How to Communicate when Submitting Patches: an Empirical Study of the Linux Kernel

Communication when submitting patches (CSP) is critical in software development, because ineffective communication wastes the time of developers and reviewers, and is even harmful to future product release and maintenance. In distributed software development, CSP is usually in the form of computer-mediated communication (CMC), which is a crucial topic concerned by the CSCW community. However, what to say and how to say in communication including CSP has been rarely studied. To bridge this knowledge gap and provide relevant guidance for developers to conduct CSP, in this study, we conducted an empirical study on the Linux kernel. We found four themes involving 17 expression elements that characterize what to express when submitting patches and three themes of contextual factors that determine how these elements are applied. Considering both expression elements and context, combined with an online survey, we obtained 17 practices for communication. Among them, four practices, such as "provide sufficient reasons'' and "provide a trade-off'' are the most important but difficult practices, for which we provide specific instructions. We also found that the "individual factors'' plays a special role in communication, which may lead to potential problems even in accepted patches. Based on these findings, we discuss the recommendations for different practitioners, including patch submitters, reviewers, and tool designers, and the implications for open source software (OSS) communities and the CSCW researchers.