write_state_without_persistence confusion

[robolson]

While attempting to use this gem I kept running into the issue where the persistence method with a bang(!) was not working.

In the README it talks about how "both events will call write_state_without_persistence on successful transition". What it does not say is that write_state_without_persistence is not defined for you in Rails or in the transitions gem. Which leaves the gem author to implement this method if the non bang-version is going to do anything other than set the @default_current_state instance variable.

I added the following to my ActiveRecord user class:

def write_state_without_persistence(sm, new_state)
  self.state = new_state.to_s
end

which does the trick, but it also means self.state= is called once inside write_state and again inside write_state_without_persistence.

I feel like I am missing something here. What is the proper way to use this gem with the non bang(!)-versions of the events?

[venetanji]

Totally agree! I'm using mongoid. Consider something like:

  before_save :expire_free_trial

  def expire_free_trial
    begin
      trial_expired if Time.now  - created_at > FREE_TRIAL_PERIOD
      self.state = self.current_state
    rescue Transitions::InvalidTransition
    end
  end

It took me quite a while to figure out that line that sets the state attribute. I'd expect that to be set when the non-bang event fires. Perhaps that works only for active record?
Anyways I'm ok with it, but it should be more clear. Specially if you want to call a transition in a before_save...

[troessner]

@robolson, @venetanji could you submit a pull request which updates our documentation?
If not, I'll update when I find the time.

[zmillman]

As someone who stumbled on the project and tried to use it with ActiveRecord, this issue caused me a lot of confusion.

I expected the behavior of calling an event like article.publish to update the article.state attribute and was surprised when only current_state changed. Perhaps it would be best to define write_state_without_persistence as @robolson wrote it in the ActiveRecord::Transitions plugin?

[troessner]

Closed thanks to @zmillman