Toward Developer-like Automated Program Repair — Modification Comparisons between GenProg and Developers

Abstract

Automated program repair is a way to reduce costs on program debuggingto a large extent. Repair techniques using genetic programming havebeen attracting much attention. They were applied to actual softwaresystems and they were able to fix several dozen of actual faults. However, programs generated by such techniques often include some sourcecode changes not related to fixing a given fault even if they pass allgiven test cases. Furthermore, some researchers found that suchtechniques occasionally induce new faults which are not covered byexisting test cases. The reason why those problems arise is that suchtechniques consider only given test cases. On the other hand, developers consider program behaviors not covered by test cases. Thus, those problems arise less frequently in programs modified by developers. Consequently, the authors suppose that if we make automated programmodifications close to developers' ones, we may be able to relieve thoseproblems. At this moment, there is no research study investigatingdifferences between automated modifications and developers' ones. Inthis paper, we compare GenProg's modifications with developers'ones for the same faults. As a result, we found that developers tend to(1) change more different functions, (2) change control flows in sourcecode, and (3) add/delete more code lines.