Force metadata calls to attributes to use current value if value is changing for attribute

lib/paper_trail/has_paper_trail.rb

@@ -188,7 +188,12 @@ def merge_metadata(data)
             if v.respond_to?(:call)
               v.call(self)
             elsif v.is_a?(Symbol) && respond_to?(v)
-              send(v)
+              # if it is an attribute that is changing, be sure to grab the current version
+              if has_attribute?(v) && send("#{v}_changed?".to_sym)
+                send("#{v}_was".to_sym)
+              else
+                send(v)
+              end
             else
               v
             end

test/dummy/app/models/article.rb

@@ -2,10 +2,13 @@ class Article < ActiveRecord::Base
   has_paper_trail :ignore => :title,
                   :only => [:content],
                   :skip => [:file_upload],
-                  :meta   => {:answer => 42,
+                  :meta => {
+                              :answer => 42,
                               :action => :action_data_provider_method,
                               :question => Proc.new { "31 + 11 = #{31 + 11}" },
-                              :article_id => Proc.new { |article| article.id } }
+                              :article_id => Proc.new { |article| article.id },
+                              :title => :title
+                            }
 
   def action_data_provider_method
     self.object_id.to_s

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

@@ -29,6 +29,7 @@ def self.up
       t.string :action
       t.string  :question
       t.integer :article_id
+      t.string :title
 
       # Controller info columns.
       t.string :ip

test/test_helper.rb

@@ -45,5 +45,5 @@ def change_schema
 
 class Version < ActiveRecord::Base
   attr_accessible :created_at, :updated_at,
-    :answer, :action, :question, :article_id, :ip, :user_agent
+    :answer, :action, :question, :article_id, :ip, :user_agent, :title
 end

test/unit/model_test.rb

@@ -631,7 +631,10 @@ def without(&block)
 
 
   context 'An item' do
-    setup { @article = Article.new }
+    setup do
+      @initial_title = 'Foobar'
+      @article = Article.new :title => @initial_title
+    end
 
     context 'which is created' do
       setup { @article.save }
@@ -651,10 +654,16 @@ def without(&block)
       should 'store dynamic meta data based on a method of the item' do
         assert_equal @article.action_data_provider_method, @article.versions.last.action
       end
+
+      should 'store dynamic meta data based on an attribute of the item prior to creation' do
+        assert_equal nil, @article.versions.last.title
+      end
 
 
       context 'and updated' do
-        setup { @article.update_attributes! :content => 'Better text.' }
+        setup do
+          @article.update_attributes! :content => 'Better text.', :title => 'Rhubarb'
+        end
 
         should 'store fixed meta data' do
           assert_equal 42, @article.versions.last.answer
@@ -667,6 +676,10 @@ def without(&block)
         should 'store dynamic meta data which depends on the item' do
           assert_equal @article.id, @article.versions.last.article_id
         end
+
+        should 'store dynamic meta data based on an attribute of the item prior to the update' do
+          assert_equal @initial_title, @article.versions.last.title
+        end
       end
 
 
@@ -684,7 +697,10 @@ def without(&block)
         should 'store dynamic meta data which depends on the item' do
           assert_equal @article.id, @article.versions.last.article_id
         end
-
+
+        should 'store dynamic meta data based on an attribute of the item prior to the destruction' do
+          assert_equal @initial_title, @article.versions.last.title
+        end
       end
     end
   end