Can Program Synthesis be Used to Learn Merge Conflict Resolutions? An Empirical Analysis
This addresses merge conflicts in collaborative software development, particularly for large forks like Microsoft Edge, by automating repetitive resolutions, though it is incremental as it builds on existing program synthesis methods.
The study tackled the problem of textual merge conflicts in large software forks by analyzing Microsoft Edge's conflicts and found that 28% are small (1-2 lines) with repetitive patterns. It then used program synthesis with a novel DSL to learn resolution strategies, achieving 11.4% conflict resolution (41% of small changes) with 93.2% accuracy.
Forking structure is widespread in the open-source repositories and that causes a significant number of merge conflicts. In this paper, we study the problem of textual merge conflicts from the perspective of Microsoft Edge, a large, highly collaborative fork off the main Chromium branch with significant merge conflicts. Broadly, this study is divided into two sections. First, we empirically evaluate textual merge conflicts in Microsoft Edge and classify them based on the type of files, location of conflicts in a file, and the size of conflicts. We found that ~28% of the merge conflicts are 1-2 line changes, and many resolutions have frequent patterns. Second, driven by these findings, we explore Program Synthesis (for the first time) to learn patterns and resolve structural merge conflicts. We propose a novel domain-specific language (DSL) that captures many of the repetitive merge conflict resolution patterns and learn resolution strategies as programs in this DSL from example resolutions. We found that the learned strategies can resolve 11.4% of the conflicts (~41% of 1-2 line changes) that arise in the C++ files with 93.2% accuracy.