asyncio: update cancels for py39 (#4135)

Co-authored-by: hauntsaninja <>

stdlib/3/asyncio/futures.pyi

@@ -46,7 +46,10 @@ class Future(Awaitable[_T], Iterable[_T]):
         @property
         def _callbacks(self: _S) -> List[Callable[[_S], Any]]: ...
         def add_done_callback(self: _S, __fn: Callable[[_S], Any]) -> None: ...
-    def cancel(self) -> bool: ...
+    if sys.version_info >= (3, 9):
+        def cancel(self, msg: Optional[str] = ...) -> bool: ...
+    else:
+        def cancel(self) -> bool: ...
     def cancelled(self) -> bool: ...
     def done(self) -> bool: ...
     def result(self) -> _T: ...

stdlib/3/asyncio/tasks.pyi

@@ -113,7 +113,10 @@ class Task(Future[_T], Generic[_T]):
         def set_name(self, __value: object) -> None: ...
     def get_stack(self, *, limit: int = ...) -> List[FrameType]: ...
     def print_stack(self, *, limit: int = ..., file: TextIO = ...) -> None: ...
-    def cancel(self) -> bool: ...
+    if sys.version_info >= (3, 9):
+        def cancel(self, msg: Optional[str] = ...) -> bool: ...
+    else:
+        def cancel(self) -> bool: ...
     if sys.version_info < (3, 7):
         def _wakeup(self, fut: Future[Any]) -> None: ...
 

tests/stubtest_whitelists/py39.txt

@@ -16,18 +16,14 @@ ast.Str.__new__
 asyncio.AbstractEventLoop.sock_sendfile
 asyncio.Future.__init__
 asyncio.Future._callbacks
-asyncio.Future.cancel
 asyncio.Handle.__init__
-asyncio.Task.cancel
 asyncio.TimerHandle.__init__
 asyncio.events.AbstractEventLoop.sock_sendfile
 asyncio.events.Handle.__init__
 asyncio.events.TimerHandle.__init__
 asyncio.futures.Future.__init__
 asyncio.futures.Future._callbacks
-asyncio.futures.Future.cancel
 asyncio.proactor_events._ProactorBasePipeTransport.__del__
-asyncio.tasks.Task.cancel
 builtins.bytearray.extend
 builtins.bytearray.pop
 builtins.compile