Handling of current state when persisted state is invalid

[pascal-za]

Given

class Robot
  include Stateflow

  stateflow do
    state :red, :green
  end
end

robot = Robot.new
def robot.load_from_persistence
  :some_invalid_state
end

> robot.green?
NoMethodError: undefined method `name' for nil:NilClass
    from .../stateflow-0.4.2/lib/stateflow.rb:25:in `new?'

The error isn't immediately obvious to the user/developer.

Possible solutions:

• Revert to initial state if the persisted state is invalid
• Raise a specific exception in current_state specifically informing the user of the invalid state

Let me know what direction you want to go with this and I'll submit a patch.

[cgriego]

I ran into this today. An unpersisted model was set with an invalid state to prove that the validations would not allow it and I later added an :if => :my_state? validation conditional and then validating the invalid model raised an exception.