Improving early detection of software merge conflicts

Merge conflicts cause software defects which if detected late may require expensive resolution. This is especially true when developers work too long without integrating concurrent changes, which in practice is common as integration generally occurs at check-in. Awareness of others' activities was proposed to help developers detect conflicts earlier. However, it requires developers to detect conflicts by themselves and may overload them with notifications, thus making detection harder. This paper presents a novel solution that continuously merges uncommitted and committed changes to create a background system that is analyzed, compiled, and tested to precisely and accurately detect conflicts on behalf of developers, before check-in. An empirical study confirms that our solution avoids overloading developers and improves early detection of conflicts over existing approaches. Similarly to what happened with continuous compilation, this introduces the case for continuous merging inside the IDE.