From dec367261e7e2bb4dd42feeb58031abed2ade683 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Batuhan=20Ta=C5=9Fkaya?=
 <47358913+isidentical@users.noreply.github.com>
Date: Sat, 7 Dec 2019 14:05:07 +0300
Subject: bpo-38978: Implement __class_getitem__ for asyncio objects (GH-17491)

https://bugs.python.org/issue38978
---
 Lib/asyncio/futures.py                                    |  3 +++
 Lib/asyncio/queues.py                                     |  3 +++
 Lib/asyncio/tasks.py                                      |  3 +++
 .../next/Library/2019-12-07-13-40-52.bpo-38978.R3gHZI.rst |  2 ++
 Modules/_asynciomodule.c                                  | 15 +++++++++++++++
 5 files changed, 26 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Library/2019-12-07-13-40-52.bpo-38978.R3gHZI.rst

diff --git a/Lib/asyncio/futures.py b/Lib/asyncio/futures.py
index 9afda22..a3cf379 100644
--- a/Lib/asyncio/futures.py
+++ b/Lib/asyncio/futures.py
@@ -103,6 +103,9 @@ class Future:
             context['source_traceback'] = self._source_traceback
         self._loop.call_exception_handler(context)
 
+    def __class_getitem__(cls, type):
+        return cls
+
     @property
     def _log_traceback(self):
         return self.__log_traceback
diff --git a/Lib/asyncio/queues.py b/Lib/asyncio/queues.py
index 390ae9a..cd3f7c6 100644
--- a/Lib/asyncio/queues.py
+++ b/Lib/asyncio/queues.py
@@ -76,6 +76,9 @@ class Queue:
     def __str__(self):
         return f'<{type(self).__name__} {self._format()}>'
 
+    def __class_getitem__(cls, type):
+        return cls
+
     def _format(self):
         result = f'maxsize={self._maxsize!r}'
         if getattr(self, '_queue', None):
diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 38d9827..894d28e 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -175,6 +175,9 @@ class Task(futures._PyFuture):  # Inherit Python Task implementation
             self._loop.call_exception_handler(context)
         super().__del__()
 
+    def __class_getitem__(cls, type):
+        return cls
+
     def _repr_info(self):
         return base_tasks._task_repr_info(self)
 
diff --git a/Misc/NEWS.d/next/Library/2019-12-07-13-40-52.bpo-38978.R3gHZI.rst b/Misc/NEWS.d/next/Library/2019-12-07-13-40-52.bpo-38978.R3gHZI.rst
new file mode 100644
index 0000000..8b2eab0
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-12-07-13-40-52.bpo-38978.R3gHZI.rst
@@ -0,0 +1,2 @@
+Implement ``__class_getitem__`` on asyncio objects (Future, Task, Queue).
+Patch by Batuhan Taskaya.
diff --git a/Modules/_asynciomodule.c b/Modules/_asynciomodule.c
index aa46e3c..2d14744 100644
--- a/Modules/_asynciomodule.c
+++ b/Modules/_asynciomodule.c
@@ -1381,6 +1381,12 @@ finally:
     PyErr_Restore(error_type, error_value, error_traceback);
 }
 
+static PyObject *
+future_cls_getitem(PyObject *cls, PyObject *type)
+{
+    Py_INCREF(cls);
+    return cls;
+}
 
 static PyAsyncMethods FutureType_as_async = {
     (unaryfunc)future_new_iter,         /* am_await */
@@ -1400,6 +1406,7 @@ static PyMethodDef FutureType_methods[] = {
     _ASYNCIO_FUTURE_DONE_METHODDEF
     _ASYNCIO_FUTURE_GET_LOOP_METHODDEF
     _ASYNCIO_FUTURE__REPR_INFO_METHODDEF
+    {"__class_getitem__", future_cls_getitem, METH_O|METH_CLASS, NULL},
     {NULL, NULL}        /* Sentinel */
 };
 
@@ -2429,6 +2436,13 @@ done:
     FutureObj_finalize((FutureObj*)task);
 }
 
+static PyObject *
+task_cls_getitem(PyObject *cls, PyObject *type)
+{
+    Py_INCREF(cls);
+    return cls;
+}
+
 static void TaskObj_dealloc(PyObject *);  /* Needs Task_CheckExact */
 
 static PyMethodDef TaskType_methods[] = {
@@ -2449,6 +2463,7 @@ static PyMethodDef TaskType_methods[] = {
     _ASYNCIO_TASK_GET_NAME_METHODDEF
     _ASYNCIO_TASK_SET_NAME_METHODDEF
     _ASYNCIO_TASK_GET_CORO_METHODDEF
+    {"__class_getitem__", task_cls_getitem, METH_O|METH_CLASS, NULL},
     {NULL, NULL}        /* Sentinel */
 };
 
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