Towards a Formalism for Specifying N-way Model Merging Rules

Integrating multiple versions of a model into a unified yet consistent model, which is called N-way merging, is a key challenge in collaborative modeling. Recently, several approaches have been proposed that construct a merged model by incorporating all elements of parallel versions. Despite these efforts, techniques for the high-level specification of N-way merging have hardly been addressed, and research on proposing a formalism for this problem is scarce. Such a formalism can be used to better understand and analyze the behavior of merging real-world systems. This paper presents a formalism to facilitate the specification of the logic behind merging N concurrent versions. The proposed formalism can be used in different merging scenarios to help domain experts analyze their integration requirements more precisely. We introduced three types of merging rules to empower our formalism for specifying all possible scenarios in merging N model versions. We also provide a proof-of-concept implementation in which the N-way merging formalism is equipped with a syntax-aware editor and a parser to promote N-way merging rules for EMF-based models. We conducted a case study to evaluate the applicability of our formalism via a real-world versioning scenario. The results are promising for specifying merging rules in various situations.