Managing Change When Proving Software Correct

We propose a new and systematic framework for proof reuse in the context of deductive software verification. The framework generalizes abstract contracts into incremental proof repositories. Abstract contracts enable a separation of concerns between called methods and their implementations, facilitating proof reuse. Proof repositories allow the systematic caching of partial proofs that can be adapted to different method implementations. The framework provides flexible support for compositional verification in the context of, e.g., partly developed programs, evolution of programs and contracts, and product variability. Partly funded by the EU project H2020-644298 HyVar: Scalable Hybrid Variability for Distributed Evolving Software Systems (www.hyvar-project.eu), the EU project FP7-610582 Envisage: Engineering Virtualized Services (www.envisage-project.eu), the Ateneo/CSP project RunVar, and the ICT COST Actions IC1402 ARVI (www.cost-arvi.eu) and IC1201 BETTY (www.behavioural-types.eu). R. Bubel, R. Hähnle Department of Computer Science, Technische Universität Darmstadt E-mail: {bubel, haehnle}@cs.tu-darmstadt.de F. Damiani Department of Computer Science, University of Torino E-mail: [email protected] E. B. Johnsen, O. Owe, I. Chieh Yu Department of Informatics, University of Oslo E-mail: {einarj,olaf,ingridcy}@ifi.uio.no I. Schaefer Institute for Software Engineering, Technische Universität Braunschweig E-mail: [email protected] 2 Richard Bubel et al.