1 files changed, 7 insertions, 3 deletions
diff --git a/actionmailer/lib/action_mailer/adv_attr_accessor.rb b/actionmailer/lib/action_mailer/adv_attr_accessor.rb
index a8b83c5e64..50afe4d742 100644
--- a/actionmailer/lib/action_mailer/adv_attr_accessor.rb
+++ b/actionmailer/lib/action_mailer/adv_attr_accessor.rb
@@ -8,16 +8,20 @@ module ActionMailer
     module ClassMethods #:nodoc:
       def adv_attr_accessor(*names)
         names.each do |name|
+          ivar = "@#{name}"
+
           define_method("#{name}=") do |value|
-            instance_variable_set("@#{name}", value)
+            instance_variable_set(ivar, value)
           end
 
           define_method(name) do |*parameters|
             raise ArgumentError, "expected 0 or 1 parameters" unless parameters.length <= 1
             if parameters.empty?
-              instance_variable_get("@#{name}")
+              if instance_variables.include?(ivar)
+                instance_variable_get(ivar)
+              end
             else
-              instance_variable_set("@#{name}", parameters.first)
+              instance_variable_set(ivar, parameters.first)
             end
           end
         end