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# util/typing.py
# Copyright (C) 2022-2024 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: https://www.opensource.org/licenses/mit-license.php
# mypy: allow-untyped-defs, allow-untyped-calls
from __future__ import annotations
import builtins
import collections.abc as collections_abc
import re
import sys
import typing
from typing import Any
from typing import Callable
from typing import cast
from typing import Dict
from typing import ForwardRef
from typing import Generic
from typing import Iterable
from typing import Mapping
from typing import NewType
from typing import NoReturn
from typing import Optional
from typing import overload
from typing import Set
from typing import Tuple
from typing import Type
from typing import TYPE_CHECKING
from typing import TypeVar
from typing import Union
from . import compat
if True: # zimports removes the tailing comments
from typing_extensions import Annotated as Annotated # 3.8
from typing_extensions import Concatenate as Concatenate # 3.10
from typing_extensions import (
dataclass_transform as dataclass_transform, # 3.11,
)
from typing_extensions import Final as Final # 3.8
from typing_extensions import final as final # 3.8
from typing_extensions import get_args as get_args # 3.10
from typing_extensions import get_origin as get_origin # 3.10
from typing_extensions import Literal as Literal # 3.8
from typing_extensions import NotRequired as NotRequired # 3.11
from typing_extensions import ParamSpec as ParamSpec # 3.10
from typing_extensions import Protocol as Protocol # 3.8
from typing_extensions import SupportsIndex as SupportsIndex # 3.8
from typing_extensions import TypeAlias as TypeAlias # 3.10
from typing_extensions import TypedDict as TypedDict # 3.8
from typing_extensions import TypeGuard as TypeGuard # 3.10
from typing_extensions import Self as Self # 3.11
from typing_extensions import TypeAliasType as TypeAliasType # 3.12
_T = TypeVar("_T", bound=Any)
_KT = TypeVar("_KT")
_KT_co = TypeVar("_KT_co", covariant=True)
_KT_contra = TypeVar("_KT_contra", contravariant=True)
_VT = TypeVar("_VT")
_VT_co = TypeVar("_VT_co", covariant=True)
if compat.py310:
# why they took until py310 to put this in stdlib is beyond me,
# I've been wanting it since py27
from types import NoneType as NoneType
else:
NoneType = type(None) # type: ignore
NoneFwd = ForwardRef("None")
typing_get_args = get_args
typing_get_origin = get_origin
_AnnotationScanType = Union[
Type[Any], str, ForwardRef, NewType, TypeAliasType, "GenericProtocol[Any]"
]
class ArgsTypeProcotol(Protocol):
"""protocol for types that have ``__args__``
there's no public interface for this AFAIK
"""
__args__: Tuple[_AnnotationScanType, ...]
class GenericProtocol(Protocol[_T]):
"""protocol for generic types.
this since Python.typing _GenericAlias is private
"""
__args__: Tuple[_AnnotationScanType, ...]
__origin__: Type[_T]
# Python's builtin _GenericAlias has this method, however builtins like
# list, dict, etc. do not, even though they have ``__origin__`` and
# ``__args__``
#
# def copy_with(self, params: Tuple[_AnnotationScanType, ...]) -> Type[_T]:
# ...
# copied from TypeShed, required in order to implement
# MutableMapping.update()
class SupportsKeysAndGetItem(Protocol[_KT, _VT_co]):
def keys(self) -> Iterable[_KT]: ...
def __getitem__(self, __k: _KT) -> _VT_co: ...
# work around https://github.com/microsoft/pyright/issues/3025
_LiteralStar = Literal["*"]
def de_stringify_annotation(
cls: Type[Any],
annotation: _AnnotationScanType,
originating_module: str,
locals_: Mapping[str, Any],
*,
str_cleanup_fn: Optional[Callable[[str, str], str]] = None,
include_generic: bool = False,
_already_seen: Optional[Set[Any]] = None,
) -> Type[Any]:
"""Resolve annotations that may be string based into real objects.
This is particularly important if a module defines "from __future__ import
annotations", as everything inside of __annotations__ is a string. We want
to at least have generic containers like ``Mapped``, ``Union``, ``List``,
etc.
"""
# looked at typing.get_type_hints(), looked at pydantic. We need much
# less here, and we here try to not use any private typing internals
# or construct ForwardRef objects which is documented as something
# that should be avoided.
original_annotation = annotation
if is_fwd_ref(annotation):
annotation = annotation.__forward_arg__
if isinstance(annotation, str):
if str_cleanup_fn:
annotation = str_cleanup_fn(annotation, originating_module)
annotation = eval_expression(
annotation, originating_module, locals_=locals_, in_class=cls
)
if (
include_generic
and is_generic(annotation)
and not is_literal(annotation)
):
if _already_seen is None:
_already_seen = set()
if annotation in _already_seen:
# only occurs recursively. outermost return type
# will always be Type.
# the element here will be either ForwardRef or
# Optional[ForwardRef]
return original_annotation # type: ignore
else:
_already_seen.add(annotation)
elements = tuple(
de_stringify_annotation(
cls,
elem,
originating_module,
locals_,
str_cleanup_fn=str_cleanup_fn,
include_generic=include_generic,
_already_seen=_already_seen,
)
for elem in annotation.__args__
)
return _copy_generic_annotation_with(annotation, elements)
return annotation # type: ignore
def _copy_generic_annotation_with(
annotation: GenericProtocol[_T], elements: Tuple[_AnnotationScanType, ...]
) -> Type[_T]:
if hasattr(annotation, "copy_with"):
# List, Dict, etc. real generics
return annotation.copy_with(elements) # type: ignore
else:
# Python builtins list, dict, etc.
return annotation.__origin__[elements] # type: ignore
def eval_expression(
expression: str,
module_name: str,
*,
locals_: Optional[Mapping[str, Any]] = None,
in_class: Optional[Type[Any]] = None,
) -> Any:
try:
base_globals: Dict[str, Any] = sys.modules[module_name].__dict__
except KeyError as ke:
raise NameError(
f"Module {module_name} isn't present in sys.modules; can't "
f"evaluate expression {expression}"
) from ke
try:
if in_class is not None:
cls_namespace = dict(in_class.__dict__)
cls_namespace.setdefault(in_class.__name__, in_class)
# see #10899. We want the locals/globals to take precedence
# over the class namespace in this context, even though this
# is not the usual way variables would resolve.
cls_namespace.update(base_globals)
annotation = eval(expression, cls_namespace, locals_)
else:
annotation = eval(expression, base_globals, locals_)
except Exception as err:
raise NameError(
f"Could not de-stringify annotation {expression!r}"
) from err
else:
return annotation
def eval_name_only(
name: str,
module_name: str,
*,
locals_: Optional[Mapping[str, Any]] = None,
) -> Any:
if "." in name:
return eval_expression(name, module_name, locals_=locals_)
try:
base_globals: Dict[str, Any] = sys.modules[module_name].__dict__
except KeyError as ke:
raise NameError(
f"Module {module_name} isn't present in sys.modules; can't "
f"resolve name {name}"
) from ke
# name only, just look in globals. eval() works perfectly fine here,
# however we are seeking to have this be faster, as this occurs for
# every Mapper[] keyword, etc. depending on configuration
try:
return base_globals[name]
except KeyError as ke:
# check in builtins as well to handle `list`, `set` or `dict`, etc.
try:
return builtins.__dict__[name]
except KeyError:
pass
raise NameError(
f"Could not locate name {name} in module {module_name}"
) from ke
def resolve_name_to_real_class_name(name: str, module_name: str) -> str:
try:
obj = eval_name_only(name, module_name)
except NameError:
return name
else:
return getattr(obj, "__name__", name)
def de_stringify_union_elements(
cls: Type[Any],
annotation: ArgsTypeProcotol,
originating_module: str,
locals_: Mapping[str, Any],
*,
str_cleanup_fn: Optional[Callable[[str, str], str]] = None,
) -> Type[Any]:
return make_union_type(
*[
de_stringify_annotation(
cls,
anno,
originating_module,
{},
str_cleanup_fn=str_cleanup_fn,
)
for anno in annotation.__args__
]
)
def is_pep593(type_: Optional[_AnnotationScanType]) -> bool:
return type_ is not None and typing_get_origin(type_) is Annotated
def is_non_string_iterable(obj: Any) -> TypeGuard[Iterable[Any]]:
return isinstance(obj, collections_abc.Iterable) and not isinstance(
obj, (str, bytes)
)
def is_literal(type_: _AnnotationScanType) -> bool:
return get_origin(type_) is Literal
def is_newtype(type_: Optional[_AnnotationScanType]) -> TypeGuard[NewType]:
return hasattr(type_, "__supertype__")
# doesn't work in 3.8, 3.7 as it passes a closure, not an
# object instance
# return isinstance(type_, NewType)
def is_generic(type_: _AnnotationScanType) -> TypeGuard[GenericProtocol[Any]]:
return hasattr(type_, "__args__") and hasattr(type_, "__origin__")
def is_pep695(type_: _AnnotationScanType) -> TypeGuard[TypeAliasType]:
return isinstance(type_, TypeAliasType)
def flatten_newtype(type_: NewType) -> Type[Any]:
super_type = type_.__supertype__
while is_newtype(super_type):
super_type = super_type.__supertype__
return super_type # type: ignore[return-value]
def is_fwd_ref(
type_: _AnnotationScanType, check_generic: bool = False
) -> TypeGuard[ForwardRef]:
if isinstance(type_, ForwardRef):
return True
elif check_generic and is_generic(type_):
return any(is_fwd_ref(arg, True) for arg in type_.__args__)
else:
return False
@overload
def de_optionalize_union_types(type_: str) -> str: ...
@overload
def de_optionalize_union_types(type_: Type[Any]) -> Type[Any]: ...
@overload
def de_optionalize_union_types(
type_: _AnnotationScanType,
) -> _AnnotationScanType: ...
def de_optionalize_union_types(
type_: _AnnotationScanType,
) -> _AnnotationScanType:
"""Given a type, filter out ``Union`` types that include ``NoneType``
to not include the ``NoneType``.
"""
if is_fwd_ref(type_):
return de_optionalize_fwd_ref_union_types(type_)
elif is_optional(type_):
typ = set(type_.__args__)
typ.discard(NoneType)
typ.discard(NoneFwd)
return make_union_type(*typ)
else:
return type_
def de_optionalize_fwd_ref_union_types(
type_: ForwardRef,
) -> _AnnotationScanType:
"""return the non-optional type for Optional[], Union[None, ...], x|None,
etc. without de-stringifying forward refs.
unfortunately this seems to require lots of hardcoded heuristics
"""
annotation = type_.__forward_arg__
mm = re.match(r"^(.+?)\[(.+)\]$", annotation)
if mm:
if mm.group(1) == "Optional":
return ForwardRef(mm.group(2))
elif mm.group(1) == "Union":
elements = re.split(r",\s*", mm.group(2))
return make_union_type(
*[ForwardRef(elem) for elem in elements if elem != "None"]
)
else:
return type_
pipe_tokens = re.split(r"\s*\|\s*", annotation)
if "None" in pipe_tokens:
return ForwardRef("|".join(p for p in pipe_tokens if p != "None"))
return type_
def make_union_type(*types: _AnnotationScanType) -> Type[Any]:
"""Make a Union type.
This is needed by :func:`.de_optionalize_union_types` which removes
``NoneType`` from a ``Union``.
"""
return cast(Any, Union).__getitem__(types) # type: ignore
def expand_unions(
type_: Type[Any], include_union: bool = False, discard_none: bool = False
) -> Tuple[Type[Any], ...]:
"""Return a type as a tuple of individual types, expanding for
``Union`` types."""
if is_union(type_):
typ = set(type_.__args__)
if discard_none:
typ.discard(NoneType)
if include_union:
return (type_,) + tuple(typ) # type: ignore
else:
return tuple(typ) # type: ignore
else:
return (type_,)
def is_optional(type_: Any) -> TypeGuard[ArgsTypeProcotol]:
return is_origin_of(
type_,
"Optional",
"Union",
"UnionType",
)
def is_optional_union(type_: Any) -> bool:
return is_optional(type_) and NoneType in typing_get_args(type_)
def is_union(type_: Any) -> TypeGuard[ArgsTypeProcotol]:
return is_origin_of(type_, "Union")
def is_origin_of_cls(
type_: Any, class_obj: Union[Tuple[Type[Any], ...], Type[Any]]
) -> bool:
"""return True if the given type has an __origin__ that shares a base
with the given class"""
origin = typing_get_origin(type_)
if origin is None:
return False
return isinstance(origin, type) and issubclass(origin, class_obj)
def is_origin_of(
type_: Any, *names: str, module: Optional[str] = None
) -> bool:
"""return True if the given type has an __origin__ with the given name
and optional module."""
origin = typing_get_origin(type_)
if origin is None:
return False
return _get_type_name(origin) in names and (
module is None or origin.__module__.startswith(module)
)
def _get_type_name(type_: Type[Any]) -> str:
if compat.py310:
return type_.__name__
else:
typ_name = getattr(type_, "__name__", None)
if typ_name is None:
typ_name = getattr(type_, "_name", None)
return typ_name # type: ignore
class DescriptorProto(Protocol):
def __get__(self, instance: object, owner: Any) -> Any: ...
def __set__(self, instance: Any, value: Any) -> None: ...
def __delete__(self, instance: Any) -> None: ...
_DESC = TypeVar("_DESC", bound=DescriptorProto)
class DescriptorReference(Generic[_DESC]):
"""a descriptor that refers to a descriptor.
used for cases where we need to have an instance variable referring to an
object that is itself a descriptor, which typically confuses typing tools
as they don't know when they should use ``__get__`` or not when referring
to the descriptor assignment as an instance variable. See
sqlalchemy.orm.interfaces.PropComparator.prop
"""
if TYPE_CHECKING:
def __get__(self, instance: object, owner: Any) -> _DESC: ...
def __set__(self, instance: Any, value: _DESC) -> None: ...
def __delete__(self, instance: Any) -> None: ...
_DESC_co = TypeVar("_DESC_co", bound=DescriptorProto, covariant=True)
class RODescriptorReference(Generic[_DESC_co]):
"""a descriptor that refers to a descriptor.
same as :class:`.DescriptorReference` but is read-only, so that subclasses
can define a subtype as the generically contained element
"""
if TYPE_CHECKING:
def __get__(self, instance: object, owner: Any) -> _DESC_co: ...
def __set__(self, instance: Any, value: Any) -> NoReturn: ...
def __delete__(self, instance: Any) -> NoReturn: ...
_FN = TypeVar("_FN", bound=Optional[Callable[..., Any]])
class CallableReference(Generic[_FN]):
"""a descriptor that refers to a callable.
works around mypy's limitation of not allowing callables assigned
as instance variables
"""
if TYPE_CHECKING:
def __get__(self, instance: object, owner: Any) -> _FN: ...
def __set__(self, instance: Any, value: _FN) -> None: ...
def __delete__(self, instance: Any) -> None: ...
# $def ro_descriptor_reference(fn: Callable[])