Enhancing Clone-and-Own with Systematic Reuse for Developing Software Variants

To keep pace with the increasing demand for custom-tailored software systems, companies often apply a practice called clone-and-own, whereby a new variant of a software system is built by coping and adapting existing variants. Instead of a single and configurable system, clone-and-own leads to ad hoc product portfolios of multiple yet similar variants that soon become impossible to maintain effectively. Clone-and-own has widespread industrial use because it requires no major upfront investments and is intuitive, but it lacks a methodology for systematic reuse. In this work we propose ECCO (Extraction and Composition for Clone-and-Own), a novel approach to enhance clone and-own that actively supports the development and maintenance of software product variants. A software engineer selects the desired features and ECCO finds the proper software artifacts to reuse and then provides guidance during the manual completion by hinting which software artifacts may need adaptation. We evaluated our approach on 6 case studies, covering 402 variants having up to 344KLOC, and found that precision and recall of composed products quickly reach a near optimum (>95% reuse).