A Large-Scale Empirical Review of Patch Correctness Checking Approaches

Automated Program Repair (APR) techniques have drawn wide attention from both academia and industry. Meanwhile, one main limitation with the current state-of-the-art APR tools is that patches passing all the original tests are not necessarily the correct ones wanted by developers, i.e., the plausible patch problem. To date, various Patch-Correctness Checking (PCC) techniques have been proposed to address this important issue. However, they are only evaluated on very limited datasets as the APR tools used for generating such patches can only explore a small subset of the search space of possible patches, posing serious threats to external validity to existing PCC studies. In this paper, we construct an extensive PCC dataset, PraPatch (the largest manually labeled PCC dataset to our knowledge), to revisit all nine state-of-the-art PCC techniques. More specifically, our PCC dataset PraPatch includes 1,988 patches generated from the recent PraPR APR tool, which leverages highly-optimized bytecode-level patch executions and can exhaustively explore all possible plausible patches within its large predefined search space (including well-known fixing patterns from various prior APR tools). Our extensive study of representative PCC techniques on PraPatchhas revealed various findings, including: 1) the assumption made by existing static PCC techniques that correct patches are more similar to buggy code than incorrect plausible patches no longer holds, 2) state-of-the-art learning-based techniques tend to suffer from the dataset overfitting problem, 3) while dynamic techniques overall retain their effectiveness on our new dataset, their performance drops substantially on patches with more complicated changes and 4) the very recent naturalness-based techniques can substantially outperform traditional static techniques and could be a promising direction for PCC. Based on our findings, we also provide various guidelines/suggestions for advancing PCC in the near future.