Transition callback fired in spite of failed general validation

[Gurpartap Singh]

Even when the following general validation[1] fails, the changed state_event param passed from the form triggers it's transition callbacks to be fired.

  validate :validate_name_change, :on => :update

  def validate_name_change

    if name.to_s != name_was.to_s

      errors.add(:name, "can't be changed")

      return false

    end

  end

[1] not inside the state_machine block.

What's the way out? Sorry I have been asking a lot here lately, but I guess my questions and their subsequent answers would help others in doubt.

[Aaron Pfeifer]

Hey Gurpartap -

before_transition callbacks are run prior to validations.  after_transition callbacks are run after the record saves successfully.

There really aren't any transition callbacks that run after validations but prior to saving.

Hope this helps clarify things!

-Aaron

[Gurpartap Singh]

Shouldn't the transition callbacks only run after validation, before and after save?

[Aaron Pfeifer]

Validations need to run within the context of the state of a record.  In order for that to happen, the transition needs to start prior to validations getting run.  As a result, transition callbacks run prior to validations.

You can always customize this behavior using something like below, but I wouldn't recommend it.. (note that I haven't tested an implementation like this)

class Vehicle < ActiveRecord::Base

  ...

  state_machine :action => nil do

    before_transition {|vehicle, transition| ...}

    before_transition :save

    ...

  end

end

-Aaron