simplify subprocess state changes

SpiffWorkflow/bpmn/specs/mixins/subworkflow_task.py

@@ -47,14 +47,12 @@ def _on_subworkflow_completed(self, subworkflow, my_task):
         # could be used to run post-completed actions automatically.
         # However, until I align the events with state transitions, I don't want to encourage external use of
         # callback methods (though completed event is not going to change).
-        if my_task.state is TaskState.COMPLETED:
-            my_task._set_state(TaskState.READY)
+        my_task._set_state(TaskState.READY)
 
     def _update_hook(self, my_task):
         subprocess = my_task.workflow.top_workflow.subprocesses.get(my_task.id)
         if subprocess is None:
             super()._update_hook(my_task)
-            self.create_workflow(my_task)
             self.start_workflow(my_task)
             my_task._set_state(TaskState.STARTED)
         else:
@@ -72,16 +70,12 @@ def copy_data(self, my_task, subworkflow):
     def update_data(self, my_task, subworkflow):
         my_task.data = deepcopy(subworkflow.last_task.data)
 
-    def create_workflow(self, my_task):
+    def start_workflow(self, my_task):
         subworkflow = my_task.workflow.top_workflow.create_subprocess(my_task, self.spec)
         subworkflow.completed_event.connect(self._on_subworkflow_completed, my_task)
-
-    def start_workflow(self, my_task):
-        subworkflow = my_task.workflow.top_workflow.get_subprocess(my_task)
         self.copy_data(my_task, subworkflow)
         start = subworkflow.get_next_task(spec_name='Start')
         start.run()
-        my_task._set_state(TaskState.WAITING)
 
 
 class CallActivity(SubWorkflowTask):