Handle non-default inheritance column.

lib/paper_trail/version.rb

@@ -52,7 +52,8 @@ class Version < ActiveRecord::Base
       if item
         model = item
       else
-        class_name = attrs['type'].blank? ? item_type : attrs['type']
+        inheritance_column_name = item_type.constantize.inheritance_column
+        class_name = attrs[inheritance_column_name].blank? ? item_type : attrs[inheritance_column_name]
         klass = class_name.constantize
         model = klass.new
       end

test/dummy/app/models/animal.rb

@@ -0,0 +1,3 @@
+class Animal < ActiveRecord::Base
+  has_paper_trail
+end

test/dummy/app/models/cat.rb

@@ -0,0 +1,3 @@
+class Cat < Animal
+  set_inheritance_column 'species'
+end

test/dummy/app/models/dog.rb

@@ -0,0 +1,3 @@
+class Dog < Animal
+  set_inheritance_column 'species'
+end

test/dummy/db/migrate/20110208155312_set_up_test_tables.rb

@@ -82,14 +82,20 @@ class SetUpTestTables < ActiveRecord::Migration
     create_table :songs, :force => true do |t|
       t.integer :length
     end
-    
+
     create_table :posts, :force => true do |t|
       t.string :title
       t.string :content
     end
+
+    create_table :animals, :force => true do |t|
+      t.string :name
+      t.string :species   # single table inheritance column
+    end
   end
 
   def self.down
+    drop_table :animals
     drop_table :posts
     drop_table :songs
     drop_table :people

test/unit/inheritance_column_test.rb

@@ -0,0 +1,32 @@
+require 'test_helper'
+
+class InheritanceColumnTest < ActiveSupport::TestCase
+
+  context 'STI models' do
+    setup do
+      @animal = Animal.create :name => 'Animal'
+      @animal.update_attributes :name => 'Animal from the Muppets'
+      @animal.update_attributes :name => 'Animal Muppet'
+
+      @dog = Dog.create :name => 'Snoopy'
+      @dog.update_attributes :name => 'Scooby'
+      @dog.update_attributes :name => 'Scooby Doo'
+
+      @cat = Cat.create :name => 'Garfield'
+      @cat.update_attributes :name => 'Garfield (I hate Mondays)'
+      @cat.update_attributes :name => 'Garfield The Cat'
+    end
+
+    should 'work with custom STI inheritance column' do
+      assert_equal 9, Version.count
+      assert_equal 3, @animal.versions.count
+      assert_equal 3, @dog.versions.count
+      assert_equal 3, @cat.versions.count
+
+      assert_equal 'Animal from the Muppets',   @animal.versions.last.reify.name
+      assert_equal 'Scooby',       @dog.versions.last.reify.name
+      assert_equal 'Garfield (I hate Mondays)', @cat.versions.last.reify.name
+    end
+  end
+
+end