Really make include_root_in_json default to true [#3770 state:resolved]

activemodel/lib/active_model/serializers/json.rb

 require 'active_support/json'
-require 'active_support/core_ext/class/attribute_accessors'
+require 'active_support/core_ext/class/attribute'
 
 module ActiveModel
   module Serializers
@@ -10,7 +10,8 @@ module JSON
       included do
         extend ActiveModel::Naming
 
-        cattr_accessor :include_root_in_json, :instance_writer => true
+        class_attribute :include_root_in_json
+        self.include_root_in_json = true
       end
 
       # Returns a JSON string representing the model. Some configuration is
@@ -92,7 +93,9 @@ def as_json(options = nil)
       end
 
       def from_json(json)
-        self.attributes = ActiveSupport::JSON.decode(json)
+        hash = ActiveSupport::JSON.decode(json)
+        hash = hash.values.first if include_root_in_json
+        self.attributes = hash
         self
       end
     end

activemodel/test/cases/serializeration/json_serialization_test.rb

@@ -22,35 +22,41 @@ def setup
   end
 
   test "should include root in json" do
+    json = @contact.to_json
+
+    assert_match %r{^\{"contact":\{}, json
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_match %r{"age":16}, json
+    assert json.include?(%("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))}))
+    assert_match %r{"awesome":true}, json
+    assert_match %r{"preferences":\{"shows":"anime"\}}, json
+  end
+
+  test "should not include root in json" do
     begin
-      Contact.include_root_in_json = true
+      Contact.include_root_in_json = false
       json = @contact.to_json
 
-      assert_match %r{^\{"contact":\{}, json
+      assert_no_match %r{^\{"contact":\{}, json
       assert_match %r{"name":"Konata Izumi"}, json
       assert_match %r{"age":16}, json
       assert json.include?(%("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))}))
       assert_match %r{"awesome":true}, json
       assert_match %r{"preferences":\{"shows":"anime"\}}, json
     ensure
-      Contact.include_root_in_json = false
+      Contact.include_root_in_json = true
     end
   end
 
   test "should include custom root in json" do
-    begin
-      Contact.include_root_in_json = true
-      json = @contact.to_json(:root => 'json_contact')
+    json = @contact.to_json(:root => 'json_contact')
 
-      assert_match %r{^\{"json_contact":\{}, json
-      assert_match %r{"name":"Konata Izumi"}, json
-      assert_match %r{"age":16}, json
-      assert json.include?(%("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))}))
-      assert_match %r{"awesome":true}, json
-      assert_match %r{"preferences":\{"shows":"anime"\}}, json
-    ensure
-      Contact.include_root_in_json = false
-    end
+    assert_match %r{^\{"json_contact":\{}, json
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_match %r{"age":16}, json
+    assert json.include?(%("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))}))
+    assert_match %r{"awesome":true}, json
+    assert_match %r{"preferences":\{"shows":"anime"\}}, json
   end
 
   test "should encode all encodable attributes" do

activerecord/test/cases/json_serialization_test.rb

@@ -8,7 +8,7 @@
 
 class JsonSerializationTest < ActiveRecord::TestCase
   class NamespacedContact < Contact
-    column :name,        :string
+    column :name, :string
   end
 
   def setup
@@ -23,16 +23,12 @@ def setup
   end
 
   def test_should_demodulize_root_in_json
-    NamespacedContact.include_root_in_json = true
     @contact = NamespacedContact.new :name => 'whatever'
     json = @contact.to_json
     assert_match %r{^\{"namespaced_contact":\{}, json
-  ensure
-    NamespacedContact.include_root_in_json = false
   end
 
   def test_should_include_root_in_json
-    Contact.include_root_in_json = true
     json = @contact.to_json
 
     assert_match %r{^\{"contact":\{}, json
@@ -41,8 +37,6 @@ def test_should_include_root_in_json
     assert json.include?(%("created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))}))
     assert_match %r{"awesome":true}, json
     assert_match %r{"preferences":\{"shows":"anime"\}}, json
-  ensure
-    Contact.include_root_in_json = false
   end
 
   def test_should_encode_all_encodable_attributes
@@ -170,15 +164,19 @@ def @david.favorite_quote; "Constraints are liberating"; end
   end
 
   def test_should_allow_only_option_for_list_of_authors
+    ActiveRecord::Base.include_root_in_json = false
     authors = [@david, @mary]
-
     assert_equal %([{"name":"David"},{"name":"Mary"}]), ActiveSupport::JSON.encode(authors, :only => :name)
+  ensure
+    ActiveRecord::Base.include_root_in_json = true
   end
 
   def test_should_allow_except_option_for_list_of_authors
+    ActiveRecord::Base.include_root_in_json = false
     authors = [@david, @mary]
-
     assert_equal %([{"id":1},{"id":2}]), ActiveSupport::JSON.encode(authors, :except => [:name, :author_address_id, :author_address_extra_id])
+  ensure
+    ActiveRecord::Base.include_root_in_json = true
   end
 
   def test_should_allow_includes_for_list_of_authors
@@ -201,7 +199,6 @@ def test_should_allow_options_for_hash_of_authors
       1 => @david,
       2 => @mary
     }
-
-    assert_equal %({"1":{"name":"David"}}), ActiveSupport::JSON.encode(authors_hash, :only => [1, :name])
+    assert_equal %({"1":{"author":{"name":"David"}}}), ActiveSupport::JSON.encode(authors_hash, :only => [1, :name])
   end
 end