Backport fix for #428 (avoids invoking #dup on model instances); fixes …

…#404

Conflicts:
	lib/paper_trail/has_paper_trail.rb

lib/paper_trail/has_paper_trail.rb

@@ -338,24 +338,19 @@ def merge_metadata(data)
       end
 
       def item_before_change
-        previous = self.dup
-        # `dup` clears timestamps so we add them back.
-        all_timestamp_attributes.each do |column|
-          previous[column] = send(column) if self.class.column_names.include?(column.to_s) and not send(column).nil?
-        end
-        enums = previous.respond_to?(:defined_enums) ? previous.defined_enums : {}
-        previous.tap do |prev|
-          prev.id = id # `dup` clears the `id` so we add that back
+        attributes.tap do |prev|
+          enums = self.respond_to?(:defined_enums) ? self.defined_enums : {}
           changed_attributes.select { |k,v| self.class.column_names.include?(k) }.each do |attr, before|
             before = enums[attr][before] if enums[attr]
             prev[attr] = before
           end
         end
       end
 
-      # returns hash of object attributes (with appropriate attributes serialized), ommitting attributes to be skipped
-      def object_attrs_for_paper_trail(object)
-        _attrs = object.attributes.except(*self.paper_trail_options[:skip]).tap do |attributes|
+      # returns hash of attributes (with appropriate attributes serialized),
+      # ommitting attributes to be skipped
+      def object_attrs_for_paper_trail(attributes_hash)
+        attributes_hash.except(*self.paper_trail_options[:skip]).tap do |attributes|
           self.class.serialize_attributes_for_paper_trail(attributes)
         end
       end

test/unit/serializer_test.rb

@@ -10,7 +10,7 @@ class SerializerTest < ActiveSupport::TestCase
       END
 
       @fluxor = Fluxor.create :name => 'Some text.'
-      @original_fluxor_attributes = @fluxor.send(:item_before_change).attributes # this is exactly what PaperTrail serializes
+      @original_fluxor_attributes = @fluxor.send(:item_before_change) # this is exactly what PaperTrail serializes
       @fluxor.update_attributes :name => 'Some more text.'
     end
 
@@ -41,7 +41,7 @@ class SerializerTest < ActiveSupport::TestCase
       END
 
       @fluxor = Fluxor.create :name => 'Some text.'
-      @original_fluxor_attributes = @fluxor.send(:item_before_change).attributes # this is exactly what PaperTrail serializes
+      @original_fluxor_attributes = @fluxor.send(:item_before_change) # this is exactly what PaperTrail serializes
       @fluxor.update_attributes :name => 'Some more text.'
     end
 
@@ -83,7 +83,7 @@ class SerializerTest < ActiveSupport::TestCase
       END
 
       @fluxor = Fluxor.create
-      @original_fluxor_attributes = @fluxor.send(:item_before_change).attributes.reject { |k,v| v.nil? } # this is exactly what PaperTrail serializes
+      @original_fluxor_attributes = @fluxor.send(:item_before_change).reject { |k,v| v.nil? } # this is exactly what PaperTrail serializes
       @fluxor.update_attributes :name => 'Some more text.'
     end