Visualizing and exploring software version control repositories using interactive tag clouds over formal concept lattices

Abstract

Context: version control repositories contain a wealth of implicit information that can be used to answer many questions about a project’s development process. However, this information is not directly accessible in the repositories and must be extracted and visualized.Objective: the main objective of this work is to develop a flexible and generic interactive visualization engine called ConceptCloud that supports exploratory search in version control repositories.Method: ConceptCloud is a flexible, interactive browser for SVN and Git repositories. Its main novelty is the combination of an intuitive tag cloud visualization with an underlying concept lattice that provides a formal structure for navigation. ConceptCloud supports concurrent navigation in multiple linked but individually customizable tag clouds, which allows for multi-faceted repository browsing, and scriptable construction of unique visualizations.Results: we describe the mathematical foundations and implementation of our approach and use ConceptCloud to quickly gain insight into the team structure and development process of three projects. We perform a user study to determine the usability of ConceptCloud. We show that untrained participants are able to answer historical questions about a software project better using ConceptCloud than using a linear list of commits.Conclusion: ConceptCloud can be used to answer many difficult questions such as “What has happened in this project while I was away?” and “Which developers collaborate?”. Tag clouds generated from our approach provide a visualization in which version control data can be aggregated and explored interactively.