3 files changed, 17 insertions, 77 deletions

diff --git a/activemodel/lib/active_model/serializable.rb b/activemodel/lib/active_model/serializable.rb
index 769e934dbe..70e27c5683 100644
--- a/activemodel/lib/active_model/serializable.rb
+++ b/activemodel/lib/active_model/serializable.rb
@@ -1,6 +1,7 @@
 require 'active_support/core_ext/hash/except'
 require 'active_support/core_ext/hash/slice'
 require 'active_support/core_ext/array/wrap'
+require 'active_support/core_ext/string/inflections'
 
 module ActiveModel
   # == Active Model Serializable
@@ -72,11 +73,10 @@ module ActiveModel
     autoload :JSON, "active_model/serializable/json"
     autoload :XML,  "active_model/serializable/xml"
 
-    include ActiveModel::Serializer::Scope
-
     module ClassMethods #:nodoc:
-      def _model_serializer
-        @_model_serializer ||= ActiveModel::Serializer::Finder.find(self, self)
+      def active_model_serializer
+        return @active_model_serializer if defined?(@active_model_serializer)
+        @active_model_serializer = "#{self.name}Serializer".safe_constantize
       end
     end
 
@@ -108,8 +108,8 @@ module ActiveModel
     end
 
     # Returns a model serializer for this object considering its namespace.
-    def model_serializer
-      self.class._model_serializer
+    def active_model_serializer
+      self.class.active_model_serializer
     end
 
   private
diff --git a/activemodel/lib/active_model/serializer.rb b/activemodel/lib/active_model/serializer.rb
index a541a1053d..5478da15c8 100644
--- a/activemodel/lib/active_model/serializer.rb
+++ b/activemodel/lib/active_model/serializer.rb
@@ -1,7 +1,6 @@
 require "active_support/core_ext/class/attribute"
 require "active_support/core_ext/string/inflections"
 require "active_support/core_ext/module/anonymous"
-require "active_support/core_ext/module/introspection"
 require "set"
 
 module ActiveModel
@@ -15,7 +14,7 @@ module ActiveModel
 
     def serializable_array
       @object.map do |item|
-        if serializer = Serializer::Finder.find(item, scope)
+        if item.respond_to?(:active_model_serializer) && (serializer = item.active_model_serializer)
           serializer.new(item, scope)
         else
           item
@@ -30,41 +29,6 @@ module ActiveModel
 
   # Active Model Serializer
   class Serializer
-    module Finder
-      mattr_accessor :constantizer
-      @@constantizer = ActiveSupport::Inflector
-
-      # Finds a serializer for the given object in the given scope.
-      # If the object implements a +model_serializer+ method, it does
-      # not do a scope lookup but uses the model_serializer method instead.
-      def self.find(object, scope)
-        if object.respond_to?(:model_serializer)
-          object.model_serializer
-        else
-          scope      = scope.class  unless scope.respond_to?(:const_defined?)
-          object     = object.class unless object.respond_to?(:name)
-          serializer = "#{object.name.demodulize}Serializer"
-
-          begin
-            scope.const_get serializer
-          rescue NameError => e
-            raise unless e.message =~ /uninitialized constant ([\w_]+::)*#{serializer}$/
-            scope.parents.each do |parent|
-              return parent.const_get(serializer) if parent.const_defined?(serializer)
-            end
-            nil
-          end
-        end
-      end
-    end
-
-    # Defines the serialization scope. Core extension serializers
-    # are defined in this module so a scoped lookup is able to find
-    # core extension serializers.
-    module Scope
-      ArraySerializer = ::ActiveModel::ArraySerializer
-    end
-
     module Associations
       class Config < Struct.new(:name, :options)
         def serializer
@@ -216,3 +180,10 @@ module ActiveModel
     end
   end
 end
+
+class Array
+  # Array uses ActiveModel::ArraySerializer.
+  def active_model_serializer
+    ActiveModel::ArraySerializer
+  end
+end
\ No newline at end of file
diff --git a/activemodel/test/cases/serializer_test.rb b/activemodel/test/cases/serializer_test.rb
index e99b3692ec..f6c4282d39 100644
--- a/activemodel/test/cases/serializer_test.rb
+++ b/activemodel/test/cases/serializer_test.rb
@@ -19,10 +19,8 @@ class SerializerTest < ActiveModel::TestCase
     include ActiveModel::Serializable
 
     attr_accessor :superuser
-    attr_writer   :model_serializer
 
     def initialize(hash={})
-      @model_serializer = nil
       @attributes = hash.merge(:first_name => "Jose", :last_name => "Valim", :password => "oh noes yugive my password")
     end
 
@@ -33,17 +31,15 @@ class SerializerTest < ActiveModel::TestCase
     def super_user?
       @superuser
     end
-
-    def model_serializer
-      @model_serializer || super
-    end
   end
 
   class Post < Model
     attr_accessor :comments
+    def active_model_serializer; PostSerializer; end
   end
 
   class Comment < Model
+    def active_model_serializer; CommentSerializer; end
   end
 
   class UserSerializer < ActiveModel::Serializer
@@ -428,38 +424,11 @@ class SerializerTest < ActiveModel::TestCase
     post.comments = []
 
     array = [model, post, comments]
-    serializer = ActiveModel::Serializer::Finder.find(array, user).new(array, user)
+    serializer = array.active_model_serializer.new(array, user)
     assert_equal([
       { :model => "Model" },
       { :post => { :body => "Body of new post", :comments => [], :title => "New Post" } },
       { :comment => { :title => "Comment1" } }
     ], serializer.as_json)
   end
-
-  def test_array_serializer_respects_model_serializer
-    user = User.new(:first_name => "Jose", :last_name => "Valim")
-    user.model_serializer = User2Serializer
-
-    array = [user]
-    serializer = ActiveModel::Serializer::Finder.find(array, user).new(array, {})
-    assert_equal([
-      { :user2 => { :last_name => "Valim", :first_name => "Jose", :ok => true } },
-    ], serializer.as_json)
-  end
-
-  def test_finder_respects_model_serializer
-    user = User.new(:first_name => "Jose", :last_name => "Valim")
-    assert_equal UserSerializer, user.model_serializer
-
-    serializer = ActiveModel::Serializer::Finder.find(user, self).new(user, {})
-    assert_equal({
-      :user => { :last_name => "Valim", :first_name => "Jose"},
-    }, serializer.as_json)
-
-    user.model_serializer = User2Serializer
-    serializer = ActiveModel::Serializer::Finder.find(user, self).new(user, {})
-    assert_equal({
-      :user2 => { :last_name => "Valim", :first_name => "Jose", :ok => true },
-    }, serializer.as_json)
-  end
 end
\ No newline at end of file