Add Protocols for mapping inside dictionary view objects

Author: Gatsik

stdlib/_typeshed/__init__.pyi

@@ -377,3 +377,7 @@ if sys.version_info >= (3, 14):
     # These return annotations, which can be arbitrary objects
     AnnotateFunc: TypeAlias = Callable[[Format], dict[str, AnnotationForm]]
     EvaluateFunc: TypeAlias = Callable[[Format], AnnotationForm]
+
+# Suitable for dictionary view objects
+class Viewable(Sized, Iterable[_KT_co], Protocol): ...
+class SupportsGetItemViewable(Viewable[_KT], SupportsGetItem[_KT, _VT_co], Protocol): ...

stdlib/typing.pyi

@@ -5,7 +5,7 @@ import collections  # noqa: F401  # pyright: ignore[reportUnusedImport]
 import sys
 import typing_extensions
 from _collections_abc import dict_items, dict_keys, dict_values
-from _typeshed import IdentityFunction, ReadableBuffer, SupportsKeysAndGetItem
+from _typeshed import IdentityFunction, ReadableBuffer, SupportsGetItemViewable, SupportsKeysAndGetItem, Viewable
 from abc import ABCMeta, abstractmethod
 from re import Match as Match, Pattern as Pattern
 from types import (
@@ -703,11 +703,11 @@ class MutableSet(AbstractSet[_T]):
     def __isub__(self, it: AbstractSet[Any]) -> typing_extensions.Self: ...
 
 class MappingView(Sized):
-    def __init__(self, mapping: Mapping[Any, Any]) -> None: ...  # undocumented
+    def __init__(self, mapping: Sized) -> None: ...  # undocumented
     def __len__(self) -> int: ...
 
 class ItemsView(MappingView, AbstractSet[tuple[_KT_co, _VT_co]], Generic[_KT_co, _VT_co]):
-    def __init__(self, mapping: Mapping[_KT_co, _VT_co]) -> None: ...  # undocumented
+    def __init__(self, mapping: SupportsGetItemViewable[_KT_co, _VT_co]) -> None: ...  # undocumented
     def __and__(self, other: Iterable[Any]) -> set[tuple[_KT_co, _VT_co]]: ...
     def __rand__(self, other: Iterable[_T]) -> set[_T]: ...
     def __contains__(self, item: object) -> bool: ...
@@ -720,7 +720,7 @@ class ItemsView(MappingView, AbstractSet[tuple[_KT_co, _VT_co]], Generic[_KT_co,
     def __rxor__(self, other: Iterable[_T]) -> set[tuple[_KT_co, _VT_co] | _T]: ...
 
 class KeysView(MappingView, AbstractSet[_KT_co]):
-    def __init__(self, mapping: Mapping[_KT_co, Any]) -> None: ...  # undocumented
+    def __init__(self, mapping: Viewable[_KT_co]) -> None: ...  # undocumented
     def __and__(self, other: Iterable[Any]) -> set[_KT_co]: ...
     def __rand__(self, other: Iterable[_T]) -> set[_T]: ...
     def __contains__(self, key: object) -> bool: ...
@@ -733,7 +733,7 @@ class KeysView(MappingView, AbstractSet[_KT_co]):
     def __rxor__(self, other: Iterable[_T]) -> set[_KT_co | _T]: ...
 
 class ValuesView(MappingView, Collection[_VT_co]):
-    def __init__(self, mapping: Mapping[Any, _VT_co]) -> None: ...  # undocumented
+    def __init__(self, mapping: SupportsGetItemViewable[Any, _VT_co]) -> None: ...  # undocumented
     def __contains__(self, value: object) -> bool: ...
     def __iter__(self) -> Iterator[_VT_co]: ...