change AMS::JSON.include_root_in_json default value to false

Changes:

* Update `include_root_in_json` default value to false for default value
  to false for `ActiveModel::Serializers::JSON`.
* Remove unnecessary change to include_root_in_json option in
  wrap_parameters template.
* Update `as_json` documentation.
* Fix JSONSerialization tests.

Problem:

It's confusing that AM serializers behave differently from AR,
even when AR objects include AM serializers module.

    class User < ActiveRecord::Base; end

    class Person
      include ActiveModel::Model
      include ActiveModel::AttributeMethods
      include ActiveModel::Serializers::JSON

      attr_accessor :name, :age

      def attributes
        instance_values
      end
    end

    user.as_json
    => {"id"=>1, "name"=>"Konata Izumi", "age"=>16, "awesome"=>true}
    # root is not included

    person.as_json
    => {"person"=>{"name"=>"Francesco", "age"=>22}}
    # root is included

    ActiveRecord::Base.include_root_in_json
    => false

    Person.include_root_in_json
    => true

    # different default values for include_root_in_json

Proposal:

Change the default value of AM serializers to false, update
the misleading documentation and remove unnecessary change
to false of include_root_in_json option with AR objects.

    class User < ActiveRecord::Base; end

    class Person
      include ActiveModel::Model
      include ActiveModel::AttributeMethods
      include ActiveModel::Serializers::JSON

      attr_accessor :name, :age

      def attributes
        instance_values
      end
    end

    user.as_json
    => {"id"=>1, "name"=>"Konata Izumi", "age"=>16, "awesome"=>true}
    # root is not included

    person.as_json
    => {"name"=>"Francesco", "age"=>22}
    # root is not included

    ActiveRecord::Base.include_root_in_json
    => false

    Person.include_root_in_json
    => false

    # same behaviour, more consistent

Fixes #6578.

1 files changed, 40 insertions, 50 deletions

diff --git a/activemodel/test/cases/serializers/json_serialization_test.rb b/activemodel/test/cases/serializers/json_serialization_test.rb
index 7160635eb4..e2690f1827 100644
--- a/activemodel/test/cases/serializers/json_serialization_test.rb
+++ b/activemodel/test/cases/serializers/json_serialization_test.rb
@@ -31,10 +31,15 @@ class JsonSerializationTest < ActiveModel::TestCase
     @contact.preferences = { 'shows' => 'anime' }
   end
 
-  test "should include root in json" do
+  def teardown
+    # set to the default value
+    Contact.include_root_in_json = false
+  end
+
+  test "should not include root in json (class method)" do
     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))}))
@@ -42,41 +47,31 @@ class JsonSerializationTest < ActiveModel::TestCase
     assert_match %r{"preferences":\{"shows":"anime"\}}, json
   end
 
-  test "should not include root in json (class method)" do
-    begin
-      Contact.include_root_in_json = false
-      json = @contact.to_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 = true
-    end
+  test "should include root in json if include_root_in_json is true" do
+    Contact.include_root_in_json = true
+    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 include root in json (option) even if the default is set to false" do
-    begin
-      Contact.include_root_in_json = false
-      json = @contact.to_json(:root => true)
-      assert_match %r{^\{"contact":\{}, json
-    ensure
-      Contact.include_root_in_json = true
-    end
+    json = @contact.to_json(root: true)
+    assert_match %r{^\{"contact":\{}, json
   end
 
   test "should not include root in json (option)" do
-
-    json = @contact.to_json(:root => false)
+    json = @contact.to_json(root: false)
 
     assert_no_match %r{^\{"contact":\{}, json
   end
 
   test "should include custom root in json" do
-    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
@@ -107,7 +102,7 @@ class JsonSerializationTest < ActiveModel::TestCase
   end
 
   test "should allow attribute filtering with except" do
-    json = @contact.to_json(:except => [:name, :age])
+    json = @contact.to_json(except: [:name, :age])
 
     assert_no_match %r{"name":"Konata Izumi"}, json
     assert_no_match %r{"age":16}, json
@@ -122,10 +117,10 @@ class JsonSerializationTest < ActiveModel::TestCase
     def @contact.favorite_quote; "Constraints are liberating"; end
 
     # Single method.
-    assert_match %r{"label":"Has cheezburger"}, @contact.to_json(:only => :name, :methods => :label)
+    assert_match %r{"label":"Has cheezburger"}, @contact.to_json(only: :name, methods: :label)
 
     # Both methods.
-    methods_json = @contact.to_json(:only => :name, :methods => [:label, :favorite_quote])
+    methods_json = @contact.to_json(only: :name, methods: [:label, :favorite_quote])
     assert_match %r{"label":"Has cheezburger"}, methods_json
     assert_match %r{"favorite_quote":"Constraints are liberating"}, methods_json
   end
@@ -143,14 +138,15 @@ class JsonSerializationTest < ActiveModel::TestCase
   end
 
   test "serializable_hash should not modify options passed in argument" do
-    options = { :except => :name }
+    options = { except: :name }
     @contact.serializable_hash(options)
 
     assert_nil options[:only]
     assert_equal :name, options[:except]
   end
 
-  test "as_json should return a hash" do
+  test "as_json should return a hash if include_root_in_json is true" do
+    Contact.include_root_in_json = true
     json = @contact.as_json
 
     assert_kind_of Hash, json
@@ -160,7 +156,7 @@ class JsonSerializationTest < ActiveModel::TestCase
     end
   end
 
-  test "from_json should set the object's attributes" do
+  test "from_json should work without a root (class attribute)" do
     json = @contact.to_json
     result = Contact.new.from_json(json)
 
@@ -172,7 +168,7 @@ class JsonSerializationTest < ActiveModel::TestCase
   end
 
   test "from_json should work without a root (method parameter)" do
-    json = @contact.to_json(:root => false)
+    json = @contact.to_json
     result = Contact.new.from_json(json, false)
 
     assert_equal result.name, @contact.name
@@ -182,24 +178,19 @@ class JsonSerializationTest < ActiveModel::TestCase
     assert_equal result.preferences, @contact.preferences
   end
 
-  test "from_json should work without a root (class attribute)" do
-    begin
-      Contact.include_root_in_json = false
-      json = @contact.to_json
-      result = Contact.new.from_json(json)
-
-      assert_equal result.name, @contact.name
-      assert_equal result.age, @contact.age
-      assert_equal Time.parse(result.created_at), @contact.created_at
-      assert_equal result.awesome, @contact.awesome
-      assert_equal result.preferences, @contact.preferences
-    ensure
-      Contact.include_root_in_json = true
-    end
+  test "from_json should work with a root (method parameter)" do
+    json = @contact.to_json(root: :true)
+    result = Contact.new.from_json(json, true)
+
+    assert_equal result.name, @contact.name
+    assert_equal result.age, @contact.age
+    assert_equal Time.parse(result.created_at), @contact.created_at
+    assert_equal result.awesome, @contact.awesome
+    assert_equal result.preferences, @contact.preferences
   end
 
   test "custom as_json should be honored when generating json" do
-    def @contact.as_json(options); { :name => name, :created_at => created_at }; end
+    def @contact.as_json(options); { name: name, created_at: created_at }; end
     json = @contact.to_json
 
     assert_match %r{"name":"Konata Izumi"}, json
@@ -209,7 +200,7 @@ class JsonSerializationTest < ActiveModel::TestCase
   end
 
   test "custom as_json options should be extendible" do
-    def @contact.as_json(options = {}); super(options.merge(:only => [:name])); end
+    def @contact.as_json(options = {}); super(options.merge(only: [:name])); end
     json = @contact.to_json
 
     assert_match %r{"name":"Konata Izumi"}, json
@@ -217,5 +208,4 @@ class JsonSerializationTest < ActiveModel::TestCase
     assert_no_match %r{"awesome":}, json
     assert_no_match %r{"preferences":}, json
   end
-
 end