ChangeViz: Enhancing the GitHub Pull Request Interface with Method Call Information

Code review is a widely adopted software development practice aimed at finding defects, improving software quality, and transferring knowledge among developers. Performing an effective code review is a challenging task for developers. Two of the main challenges reviewers face are (1) understanding the content of a review change-set and (2) assessing the impact of a change on the codebase. Visualization techniques can be used to increase developers’ understanding of a changeset to review and its context. However, only a few attempts have been made to apply visualization to code review.In this paper, we present a novel approach we devised to support developers in understanding GitHub pull requests. Our approach expands the GitHub interface with two lateral bars to let developers navigate to the definition/uses of the methods in the changeset under review.We evaluated our approach’s interface through (1) interviews with eight developers and (2) a survey with 12 participants. Based on the results of this evaluation, we implemented our approach in a web-based tool, ChangeViz.Pre-print, data and materials, and demo video: https://doi.org/10.5281/zenodo.5175927.