bpo-30048: asyncio: fix Task.cancel() was ignored. (GH-1546)
when there are no more `await` or `yield (from)` before return in coroutine,
cancel was ignored.
example:
async def coro():
asyncio.Task.current_task().cancel()
return 42
...
res = await coro() # should raise CancelledError
(cherry picked from commit 991adca012f5e106c2d4040ce619c696ba6f9c46)diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index f91e70a..d7867d1 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -180,7 +180,12 @@
else:
result = coro.throw(exc)
except StopIteration as exc:
- self.set_result(exc.value)
+ if self._must_cancel:
+ # Task is cancelled right before coro stops.
+ self._must_cancel = False
+ self.set_exception(futures.CancelledError())
+ else:
+ self.set_result(exc.value)
except futures.CancelledError:
super().cancel() # I.e., Future.cancel(self).
except Exception as exc: