New take on configuration

lib/active_model/serializer.rb

@@ -1,7 +1,7 @@
 require 'active_model/array_serializer'
 require 'active_model/serializable'
 require 'active_model/serializer/associations'
-require 'active_model/serializer/config'
+require 'active_model/serializer/configuration'
 require 'active_model/serializer/dsl'
 
 require 'thread'
@@ -22,22 +22,13 @@ def inherited(base)
 
       def setup
         @mutex.synchronize do
-          yield CONFIG
+          yield Configuration.global
         end
       end
 
       def embed(type, options={})
-        CONFIG.embed = type
-        CONFIG.embed_in_root = true if options[:embed_in_root] || options[:include]
-        ActiveSupport::Deprecation.warn <<-WARN
-** Notice: embed is deprecated. **
-The use of .embed method on a Serializer will be soon removed, as this should have a global scope and not a class scope.
-Please use the global .setup method instead:
-ActiveModel::Serializer.setup do |config|
-  config.embed = :#{type}
-  config.embed_in_root = #{CONFIG.embed_in_root || false}
-end
-        WARN
+        Configuration.global.embed = type
+        Configuration.global.embed_in_root = true if options[:embed_in_root] || options[:include]
       end
 
       if RUBY_VERSION >= '2.0'
@@ -74,22 +65,28 @@ def root_name
 
       def_delegators :dsl, :attributes, :has_one, :has_many
 
+      def configuration
+        @configuration ||= Configuration.global.build
+      end
+
       private
 
       def dsl
         @dsl ||= DSL.new self
       end
     end
 
+    attr_accessor :object, :scope, :root, :meta_key, :meta, :configuration
+
     def initialize(object, options={})
       @object        = object
       @scope         = options[:scope]
       @root          = options.fetch(:root, self.class._root)
       @meta_key      = options[:meta_key] || :meta
       @meta          = options[@meta_key]
       @wrap_in_array = options[:_wrap_in_array]
+      @configuration = self.class.configuration.build options
     end
-    attr_accessor :object, :scope, :root, :meta_key, :meta
 
     def json_key
       if root == true || root.nil?

lib/active_model/serializer/associations.rb

@@ -4,7 +4,7 @@
 module ActiveModel
   class Serializer
     class Association
-      def initialize(name, options={})
+      def initialize(name, options = {})
         if options.has_key?(:include)
           ActiveSupport::Deprecation.warn <<-WARN
 ** Notice: include was renamed to embed_in_root. **
@@ -13,8 +13,8 @@ def initialize(name, options={})
 
         @name          = name.to_s
         @options       = options
-        self.embed     = options.fetch(:embed) { CONFIG.embed }
-        @embed_in_root = options.fetch(:embed_in_root) { options.fetch(:include) { CONFIG.embed_in_root } }
+        self.embed     = options.fetch(:embed) { Configuration.global.embed }
+        @embed_in_root = options.fetch(:embed_in_root) { options.fetch(:include) { Configuration.global.embed_in_root } }
         @embed_key     = options[:embed_key] || :id
         @key           = options[:key]
         @embedded_key  = options[:root] || name

lib/active_model/serializer/configuration.rb

@@ -0,0 +1,82 @@
+require 'singleton'
+
+module ActiveModel
+  class Serializer
+    class Configuration
+      class Null
+        include Singleton
+
+        def method_missing(*)
+          nil
+        end
+
+        def respond_to?(*)
+          true
+        end
+      end
+
+      attr_accessor :parent
+
+      class << self
+        def global
+          @global ||= new default_options
+        end
+
+        def default_options
+          { embed: :objects }
+        end
+      end
+
+      def build(options = {})
+        self.class.new options, self
+      end
+
+      def initialize(options = {}, parent = Null.instance)
+        @root          = read_option options, :root
+        @embed         = read_option options, :embed
+        @embed_in_root = read_option options, :embed_in_root
+        @parent        = parent
+      end
+
+      def root
+        return_first @root, parent.root
+      end
+
+      def embed
+        return_first @embed, parent.embed
+      end
+
+      def embed_in_root
+        return_first @embed_in_root, parent.embed_in_root
+      end
+
+      # FIXME: Get rid of this mess.
+      def embed_objects=(value)
+        @embed = :objects if value
+      end
+
+      # FIXME: Get rid of this mess.
+      def embed_ids=(value)
+        @embed = :ids if value
+      end
+
+      def embed_objects
+        [:objects, :object].include? embed
+      end
+
+      def embed_ids
+        [:ids, :id].include? embed
+      end
+
+      private
+
+      def read_option(options, name)
+        options[name] || false if options.has_key? name
+      end
+
+      def return_first(*values)
+        values.compact.first
+      end
+    end
+  end
+end

test/unit/active_model/serializer/configuration_test.rb

@@ -0,0 +1,41 @@
+require 'test_helper'
+
+module ActiveModel
+  class Serializer
+    class Configuration
+      class GlobalTest < Minitest::Test
+        def test_returns_global_configuration
+          assert_kind_of Configuration, Configuration.global
+        end
+
+        def test_global_configuration_returns_the_same_instance
+          assert_equal Configuration.global.object_id, Configuration.global.object_id
+        end
+
+        def test_global_configuration_has_default_options_set
+          assert Configuration.default_options.all? do |name, value|
+            Configuration.global.send(name) == value
+          end
+        end
+      end
+
+      class OptionsTest < Minitest::Test
+        def setup
+          @configuration = Configuration.global.build(root: 'root', embed: :ids, embed_in_root: false)
+        end
+
+        def test_configuration_has_root_option
+          assert_equal 'root', @configuration.root
+        end
+
+        def test_configuration_has_embed_option
+          assert_equal :ids, @configuration.embed
+        end
+
+        def test_configuration_has_embed_in_root_option
+          assert_equal false, @configuration.embed_in_root
+        end
+      end
+    end
+  end
+end