bpo-46829: Deprecate passing a message into Future.cancel() and Task.cancel() (GH-31840)

After a long deliberation we ended up feeling that the message argument for Future.cancel(), added in 3.9, was a bad idea, so we're deprecating it in 3.11 and plan to remove it in 3.13.

2 files changed, 11 insertions, 0 deletions

diff --git a/Lib/asyncio/futures.py b/Lib/asyncio/futures.py
index bfd4ee9..08c79e7 100644
--- a/Lib/asyncio/futures.py
+++ b/Lib/asyncio/futures.py
@@ -8,6 +8,7 @@ import concurrent.futures
 import contextvars
 import logging
 import sys
+import warnings
 from types import GenericAlias
 
 from . import base_futures
@@ -150,6 +151,11 @@ class Future:
         change the future's state to cancelled, schedule the callbacks and
         return True.
         """
+        if msg is not None:
+            warnings.warn("Passing 'msg' argument to Future.cancel() "
+                          "is deprecated since Python 3.11, and "
+                          "scheduled for removal in Python 3.14.",
+                          DeprecationWarning, stacklevel=2)
         self.__log_traceback = False
         if self._state != _PENDING:
             return False
diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index e876f8d..27fe58d 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -207,6 +207,11 @@ class Task(futures._PyFuture):  # Inherit Python Task implementation
 
         This also increases the task's count of cancellation requests.
         """
+        if msg is not None:
+            warnings.warn("Passing 'msg' argument to Task.cancel() "
+                          "is deprecated since Python 3.11, and "
+                          "scheduled for removal in Python 3.14.",
+                          DeprecationWarning, stacklevel=2)
         self._log_traceback = False
         if self.done():
             return False