Software Evolution Comprehension: Replay to the Rescue

Developers often need to find answers to questions regarding the evolution of a system when working on its code base. While their information needs require data analysis spanning over different repository types, the source code repository has a pivotal role for program comprehension tasks. However, the coarse-grained nature of the data stored by commit-based software configuration management systems often makes it challenging for a developer to search for an answer. We present Replay, an Eclipse plug-in that allows one to explore the change history of a system by capturing the changes at a finer granularity level than commits, and by replaying the past changes chronologically inside the integrated development environment with the source code at hand. We conducted a controlled experiment to empirically assess whether Replay outperforms a baseline (SVN client in Eclipse) on helping developers to answer common questions related to software evolution. The experiment shows that Replay leads to a decrease in completion time with respect to a set of software evolution comprehension tasks.