Barriers for Students During Code Change Comprehension

Modern code review (MCR) is a key practice for many software engineering organizations, so undergraduate software engineering courses often teach some form of it to prepare students. However, research on MCR describes how many its professional implementations can fail, to say nothing on how these barriers manifest under students' particular contexts. To uncover barriers students face when evaluating code changes during review, we combine interviews and surveys with an observational study. In a junior-level software engineering course, we rst interviewed 29 undergraduate students about their experiences in code review. Next, we performed an observational study that presented 44 students from the same course with eight code change comprehension activities. These activities provided students with pull requests of potential refactorings in a familiar code base, collecting feedback on accuracy and challenges. This was followed by a reection survey. Building on these methods, we combine (1) a qualitative analysis of the interview transcripts, activity comments, and reection survey with (2) a quantitative assessment of their performance in identifying behavioral changes in order to outline the barriers that students face during code change comprehension. Our results reveal that students struggle with a number of facets around a program: the context for review, the review tools, the code itself, and the implications of the code changes. These ndings -along with our result that student developers tend to overestimate behavioral similarity during code comparison -have implications for future support to help student developers have smoother code review experiences. We motivate a need for several interventions, including sentiment analysis on pull request comments to ag toxicity, scaolding for code comprehension while reviewing large changes, and behavioral ding to contrast the evolution of syntax and semantics. CCS CONCEPTS • Software and its engineering ! Software evolution; Software development process management; • General and reference ! Empirical studies.