Scalable Software Merging Studies with MERGANSER

Software merging researchers constantly need empirical data of real-world merge scenarios to analyze. Such data is currently extracted through individual and isolated efforts, often with non-systematically designed scripts that may not easily scale to large studies. This hinders replication and proper comparison of results. In this paper, we introduce MERGANSER, a scalable and easy-to-use tool for extracting and analyzing merge scenarios in Git repositories. In addition to extracting basic information about merge scenarios from Git history, our tool also replays each merge to detect conflicts and stores the corresponding information of conflicting files and regions. We design a normalized and extensible SQL data schema to store the information of the analyzed repositories, merge scenarios and involved commits, and merge replays and conflicts. By running only one command, our proposed tool clones the target repositories, detects their merge scenarios, and stores their information in a SQL database. MERGANSER is written in Python and released under the MIT license. In this tool paper, we describe MERGANSER's architecture and provide guidance for its usage in practice.