Remove dependency on build_class in Evaluator

lib/factory_girl.rb

@@ -42,6 +42,7 @@ require 'factory_girl/decorator/class_key_hash'
 require 'factory_girl/decorator/disallows_duplicates_registry'
 require 'factory_girl/decorator/invocation_tracker'
 require 'factory_girl/decorator/invocation_ignorer'
+require 'factory_girl/decorator/new_constructor'
 require 'factory_girl/version'
 
 module FactoryGirl

lib/factory_girl/attribute_assigner.rb

@@ -31,7 +31,13 @@ module FactoryGirl
     private
 
     def method_tracking_evaluator
-      @method_tracking_evaluator ||= Decorator::AttributeHash.new(invocation_decorator.new(@evaluator), attribute_names_to_assign)
+      @method_tracking_evaluator ||= Decorator::AttributeHash.new(decorated_evaluator, attribute_names_to_assign)
+    end
+
+    def decorated_evaluator
+      invocation_decorator.new(
+        Decorator::NewConstructor.new(@evaluator, @build_class)
+      )
     end
 
     def invocation_decorator

lib/factory_girl/decorator/new_constructor.rb

@@ -0,0 +1,12 @@
+module FactoryGirl
+  class Decorator
+    class NewConstructor < Decorator
+      def initialize(component, build_class)
+        super(component)
+        @build_class = build_class
+      end
+
+      delegate :new, to: :@build_class
+    end
+  end
+end

lib/factory_girl/evaluator.rb

@@ -10,8 +10,7 @@ module FactoryGirl
       undef_method(method) unless method =~ /^__|initialize/
     end
 
-    def initialize(build_class, build_strategy, overrides = {})
+    def initialize(build_strategy, overrides = {})
-      @build_class       = build_class
       @build_strategy    = build_strategy
       @overrides         = overrides
       @cached_attributes = overrides
@@ -21,8 +20,6 @@ module FactoryGirl
       end
     end
 
-    delegate :new, to: :@build_class
-
     def association(factory_name, *traits_and_overrides)
       overrides = traits_and_overrides.extract_options!
       strategy_override = overrides.fetch(:strategy) { :create }

lib/factory_girl/factory.rb

@@ -33,7 +33,7 @@ module FactoryGirl
 
       strategy = StrategyCalculator.new(build_strategy).strategy.new
 
-      evaluator = evaluator_class.new(build_class, strategy, overrides.symbolize_keys)
+      evaluator = evaluator_class.new(strategy, overrides.symbolize_keys)
       attribute_assigner = AttributeAssigner.new(evaluator, build_class, &compiled_constructor)
 
       evaluation = Evaluation.new(attribute_assigner, compiled_to_create)

spec/factory_girl/evaluator_class_definer_spec.rb

@@ -7,7 +7,7 @@ describe FactoryGirl::EvaluatorClassDefiner do
 
   let(:attributes)    { [simple_attribute, relative_attribute, attribute_that_raises_a_second_time] }
   let(:class_definer) { FactoryGirl::EvaluatorClassDefiner.new(attributes, FactoryGirl::Evaluator) }
-  let(:evaluator)     { class_definer.evaluator_class.new(Object, stub("build strategy", add_observer: true)) }
+  let(:evaluator)     { class_definer.evaluator_class.new(stub("build strategy", add_observer: true)) }
 
   it "returns an evaluator when accessing the evaluator class" do
     evaluator.should be_a(FactoryGirl::Evaluator)