Index: app/models/mail_handler.rb
===================================================================
--- app/models/mail_handler.rb	(リビジョン 18187)
+++ app/models/mail_handler.rb	(作業コピー)
@@ -286,7 +286,7 @@
         reply
       else
         if logger
-          logger.info "MailHandler: ignoring reply from [#{sender_email}] to a locked topic"
+          logger.info "MailHandler: ignoring reply from [#{email.from.first}] to a locked topic"
         end
       end
     end
Index: test/unit/mail_handler_test.rb
===================================================================
--- test/unit/mail_handler_test.rb	(リビジョン 18187)
+++ test/unit/mail_handler_test.rb	(作業コピー)
@@ -955,6 +955,15 @@
     assert_equal Message.find(1), m.parent
   end
 
+  def test_reply_to_a_locked_message
+    # Lock the topic
+    Message.find(2).parent.update_attribute :locked, true
+
+    assert_no_difference('Message.find(1).replies_count') do
+      m = submit_email('message_reply_by_subject.eml')
+    end
+  end
+
   def test_should_convert_tags_of_html_only_emails
     with_settings :text_formatting => 'textile' do
       issue = submit_email('ticket_html_only.eml', :issue => {:project => 'ecookbook'})