Support for custom association name

lib/paper_trail/has_paper_trail.rb

@@ -41,7 +41,10 @@ module PaperTrail
         cattr_accessor :paper_trail_enabled_for_model
         self.paper_trail_enabled_for_model = true
 
-        has_many :versions, :class_name => version_class_name, :as => :item, :order => "created_at ASC, #{self.primary_key} ASC"
+        cattr_accessor :paper_trail_assoc
+        self.paper_trail_assoc = options[:association] || :versions
+
+        has_many self.paper_trail_assoc, :class_name => version_class_name, :as => :item, :order => "created_at ASC, #{self.primary_key} ASC"
 
         after_create  :record_create
         before_update :record_update
@@ -77,13 +80,13 @@ module PaperTrail
       def version_at(timestamp, reify_options={})
         # Because a version stores how its object looked *before* the change,
         # we need to look for the first version created *after* the timestamp.
-        version = versions.after(timestamp).first
+        version = send(self.class.paper_trail_assoc).after(timestamp).first
         version ? version.reify(reify_options) : self
       end
 
       # Returns the object (not a Version) as it was most recently.
       def previous_version
-        preceding_version = version ? version.previous : versions.last
+        preceding_version = version ? version.previous : send(self.class.paper_trail_assoc).last
         preceding_version.try :reify
       end
 
@@ -103,7 +106,7 @@ module PaperTrail
 
       def record_create
         if switched_on?
-          versions.create merge_metadata(:event => 'create', :whodunnit => PaperTrail.whodunnit)
+          send(self.class.paper_trail_assoc).create merge_metadata(:event => 'create', :whodunnit => PaperTrail.whodunnit)
         end
       end
 
@@ -120,7 +123,7 @@ module PaperTrail
               !notably_changed.include?(key)
             end.to_yaml
           end
-          versions.build merge_metadata(data)
+          send(self.class.paper_trail_assoc).build merge_metadata(data)
         end
       end
 
@@ -132,7 +135,7 @@ module PaperTrail
                                               :object    => object_to_string(item_before_change),
                                               :whodunnit => PaperTrail.whodunnit)
         end
-        versions.send :load_target
+        send(self.class.paper_trail_assoc).send :load_target
       end
 
       def merge_metadata(data)

test/dummy/app/models/document.rb

@@ -0,0 +1,3 @@
+class Document < ActiveRecord::Base
+  has_paper_trail :association => :paper_trail_versions
+end

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

@@ -93,6 +93,10 @@ class SetUpTestTables < ActiveRecord::Migration
       t.string :name
       t.string :species   # single table inheritance column
     end
+
+    create_table :documents, :force => true do |t|
+      t.string :name
+    end
   end
 
   def self.down
@@ -110,5 +114,6 @@ class SetUpTestTables < ActiveRecord::Migration
     remove_index :versions, :column => [:item_type, :item_id]
     drop_table :versions
     drop_table :widgets
+    drop_table :documents
   end
 end

test/unit/model_test.rb

@@ -815,6 +815,26 @@ class HasPaperTrailModelTest < ActiveSupport::TestCase
     end
   end
 
+  context 'An model with custom association' do
+    setup do
+      @doc = Document.create
+      @doc.update_attributes :name => 'Doc 1'
+    end
+
+    should 'should not respond on versions method' do
+      assert !@doc.respond_to?(:versions)
+    end
+
+    should 'should create new version record' do
+      assert_equal 2, @doc.paper_trail_versions.length
+    end
+
+    should 'should normally respond to prevous_version' do
+      @doc.update_attributes :name => 'Doc 2'
+      assert_equal 3, @doc.paper_trail_versions.length
+      assert_equal 'Doc 1', @doc.previous_version.name
+    end
+  end
 
   private