Don't raise if the task already have been cancelled explicitly

.gitignore

@@ -89,4 +89,4 @@ ENV/
 .ropeproject
 
 .mypy_cache
-.pytest_cache
+.pytest_cache

CHANGES.rst

@@ -10,6 +10,8 @@ CHANGES
 
 * Deprecate synchronous context manager usage
 
+* Don't raise `TimeoutError` if the task already have been cancelled explicitly (#229)
+
 3.0.1 (2018-10-09)
 ------------------
 

async_timeout/__init__.py

@@ -142,7 +142,7 @@ def reject(self) -> None:
         # cancel is maybe better name but
         # task.cancel() raises CancelledError in asyncio world.
         if self._state not in (_State.INIT, _State.ENTER):
-            raise RuntimeError("invalid state {}".format(self._state.value))
+            raise RuntimeError(f"invalid state {self._state.value}")
         self._reject()
 
     def _reject(self) -> None:
@@ -179,30 +179,31 @@ def shift_to(self, deadline: float) -> None:
             else:
                 # state is ENTER
                 raise asyncio.CancelledError
-        self._timeout_handler = self._loop.call_at(
-            deadline, self._on_timeout, self._task
-        )
+        self._timeout_handler = self._loop.call_at(deadline, self._on_timeout)
 
     def _do_enter(self) -> None:
         if self._state != _State.INIT:
-            raise RuntimeError("invalid state {}".format(self._state.value))
+            raise RuntimeError(f"invalid state {self._state.value}")
         self._state = _State.ENTER
 
     def _do_exit(self, exc_type: Type[BaseException]) -> None:
+        self._task = None  # Early drop circular reference
         if exc_type is asyncio.CancelledError and self._state == _State.TIMEOUT:
             self._timeout_handler = None
             raise asyncio.TimeoutError
-        # timeout is not expired
+        # timeout is not expired, propagate the exception
         self._state = _State.EXIT
         self._reject()
         return None
 
-    def _on_timeout(self, task: "asyncio.Task[None]") -> None:
+    def _on_timeout(self) -> None:
         # See Issue #229 and PR #230 for details
-        if task._fut_waiter and task._fut_waiter.cancelled():  # type: ignore[attr-defined]  # noqa: E501
-            return
-        task.cancel()
-        self._state = _State.TIMEOUT
+        self._loop.call_soon(self._cancel)
+
+    def _cancel(self) -> None:
+        if self._task is not None:
+            self._task.cancel()
+            self._state = _State.TIMEOUT
 
 
 def _current_task(loop: asyncio.AbstractEventLoop) -> "Optional[asyncio.Task[Any]]":

async_timeout/py.typed

@@ -1 +1 @@
-Placeholder
+Placeholder

requirements.txt

@@ -1,10 +1,10 @@
-isort==5.9.3
+-e .
 black==21.8b0; implementation_name=="cpython"
-pytest==6.2.5
-pytest-asyncio==0.15.1
-pytest-cov==2.12.1
 docutils==0.17.1
-mypy==0.910; implementation_name=="cpython"
 flake8==3.9.2
+isort==5.9.3
+mypy==0.910; implementation_name=="cpython"
 pre-commit==2.15
--e .
+pytest==6.2.5
+pytest-asyncio==0.15.1
+pytest-cov==2.12.1

tests/test_timeout.py

@@ -373,9 +373,9 @@ async def test_task(deadline: float, loop: asyncio.AbstractEventLoop) -> None:
         await t
 
 
-@pytest.mark.xfail(
-    reason="The test is CPU performance sensitive, might fail on slow CI box"
-)
+# @pytest.mark.xfail(
+#    reason="The test is CPU performance sensitive, might fail on slow CI box"
+# )
 @pytest.mark.skipif(sys.version_info < (3, 7), reason="Not supported in 3.6")
 @pytest.mark.asyncio
 async def test_race_condition_cancel_after() -> None:
@@ -396,7 +396,7 @@ async def test_task(deadline: float, loop: asyncio.AbstractEventLoop) -> None:
     loop = asyncio.get_running_loop()
     deadline = loop.time() + 1
     t = asyncio.create_task(test_task(deadline, loop))
-    loop.call_at(deadline + 0.0000000000001, t.cancel)
+    loop.call_at(deadline + 0.00000000001, t.cancel)
     # If we get a TimeoutError, then the code is broken.
     with pytest.raises(asyncio.CancelledError):
         await t