Question

When using state_machine, how can you conditionally validate fields in the below way?

state :unlit do      
end

state :fire do
  if is_big_fire?
    validates_presence_of :big_log
  end
  if is_small_fire?
    validates_presence_of :small_log
  end
end

It seems to just ignore the if conditions and validate everything inside the state D:

The only sort of solution I came up with was

validates_presence_of :big_log, :if  => Proc.new { |fire| fire.is_big_fire? }

But this gets nuts if there are more validations.

validates_presence_of :big_log, :if  => Proc.new { |fire| fire.is_big_fire? }
validates :fire_epicness_rating, :inclusion => { :in => %w(epic whowa RUNFORTHEHILLS) }, :if  => Proc.new { |fire| fire.is_big_fire? }
etc

Is there some nice way of neatly wrapping these in if blocks?

Answer 1

Grouping validations thanks to with_optionsis really neat. See here.