Add nooz

newsfragments/266.bug.rst

@@ -0,0 +1,12 @@
+Fix graceful cancellation of daemon actors
+
+Previously, his was a bug where if the soft wait on a sub-process (the
+``await .proc.wait()``) in the reaper task teardown was cancelled we
+would fail over to the hard reaping sequence (meant for culling off any
+potential zombies via system kill signals). The hard reap has a timeout
+of 3s (currently though in theory we could make it shorter?) before
+system signalling kicks in. This means that any daemon actor still
+running during nursery exit would get hard reaped (3s later) instead of
+cancelled via IPC message. Now we catch the ``trio.Cancelled``, call
+``Portal.cancel_actor()`` on the daemon and expect the child to
+self-terminate after the runtime cancels and shuts down the process.

tractor/_spawn.py

@@ -298,11 +298,11 @@ async def new_proc(
                 try:
                     await proc.wait()
                 except trio.Cancelled:
-                    # if cancelled during a soft wait cancel the child
-                    # actor before entering the hard reap
-                    # sequence below. This means we try to do a
-                    # graceful teardown before getting out zombie
-                    # killing tools.
+                    # if cancelled during a soft wait, cancel the child
+                    # actor before entering the hard reap sequence
+                    # below. This means we try to do a graceful teardown
+                    # via sending a cancel message before getting out
+                    # zombie killing tools.
                     with trio.CancelScope(shield=True):
                         await portal.cancel_actor()
                     raise