Re-raise any sidestepped trio.Cancelled

tractor/_spawn.py

@@ -283,14 +283,15 @@ async def new_proc(
                 await proc.wait()
 
             log.debug(f"Joined {proc}")
-            # pop child entry to indicate we are no longer managing this subactor
+            # pop child entry to indicate we no longer managing this subactor
             subactor, proc, portal = actor_nursery._children.pop(subactor.uid)
 
             # cancel result waiter that may have been spawned in
             # tandem if not done already
             if cancel_scope:
                 log.warning(
-                    f"Cancelling existing result waiter task for {subactor.uid}")
+                    "Cancelling existing result waiter task for "
+                    f"{subactor.uid}")
                 cancel_scope.cancel()
     else:
         # `multiprocessing`
@@ -409,8 +410,9 @@ async def mp_new_proc(
             # registered itself back we must be sure to try and clean
             # any process we may have started.
 
-            reaping_cancelled = False
-            cancel_scope = None
+            reaping_cancelled: bool = False
+            cancel_scope: Optional[trio.CancelScope] = None
+            cancel_exc: Optional[trio.Cancelled] = None
 
             if portal in actor_nursery._cancel_after_result_on_exit:
                 try:
@@ -422,7 +424,9 @@ async def mp_new_proc(
                         subactor,
                         errors
                     )
-                except trio.Cancelled:
+                except trio.Cancelled as err:
+                    cancel_exc = err
+
                     # if the reaping task was cancelled we may have hit
                     # a race where the subproc disconnected before we
                     # could send it a message to cancel (classic 2 generals)
@@ -437,20 +441,24 @@ async def mp_new_proc(
                         if cs.cancelled_caught:
                             proc.terminate()
 
-            if not reaping_cancelled:
-                if proc.is_alive():
-                    await proc_waiter(proc)
+            if not reaping_cancelled and proc.is_alive():
+                await proc_waiter(proc)
 
             # TODO: timeout block here?
             proc.join()
 
             log.debug(f"Joined {proc}")
-            # pop child entry to indicate we are no longer managing this subactor
+            # pop child entry to indicate we are no longer managing subactor
             subactor, proc, portal = actor_nursery._children.pop(subactor.uid)
 
             # cancel result waiter that may have been spawned in
             # tandem if not done already
             if cancel_scope:
                 log.warning(
-                    f"Cancelling existing result waiter task for {subactor.uid}")
+                    "Cancelling existing result waiter task for "
+                    f"{subactor.uid}")
                 cancel_scope.cancel()
+
+            elif reaping_cancelled:  # let the cancellation bubble up
+                assert cancel_exc
+                raise cancel_exc