The impact analysis task in software maintenance: a model and a case study

If better tools are to be developed to support the impact analysis task, greater clarity is needed about the exact nature of that task. This paper presents a definition of impact analysis and distinguishes between impact analysis and program understanding. Impact analysis is a necessarily approximate technique which must focus on the cost-effective minimization of unwanted side-effects. A key to effectiveness would be a way of precisely describing the semantics of each software change. A general model of software impacts is presented that uses flexible declarative propagation rules to describe the way software objects affect each other. Preliminary versions of the model have been implemented in an impact analysis system. A small case study was performed to gain experience in applying the model as part of a software change process. Recommendations are made for impact analysis tool support and for further research directions