Improving change descriptions with change contexts

Software archives are one of the best sources available to researchers for understanding the software development process. However, much detective work is still necessary in order to unravel the software development story. During this process, researchers must isolate changes and follow their trails over time. In support of this analysis, several research tools have provided different representations for connecting the many changes extracted from software archives. Most of these tools are based on textual analysis of source code and use line-based differencing between software versions. This approach limits the ability to process changes structurally resulting in less concise and comparable items. Adoption of structure-based approaches have been hampered by complex implementations and overly verbose change descriptions. We present a technique for expressing changes that is fine-grained but preserves some structural aspects. The structural information itself may not have changed, but instead provides a context for interpreting the change. This in turn, enables more relevant and concise descriptions in terms of software types and programming activities. We apply our technique to common challenges that researchers face, and then we discuss and compare our results with other techniques.