Merge pull request troessner#48 from zmillman/master

README info on write_state_without_persistence

README.rdoc

@@ -55,6 +55,14 @@ you: <tt>discontinue</tt> and <tt>discontinue!</tt>. Both events will call
 <tt>write_state_without_persistence</tt> on successful transition, but only the
 bang(!)-version will call <tt>write_state</tt>.
 
+Note that <tt>write_state_without_persistence</tt> is not defined for you in Rails or in the transitions gem, so if you want the state attribute to be updated, you must define <tt>write_state_without_persistence</tt> yourself.
+
+The following is an example implementation:
+
+  def write_state_without_persistence(sm, new_state)
+    self.state = new_state.to_s
+  end
+
 == Automatic scope generation
 
 `transitions` will automatically generate scopes for you if you are using ActiveRecord and tell it to do so via the `auto_scopes` option:

lib/active_model/transitions.rb

@@ -45,16 +45,19 @@ def reload(options = nil)
     protected
 
     def write_state(state_machine, state)
-      ivar = state_machine.current_state_variable
       prev_state = current_state(state_machine.name)
-      instance_variable_set(ivar, state)
-      self.state = state.to_s
+      write_state_without_persistence(state_machine, state)
       save!
     rescue ActiveRecord::RecordInvalid
-      self.state = prev_state.to_s
-      instance_variable_set(ivar, prev_state)
+      write_state_without_persistence(state_machine, prev_state)
       raise
     end
+
+    def write_state_without_persistence(state_machine, state)
+      ivar = state_machine.current_state_variable
+      instance_variable_set(ivar, state)
+      self.state = state.to_s
+    end
 
     def read_state(state_machine)
       self.state && self.state.to_sym