Supporting Modern Code Review

Modern code review is a lightweight and asynchronous process of auditing code changes that is done by a reviewer other than the author of the changes. Code review is widely used in both open source and industrial projects because of its diverse benefits, which include defect identification, code improvement, and knowledge transfer. This thesis presents three research results on code review. First, we conduct a large-scale developer survey. The objective of the survey is to understand how developers conduct code review and what difficulties they face in the process. We also reproduce the survey questions from the previous studies to broaden the base of empirical knowledge in the code review research community. Second, we investigate in depth the coding conventions applied during code review. These coding conventions guide developers to write source code in a consistent format. We determine how many coding convention violations are introduced, removed, and addressed, based on comments left by reviewers. The results show that developers put a great deal of effort into checking for convention violations, although various convention checking tools are available. Third, we propose a technique that automatically recommends related code review requests. When a new patch is submitted for code review, our technique recommends previous code review requests that contain a patch similar to the new one. Developers can locate meaningful information and development context from our recommendations. With two empirical studies and an automation technique for recommending related code reviews, this thesis broadens the empirical knowledge base for code review practitioners and provides a useful approach that supports developers in streamlining their review efforts

Quid Pro Quo: An Exploration of Reciprocity in Code Review

We explore the role of reciprocity in code review processes. Reciprocity manifests itself in two ways: 1) reviewing code for others translates to accepted code contributions, and 2) having contributions accepted increases the reviews made for others. We use vector autoregressive (VAR) models to explore the causal relation between reviews performed and accepted contributions. After fitting VAR models for 24 active open-source developers, we found evidence of reciprocity in 6 of them. These results suggest reciprocity does play a role in code review, that can potentially be exploited to increase reviewer participation

Answer Summarization for Technical Queries: Benchmark and New Approach

Prior studies have demonstrated that approaches to generate an answer summary for a given technical query in Software Question and Answer (SQA) sites are desired. We find that existing approaches are assessed solely through user studies. There is a need for a benchmark with ground truth summaries to complement assessment through user studies. Unfortunately, such a benchmark is non-existent for answer summarization for technical queries from SQA sites. To fill the gap, we manually construct a high-quality benchmark to enable automatic evaluation of answer summarization for technical queries for SQA sites. Using the benchmark, we comprehensively evaluate the performance of existing approaches and find that there is still a big room for improvement. Motivated by the results, we propose a new approach TechSumBot with three key modules:1) Usefulness Ranking module, 2) Centrality Estimation module, and 3) Redundancy Removal module. We evaluate TechSumBot in both automatic (i.e., using our benchmark) and manual (i.e., via a user study) manners. The results from both evaluations consistently demonstrate that TechSumBot outperforms the best performing baseline approaches from both SE and NLP domains by a large margin, i.e., 10.83%-14.90%, 32.75%-36.59%, and 12.61%-17.54%, in terms of ROUGE-1, ROUGE-2, and ROUGE-L on automatic evaluation, and 5.79%-9.23% and 17.03%-17.68%, in terms of average usefulness and diversity score on human evaluation. This highlights that the automatic evaluation of our benchmark can uncover findings similar to the ones found through user studies. More importantly, automatic evaluation has a much lower cost, especially when it is used to assess a new approach. Additionally, we also conducted an ablation study, which demonstrates that each module in TechSumBot contributes to boosting the overall performance of TechSumBot.Comment: Accepted by ASE 202