gh-91323: Revert "Allow overriding a future compliance check in asyncio.Task (GH-32197)" (GH-95442) (GH-95652)

This reverts commit d4bb38f.
(cherry picked from commit 0342c93)

Co-authored-by: Łukasz Langa <[email protected]>

Author: miss-islington

Doc/library/asyncio-extending.rst

@@ -63,12 +63,6 @@ For this purpose the following, *private* constructors are listed:
 
       *context* argument is added.
 
-.. method:: Task._check_future(future)
-
-   Return ``True`` if *future* is attached to the same loop as the task, ``False``
-   otherwise.
-
-   .. versionadded:: 3.11
 
 
 Task lifetime support

Lib/asyncio/tasks.py

@@ -252,10 +252,6 @@ def uncancel(self):
             self._num_cancels_requested -= 1
         return self._num_cancels_requested
 
-    def _check_future(self, future):
-        """Return False if task and future loops are not compatible."""
-        return futures._get_loop(future) is self._loop
-
     def __step(self, exc=None):
         if self.done():
             raise exceptions.InvalidStateError(
@@ -296,7 +292,7 @@ def __step(self, exc=None):
             blocking = getattr(result, '_asyncio_future_blocking', None)
             if blocking is not None:
                 # Yielded Future must come from Future.__iter__().
-                if not self._check_future(result):
+                if futures._get_loop(result) is not self._loop:
                     new_exc = RuntimeError(
                         f'Task {self!r} got Future '
                         f'{result!r} attached to a different loop')

Lib/test/test_asyncio/test_tasks.py

@@ -2384,13 +2384,7 @@ def add_done_callback(self, *args, **kwargs):
             return super().add_done_callback(*args, **kwargs)
 
     class Task(CommonFuture, BaseTask):
-        def __init__(self, *args, **kwargs):
-            self._check_future_called = 0
-            super().__init__(*args, **kwargs)
-
-        def _check_future(self, future):
-            self._check_future_called += 1
-            return super()._check_future(future)
+        pass
 
     class Future(CommonFuture, BaseFuture):
         pass
@@ -2416,8 +2410,6 @@ async def func():
             dict(fut.calls),
             {'add_done_callback': 1})
 
-        self.assertEqual(1, task._check_future_called)
-
     # Add patched Task & Future back to the test case
     cls.Task = Task
     cls.Future = Future

Modules/_asynciomodule.c

@@ -23,7 +23,6 @@ _Py_IDENTIFIER(call_soon);
 _Py_IDENTIFIER(cancel);
 _Py_IDENTIFIER(get_event_loop);
 _Py_IDENTIFIER(throw);
-_Py_IDENTIFIER(_check_future);
 
 
 /* State of the _asyncio module */
@@ -1810,8 +1809,6 @@ class _asyncio.Task "TaskObj *" "&Task_Type"
 static int task_call_step_soon(TaskObj *, PyObject *);
 static PyObject * task_wakeup(TaskObj *, PyObject *);
 static PyObject * task_step(TaskObj *, PyObject *);
-static int task_check_future(TaskObj *, PyObject *);
-static int task_check_future_exact(TaskObj *, PyObject *);
 
 /* ----- Task._step wrapper */
 
@@ -2286,28 +2283,14 @@ Returns the remaining number of cancellation requests.
 static PyObject *
 _asyncio_Task_uncancel_impl(TaskObj *self)
 /*[clinic end generated code: output=58184d236a817d3c input=68f81a4b90b46be2]*/
+/*[clinic end generated code]*/
 {
     if (self->task_num_cancels_requested > 0) {
         self->task_num_cancels_requested -= 1;
     }
     return PyLong_FromLong(self->task_num_cancels_requested);
 }
 
-/*[clinic input]
-_asyncio.Task._check_future -> bool
-
-    future: object
-
-Return False if task and future loops are not compatible.
-[clinic start generated code]*/
-
-static int
-_asyncio_Task__check_future_impl(TaskObj *self, PyObject *future)
-/*[clinic end generated code: output=a3bfba79295c8d57 input=3b1d6dfd6fe90aa5]*/
-{
-    return task_check_future_exact(self, future);
-}
-
 /*[clinic input]
 _asyncio.Task.get_stack
 
@@ -2533,7 +2516,6 @@ static PyMethodDef TaskType_methods[] = {
     _ASYNCIO_TASK_CANCEL_METHODDEF
     _ASYNCIO_TASK_CANCELLING_METHODDEF
     _ASYNCIO_TASK_UNCANCEL_METHODDEF
-    _ASYNCIO_TASK__CHECK_FUTURE_METHODDEF
     _ASYNCIO_TASK_GET_STACK_METHODDEF
     _ASYNCIO_TASK_PRINT_STACK_METHODDEF
     _ASYNCIO_TASK__MAKE_CANCELLED_ERROR_METHODDEF
@@ -2601,43 +2583,6 @@ TaskObj_dealloc(PyObject *self)
     Py_TYPE(task)->tp_free(task);
 }
 
-static int
-task_check_future_exact(TaskObj *task, PyObject *future)
-{
-    int res;
-    if (Future_CheckExact(future) || Task_CheckExact(future)) {
-        FutureObj *fut = (FutureObj *)future;
-        res = (fut->fut_loop == task->task_loop);
-    } else {
-        PyObject *oloop = get_future_loop(future);
-        if (oloop == NULL) {
-            return -1;
-        }
-        res = (oloop == task->task_loop);
-        Py_DECREF(oloop);
-    }
-    return res;
-}
-
-
-static int
-task_check_future(TaskObj *task, PyObject *future)
-{
-    if (Task_CheckExact(task)) {
-        return task_check_future_exact(task, future);
-    } else {
-        PyObject * ret = _PyObject_CallMethodIdOneArg((PyObject *)task,
-                                                      &PyId__check_future,
-                                                      future);
-        if (ret == NULL) {
-            return -1;
-        }
-        int is_true = PyObject_IsTrue(ret);
-        Py_DECREF(ret);
-        return is_true;
-    }
-}
-
 static int
 task_call_step_soon(TaskObj *task, PyObject *arg)
 {
@@ -2859,11 +2804,7 @@ task_step_impl(TaskObj *task, PyObject *exc)
         FutureObj *fut = (FutureObj*)result;
 
         /* Check if `result` future is attached to a different loop */
-        res = task_check_future(task, result);
-        if (res == -1) {
-            goto fail;
-        }
-        if (res == 0) {
+        if (fut->fut_loop != task->task_loop) {
             goto different_loop;
         }
 
@@ -2935,13 +2876,15 @@ task_step_impl(TaskObj *task, PyObject *exc)
         }
 
         /* Check if `result` future is attached to a different loop */
-        res = task_check_future(task, result);
-        if (res == -1) {
+        PyObject *oloop = get_future_loop(result);
+        if (oloop == NULL) {
             goto fail;
         }
-        if (res == 0) {
+        if (oloop != task->task_loop) {
+            Py_DECREF(oloop);
             goto different_loop;
         }
+        Py_DECREF(oloop);
 
         if (!blocking) {
             goto yield_insteadof_yf;