An Empirical Study of Code Clones from Commercial AI Code Generators

Deep learning (DL) has revolutionized various software engineering tasks. Particularly, the emergence of AI code generators has pushed the boundaries of automatic programming to synthesize entire programs based on user-defined specifications in natural language. However, it remains a mystery if these AI code generators rely on the copy-and-paste programming practice, resulting in code clone concerns. In this work, to comprehensively study the code cloning behavior of AI code generators, we conduct an empirical study on three state-of-the-art commercial AI code generators to investigate the existence of all types of clones, which remains underexplored. Our experimental results show that the total Type-1 and Type-2 clone rates of the state-of-the-art commercial AI code generators can reach up to 7.50%, indicating marked code clone issues. Furthermore, it is observed that AI code generators risk infringing copyrights and propagating buggy and vulnerable code resulting from cloning code and show a certain degree of stability in generating code clones.