Consistent merging of model versions

•Proposing a novel approach to merging versions of models.•Dealing with both conflicts and inconsistencies arising in the merging process.•Our approach has been formally proven to be correct (sound and complete).•Scalability was empirically validated using real, industrial design models.

While many engineering tasks can, and should be, manageable independently, it does place a great burden on explicit collaboration needs—including the need for frequent and incremental merging of artifacts that software engineers manipulate using these tools. State-of-the-art merging techniques are often limited to textual artifacts (e.g., source code) and they are unable to discover and resolve complex merging issues beyond simple conflicts. This work focuses on the merging of models where we consider not only conflicts but also arbitrary syntactic and semantic consistency issues. Consistent artifacts are merged fully automatically and only inconsistent/conflicting artifacts are brought to the users’ attention, together with a systematic proposal of how to resolve them. Our approach is neutral with regard to who made the changes and hence reduces the bias caused by any individual engineer’s limited point of view. Our approach also applies to arbitrary design or models, provided that they follow a well-defined metamodel with explicit constraints—the norm nowadays. The extensive empirical evaluation suggests that our approach scales to practical settings.