Multi-Perspective Visualization to Assist Code Change Review

Change-based code review plays an important role in open-source project development. Due to the large amount of human involvement and tight time schedule, tools that can facilitate this activity would be of great help. Current tools mainly focus on difference extraction, code style examination, static analysis, comment and discussion, etc. However, there is little support to change impact analysis for code change review. In this paper, we serve this purpose by providing a change review assistance tool, namely, MultiViewer, for the most popular OSS GitHub. We define metrics to characterize code changes from multiple perspectives. Specifically, these metrics mine coupling relations among related files in the changes, as well as estimate the change effort, risk and impact. Such information is visualized by MultiViewer in two formats. We demonstrate the helpfulness of MultiViewer by showing its ability as indicators to some important project features with real-life case studies.