Parameterize SupportsItems to handle Mapping key invariance (#7426)

Author: nateprewitt

src/requests/_types.py

@@ -20,6 +20,8 @@
 )
 
 _T_co = TypeVar("_T_co", covariant=True)
+_KT_co = TypeVar("_KT_co", covariant=True)
+_VT_co = TypeVar("_VT_co", covariant=True)
 
 
 @runtime_checkable
@@ -28,8 +30,8 @@ def read(self, length: int = ..., /) -> _T_co: ...
 
 
 @runtime_checkable
-class SupportsItems(Protocol):
-    def items(self) -> Iterable[tuple[Any, Any]]: ...
+class SupportsItems(Protocol[_KT_co, _VT_co]):
+    def items(self) -> Iterable[tuple[_KT_co, _VT_co]]: ...
 
 
 # These are needed at runtime for default_hooks() return type
@@ -79,15 +81,15 @@ class _ValidatedRequest(PreparedRequest):
         str | bytes | int | float | Iterable[str | bytes | int | float] | None
     )
     ParamsType: TypeAlias = (
-        Mapping[_ParamsMappingKeyType, _ParamsMappingValueType]
+        SupportsItems[_ParamsMappingKeyType, _ParamsMappingValueType]
         | tuple[tuple[_ParamsMappingKeyType, _ParamsMappingValueType], ...]
         | Iterable[tuple[_ParamsMappingKeyType, _ParamsMappingValueType]]
         | str
         | bytes
         | None
     )
 
-    KVDataType: TypeAlias = Iterable[tuple[Any, Any]] | Mapping[Any, Any]
+    KVDataType: TypeAlias = Iterable[tuple[Any, Any]] | SupportsItems[Any, Any]
 
     RawDataType: TypeAlias = KVDataType | str | bytes
     StreamDataType: TypeAlias = SupportsRead[str | bytes]

src/requests/utils.py

@@ -147,7 +147,7 @@ def proxy_bypass(host: str) -> bool:  # noqa
 
 
 def dict_to_sequence(
-    d: _t.SupportsItems | Iterable[tuple[Any, Any]],
+    d: _t.SupportsItems[Any, Any] | Iterable[tuple[Any, Any]],
 ) -> Iterable[tuple[Any, Any]]:
     """Returns an internal sequence dictionary update."""
 
@@ -371,10 +371,10 @@ def from_key_val_list(
 def to_key_val_list(value: None) -> None: ...
 @overload
 def to_key_val_list(
-    value: Mapping[_KT, _VT] | Iterable[tuple[_KT, _VT]],
+    value: _t.SupportsItems[_KT, _VT] | Iterable[tuple[_KT, _VT]],
 ) -> list[tuple[_KT, _VT]]: ...
 def to_key_val_list(
-    value: Mapping[_KT, _VT] | Iterable[tuple[_KT, _VT]] | None,
+    value: _t.SupportsItems[_KT, _VT] | Iterable[tuple[_KT, _VT]] | None,
 ) -> list[tuple[_KT, _VT]] | None:
     """Take an object and test to see if it can be represented as a
     dictionary. If it can be, return a list of tuples, e.g.,