not ok | |
See PEP 675 for details. | |
""" | |
raise TypeError(f"{self} is not subscriptable") | |
if hasattr(typing, "Self"): | |
Self = typing.Self | |
else: | |
def Self(self, params): | |
"""Used to spell the type of "self" in classes. | |
Example:: | |
from typing import Self | |
class ReturnsSelf: | |
def parse(self, data: bytes) -> Self: | |
... | |
return self | |
""" | |
raise TypeError(f"{self} is not subscriptable") | |
if hasattr(typing, "Never"): | |
Never = typing.Never | |
else: | |
def Never(self, params): | |
"""The bottom type, a type that has no members. | |
This can be used to define a function that should never be | |
called, or a function that never returns:: | |
from pip._vendor.typing_extensions import Never | |
def never_call_me(arg: Never) -> None: | |
pass | |
def int_or_str(arg: int | str) -> None: | |
never_call_me(arg) # type checker error | |
match arg: | |
case int(): | |
print("It's an int") | |
case str(): | |
print("It's a str") | |
case _: | |
never_call_me(arg) # ok, arg is of type Never | |
""" | |
raise TypeError(f"{self} is not subscriptable") | |
if hasattr(typing, 'Required'): | |
Required = typing.Required | |
NotRequired = typing.NotRequired | |
elif sys.version_info[:2] >= (3, 9): | |
class _ExtensionsSpecialForm(typing._SpecialForm, _root=True): | |
def __repr__(self): | |
return 'typing_extensions.' + self._name | |
def Required(self, parameters): | |
"""A special typing construct to mark a key of a total=False TypedDict | |
as required. For example: | |
class Movie(TypedDict, total=False): | |
title: Required[str] | |
year: int | |
m = Movie( | |
title='The Matrix', # typechecker error if key is omitted | |
year=1999, | |
) | |
There is no runtime checking that a required key is actually provided | |
when instantiating a related TypedDict. | |
""" | |
item = typing._type_check(parameters, f'{self._name} accepts only a single type.') | |
return typing._GenericAlias(self, (item,)) | |
def NotRequired(self, parameters): | |
"""A special typing construct to mark a key of a TypedDict as | |
potentially missing. For example: | |
class Movie(TypedDict): | |
title: str | |
year: NotRequired[int] | |
m = Movie( | |
title='The Matrix', # typechecker error if key is omitted | |
year=1999, | |
) | |
""" | |
item = typing._type_check(parameters, f'{self._name} accepts only a single type.') | |
return typing._GenericAlias(self, (item,)) | |
else: | |
class _RequiredForm(typing._SpecialForm, _root=True): | |
def __repr__(self): | |
return 'typing_extensions.' + self._name | |
def __getitem__(self, parameters): | |
item = typing._type_check(parameters, | |
f'{self._name} accepts only a single type.') | |
return typing._GenericAlias(self, (item,)) | |
Required = _RequiredForm( | |
'Required', | |
doc="""A special typing construct to mark a key of a total=False TypedDict | |
as required. For example: | |
class Movie(TypedDict, total=False): | |
title: Required[str] | |
year: int | |
m = Movie( | |
title='The Matrix', # typechecker error if key is omitted | |
year=1999, | |
) | |
There is no runtime checking that a required key is actually provided | |
when instantiating a related TypedDict. | |
""") | |
NotRequired = _RequiredForm( | |
'NotRequired', | |
doc="""A special typing construct to mark a key of a TypedDict as | |
potentially missing. For example: | |
class Movie(TypedDict): | |
title: str | |
year: NotRequired[int] | |
m = Movie( | |
title='The Matrix', # typechecker error if key is omitted | |
year=1999, | |
) | |
""") | |
if hasattr(typing, "Unpack"): # 3.11+ | |
Unpack = typing.Unpack | |
elif sys.version_info[:2] >= (3, 9): | |
class _UnpackSpecialForm(typing._SpecialForm, _root=True): | |
def __repr__(self): | |
return 'typing_extensions.' + self._name | |
class _UnpackAlias(typing._GenericAlias, _root=True): | |
__class__ = typing.TypeVar | |
def Unpack(self, parameters): | |
"""A special typing construct to unpack a variadic type. For example: | |
Shape = TypeVarTuple('Shape') | |
Batch = NewType('Batch', int) | |
def add_batch_axis( | |
x: Array[Unpack[Shape]] | |
) -> Array[Batch, Unpack[Shape]]: ... | |
""" | |
item = typing._type_check(parameters, f'{self._name} accepts only a single type.') | |
return _UnpackAlias(self, (item,)) | |
def _is_unpack(obj): | |
return isinstance(obj, _UnpackAlias) | |
else: | |
class _UnpackAlias(typing._GenericAlias, _root=True): | |
__class__ = typing.TypeVar | |
class _UnpackForm(typing._SpecialForm, _root=True): | |
def __repr__(self): | |
return 'typing_extensions.' + self._name | |
def __getitem__(self, parameters): | |
item = typing._type_check(parameters, | |
f'{self._name} accepts only a single type.') | |
return _UnpackAlias(self, (item,)) | |
Unpack = _UnpackForm( | |
'Unpack', | |
doc="""A special typing construct to unpack a variadic type. For example: | |
Shape = TypeVarTuple('Shape') | |
Batch = NewType('Batch', int) | |
def add_batch_axis( | |
x: Array[Unpack[Shape]] | |
) -> Array[Batch, Unpack[Shape]]: ... | |
""") | |
def _is_unpack(obj): | |
return isinstance(obj, _UnpackAlias) | |
if hasattr(typing, "TypeVarTuple"): # 3.11+ | |
# Add default Parameter - PEP 696 | |
class TypeVarTuple(typing.TypeVarTuple, _DefaultMixin, _root=True): | |
"""Type variable tuple.""" | |
def __init__(self, name, *, default=None): | |
super().__init__(name) | |
_DefaultMixin.__init__(self, default) | |
# for pickling: | |
try: | |
def_mod = sys._getframe(1).f_globals.get('__name__', '__main__') | |
except (AttributeError, ValueError): | |
def_mod = None | |
if def_mod != 'typing_extensions': | |
self.__module__ = def_mod | |
else: | |
class TypeVarTuple(_DefaultMixin): | |
"""Type variable tuple. | |
Usage:: | |
Ts = TypeVarTuple('Ts') | |
In the same way that a normal type variable is a stand-in for a single | |
type such as ``int``, a type variable *tuple* is a stand-in for a *tuple* | |
type such as ``Tuple[int, str]``. | |
Type variable tuples can be used in ``Generic`` declarations. | |
Consider the following example:: | |
class Array(Generic[*Ts]): ... | |
The ``Ts`` type variable tuple here behaves like ``tuple[T1, T2]``, | |
where ``T1`` and ``T2`` are type variables. To use these type variables | |
as type parameters of ``Array``, we must *unpack* the type variable tuple using | |
the star operator: ``*Ts``. The signature of ``Array`` then behaves | |
as if we had simply written ``class Array(Generic[T1, T2]): ...``. | |
In contrast to ``Generic[T1, T2]``, however, ``Generic[*Shape]`` allows | |
us to parameterise the class with an *arbitrary* number of type parameters. | |
Type variable tuples can be used anywhere a normal ``TypeVar`` can. | |
This includes class definitions, as shown above, as well as function | |
signatures and variable annotations:: | |
class Array(Generic[*Ts]): | |
def __init__(self, shape: Tuple[*Ts]): | |
self._shape: Tuple[*Ts] = shape | |
def get_shape(self) -> Tuple[*Ts]: | |
return self._shape | |
shape = (Height(480), Width(640)) | |
x: Array[Height, Width] = Array(shape) | |
y = abs(x) # Inferred type is Array[Height, Width] | |
z = x + x # ... is Array[Height, Width] | |
x.get_shape() # ... is tuple[Height, Width] | |
""" | |
# Trick Generic __parameters__. | |
__class__ = typing.TypeVar | |
def __iter__(self): | |
yield self.__unpacked__ | |
def __init__(self, name, *, default=None): | |
self.__name__ = name | |
_DefaultMixin.__init__(self, default) | |
# for pickling: | |
try: | |
def_mod = sys._getframe(1).f_globals.get('__name__', '__main__') | |
except (AttributeError, ValueError): | |
def_mod = None | |
if def_mod != 'typing_extensions': | |
self.__module__ = def_mod | |
self.__unpacked__ = Unpack[self] | |
def __repr__(self): | |
return self.__name__ | |
def __hash__(self): | |
return object.__hash__(self) | |
def __eq__(self, other): | |
return self is other | |
def __reduce__(self): | |
return self.__name__ | |
def __init_subclass__(self, *args, **kwds): | |
if '_root' not in kwds: | |
raise TypeError("Cannot subclass special typing classes") | |
if hasattr(typing, "reveal_type"): | |
reveal_type = typing.reveal_type | |
else: | |
def reveal_type(__obj: T) -> T: | |
"""Reveal the inferred type of a variable. | |
When a static type checker encounters a call to ``reveal_type()``, | |
it will emit the inferred type of the argument:: | |
x: int = 1 | |
reveal_type(x) | |
Running a static type checker (e.g., ``mypy``) on this example | |
will produce output similar to 'Revealed type is "builtins.int"'. | |
At runtime, the function prints the runtime type of the | |
argument and returns it unchanged. | |
""" | |
print(f"Runtime type is {type(__obj).__name__!r}", file=sys.stderr) | |
return __obj | |
if hasattr(typing, "assert_never"): | |
assert_never = typing.assert_never | |
else: | |
def assert_never(__arg: Never) -> Never: | |
"""Assert to the type checker that a line of code is unreachable. | |
Example:: | |
def int_or_str(arg: int | str) -> None: | |
match arg: | |
case int(): | |
print("It's an int") | |
case str(): | |
print("It's a str") | |
case _: | |
assert_never(arg) | |
If a type checker finds that a call to assert_never() is | |
reachable, it will emit an error. | |
At runtime, this throws an exception when called. | |
""" | |
raise AssertionError("Expected code to be unreachable") | |
if hasattr(typing, 'dataclass_transform'): | |
dataclass_transform = typing.dataclass_transform | |
else: | |
def dataclass_transform( | |
*, | |
eq_default: bool = True, | |
order_default: bool = False, | |
kw_only_default: bool = False, | |
field_specifiers: typing.Tuple[ | |
typing.Union[typing.Type[typing.Any], typing.Callable[..., typing.Any]], | |
... | |
] = (), | |
**kwargs: typing.Any, | |
) -> typing.Callable[[T], T]: | |
"""Decorator that marks a function, class, or metaclass as providing | |
dataclass-like behavior. | |
Example: | |
from pip._vendor.typing_extensions import dataclass_transform | |
_T = TypeVar("_T") | |
# Used on a decorator function | |
@dataclass_transform() | |
def create_model(cls: type[_T]) -> type[_T]: | |
... | |
return cls | |
@create_model | |
class CustomerModel: | |
id: int | |
name: str | |
# Used on a base class | |
@dataclass_transform() | |
class ModelBase: ... | |
class CustomerModel(ModelBase): | |
id: int | |
name: str | |
# Used on a metaclass | |
@dataclass_transform() | |
class ModelMeta(type): ... | |
class ModelBase(metaclass=ModelMeta): ... | |
class CustomerModel(ModelBase): | |
id: int | |
name: str | |
Each of the ``CustomerModel`` classes defined in this example will now | |
behave similarly to a dataclass created with the ``@dataclasses.dataclass`` | |
decorator. For example, the type checker will synthesize an ``__init__`` | |
method. | |
The arguments to this decorator can be used to customize this behavior: | |
- ``eq_default`` indicates whether the ``eq`` parameter is assumed to be | |
True or False if it is omitted by the caller. | |
- ``order_default`` indicates whether the ``order`` parameter is | |
assumed to be True or False if it is omitted by the caller. | |
- ``kw_only_default`` indicates whether the ``kw_only`` parameter is | |
assumed to be True or False if it is omitted by the caller. | |
- ``field_specifiers`` specifies a static list of supported classes | |
or functions that describe fields, similar to ``dataclasses.field()``. | |
At runtime, this decorator records its arguments in the | |
``__dataclass_transform__`` attribute on the decorated object. | |
See PEP 681 for details. | |
""" | |
def decorator(cls_or_fn): | |
cls_or_fn.__dataclass_transform__ = { | |
"eq_default": eq_default, | |
"order_default": order_default, | |
"kw_only_default": kw_only_default, | |
"field_specifiers": field_specifiers, | |
"kwargs": kwargs, | |
} | |
return cls_or_fn | |
return decorator | |
if hasattr(typing, "override"): | |
override = typing.override | |
else: | |
_F = typing.TypeVar("_F", bound=typing.Callable[..., typing.Any]) | |
def override(__arg: _F) -> _F: | |
"""Indicate that a method is intended to override a method in a base class. | |
Usage: | |
class Base: | |
def method(self) -> None: ... | |
pass | |
class Child(Base): | |
@override | |
def method(self) -> None: | |
super().method() | |
When this decorator is applied to a method, the type checker will | |
validate that it overrides a method with the same name on a base class. | |
This helps prevent bugs that may occur when a base class is changed | |
without an equivalent change to a child class. | |
See PEP 698 for details. | |
""" | |
return __arg | |
# We have to do some monkey patching to deal with the dual nature of | |
# Unpack/TypeVarTuple: | |
# - We want Unpack to be a kind of TypeVar so it gets accepted in | |
# Generic[Unpack[Ts]] | |
# - We want it to *not* be treated as a TypeVar for the purposes of | |
# counting generic parameters, so that when we subscript a generic, | |
# the runtime doesn't try to substitute the Unpack with the subscripted type. | |
if not hasattr(typing, "TypeVarTuple"): | |
typing._collect_type_vars = _collect_type_vars | |
typing._check_generic = _check_generic | |
# Backport typing.NamedTuple as it exists in Python 3.11. | |
# In 3.11, the ability to define generic `NamedTuple`s was supported. | |
# This was explicitly disallowed in 3.9-3.10, and only half-worked in <=3.8. | |
if sys.version_info >= (3, 11): | |
NamedTuple = typing.NamedTuple | |
else: | |
def _caller(): | |
try: | |
return sys._getframe(2).f_globals.get('__name__', '__main__') | |
except (AttributeError, ValueError): # For platforms without _getframe() | |
return None | |
def _make_nmtuple(name, types, module, defaults=()): | |
fields = [n for n, t in types] | |
annotations = {n: typing._type_check(t, f"field {n} annotation must be a type") | |
for n, t in types} | |
nm_tpl = collections.namedtuple(name, fields, | |
defaults=defaults, module=module) | |
nm_tpl.__annotations__ = nm_tpl.__new__.__annotations__ = annotations | |
# The `_field_types` attribute was removed in 3.9; | |
# in earlier versions, it is the same as the `__annotations__` attribute | |
if sys.version_info < (3, 9): | |
nm_tpl._field_types = annotations | |
return nm_tpl | |
_prohibited_namedtuple_fields = typing._prohibited | |
_special_namedtuple_fields = frozenset({'__module__', '__name__', '__annotations__'}) | |
class _NamedTupleMeta(type): | |
def __new__(cls, typename, bases, ns): | |
assert _NamedTuple in bases | |
for base in bases: | |
if base is not _NamedTuple and base is not typing.Generic: | |
raise TypeError( | |
'can only inherit from a NamedTuple type and Generic') | |
bases = tuple(tuple if base is _NamedTuple else base for base in bases) | |
types = ns.get('__annotations__', {}) | |
default_names = [] | |
for field_name in types: | |
if field_name in ns: | |
default_names.append(field_name) | |
elif default_names: | |
raise TypeError(f"Non-default namedtuple field {field_name} " | |
f"cannot follow default field" | |
f"{'s' if len(default_names) > 1 else ''} " | |
f"{', '.join(default_names)}") | |
nm_tpl = _make_nmtuple( | |
typename, types.items(), | |
defaults=[ns[n] for n in default_names], | |
module=ns['__module__'] | |
) | |
nm_tpl.__bases__ = bases | |
if typing.Generic in bases: | |
class_getitem = typing.Generic.__class_getitem__.__func__ | |
nm_tpl.__class_getitem__ = classmethod(class_getitem) | |
# update from user namespace without overriding special namedtuple attributes | |
for key in ns: | |
if key in _prohibited_namedtuple_fields: | |
raise AttributeError("Cannot overwrite NamedTuple attribute " + key) | |
elif key not in _special_namedtuple_fields and key not in nm_tpl._fields: | |
setattr(nm_tpl, key, ns[key]) | |
if typing.Generic in bases: | |
nm_tpl.__init_subclass__() | |
return nm_tpl | |
def NamedTuple(__typename, __fields=None, **kwargs): | |
if __fields is None: | |
__fields = kwargs.items() | |
elif kwargs: | |
raise TypeError("Either list of fields or keywords" | |
" can be provided to NamedTuple, not both") | |
return _make_nmtuple(__typename, __fields, module=_caller()) | |
NamedTuple.__doc__ = typing.NamedTuple.__doc__ | |
_NamedTuple = type.__new__(_NamedTupleMeta, 'NamedTuple', (), {}) | |
# On 3.8+, alter the signature so that it matches typing.NamedTuple. | |
# The signature of typing.NamedTuple on >=3.8 is invalid syntax in Python 3.7, | |
# so just leave the signature as it is on 3.7. | |
if sys.version_info >= (3, 8): | |
NamedTuple.__text_signature__ = '(typename, fields=None, /, **kwargs)' | |
def _namedtuple_mro_entries(bases): | |
assert NamedTuple in bases | |
return (_NamedTuple,) | |
NamedTuple.__mro_entries__ = _namedtuple_mro_entries | |