fix task expire ... [skip ci]

Author: hjoliver

cylc/flow/task_pool.py

@@ -1654,8 +1654,14 @@ def _set_outputs(self, point, taskdef, outputs, flow_nums, flow_wait):
 
         # Try to spawn children of the outputs.
         for msg in good:
+            if msg == TASK_OUTPUT_EXPIRED:
+                # not caused by task messages
+                self._expire_task(itask)
+                self.spawn_on_output(itask, expired)  ## TODO CONTINUE FROM pr 5412
+            else: 
+                self.task_events_mgr.process_message(itask, logging.INFO, msg)
+            # TODO remove this - just log the actual spawning events
             LOG.info(f"[{itask}] Forced spawning on {msg}")
-            self.task_events_mgr.process_message(itask, logging.INFO, msg)
 
     def _set_prereqs(self, point, taskdef, prereqs, flow_nums, flow_wait):
         """Set given prerequisites of a target task.
@@ -1897,18 +1903,19 @@ def _set_expired_task(self, itask):
                 itask.get_point_as_seconds() +
                 itask.get_offset_as_seconds(itask.tdef.expiration_offset))
         if time() > itask.expire_time:
-            msg = 'Task expired (skipping job).'
-            LOG.warning(f"[{itask}] {msg}")
-            self.task_events_mgr.setup_event_handlers(itask, "expired", msg)
-            # TODO succeeded and expired states are useless due to immediate
-            # removal under all circumstances (unhandled failed is still used).
-            if itask.state_reset(TASK_STATUS_EXPIRED, is_held=False):
-                self.data_store_mgr.delta_task_state(itask)
-                self.data_store_mgr.delta_task_held(itask)
-            self.remove(itask, 'expired')
+            self._expire_task(itask)
             return True
         return False
 
+    def _expire_task(self, itask):
+        msg = 'Task expired (skipping job).'
+        LOG.warning(f"[{itask}] {msg}")
+        self.task_events_mgr.setup_event_handlers(itask, "expired", msg)
+        if itask.state_reset(TASK_STATUS_EXPIRED, is_held=False):
+            self.data_store_mgr.delta_task_state(itask)
+            self.data_store_mgr.delta_task_held(itask)
+        self.remove(itask, 'expired')
+
     def task_succeeded(self, id_):
         """Return True if task with id_ is in the succeeded state."""
         return any(