Automatic Detection and Resolution of Software Merge Conflicts: Are We There Yet?

Abstract

Developers create software branches for tentative feature addition and bug fixing, and periodically merge branches to release software with new features or repairing patches. When the program edits from different branches textually overlap (i.e., textual conflicts), or the co-application of those edits lead to compilation or runtime errors (i.e., compiling or dynamic conflicts), it is challenging and time-consuming for developers to eliminate merge conflicts. Prior studies examined how conflicts were related to code smells or software development process; tools were built to find and solve conflicts. However, some fundamental research questions are still not comprehensively explored, including (1) how conflicts were introduced, (2) how developers manually resolved conflicts, and ( 3) what conflicts cannot be handled by current tools.For this paper, we took a hybrid approach that combines automatic detection with manual inspection to reveal 204 merge conflicts and their resolutions in 15 open-source repositories. Our data analysis reveals three phenomena. First, compiling and dynamic conflicts are harder to detect, although current tools mainly focus on textual conflicts. Second, in the same merging context, developers usually resolved similar textual conflicts with similar strategies. Third, developers manually fixed most of the inspected compiling and dynamic conflicts by similarly editing the merged version as what they did for one of the branches. Our research reveals the challenges and opportunities for automatic detection and resolution of merge conflicts; it also sheds light on related areas like systematic program editing and change recommendation. CCS CONCEPTS• Software and its engineering → Software maintenance tools; Maintaining software; Software evolution.

Merge Nature: a tool to support research about merge conflicts

“…This shows how frequent merge conflicts are in the life of software developers. Despite the broad array of programming languages available to developers, most studies [1,6,7,9,13] have investigated merge conflicts on Java projects only, neglecting other programming languages since each programming language has its grammar that should be considered during a tool implementation.…”