Merging problems in modern version control systems

Abstract

During software development, when developers change the same part of the code concurrently, this may be led to merging conflicts. Resolving these conflicts might be costly and time-consuming. Three types of conflicts may arise during merge processes: textual, syntactic, and semantic. Textual conflicts occur when merging a concurrent operation, such as addition, removal or edition take place over the same parts of code. Syntactic conflicts occur when concurrent operations break the syntactic structure of the source code files when merged. Finally, a semantic conflict occurs when the merged modification is compiled without error but malfunctions. Version management systems usually use textual merging technique; users can synchronize their modifications with other users working in parallel with them, in this process, a merge is performed between local modifications and remote modifications. The previous work has examined different mechanisms to detect and resolve conflicts and proposed different tools for resolving merge conflicts, such as two-way merging, three-way merging, state-based merging, and operation-based merging. This paper discusses and investigates many concepts related to merging conflicts by asking and answering these questions; what are the factors that most affect in a merge conflict, how to avoiding and reducing merge conflicts, how to detecting merge conflicts, and how to resolve them.