Who should review my code? A file location-based code-reviewer recommendation approach for Modern Code Review

Abstract

Software code review is an inspection of a code change by an independent third-party developer in order to identify and fix defects before an integration. Effectively performing code review can improve the overall software quality. In recent years, Modern Code Review (MCR), a lightweight and tool-based code inspection, has been widely adopted in both proprietary and open-source software systems. Finding appropriate codereviewers in MCR is a necessary step of reviewing a code change. However, little research is known the difficulty of finding codereviewers in a distributed software development and its impact on reviewing time. In this paper, we investigate the impact of reviews with code-reviewer assignment problem has on reviewing time. We find that reviews with code-reviewer assignment problem take 12 days longer to approve a code change. To help developers find appropriate code-reviewers, we propose REVFINDER, a file location-based code-reviewer recommendation approach. We leverage a similarity of previously reviewed file path to recommend an appropriate code-reviewer. The intuition is that files that are located in similar file paths would be managed and reviewed by similar experienced code-reviewers. Through an empirical evaluation on a case study of 42,045 reviews of Android Open Source Project (AOSP), OpenStack, Qt and LibreOffice projects, we find that REVFINDER accurately recommended 79% of reviews with a top 10 recommendation. REVFINDER also correctly recommended the code-reviewers with a median rank of 4. The overall ranking of REVFINDER is 3 times better than that of a baseline approach. We believe that REVFINDER could be applied to MCR in order to help developers find appropriate code-reviewers and speed up the overall code review process.

Understanding Review Expertise of Developers: A Reviewer Recommendation Approach Based on Latent Dirichlet Allocation

“…We evaluated the proposed reviewer recommendation approach by comparing it with REVFINDER [10] and cHRev [13]. REVFINDER is a reviewer recommendation approach based on file location similarity.…”

“…The top-N accuracy metric has been widely used in evaluating recommendation systems [10,32]. The top-N accuracy of a reviewer recommendation approach is the proportion of the number of correct recommendation results against the total number of recommendations.…”

“…isCollect(ActualReviewers r , TopN) has a value of 1 if TopN includes at least one reviewer involved in ActualReviewer r ; otherwise, it has a value of 0. According to [6,10,33], we chose the value of N to be 1, 3, 5, and 10.…”

“…Recently, a modern code review process has been adopted to more efficiently perform code reviews in both open source projects and industry software projects [10]. The modern code review process is a tool-based, lightweight code review mechanism [11].…”

“…The reviewer assignment is a major challenge in performing the code review process rapidly and successfully [2,[5][6][7]10,12,13]. Thongtanunam et al investigated the impact of the reviewer assignment problem by conducting an exploratory study in open source projects.…”