Fix attributes_before_type_cast for serialised attributes.

Public method `attributes_before_type_cast` used to return internal AR structure (ActiveRecord::AttributeMethods::Serialization::Attribute), patch fixes this. Now behaves like `read_attribute_before_type_cast` and returns unserialised values.

activerecord/CHANGELOG.md

@@ -1,5 +1,9 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   `AR::Base#attributes_before_type_cast` now returns unserialized values for serialized attributes.
+
+    *Nikita Afanasenko*
+
 *   Use query cache/uncache when using DATABASE_URL.
     Fix #6951.
 

activerecord/lib/active_record/attribute_methods/serialization.rb

@@ -119,6 +119,16 @@ module ActiveRecord
             super
           end
         end
+
+        def attributes_before_type_cast
+          super.dup.tap do |attributes|
+            self.class.serialized_attributes.each_key do |key|
+              if attributes.key?(key)
+                attributes[key] = attributes[key].unserialized_value
+              end
+            end
+          end
+        end
       end
     end
   end

activerecord/test/cases/serialized_attribute_test.rb

@@ -56,11 +56,21 @@ class SerializedAttributeTest < ActiveRecord::TestCase
   def test_serialized_attribute_before_type_cast_returns_unserialized_value
     Topic.serialize :content, Hash
 
-    t = Topic.new(:content => { :foo => :bar })
-    assert_equal({ :foo => :bar }, t.content_before_type_cast)
+    t = Topic.new(content: { foo: :bar })
+    assert_equal({ foo: :bar }, t.content_before_type_cast)
     t.save!
     t.reload
-    assert_equal({ :foo => :bar }, t.content_before_type_cast)
+    assert_equal({ foo: :bar }, t.content_before_type_cast)
+  end
+
+  def test_serialized_attributes_before_type_cast_returns_unserialized_value
+    Topic.serialize :content, Hash
+
+    t = Topic.new(content: { foo: :bar })
+    assert_equal({ foo: :bar }, t.attributes_before_type_cast["content"])
+    t.save!
+    t.reload
+    assert_equal({ foo: :bar }, t.attributes_before_type_cast["content"])
   end
 
   def test_serialized_attribute_calling_dup_method