Re-add save parameter to @transition decorator as a feature

[zenefitsbob]

I looked through the history and it looks like this used to be a feature. Why was it removed? I would like to use something like this for my own project.

@transition(... save=True)

Thanks for providing a nice library for me to use! :)

[kmmbvnr]

There are no advantages of having that inside transition decorator.

Just call .save() explicitly.

[zenefitsbob]

The advantage is more concise code:

post.publish()

Instead of:

post.publish()
post.save()

Am I missing something?

[kmmbvnr]

Concise is not an advantage.

Without explicit save you have no information is model saved or not, till take a look to models.py file.
This also makes hard to implement generic actions (it would save things twice)

[tachang]

I found it pretty useful though because sometimes I am in the shell and need to transition an element. Also I sometimes forget to save but I know I really want to transition a model.

[variable]

class Cart(TimestampModel):
    class STATE(object):
        NEW = 'new'
        LOCKED = 'locked'

    state = FSMField(default=STATE.NEW)

    @property
    def total(self):
        return sum(item.total for item in self.items.all())

    def create_order(self, data={}):
        assert self.items.count()
        # locks the cart itself and save state
        # https://github.com/kmmbvnr/django-fsm/issues/79
        self.lock()
        self.save()
        order = Order.objects.create(cart=self, total=self.total, data=data)
        return order

    @transition(field=state, source=STATE.NEW, target=STATE.LOCKED)
    def lock(self):
        # https://github.com/kmmbvnr/django-fsm/issues/79
        # would have been nice if this feature is accepted
        # so we don't have to have a dummy function just to change state...
        pass

if we have the save param, I can simply do

@transition(field=state, source=STATE.NEW, target=STATE.LOCKED)
def create_order(self, data={}):
        assert self.items.count()
        order = Order.objects.create(cart=self, total=self.total, data=data)
        return order

[kmmbvnr]

If I'll have a time to few more BSD licensed code, the next version of django-fsm would set state before function entry, like I did in the viewflow - https://github.com/viewflow/viewflow/blob/master/viewflow/fsm.py#L165

That would allow writing just

@transition(field=state, source=STATE.NEW, target=STATE.LOCKED)
def lock(self):
    this.save()

[oxalorg]

the next version of django-fsm would set state before function entry

@kmmbvnr Thank you for everything, but was this implemented? Can we use self.save() inside the transition function?

[kmmbvnr]

@oxalorg i'm working on new version of viewflow that would contain new version of state management. The main difference that fsm became decoupled from django models and composition used to make it plays together

no ETA on release though (