Partial typeshed cherry-pick: Add SupportsRichComparison type to _typeshed (#6583)

The original PR doesn't apply cleanly so I only included the changes to
builtins to avoid having to manually deal with all the conflicts.

Author: JukkaL

mypy/typeshed/stdlib/_typeshed/__init__.pyi

@@ -45,6 +45,26 @@ class SupportsGreaterThan(Protocol):
 
 SupportsGreaterThanT = TypeVar("SupportsGreaterThanT", bound=SupportsGreaterThan)  # noqa: Y001
 
+# Comparison protocols
+
+class SupportsDunderLT(Protocol):
+    def __lt__(self, __other: Any) -> Any: ...
+
+class SupportsDunderGT(Protocol):
+    def __gt__(self, __other: Any) -> Any: ...
+
+class SupportsDunderLE(Protocol):
+    def __le__(self, __other: Any) -> Any: ...
+
+class SupportsDunderGE(Protocol):
+    def __ge__(self, __other: Any) -> Any: ...
+
+class SupportsAllComparisons(SupportsDunderLT, SupportsDunderGT, SupportsDunderLE, SupportsDunderGE, Protocol): ...
+
+SupportsRichComparison = Union[SupportsDunderLT, SupportsDunderGT]
+SupportsRichComparisonT = TypeVar("SupportsRichComparisonT", bound=SupportsRichComparison)  # noqa: Y001
+SupportsAnyComparison = Union[SupportsDunderLE, SupportsDunderGE, SupportsDunderGT, SupportsDunderLT]
+
 class SupportsDivMod(Protocol[_T_contra, _T_co]):
     def __divmod__(self, __other: _T_contra) -> _T_co: ...
 

mypy/typeshed/stdlib/builtins.pyi

@@ -13,14 +13,12 @@ from _typeshed import (
     StrOrBytesPath,
     SupportsAnext,
     SupportsDivMod,
-    SupportsGreaterThan,
-    SupportsGreaterThanT,
     SupportsKeysAndGetItem,
     SupportsLenAndGetItem,
-    SupportsLessThan,
-    SupportsLessThanT,
     SupportsNext,
     SupportsRDivMod,
+    SupportsRichComparison,
+    SupportsRichComparisonT,
     SupportsTrunc,
     SupportsWrite,
 )
@@ -779,9 +777,9 @@ class list(MutableSequence[_T], Generic[_T]):
     def remove(self, __value: _T) -> None: ...
     def reverse(self) -> None: ...
     @overload
-    def sort(self: list[SupportsLessThanT], *, key: None = ..., reverse: bool = ...) -> None: ...
+    def sort(self: list[SupportsRichComparisonT], *, key: None = ..., reverse: bool = ...) -> None: ...
     @overload
-    def sort(self, *, key: Callable[[_T], SupportsLessThan], reverse: bool = ...) -> None: ...
+    def sort(self, *, key: Callable[[_T], SupportsRichComparison], reverse: bool = ...) -> None: ...
     def __len__(self) -> int: ...
     def __iter__(self) -> Iterator[_T]: ...
     def __str__(self) -> str: ...
@@ -1146,32 +1144,32 @@ class map(Iterator[_S], Generic[_S]):
 
 @overload
 def max(
-    __arg1: SupportsGreaterThanT, __arg2: SupportsGreaterThanT, *_args: SupportsGreaterThanT, key: None = ...
-) -> SupportsGreaterThanT: ...
+    __arg1: SupportsRichComparisonT, __arg2: SupportsRichComparisonT, *_args: SupportsRichComparisonT, key: None = ...
+) -> SupportsRichComparisonT: ...
 @overload
-def max(__arg1: _T, __arg2: _T, *_args: _T, key: Callable[[_T], SupportsGreaterThan]) -> _T: ...
+def max(__arg1: _T, __arg2: _T, *_args: _T, key: Callable[[_T], SupportsRichComparison]) -> _T: ...
 @overload
-def max(__iterable: Iterable[SupportsGreaterThanT], *, key: None = ...) -> SupportsGreaterThanT: ...
+def max(__iterable: Iterable[SupportsRichComparisonT], *, key: None = ...) -> SupportsRichComparisonT: ...
 @overload
-def max(__iterable: Iterable[_T], *, key: Callable[[_T], SupportsGreaterThan]) -> _T: ...
+def max(__iterable: Iterable[_T], *, key: Callable[[_T], SupportsRichComparison]) -> _T: ...
 @overload
-def max(__iterable: Iterable[SupportsGreaterThanT], *, key: None = ..., default: _T) -> SupportsGreaterThanT | _T: ...
+def max(__iterable: Iterable[SupportsRichComparisonT], *, key: None = ..., default: _T) -> SupportsRichComparisonT | _T: ...
 @overload
-def max(__iterable: Iterable[_T1], *, key: Callable[[_T1], SupportsGreaterThan], default: _T2) -> _T1 | _T2: ...
+def max(__iterable: Iterable[_T1], *, key: Callable[[_T1], SupportsRichComparison], default: _T2) -> _T1 | _T2: ...
 @overload
 def min(
-    __arg1: SupportsLessThanT, __arg2: SupportsLessThanT, *_args: SupportsLessThanT, key: None = ...
-) -> SupportsLessThanT: ...
+    __arg1: SupportsRichComparisonT, __arg2: SupportsRichComparisonT, *_args: SupportsRichComparisonT, key: None = ...
+) -> SupportsRichComparisonT: ...
 @overload
-def min(__arg1: _T, __arg2: _T, *_args: _T, key: Callable[[_T], SupportsLessThan]) -> _T: ...
+def min(__arg1: _T, __arg2: _T, *_args: _T, key: Callable[[_T], SupportsRichComparison]) -> _T: ...
 @overload
-def min(__iterable: Iterable[SupportsLessThanT], *, key: None = ...) -> SupportsLessThanT: ...
+def min(__iterable: Iterable[SupportsRichComparisonT], *, key: None = ...) -> SupportsRichComparisonT: ...
 @overload
-def min(__iterable: Iterable[_T], *, key: Callable[[_T], SupportsLessThan]) -> _T: ...
+def min(__iterable: Iterable[_T], *, key: Callable[[_T], SupportsRichComparison]) -> _T: ...
 @overload
-def min(__iterable: Iterable[SupportsLessThanT], *, key: None = ..., default: _T) -> SupportsLessThanT | _T: ...
+def min(__iterable: Iterable[SupportsRichComparisonT], *, key: None = ..., default: _T) -> SupportsRichComparisonT | _T: ...
 @overload
-def min(__iterable: Iterable[_T1], *, key: Callable[[_T1], SupportsLessThan], default: _T2) -> _T1 | _T2: ...
+def min(__iterable: Iterable[_T1], *, key: Callable[[_T1], SupportsRichComparison], default: _T2) -> _T1 | _T2: ...
 @overload
 def next(__i: SupportsNext[_T]) -> _T: ...
 @overload
@@ -1382,9 +1380,9 @@ def round(number: SupportsRound[_T], ndigits: SupportsIndex) -> _T: ...
 # for why arg 3 of `setattr` should be annotated with `Any` and not `object`
 def setattr(__obj: object, __name: str, __value: Any) -> None: ...
 @overload
-def sorted(__iterable: Iterable[SupportsLessThanT], *, key: None = ..., reverse: bool = ...) -> list[SupportsLessThanT]: ...
+def sorted(__iterable: Iterable[SupportsRichComparisonT], *, key: None = ..., reverse: bool = ...) -> list[SupportsRichComparisonT]: ...
 @overload
-def sorted(__iterable: Iterable[_T], *, key: Callable[[_T], SupportsLessThan], reverse: bool = ...) -> list[_T]: ...
+def sorted(__iterable: Iterable[_T], *, key: Callable[[_T], SupportsRichComparison], reverse: bool = ...) -> list[_T]: ...
 
 if sys.version_info >= (3, 8):
     @overload