Program Dependency Analysis for Consolidating Customized Product Copies

To cope with project constraints, copying and customizing existing software products is a typical practice to flexibly serve customer-specific needs. In the long term, this practice becomes a limitation for growth due to redundant maintenance efforts or wasted synergy and cross selling potentials. To mitigate this limitation, customized copies need to be consolidated into a single, variable code base of a software product line (SPL). However, consolidation is tedious as one must identify and correlate differences between the copies to design future variability. For one, existing consolidation approaches lack support of the implementation level. In addition, approaches in the fields of difference analysis and feature detection are not sufficiently integrated for finding relationships between code modifications. In this paper, we present remedy to this problem by integrating a difference analysis with a program dependency analysis based on Program Dependency Graphs (PDG) to reduce the effort of consolidating developers when identifying dependent differences and deriving clusters to consider in their variability design. We successfully evaluated our approach on variants of the open source ArgoUML modeling tool, reducing the manual review effort about 72% with a precision of 99% and a recall of 80%. We further proved its industrial applicability in a case study on a commercial relationship management application.