Understanding Broadcast Based Peer Review in Open Source Software Projects

Peter C Rigby and Margaret-Anne Storey
University of Victoria, Canada

Software peer review has proven to be a successful technique in open source software (OSS) development. In contrast to industry, where reviews are typically assigned to specific individuals, changes are broadcast to thousands of potentially interested stakeholders. What is surprising is that this approach works very well, despite concerns that reviews may be ignored, or that discussions will deadlock because too many uninformed stakeholders are involved. In this paper, we describe an empirical study to investigate the mechanisms and behaviors that developers use to find code changes they are competent to review. We also explore how stakeholders interact with one another during the review process. We manually examine hundreds of reviews across five high profile OSS projects. Our findings provide insights into the simple, community-wide techniques that developers use to effectively manage large quantities of reviews. The themes that emerge from our study are validated by interviewing long-serving core developers.