How to Design a Program Repair Bot? Insights from the Repairnator Project

TL;DR

This paper presents Repairnator, an autonomous program repair bot that monitors test failures, reproduces bugs, and applies repair tools to generate patches, sharing insights from its operation on numerous open-source projects since 2017.

Contribution

It introduces Repairnator, a novel autonomous repair bot, and shares practical insights and lessons learned from its deployment across many projects over several years.

Findings

Repaired 17 bugs across 1,609 projects

Operated since February 2017 with three repair systems

Studied 11,317 test failures

Abstract

Program repair research has made tremendous progress over the last few years, and software development bots are now being invented to help developers gain productivity. In this paper, we investigate the concept of a " program repair bot " and present Repairnator. The Repairnator bot is an autonomous agent that constantly monitors test failures, reproduces bugs, and runs program repair tools against each reproduced bug. If a patch is found, Repairnator bot reports it to the developers. At the time of writing, Repairnator uses three different program repair systems and has been operating since February 2017. In total, it has studied 11 317 test failures over 1 609 open-source software projects hosted on GitHub, and has generated patches for 17 different bugs. Over months, we hit a number of hard technical challenges and had to make various design and engineering decisions. This gives us a unique experience in this area. In this paper, we reflect upon Repairnator in order to share this knowledge with the automatic program repair community.