Defending against the attack of the micro-clones

Micro-clones are small pieces of redundant code, such as repeated subexpressions or statements. In this paper, we establish the considerations and value toward automated detection and removal of micro-clones at scale. We leverage the Boa software mining infrastructure to detect micro-clones in a data set containing 380,125 Java repositories, and yield thousands of instances where redundant code may be safely removed. By filtering our results to target popular Java projects on GitHub, we proceed to issue 43 pull requests that patch micro-clones. In summary, 95% of our patches to active GitHub repositories are merged rapidly (within 15 hours on average). Moreover, none of our patches were contested; they either constituted a real flaw, or have not been considered due to repository inactivity. Our results suggest that the detection and removal of micro-clones is valued by developers, can be automated at scale, and may be fixed with rapid turnaround times.