From 9c2942afe1b08fb406acec2ae0c563c392df804f Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Fri, 3 Sep 2021 22:54:10 +0100
Subject: [PATCH 01/19] Create test for suppressing cancellations

---
 Lib/test/test_asyncio/test_tasks.py | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py
index 92b1a43500311d..368988f6dcaa5e 100644
--- a/Lib/test/test_asyncio/test_tasks.py
+++ b/Lib/test/test_asyncio/test_tasks.py
@@ -1023,6 +1023,24 @@ def gen():
         loop.call_later(0.1, task.cancel)
         res = loop.run_until_complete(task)
         self.assertEqual(res, "ok")
+        
+    def test_wait_for_does_not_suppress_cancellation(self):
+        async def inner():
+            return
+
+        async def with_for_coro():
+            await wait_for(inner(), timeout=1)
+            assert False, 'End of with_for_coro. Should not be reached!'
+
+        async def main(self):
+            task = asyncio.create_task(with_for_coro())
+            await asyncio.sleep(0)
+            self.assertFalse(task.done())
+            task.cancel()
+            with self.assertRaises(asyncio.CancelledError):
+                await task
+                
+        asyncio.run(main(self))
 
     def test_wait_for_waits_for_task_cancellation(self):
         loop = asyncio.new_event_loop()

From 7ff2c04b3273f84591f49656b1c96bb63d430f3f Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Fri, 3 Sep 2021 23:32:51 +0100
Subject: [PATCH 02/19] Update test_tasks.py

---
 Lib/test/test_asyncio/test_tasks.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py
index 368988f6dcaa5e..952d38887ae27b 100644
--- a/Lib/test/test_asyncio/test_tasks.py
+++ b/Lib/test/test_asyncio/test_tasks.py
@@ -1026,13 +1026,13 @@ def gen():
         
     def test_wait_for_does_not_suppress_cancellation(self):
         async def inner():
-            return
+            await asyncio.sleep(0)
 
         async def with_for_coro():
             await wait_for(inner(), timeout=1)
             assert False, 'End of with_for_coro. Should not be reached!'
 
-        async def main(self):
+        async def main():
             task = asyncio.create_task(with_for_coro())
             await asyncio.sleep(0)
             self.assertFalse(task.done())
@@ -1040,7 +1040,7 @@ async def main(self):
             with self.assertRaises(asyncio.CancelledError):
                 await task
                 
-        asyncio.run(main(self))
+        asyncio.run(main())
 
     def test_wait_for_waits_for_task_cancellation(self):
         loop = asyncio.new_event_loop()

From cdaa9c87ff4152d0b5d2ce6c2eea85d46105dfff Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Fri, 3 Sep 2021 23:48:24 +0100
Subject: [PATCH 03/19] Update test_tasks.py

---
 Lib/test/test_asyncio/test_tasks.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py
index 952d38887ae27b..b88f8c5d74e8da 100644
--- a/Lib/test/test_asyncio/test_tasks.py
+++ b/Lib/test/test_asyncio/test_tasks.py
@@ -1026,7 +1026,7 @@ def gen():
         
     def test_wait_for_does_not_suppress_cancellation(self):
         async def inner():
-            await asyncio.sleep(0)
+            await asyncio.sleep(.1)
 
         async def with_for_coro():
             await wait_for(inner(), timeout=1)
@@ -1034,7 +1034,7 @@ async def with_for_coro():
 
         async def main():
             task = asyncio.create_task(with_for_coro())
-            await asyncio.sleep(0)
+            await asyncio.sleep(.1)
             self.assertFalse(task.done())
             task.cancel()
             with self.assertRaises(asyncio.CancelledError):

From 342222fcebfe8c6798619485bb1302597fce912c Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Sat, 4 Sep 2021 00:08:45 +0100
Subject: [PATCH 04/19] Update test_tasks.py

---
 Lib/test/test_asyncio/test_tasks.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py
index b88f8c5d74e8da..6e111b73e08e0c 100644
--- a/Lib/test/test_asyncio/test_tasks.py
+++ b/Lib/test/test_asyncio/test_tasks.py
@@ -1026,15 +1026,15 @@ def gen():
         
     def test_wait_for_does_not_suppress_cancellation(self):
         async def inner():
-            await asyncio.sleep(.1)
+            return
 
         async def with_for_coro():
-            await wait_for(inner(), timeout=1)
+            await asyncio.wait_for(inner(), timeout=1)
             assert False, 'End of with_for_coro. Should not be reached!'
 
         async def main():
             task = asyncio.create_task(with_for_coro())
-            await asyncio.sleep(.1)
+            await asyncio.sleep(0)
             self.assertFalse(task.done())
             task.cancel()
             with self.assertRaises(asyncio.CancelledError):

From 01d988459f6020a5bd2df73946a358c07a93b74a Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Sat, 4 Sep 2021 00:26:38 +0100
Subject: [PATCH 05/19] Use a sentinel

---
 Lib/asyncio/tasks.py | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 9a9d0d6e3cc269..b60d02318690b3 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -25,6 +25,8 @@
 from . import futures
 from .coroutines import _is_coroutine
 
+_SENTINEL = object()
+
 # Helper to generate new task names
 # This uses itertools.count() instead of a "+= 1" operation because the latter
 # is not thread safe. See bpo-11866 for a longer explanation.
@@ -432,8 +434,8 @@ async def wait_for(fut, timeout):
         # wait until the future completes or the timeout
         try:
             await waiter
-        except exceptions.CancelledError:
-            if fut.done():
+        except exceptions.CancelledError as e:
+            if fut.done() and _SENTINEL in e.args:
                 return fut.result()
             else:
                 fut.remove_done_callback(cb)
@@ -516,7 +518,7 @@ async def _cancel_and_wait(fut, loop):
     fut.add_done_callback(cb)
 
     try:
-        fut.cancel()
+        fut.cancel(_SENTINEL)
         # We cannot wait on *fut* directly to make
         # sure _cancel_and_wait itself is reliably cancellable.
         await waiter

From af96f10553d835dfef8f31626987205e43b0e73b Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Sat, 4 Sep 2021 15:18:59 +0100
Subject: [PATCH 06/19] Fix test for issue37658

---
 Lib/test/test_asyncio/test_tasks.py | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py
index 6e111b73e08e0c..13e1466e2a97ab 100644
--- a/Lib/test/test_asyncio/test_tasks.py
+++ b/Lib/test/test_asyncio/test_tasks.py
@@ -1009,20 +1009,15 @@ def gen():
         self.assertEqual(res, "ok")
 
     def test_wait_for_cancellation_race_condition(self):
-        def gen():
-            yield 0.1
-            yield 0.1
-            yield 0.1
-            yield 0.1
+        async def inner():
+            await wait_for(asyncio.sleep(1), timeout=2)
+            return 1
 
-        loop = self.new_test_loop(gen)
+        async def main():
+            result = await wait_for(inner(), timeout=1)
+            assert result == 1
 
-        fut = self.new_future(loop)
-        loop.call_later(0.1, fut.set_result, "ok")
-        task = loop.create_task(asyncio.wait_for(fut, timeout=1))
-        loop.call_later(0.1, task.cancel)
-        res = loop.run_until_complete(task)
-        self.assertEqual(res, "ok")
+        asyncio.run(main())
         
     def test_wait_for_does_not_suppress_cancellation(self):
         async def inner():

From 1e5233df040dcf536db533162423160bf3c66232 Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Sat, 4 Sep 2021 15:32:37 +0100
Subject: [PATCH 07/19] Update test_tasks.py

---
 Lib/test/test_asyncio/test_tasks.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py
index 13e1466e2a97ab..1d61c354811435 100644
--- a/Lib/test/test_asyncio/test_tasks.py
+++ b/Lib/test/test_asyncio/test_tasks.py
@@ -1010,11 +1010,11 @@ def gen():
 
     def test_wait_for_cancellation_race_condition(self):
         async def inner():
-            await wait_for(asyncio.sleep(1), timeout=2)
+            await asyncio.wait_for(asyncio.sleep(1), timeout=2)
             return 1
 
         async def main():
-            result = await wait_for(inner(), timeout=1)
+            result = await asyncio.wait_for(inner(), timeout=1)
             assert result == 1
 
         asyncio.run(main())

From 743177e1102490f7a288c94b888328ac1c7ed2c1 Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Sat, 4 Sep 2021 15:49:35 +0100
Subject: [PATCH 08/19] Fix original issue

---
 Lib/asyncio/tasks.py | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index b60d02318690b3..127004bd6d8709 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -457,11 +457,9 @@ async def wait_for(fut, timeout):
             # exception, we should re-raise it
             # See https://bugs.python.org/issue40607
             try:
-                fut.result()
+                return fut.result()
             except exceptions.CancelledError as exc:
                 raise exceptions.TimeoutError() from exc
-            else:
-                raise exceptions.TimeoutError()
     finally:
         timeout_handle.cancel()
 

From d7c0965bc91568bb8f531b329aa9fc8395f2021d Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Sat, 4 Sep 2021 16:07:14 +0100
Subject: [PATCH 09/19] Remove test

---
 Lib/test/test_asyncio/test_tasks.py | 18 ------------------
 1 file changed, 18 deletions(-)

diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py
index 1d61c354811435..0ea5152789fa24 100644
--- a/Lib/test/test_asyncio/test_tasks.py
+++ b/Lib/test/test_asyncio/test_tasks.py
@@ -1114,24 +1114,6 @@ async def inner():
         with self.assertRaises(FooException):
             loop.run_until_complete(foo())
 
-    def test_wait_for_raises_timeout_error_if_returned_during_cancellation(self):
-        loop = asyncio.new_event_loop()
-        self.addCleanup(loop.close)
-
-        async def foo():
-            async def inner():
-                try:
-                    await asyncio.sleep(0.2)
-                except asyncio.CancelledError:
-                    return 42
-
-            inner_task = self.new_task(loop, inner())
-
-            await asyncio.wait_for(inner_task, timeout=_EPSILON)
-
-        with self.assertRaises(asyncio.TimeoutError):
-            loop.run_until_complete(foo())
-
     def test_wait_for_self_cancellation(self):
         loop = asyncio.new_event_loop()
         self.addCleanup(loop.close)

From 4eb5de29b4f9ba30ebe8ee23cabcd11631b95452 Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Mon, 29 Nov 2021 17:18:42 +0000
Subject: [PATCH 10/19] Create 2021-11-29-17-17-45.bpo-42130.Ho8dUh.rst

---
 .../NEWS.d/next/Library/2021-11-29-17-17-45.bpo-42130.Ho8dUh.rst | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Library/2021-11-29-17-17-45.bpo-42130.Ho8dUh.rst

diff --git a/Misc/NEWS.d/next/Library/2021-11-29-17-17-45.bpo-42130.Ho8dUh.rst b/Misc/NEWS.d/next/Library/2021-11-29-17-17-45.bpo-42130.Ho8dUh.rst
new file mode 100644
index 00000000000000..8e6e00fadf0102
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2021-11-29-17-17-45.bpo-42130.Ho8dUh.rst
@@ -0,0 +1 @@
+Fix issue where ``asyncio.wait_for()`` may suppress an explicit cancellation.

From a8f5c1fe4d7c86c91f72b612072153d6e388253d Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Wed, 1 Dec 2021 17:05:50 +0000
Subject: [PATCH 11/19] Compare to tuple

Co-authored-by: Andrew Svetlov <andrew.svetlov@gmail.com>
---
 Lib/asyncio/tasks.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 66962c2162f796..a3c75fa918ba22 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -433,7 +433,7 @@ async def wait_for(fut, timeout):
         try:
             await waiter
         except exceptions.CancelledError as e:
-            if fut.done() and _SENTINEL in e.args:
+            if fut.done() and e.args == (_SENTINEL,):
                 return fut.result()
             else:
                 fut.remove_done_callback(cb)

From 5de6b796959cdd4a74107a28dbd50589088ba8ef Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Wed, 1 Dec 2021 17:12:21 +0000
Subject: [PATCH 12/19] Use enum for sentinel

---
 Lib/asyncio/tasks.py | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index a3c75fa918ba22..0afb6b8bcf58d9 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -25,7 +25,8 @@
 from . import futures
 from .coroutines import _is_coroutine
 
-_SENTINEL = object()
+_SENTINEL = enum.Enum("_SENTINEL", "sentinel")
+sentinel = _SENTINEL.sentinel
 
 # Helper to generate new task names
 # This uses itertools.count() instead of a "+= 1" operation because the latter
@@ -433,7 +434,7 @@ async def wait_for(fut, timeout):
         try:
             await waiter
         except exceptions.CancelledError as e:
-            if fut.done() and e.args == (_SENTINEL,):
+            if fut.done() and e.args == (sentinel,):
                 return fut.result()
             else:
                 fut.remove_done_callback(cb)
@@ -514,7 +515,7 @@ async def _cancel_and_wait(fut, loop):
     fut.add_done_callback(cb)
 
     try:
-        fut.cancel(_SENTINEL)
+        fut.cancel(sentinel)
         # We cannot wait on *fut* directly to make
         # sure _cancel_and_wait itself is reliably cancellable.
         await waiter

From 5a79cf2d3b9dfdc5f439986fa11d9c1cc49424e1 Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Wed, 1 Dec 2021 17:26:42 +0000
Subject: [PATCH 13/19] Missing import

---
 Lib/asyncio/tasks.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 0afb6b8bcf58d9..118b0c50b5ef8a 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -11,6 +11,7 @@
 
 import concurrent.futures
 import contextvars
+import enum
 import functools
 import inspect
 import itertools

From 11e12141c20e8efb2387a5e19145359b2d6c748a Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Mon, 6 Dec 2021 23:35:59 +0000
Subject: [PATCH 14/19] Update tasks.py

---
 Lib/asyncio/tasks.py | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 118b0c50b5ef8a..96479b7b548f35 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -11,7 +11,6 @@
 
 import concurrent.futures
 import contextvars
-import enum
 import functools
 import inspect
 import itertools
@@ -26,9 +25,6 @@
 from . import futures
 from .coroutines import _is_coroutine
 
-_SENTINEL = enum.Enum("_SENTINEL", "sentinel")
-sentinel = _SENTINEL.sentinel
-
 # Helper to generate new task names
 # This uses itertools.count() instead of a "+= 1" operation because the latter
 # is not thread safe. See bpo-11866 for a longer explanation.
@@ -435,15 +431,12 @@ async def wait_for(fut, timeout):
         try:
             await waiter
         except exceptions.CancelledError as e:
-            if fut.done() and e.args == (sentinel,):
-                return fut.result()
-            else:
-                fut.remove_done_callback(cb)
-                # We must ensure that the task is not running
-                # after wait_for() returns.
-                # See https://bugs.python.org/issue32751
-                await _cancel_and_wait(fut, loop=loop)
-                raise
+            fut.remove_done_callback(cb)
+            # We must ensure that the task is not running
+            # after wait_for() returns.
+            # See https://bugs.python.org/issue32751
+            await _cancel_and_wait(fut, loop=loop)
+            raise
 
         if fut.done():
             return fut.result()
@@ -516,7 +509,7 @@ async def _cancel_and_wait(fut, loop):
     fut.add_done_callback(cb)
 
     try:
-        fut.cancel(sentinel)
+        fut.cancel()
         # We cannot wait on *fut* directly to make
         # sure _cancel_and_wait itself is reliably cancellable.
         await waiter

From 3a351268f41ec8ae9d8630c2470e9030cbc92431 Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Mon, 6 Dec 2021 23:36:42 +0000
Subject: [PATCH 15/19] Update tasks.py

---
 Lib/asyncio/tasks.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 96479b7b548f35..7fa66a0fd74b64 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -430,7 +430,7 @@ async def wait_for(fut, timeout):
         # wait until the future completes or the timeout
         try:
             await waiter
-        except exceptions.CancelledError as e:
+        except exceptions.CancelledError:
             fut.remove_done_callback(cb)
             # We must ensure that the task is not running
             # after wait_for() returns.

From df15ac1789f2c3eaf357477beda70eca8c2c3431 Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Wed, 15 Dec 2021 15:23:55 +0000
Subject: [PATCH 16/19] Update test_tasks.py

---
 Lib/test/test_asyncio/test_tasks.py | 69 ++++++++++++++++++++---------
 1 file changed, 49 insertions(+), 20 deletions(-)

diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py
index a2673d64700b34..5879dd128d1016 100644
--- a/Lib/test/test_asyncio/test_tasks.py
+++ b/Lib/test/test_asyncio/test_tasks.py
@@ -1009,34 +1009,63 @@ def gen():
         self.assertEqual(res, "ok")
 
     def test_wait_for_cancellation_race_condition(self):
+        def gen():
+            yield 0.1
+            yield 0.1
+            yield 0.1
+            yield 0.1
+
+        loop = self.new_test_loop(gen)
+
+        fut = self.new_future(loop)
+        # Test that if task is cancelled at the same time the future
+        # completes, the result is still returned.
+        loop.call_later(0.1, fut.set_result, "ok")
+        task = loop.create_task(asyncio.wait_for(fut, timeout=1))
+        loop.call_later(0.1, task.cancel)
+        res = loop.run_until_complete(task)
+        self.assertEqual(res, "ok")
+
+    def test_wait_for_suppress_cancellation(self):
+        def gen():
+            yield
+            yield 0.1
+            yield 0.1
+            yield 0.1
+
         async def inner():
-            with contextlib.suppress(asyncio.CancelledError):
+            try:
                 await asyncio.sleep(1)
-            return 1
+            except asyncio.CancelledError:
+                return "ok"
 
-        async def main():
-            result = await asyncio.wait_for(inner(), timeout=.01)
-            assert result == 1
+        loop = self.new_test_loop(gen)
 
-        asyncio.run(main())
+        fut = self.new_future(loop)
+        task = loop.create_task(asyncio.wait_for(inner(), timeout=1))
+        loop.call_later(0.1, task.cancel)
+        # Cancellation is suppressed in inner(), so should still return here.
+        res = loop.run_until_complete(task)
+        self.assertEqual(res, "ok")
 
-    def test_wait_for_does_not_suppress_cancellation(self):
-        async def inner():
-            return
+    def test_wait_for_cancellation_inner_race_condition(self):
+        def gen():
+            yield
+            yield 0.1
+            yield 0
+            yield 0
 
-        async def with_for_coro():
-            await asyncio.wait_for(inner(), timeout=1)
-            assert False, 'End of with_for_coro. Should not be reached!'
+        async def inner():
+            # Test that if fut completes at same time as timeout, the result
+            # is still returned.
+            return await asyncio.wait_for(fut, timeout=1)
 
-        async def main():
-            task = asyncio.create_task(with_for_coro())
-            await asyncio.sleep(0)
-            self.assertFalse(task.done())
-            task.cancel()
-            with self.assertRaises(asyncio.CancelledError):
-                await task
+        loop = self.new_test_loop(gen)
 
-        asyncio.run(main())
+        fut = self.new_future(loop)
+        loop.call_later(0.1, fut.set_result, "ok")
+        res = loop.run_until_complete(asyncio.wait_for(inner(), timeout=0.1))
+        self.assertEqual(res, "ok")
 
     def test_wait_for_waits_for_task_cancellation(self):
         loop = asyncio.new_event_loop()

From 73743665181b9e93b0e0611651a568d1ff554963 Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Wed, 15 Dec 2021 15:25:47 +0000
Subject: [PATCH 17/19] Update tasks.py

---
 Lib/asyncio/tasks.py | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 7fa66a0fd74b64..e13c0915ca7737 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -389,7 +389,7 @@ def _release_waiter(waiter, *args):
         waiter.set_result(None)
 
 
-async def wait_for(fut, timeout):
+async def wait_for(fut, timeout, *, loop=None):
     """Wait for the single Future or coroutine to complete, with timeout.
 
     Coroutine will be wrapped in Task.
@@ -402,7 +402,12 @@ async def wait_for(fut, timeout):
 
     This function is a coroutine.
     """
-    loop = events.get_running_loop()
+    if loop is None:
+        loop = events.get_running_loop()
+    else:
+        warnings.warn("The loop argument is deprecated since Python 3.8, "
+                      "and scheduled for removal in Python 3.10.",
+                      DeprecationWarning, stacklevel=2)
 
     if timeout is None:
         return await fut
@@ -421,7 +426,10 @@ async def wait_for(fut, timeout):
 
     waiter = loop.create_future()
     timeout_handle = loop.call_later(timeout, _release_waiter, waiter)
-    cb = functools.partial(_release_waiter, waiter)
+    #cb = functools.partial(_release_waiter, waiter)
+
+    def cb(f):
+        _release_waiter(waiter)
 
     fut = ensure_future(fut, loop=loop)
     fut.add_done_callback(cb)
@@ -431,12 +439,15 @@ async def wait_for(fut, timeout):
         try:
             await waiter
         except exceptions.CancelledError:
-            fut.remove_done_callback(cb)
-            # We must ensure that the task is not running
-            # after wait_for() returns.
-            # See https://bugs.python.org/issue32751
-            await _cancel_and_wait(fut, loop=loop)
-            raise
+            if fut.done():
+                return fut.result()
+            else:
+                fut.remove_done_callback(cb)
+                # We must ensure that the task is not running
+                # after wait_for() returns.
+                # See https://bugs.python.org/issue32751
+                await _cancel_and_wait(fut, loop=loop)
+                return fut.result()
 
         if fut.done():
             return fut.result()

From c6941733a7200d0a3bc4f18b8bf4567f18a0795a Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Wed, 15 Dec 2021 15:27:22 +0000
Subject: [PATCH 18/19] Revert mistaken changes.

---
 Lib/asyncio/tasks.py | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index e13c0915ca7737..a4d8b3f24fe287 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -389,7 +389,7 @@ def _release_waiter(waiter, *args):
         waiter.set_result(None)
 
 
-async def wait_for(fut, timeout, *, loop=None):
+async def wait_for(fut, timeout):
     """Wait for the single Future or coroutine to complete, with timeout.
 
     Coroutine will be wrapped in Task.
@@ -402,12 +402,7 @@ async def wait_for(fut, timeout, *, loop=None):
 
     This function is a coroutine.
     """
-    if loop is None:
-        loop = events.get_running_loop()
-    else:
-        warnings.warn("The loop argument is deprecated since Python 3.8, "
-                      "and scheduled for removal in Python 3.10.",
-                      DeprecationWarning, stacklevel=2)
+    loop = events.get_running_loop()
 
     if timeout is None:
         return await fut
@@ -426,10 +421,7 @@ async def wait_for(fut, timeout, *, loop=None):
 
     waiter = loop.create_future()
     timeout_handle = loop.call_later(timeout, _release_waiter, waiter)
-    #cb = functools.partial(_release_waiter, waiter)
-
-    def cb(f):
-        _release_waiter(waiter)
+    cb = functools.partial(_release_waiter, waiter)
 
     fut = ensure_future(fut, loop=loop)
     fut.add_done_callback(cb)

From cb593779071a0baf92c550df8082c7dfc48b7467 Mon Sep 17 00:00:00 2001
From: Sam Bull <aa6bs0@sambull.org>
Date: Wed, 15 Dec 2021 15:31:29 +0000
Subject: [PATCH 19/19] Update 2021-11-29-17-17-45.bpo-42130.Ho8dUh.rst

---
 .../next/Library/2021-11-29-17-17-45.bpo-42130.Ho8dUh.rst      | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Misc/NEWS.d/next/Library/2021-11-29-17-17-45.bpo-42130.Ho8dUh.rst b/Misc/NEWS.d/next/Library/2021-11-29-17-17-45.bpo-42130.Ho8dUh.rst
index 8e6e00fadf0102..ee837d5636cfcf 100644
--- a/Misc/NEWS.d/next/Library/2021-11-29-17-17-45.bpo-42130.Ho8dUh.rst
+++ b/Misc/NEWS.d/next/Library/2021-11-29-17-17-45.bpo-42130.Ho8dUh.rst
@@ -1 +1,2 @@
-Fix issue where ``asyncio.wait_for()`` may suppress an explicit cancellation.
+Fix issue where ``asyncio.wait_for()`` is cancelled when the coro
+actually suppresses the cancellation.