Software bugs claim ≈ 50 % of development time and cost the global economy billions of dollars. Once a bug is reported, the assigned developer attempts to identify and understand the source code responsible for the bug and then corrects the code. Over the last five decades, there has been significant research on automatically finding or correcting software bugs. However, there has been little research on automatically explaining the bugs to the developers, which is essential but a highly challenging task. In this paper, we propose Bugsplainer, a transformer-based generative model, that generates natural language explanations for software bugs by learning from a large corpus of bug-fix commits. Bugsplainer can leverage structural information and buggy patterns from the source code to generate an explanation for a bug. Our evaluation using three performance metrics shows that Bugsplainer can generate understandable and good explanations according to Google's standard, and can outperform multiple baselines from the literature. We also conduct a developer study involving 20 participants where the explanations from Bugsplainer were found to be more accurate, more precise, more concise and more useful than the baselines.

Software bugs cost the global economy billions of dollars each year and take up ≈50% of the development time. Once a bug is reported, the assigned developer attempts to identify and understand the source code responsible for the bug and then corrects the code. Over the last five decades, there has been significant research on automatically finding or correcting software bugs. However, there has been little research on automatically explaining the bugs to the developers, which is essential but a highly challenging task. In this paper, we propose Bugsplainer, a novel web-based debugging solution that generates natural language explanations for software bugs by learning from a large corpus of bug-fix commits. Bugsplainer leverages code structures to reason about a bug and employs the fine-tuned version of a text generation model – CodeT5 – to generate the explanations.Tool video: https://youtu.be/xga-ScvULpk

Review comments are one of the main building blocks of modern code reviews. Manually writing code review comments could be time-consuming and technically challenging. Recently, an information retrieval (IR) based approach has been proposed to automatically recommend relevant code review comments for method-level code changes. However, this technique overlooks the structured items (e.g., class name, library information) from the source code and is applicable only for method-level changes. In this paper, we propose a novel technique for relevant review comments recommendation – RevCom – that leverages various code-level changes using structured information retrieval. RevCom uses different structured items from source code and can recommend relevant reviews for all types of changes (e.g., method-level and non-method-level). Our evaluation using three performance metrics show that RevCom outperforms both IR-based and DL-based baselines by up to 49.45% and 23.57% margins in BLEU score in recommending review comments. We find that RevCom can recommend review comments with an average BLEU score of ≈ 26.63%. According to Google’s AutoML Translation documentation, such a BLEU score indicates that the review comments can capture the original intent of the reviewers. All these findings suggest that RevCom can recommend relevant code reviews and has the potential to reduce the cognitive effort of human code reviewers.

Defect prediction has been a popular research topic where machine learning (ML) and deep learning (DL) have found numerous applications. However, these ML/DL-based defect prediction models are often limited by the quality and size of their datasets. In this paper, we present Defectors, a large dataset for just-in-time and line-level defect prediction. Defectors consists of ≈ 213K source code files (≈ 93K defective and ≈ 120K defect- free) that span across 24 popular Python projects. These projects come from 18 different domains, including machine learning, automation, and internet-of-things. Such a scale and diversity make Defectors a suitable dataset for training ML/DL models, especially transformer models that require large and diverse datasets. We also foresee several application areas of our dataset including defect prediction and defect explanation.