Visualization of fine-grained code change history

Conventional version control systems save code changes at each check-in. Recently, some development environments retain more fine-grain changes. However, providing tools for developers to use those histories is not a trivial task, due to the difficulties in visualizing the history. We present two visualizations of fine-grained code change history, which actively interact with the code editor: a timeline visualization, and a code history diff view. Our timeline and filtering options allow developers to navigate through the history and easily focus on the information they need. The code history diff view shows the history of any particular code fragment, allowing developers to move through the history simply by dragging the marker back and forth through the timeline to instantly see the code that was in the snippet at any point in the past. We augment the usefulness of these visualizations with richer editor commands including selective undo and search, which are all implemented in an Eclipse plug-in called “Azurite”. Azurite helps developers with answering common questions developers ask about the code change history that have been identified by prior research. In addition, many of users' backtracking tasks can be achieved using Azurite, which would be tedious or error-prone otherwise.