--- /home/ncoghlan/devel/contextlib2/dev/typeshed_contextlib.pyi	2024-05-23 12:40:10.170754997 +1000
+++ /home/ncoghlan/devel/contextlib2/contextlib2/__init__.pyi	2024-05-23 16:47:15.874656809 +1000
@@ -1,3 +1,20 @@
+# Type hints copied from the typeshed project under the Apache License 2.0
+# https://github.com/python/typeshed/blob/64c85cdd449ccaff90b546676220c9ecfa6e697f/LICENSE
+
+# For updates: https://github.com/python/typeshed/blob/main/stdlib/contextlib.pyi
+
+# Last updated: 2024-05-22
+# Updated from: https://github.com/python/typeshed/blob/aa2d33df211e1e4f70883388febf750ac524d2bb/stdlib/contextlib.pyi
+# Saved to: dev/typeshed_contextlib.pyi
+
+# contextlib2 API adaptation notes:
+# * the various 'if True:' guards replace sys.version checks in the original
+#   typeshed file (those APIs are available on all supported versions)
+# * any commented out 'if True:' guards replace sys.version checks in the original
+#   typeshed file where the affected APIs haven't been backported yet
+# * deliberately omitted APIs are listed in `dev/mypy.allowlist`
+#   (e.g. deprecated experimental APIs that never graduated to the stdlib)
+
 import abc
 import sys
 from _typeshed import FileDescriptorOrPath, Unused
@@ -22,10 +39,10 @@
     "nullcontext",
 ]
 
-if sys.version_info >= (3, 10):
+if True:
     __all__ += ["aclosing"]
 
-if sys.version_info >= (3, 11):
+if True:
     __all__ += ["chdir"]
 
 _T = TypeVar("_T")
@@ -65,18 +82,14 @@
     func: Callable[..., Generator[_T_co, Any, Any]]
     args: tuple[Any, ...]
     kwds: dict[str, Any]
-    if sys.version_info >= (3, 9):
+    if True:
         def __exit__(
             self, typ: type[BaseException] | None, value: BaseException | None, traceback: TracebackType | None
         ) -> bool | None: ...
-    else:
-        def __exit__(
-            self, type: type[BaseException] | None, value: BaseException | None, traceback: TracebackType | None
-        ) -> bool | None: ...
 
 def contextmanager(func: Callable[_P, Iterator[_T_co]]) -> Callable[_P, _GeneratorContextManager[_T_co]]: ...
 
-if sys.version_info >= (3, 10):
+if True:
     _AF = TypeVar("_AF", bound=Callable[..., Awaitable[Any]])
 
     class AsyncContextDecorator:
@@ -94,17 +107,6 @@
             self, typ: type[BaseException] | None, value: BaseException | None, traceback: TracebackType | None
         ) -> bool | None: ...
 
-else:
-    class _AsyncGeneratorContextManager(AbstractAsyncContextManager[_T_co, bool | None]):
-        def __init__(self, func: Callable[..., AsyncIterator[_T_co]], args: tuple[Any, ...], kwds: dict[str, Any]) -> None: ...
-        gen: AsyncGenerator[_T_co, Any]
-        func: Callable[..., AsyncGenerator[_T_co, Any]]
-        args: tuple[Any, ...]
-        kwds: dict[str, Any]
-        async def __aexit__(
-            self, typ: type[BaseException] | None, value: BaseException | None, traceback: TracebackType | None
-        ) -> bool | None: ...
-
 def asynccontextmanager(func: Callable[_P, AsyncIterator[_T_co]]) -> Callable[_P, _AsyncGeneratorContextManager[_T_co]]: ...
 
 class _SupportsClose(Protocol):
@@ -116,7 +118,7 @@
     def __init__(self, thing: _SupportsCloseT) -> None: ...
     def __exit__(self, *exc_info: Unused) -> None: ...
 
-if sys.version_info >= (3, 10):
+if True:
     class _SupportsAclose(Protocol):
         def aclose(self) -> Awaitable[object]: ...
 
@@ -177,7 +179,7 @@
         self, exc_type: type[BaseException] | None, exc_value: BaseException | None, traceback: TracebackType | None, /
     ) -> bool: ...
 
-if sys.version_info >= (3, 10):
+if True:
     class nullcontext(AbstractContextManager[_T, None], AbstractAsyncContextManager[_T, None]):
         enter_result: _T
         @overload
@@ -189,17 +191,7 @@
         async def __aenter__(self) -> _T: ...
         async def __aexit__(self, *exctype: Unused) -> None: ...
 
-else:
-    class nullcontext(AbstractContextManager[_T, None]):
-        enter_result: _T
-        @overload
-        def __init__(self: nullcontext[None], enter_result: None = None) -> None: ...
-        @overload
-        def __init__(self: nullcontext[_T], enter_result: _T) -> None: ...  # pyright: ignore[reportInvalidTypeVarUse]  #11780
-        def __enter__(self) -> _T: ...
-        def __exit__(self, *exctype: Unused) -> None: ...
-
-if sys.version_info >= (3, 11):
+if True:
     _T_fd_or_any_path = TypeVar("_T_fd_or_any_path", bound=FileDescriptorOrPath)
 
     class chdir(AbstractContextManager[None, None], Generic[_T_fd_or_any_path]):