Enforce creation of objects with initial/default state?

[moseb]

Hi!

I have an FSM that looks like this

[review] -> active <--> paused 
   |           |           |
   |           v           |
   \------> deleted <------/

review is the initial state.

Now I noticed, that both .save and __init__ of my model allow direct creation with states that are not review, not the default/initial state. There is custom code similar to this, to enforce that behavior:

    def _deny_creation_with_non_initial_state(self):
        if self.pk is None and self.status == ............:
            raise TransitionNotAllowed()

    def save(self, **kwargs):
        self._deny_creation_with_non_initial_state()
        super().save(**kwargs)

I have a feeling though that my approach is more complicated than necessary. Is there a way to add transitions from before existence to object creation a la source=None, target='review' or so? Any ideas?

Thanks!

[kmmbvnr]

Yeah, Django-fsm seems lack of notion of initial starting state, so there is no restrictions on it.

That's interesting point for design.

[jordanmkoncz]

I've used django-fsm in a few projects and also had this question about how I can enforce new objects to be created with a particular status. @moseb your code seems like a decent solution, but it would be great if django-fsm provided a nice way to enforce this.