Crystal: Precise and Unobtrusive Conflict Warnings

During collaborative development, individual developers can create conflicts in their copies of the code. Such conflicting edits are frequent in practice, and resolving them can be costly. The authors present Crystal, a tool that proactively examines developers' code and precisely identifies and reports on textual, compilation, and behavioral conflicts. When conflicts are present, Crystal enables developers to resolve them more quickly, and therefore at a lesser cost. When conflicts are absent, Crystal increases the developers' confidence that it is safe to merge their code. Crystal uses an unobtrusive interface to deliver pertinent information about conflicts.