gh-113848: Handle CancelledError subclasses in asyncio TaskGroup() and timeout() (GH-113850)

1 files changed, 5 insertions, 3 deletions

diff --git a/Lib/asyncio/taskgroups.py b/Lib/asyncio/taskgroups.py
index cb9c1ce4d7d..e1c56d140be 100644
--- a/Lib/asyncio/taskgroups.py
+++ b/Lib/asyncio/taskgroups.py
@@ -73,8 +73,10 @@ class TaskGroup:
                 self._base_error is None):
             self._base_error = exc
 
-        propagate_cancellation_error = \
-            exc if et is exceptions.CancelledError else None
+        if et is not None and issubclass(et, exceptions.CancelledError):
+            propagate_cancellation_error = exc
+        else:
+            propagate_cancellation_error = None
         if self._parent_cancel_requested:
             # If this flag is set we *must* call uncancel().
             if self._parent_task.uncancel() == 0:
@@ -133,7 +135,7 @@ class TaskGroup:
         if propagate_cancellation_error and not self._errors:
             raise propagate_cancellation_error
 
-        if et is not None and et is not exceptions.CancelledError:
+        if et is not None and not issubclass(et, exceptions.CancelledError):
             self._errors.append(exc)
 
         if self._errors: