define_attr_method should be able to define methods that returns nil

2 files changed, 4 insertions, 2 deletions

diff --git a/activemodel/lib/active_model/attribute_methods.rb b/activemodel/lib/active_model/attribute_methods.rb
index 76bfd4b77d..73468afe55 100644
--- a/activemodel/lib/active_model/attribute_methods.rb
+++ b/activemodel/lib/active_model/attribute_methods.rb
@@ -106,8 +106,8 @@ module ActiveModel
         if block_given?
           sing.send :define_method, name, &block
         else
-          value = value.nil? ? 'nil' : value.to_s
-          sing.send(:define_method, name) { value.dup }
+          value = value.to_s if value
+          sing.send(:define_method, name) { value && value.dup }
         end
       end
 
diff --git a/activemodel/test/cases/attribute_methods_test.rb b/activemodel/test/cases/attribute_methods_test.rb
index 7fa5a2a7d7..e814666d99 100644
--- a/activemodel/test/cases/attribute_methods_test.rb
+++ b/activemodel/test/cases/attribute_methods_test.rb
@@ -115,6 +115,8 @@ class AttributeMethodsTest < ActiveModel::TestCase
     assert_respond_to ModelWithAttributes, :bar
     assert_equal "original bar", ModelWithAttributes.original_bar
     assert_equal "bar", ModelWithAttributes.bar
+    ModelWithAttributes.define_attr_method(:bar)
+    assert !ModelWithAttributes.bar
   end
 
   test '#define_attr_method generates attribute method with invalid identifier characters' do