Automating Code Review

Code reviews are popular in both industrial and open source projects. The benefits of code reviews are widely recognized and include better code quality and lower likelihood of introducing bugs. However, code review comes at the cost of spending developers' time on reviewing their teammates' code. The goal of this research is to investigate the possibility of using Deep Learning (DL) to automate specific code review tasks. We started by training vanilla Transformer models to learn code changes performed by developers during real code review activities. This gives the models the possibility to automatically (i) revise the code submitted for review without any input from the reviewer; and (ii) implement changes required to address a specific reviewer's comment. While the preliminary results were encouraging, in this first work we tested DL models in rather simple code review scenarios, substantially simplifying the targeted problem. This was also due to the choices we made when designing both the technique and the experiments. Thus, in a subsequent work, we exploited a pre-trained Text- To- Text-Transfer-Transformer (T5) to overcome some of these limitations and experiment DL models for code review automation in more realistic and challenging scenarios. The achieved results show the improvements brought by T5 both in terms of applicability (i.e., scenarios in which it can be applied) and performance. Despite this, we are still far from performance levels making these techniques deployable in practice, thus calling for additional research in this area, as we discuss in our future work agenda.