The Impact of Peer Code Review on Software Maintainability in Open-Source Software: A Case Study

Recently, open-source software (OSS) has become a considerably popular and reliable source of functionality corrections. OSS also allows software developers to reduce technical debt in software development. However, previous studies have shown that the main problem within OSS development is the lack of systematic processes and formal documents related to system development, such as requirements, designs, and testing. This feature of OSS development causes problems in the software quality, such as those related to security and maintainability. In this research, the authors focused on the software's maintainability because this attribute has to greatest potential to reduce the cost and increase the productivity of the software development process. There is currently no existing research that examines whether OSS developers pay attention to software maintainability. To better understand how OSS developers improve software maintainability, this research aims to answer the question: "Are developers interested in software maintainability under the modern code review of open-source software projects?" To answer the research question, the authors investigated the code review process in which the OSS developers changed the code based on a review of code comments related to maintenance and collected the sub-characteristics associated with software maintainability from the existing literature. The authors examined the review comments from two OSS projects: Eclipse and Qt. The results suggest that the number of code revisions due to maintenance issues was moderate and that the OSS developers tend to improve source code quality. This direction could be observed from the increasing number of modifications on given maintenance-based comments over the years. Therefore, an implication of this is the possibility that OSS project developers are interested in software maintainability.