feat: Ignore missing event

Author: fgmacedo

statemachine/event.py

@@ -29,6 +29,7 @@ def trigger_wrapper():
         return machine._process(trigger_wrapper)
 
     def _trigger(self, trigger_data: TriggerData):
+        event_data = None
         state = trigger_data.machine.current_state
         for transition in state.transitions:
             if not transition.match(trigger_data.event):
@@ -39,9 +40,10 @@ def _trigger(self, trigger_data: TriggerData):
                 event_data.executed = True
                 break
         else:
-            raise TransitionNotAllowed(trigger_data.event, state)
+            if not trigger_data.machine.ignore_missing_event:
+                raise TransitionNotAllowed(trigger_data.event, state)
 
-        return event_data.result
+        return event_data.result if event_data else None
 
 
 def trigger_event_factory(event):

statemachine/statemachine.py

@@ -35,10 +35,12 @@ def __init__(
         state_field: str = "state",
         start_value: Any = None,
         rtc: bool = True,
+        ignore_missing_event: bool = False,
     ):
         self.model = model if model else Model()
         self.state_field = state_field
         self.start_value = start_value
+        self.ignore_missing_event = ignore_missing_event
         self.__rtc = rtc
         self.__processing: bool = False
         self._external_queue: deque = deque()

tests/examples/traffic_light_nested_machine.py

@@ -34,7 +34,7 @@ class red(State.Builder, enter="reset_elapsed"):
     def __init__(self, seconds_to_turn_state=5, seconds_running=20):
         self.seconds_to_turn_state = seconds_to_turn_state
         self.seconds_running = seconds_running
-        super().__init__(queued=True)
+        super().__init__(ignore_missing_event=True)
 
     def on_timer(self, event: str, source: State, target: State):
         print(f".. Running {event} from {source.id} to {target.id}")