Schultheiß, AlexanderBittner, Paul MaximilianThüm, ThomasKehrer, TimoEngels, GregorHebig, ReginaTichy, Matthias2023-01-182023-01-182023978-3-88579-726-5https://dl.gi.de/handle/20.500.12116/40108We report about a recent empirical study on variant synchronization in clone-and-own, originally published at the 38th IEEE International Conference on Software Maintenance and Evolution (ICSME) 2022 [Sc22]. In clone-and-own, a new variant of a software system is created by copying and adapting an existing one. While it is flexible, clone-and-own causes high maintenance effort in the long run as cloned variants evolve in parallel; certain changes, such as bug fixes, need to be propagated between variants. A recent line of research proposes to automate such synchronization tasks when migration to a software product line is not feasible. However, it is yet unclear how far this synchronization can actually be pushed. We present an empirical study in which we quantify the potential to automate the synchronization of variants in clone-and-own. We simulate automated variant synchronization using the history of BusyBox, a real-world multi-variant software system. Our results indicate that existing patching techniques propagate changes with an accuracy of up to 85%, if applied consistently from the start of a project. This can be even further improved to 93% by exploiting lightweight domain knowledge about which features are affected by a change, and which variants implement affected features.enclone-and-ownvariant synchronizationversion controlsoftware product linesText/Conference Paper1617-5468