Add context manager for contextvars.Token (3.14) (#13997)

Author: max-muoto

stdlib/@tests/stubtest_allowlists/py314.txt

@@ -6,8 +6,6 @@ _asyncio.all_tasks
 _asyncio.future_add_to_awaited_by
 _asyncio.future_discard_from_awaited_by
 _compression
-_contextvars.Token.__enter__
-_contextvars.Token.__exit__
 _ctypes.POINTER
 _ctypes.byref
 _ctypes.pointer
@@ -92,8 +90,6 @@ concurrent.futures.thread._worker
 configparser.__all__
 configparser.InvalidWriteError
 configparser.UnnamedSectionDisabledError
-contextvars.Token.__enter__
-contextvars.Token.__exit__
 ctypes.POINTER
 ctypes.byref
 ctypes.memoryview_at

stdlib/_contextvars.pyi

@@ -1,5 +1,6 @@
+import sys
 from collections.abc import Callable, Iterator, Mapping
-from types import GenericAlias
+from types import GenericAlias, TracebackType
 from typing import Any, ClassVar, Generic, TypeVar, final, overload
 from typing_extensions import ParamSpec, Self
 
@@ -35,6 +36,11 @@ class Token(Generic[_T]):
     MISSING: ClassVar[object]
     __hash__: ClassVar[None]  # type: ignore[assignment]
     def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
+    if sys.version_info >= (3, 14):
+        def __enter__(self) -> Self: ...
+        def __exit__(
+            self, exc_type: type[BaseException] | None, exc_value: BaseException | None, traceback: TracebackType | None
+        ) -> None: ...
 
 def copy_context() -> Context: ...