Fix the #using_limitable_reflections? helper to work correctly by not examining the length of an array which contains false/true, hence always passing. [#4869 state:resolved]

Signed-off-by: José Valim <jose.valim@gmail.com>

activerecord/lib/active_record/relation/finder_methods.rb

@@ -339,7 +339,7 @@ module ActiveRecord
     end
 
     def using_limitable_reflections?(reflections)
-      reflections.collect(&:collection?).length.zero?
+      reflections.none?(&:collection?)
     end
 
   end

activerecord/test/cases/associations_test.rb

@@ -65,6 +65,16 @@ class AssociationsTest < ActiveRecord::TestCase
     assert_equal 1, firm.clients(true).size, "New firm should have reloaded clients count"
   end
   
+  def test_using_limitable_reflections_helper
+    using_limitable_reflections = lambda { |reflections| Tagging.scoped.send :using_limitable_reflections?, reflections }
+    belongs_to_reflections = [Tagging.reflect_on_association(:tag), Tagging.reflect_on_association(:super_tag)]
+    has_many_reflections = [Tag.reflect_on_association(:taggings), Developer.reflect_on_association(:projects)]
+    mixed_reflections = (belongs_to_reflections + has_many_reflections).uniq
+    assert using_limitable_reflections.call(belongs_to_reflections), "Belong to associations are limitable"
+    assert !using_limitable_reflections.call(has_many_reflections), "All has many style associations are not limitable"
+    assert !using_limitable_reflections.call(mixed_reflections), "No collection associations (has many style) should pass"
+  end
+  
   def test_force_reload_is_uncached
     firm = Firm.create!("name" => "A New Firm, Inc")
     client = Client.create!("name" => "TheClient.com", :firm => firm)