bpo-37703: improve asyncio.gather documentation regarding cancellation (GH-15312)
These changes updates the doc to comprehensively mention the behaviour of gather.cancel()
Automerge-Triggered-By: @asvetlov
diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 5e0692e..c37f0e1 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -729,6 +729,13 @@
the outer Future is *not* cancelled in this case. (This is to
prevent the cancellation of one child to cause other children to
be cancelled.)
+
+ If *return_exceptions* is False, cancelling gather() after it
+ has been marked done won't cancel any submitted awaitables.
+ For instance, gather can be marked done after propagating an
+ exception to the caller, therefore, calling ``gather.cancel()``
+ after catching an exception (raised by one of the awaitables) from
+ gather won't cancel any other awaitables.
"""
if not coros_or_futures:
if loop is None: