Support for configurable column names

README.rdoc

@@ -167,6 +167,20 @@ You can easily get a listing of all available states:
     state :closed
   end
 
+=== Configuring a different column name with ActiveRecord
+
+To use a different column than <tt>state</tt> to track it's value simply do this:
+
+  class Product < ActiveRecord::Base
+    include Transitions
+
+    state_machine :attribute_name => :different_column do
+
+      ...
+
+    end
+  end
+
 === Documentation, Guides & Examples
 
 - {Online API Documentation}[http://rdoc.info/github/troessner/transitions/master/Transitions]

lib/active_model/transitions.rb

@@ -25,9 +25,31 @@ module Transitions
     extend ActiveSupport::Concern
 
     included do
+      class ::Transitions::Machine
+        unless instance_methods.include?(:new_initialize) || instance_methods.include?(:new_update)
+          attr_reader :attribute_name
+          alias :old_initialize :initialize
+          alias :old_update :update
+
+          def new_initialize(*args, &block)
+            @attribute_name = :state
+            old_initialize(*args, &block)
+          end
+
+          def new_update(options = {}, &block)
+            @attribute_name = options[:attribute_name] if options.key?(:attribute_name)
+            old_update(options, &block)
+          end
+
+          alias :initialize :new_initialize
+          alias :update :new_update
+        else
+          puts "WARNING: Transitions::Machine#new_update or Transitions::Machine#new_initialize already defined. This can possibly break ActiveModel::Transitions."
+        end
+      end
       include ::Transitions
       after_initialize :set_initial_state
-      validates_presence_of :state
+      validate :state_presence
       validate :state_inclusion
     end
 
@@ -43,6 +65,10 @@ def reload(options = nil)
 
     protected
 
+    def transitions_state_column_name
+      self.class.state_machine.attribute_name
+    end
+
     def write_state(state)
       prev_state = current_state
       write_state_without_persistence(state)
@@ -55,22 +81,27 @@ def write_state(state)
     def write_state_without_persistence(state)
       ivar = self.class.get_state_machine.current_state_variable
       instance_variable_set(ivar, state)
-      self.state = state.to_s
+      self[transitions_state_column_name] = state.to_s
     end
 
     def read_state
-      self.state && self.state.to_sym
+      self[transitions_state_column_name] && self[transitions_state_column_name].to_sym
     end
 
     def set_initial_state
-      self.state ||= self.class.get_state_machine.initial_state.to_s if self.respond_to?(:state=)
+      self[transitions_state_column_name] ||= self.class.get_state_machine.initial_state.to_s if self.has_attribute?(transitions_state_column_name)
+    end
+
+    def state_presence
+      unless self[transitions_state_column_name].present?
+        self.errors.add(transitions_state_column_name, :presence)
+      end
     end
 
     def state_inclusion
-      unless self.class.get_state_machine.states.map{|s| s.name.to_s }.include?(self.state.to_s)
-        self.errors.add(:state, :inclusion, :value => self.state)
+      unless self.class.get_state_machine.states.map{|s| s.name.to_s }.include?(self[transitions_state_column_name].to_s)
+        self.errors.add(transitions_state_column_name, :inclusion, :value => self[transitions_state_column_name])
       end
     end
   end
-end
-
+end

test/active_record/test_active_record.rb

@@ -11,6 +11,17 @@ def self.up
 
 set_up_db CreateTrafficLights
 
+class CreateDifferentTrafficLights < ActiveRecord::Migration
+  def self.up
+    create_table(:different_traffic_lights) do |t|
+      t.string :different_state
+      t.string :name
+    end
+  end
+end
+
+set_up_db CreateDifferentTrafficLights
+
 class TrafficLight < ActiveRecord::Base
   include ActiveModel::Transitions
 
@@ -147,3 +158,148 @@ def setup
     assert_equal "red", @light.reload.state
   end
 end
+
+class TestNewActiveRecord < TestActiveRecord
+
+  def setup
+    set_up_db CreateTrafficLights
+    @light = TrafficLight.new
+  end
+
+  test "new active records defaults current state to the initial state" do
+    assert_equal :off, @light.current_state
+  end
+
+end
+
+class TestScopes < Test::Unit::TestCase
+  test "scope returns correct object" do
+    @light = TrafficLight.create!
+    assert_respond_to TrafficLight, :off
+    assert_equal TrafficLight.off.first, @light
+    assert TrafficLight.red.empty?
+  end
+
+  test "scopes exist" do
+    assert_respond_to TrafficLight, :off
+    assert_respond_to TrafficLight, :red
+    assert_respond_to TrafficLight, :green
+    assert_respond_to TrafficLight, :yellow
+  end
+
+  test 'scopes are only generated if we explicitly say so' do
+    assert_not_respond_to LightBulb, :off
+    assert_not_respond_to LightBulb, :on
+  end
+
+  test 'scope generation raises an exception if we try to overwrite an existing method' do
+    assert_raise(Transitions::InvalidMethodOverride) {
+      class Light < ActiveRecord::Base
+        include ActiveModel::Transitions
+
+        state_machine :auto_scopes => true do
+          state :new
+          state :broken
+        end
+      end
+    }
+  end
+end
+
+class DifferentTrafficLight < ActiveRecord::Base
+  include ActiveModel::Transitions
+
+  state_machine :attribute_name => :different_state, :auto_scopes => true do
+    state :off
+
+    state :red
+    state :green
+    state :yellow
+
+    event :red_on do
+      transitions :to => :red, :from => [:yellow]
+    end
+
+    event :green_on do
+      transitions :to => :green, :from => [:red]
+    end
+
+    event :yellow_on do
+      transitions :to => :yellow, :from => [:green]
+    end
+
+    event :reset do
+      transitions :to => :red, :from => [:off]
+    end
+  end
+end
+
+class TestActiveRecordWithDifferentColumnName < Test::Unit::TestCase
+  def setup
+    set_up_db CreateDifferentTrafficLights
+    @light = DifferentTrafficLight.create!
+  end
+
+  test "new record has the initial state set" do
+    @light = DifferentTrafficLight.new
+    assert_equal "off", @light.different_state
+  end
+
+  test "states initial state" do
+    assert @light.off?
+    assert_equal :off, @light.current_state
+  end
+
+  test "transition to a valid state" do
+    @light.reset
+    assert @light.red?
+    assert_equal :red, @light.current_state
+
+    @light.green_on
+    assert @light.green?
+    assert_equal :green, @light.current_state
+  end
+
+  test "transition does not persist state" do
+    @light.reset
+    assert_equal :red, @light.current_state
+    @light.reload
+    assert_equal "off", @light.different_state
+  end
+
+  test "transition does persists state" do
+    @light.reset!
+    assert_equal :red, @light.current_state
+    @light.reload
+    assert_equal "red", @light.different_state
+  end
+
+  test "transition to an invalid state" do
+    assert_raise(Transitions::InvalidTransition) { @light.yellow_on }
+    assert_equal :off, @light.current_state
+  end
+
+  test "transition with wrong state will not validate" do
+    for s in @light.class.state_machine.states
+      @light.different_state = s.name
+      assert @light.valid?
+    end
+    @light.different_state = "invalid_one"
+    assert_false @light.valid?
+  end
+
+  test "reloading model resets current state" do
+    @light.reset
+    assert @light.red?
+    @light.update_attribute(:different_state, 'green')
+    assert @light.reload.green?, "reloaded state should come from database, not instance variable"
+  end
+
+  test "calling non-bang event updates state attribute" do
+    @light.reset!
+    assert @light.red?
+    @light.green_on
+    assert_equal "green", @light.different_state
+    assert_equal "red", @light.reload.different_state
+  end
+end