Allow serializable fields to be of type hash. Fixes #1311.

lib/mongoid/fields.rb

@@ -231,7 +231,7 @@ def add_field(name, options = {})
         type = options[:localize] ? Fields::Serializable::Localized : options[:type]
         Mappings.for(type, options[:identity]).instantiate(name, options).tap do |field|
           fields[name] = field
-          defaults << name unless field.default.nil?
+          defaults << name unless field.default_val.nil?
           create_accessors(name, meth, options)
           process_options(field)
           define_attribute_method(name)

lib/mongoid/fields/serializable.rb

@@ -25,8 +25,15 @@ module Fields #:nodoc:
     module Serializable
       extend ActiveSupport::Concern
 
+      included do
+        # @todo: Durran: Pull out in 3.0.0
+        unless method_defined?(:default)
+          alias :default :default_val
+        end
+      end
+
       # Set readers for the instance variables.
-      attr_accessor :default, :label, :localize, :name, :options
+      attr_accessor :default_val, :label, :localize, :name, :options
 
       # When reading the field do we need to cast the value? This holds true when
       # times are stored or for big decimals which are stored as strings.
@@ -82,10 +89,10 @@ def deserialize(object); object; end
       #
       # @since 2.1.8
       def eval_default(doc)
-        if default.respond_to?(:call)
-          serialize(doc.instance_exec(&default))
+        if default_val.respond_to?(:call)
+          serialize(doc.instance_exec(&default_val))
         else
-          serialize(default.duplicable? ? default.dup : default)
+          serialize(default_val.duplicable? ? default_val.dup : default_val)
         end
       end
 
@@ -182,9 +189,9 @@ def instantiate(name, options = {})
             field.options = options
             field.label = options[:label]
             field.localize = options[:localize]
-            field.default = options[:default]
-            unless field.default
-              field.default = {} if field.localized?
+            field.default_val = options[:default]
+            unless field.default_val
+              field.default_val = {} if field.localized?
             end
           end
         end

spec/app/models/my_hash.rb

@@ -0,0 +1,3 @@
+class MyHash < ::Hash
+  include Mongoid::Fields::Serializable
+end

spec/unit/mongoid/fields/serializable_spec.rb

@@ -0,0 +1,29 @@
+require "spec_helper"
+
+describe Mongoid::Fields::Serializable do
+
+  context "when included in a hash" do
+
+    let(:hash) do
+      MyHash.new
+    end
+
+    context "when setting a value" do
+
+      before do
+        hash[:key] = "value"
+      end
+
+      it "allows normal hash access" do
+        hash[:key].should eq("value")
+      end
+    end
+
+    context "when getting a non existant value" do
+
+      it "returns nil" do
+        hash[:key].should be_nil
+      end
+    end
+  end
+end