This paper presents initial insights into the effectiveness of ChatGPT in detecting code smells in Java projects. We utilize a large dataset comprising four code smells—Blob, Data Class, Feature Envy, and Long Method—classified into three severity levels. To assess ChatGPT’s proficiency, we employ two different prompts: (i) a generic prompt and (ii) a prompt specifying the smells selected for our research. We evaluate ChatGPT’s abilities using metrics such as precision, recall, and F-measure. Our results reveal that the odds of ChatGPT providing a correct outcome with a specific prompt are 2.54 times higher compared to a generic one. Furthermore, ChatGPT is more effective at detecting smells with critical severity (F-measure = 0.52) than those with minor severity (F-measure = 0.43). Finally, we discuss the implications of our findings and suggest future research directions for leveraging large language models to detect code smells.

Machine Learning (ML) has revolutionized the field of computer software development, enabling data-based predictions and decision-making across several domains. Following modern software development practices, developers use third-party libraries—e.g., Scikit Learn, TensorFlow, and PyTorch—to integrate ML-based functionalities into their applications. Due to the complexity inherent in ML techniques, the models available in the APIs of these tools often require an extensive list of arguments to be set up. Library maintainers overcome this issue by defining default values for most of these arguments so developers can use ML models in their client applications effortlessly. By relying on these default arguments, the clients inadvertently depend on the value defined in these parameters to keep running as expected. We interpret this problem as a semantical breaking change variant, which we named Default Argument Breaking Change (DABC). In this work, we leverage 77 DABCs in Scikit Learn—a well-known ML library—and investigate how 194K client applications are vulnerable to them. Our results show that 72 DABCs (93%) are responsible for exposing 67,747 clients (35%). We also detected that most DABCs (61, 79%) involve APIs used in ML model training and model evaluation stages. Finally, we discuss the importance of managing DABCs in third-party ML libraries and provide insights for developers to mitigate the potential impact of these changes in their applications.

Software development increasingly depends on libraries and frameworks to increase productivity and reduce time-to-market. Despite this fact, we still lack techniques to assess developers expertise in widely popular libraries and frameworks. In this paper, we evaluate the performance of unsupervised (based on clustering) and supervised machine learning classifiers (Random Forest and SVM) to identify experts in three popular JavaScript libraries: facebook/react, mongodb/node-mongodb, and socketio/socket.io. First, we collect 13 features about developers activity on GitHub projects, including commits on source code files that depend on these libraries. We also build a ground truth including the expertise of 575 developers on the studied libraries, as self-reported by them in a survey. Based on our findings, we document the challenges of using machine learning classifiers to predict expertise in software libraries, using features extracted from GitHub. Then, we propose a method to identify library experts based on clustering feature data from GitHub; by triangulating the results of this method with information available on Linkedin profiles, we show that it is able to recommend dozens of GitHub users with evidences of being experts in the studied JavaScript libraries. We also provide a public dataset with the expertise of 575 developers on the studied libraries.

Background: Open source software has an increasing importance in modern software development. However, there is also a growing concern on the sustainability of such projects, which are usually managed by a small number of developers, frequently working as volunteers. Aims: In this paper, we propose an approach to identify GitHub projects that are not actively maintained. Our goal is to alert users about the risks of using these projects and possibly motivate other developers to assume the maintenance of the projects. Method: We train machine learning models to identify unmaintained or sparsely maintained projects, based on a set of features about project activity (commits, forks, issues, etc). We empirically validate the model with the best performance with the principal developers of 129 GitHub projects. Results: The proposed machine learning approach has a precision of 80%, based on the feedback of real open source developers; and a recall of 96%. We also show that our approach can be used to assess the risks of projects becoming unmaintained. Conclusions: The model proposed in this paper can be used by open source users and developers to identify GitHub projects that are not actively maintained anymore.

Co-change clusters are groups of classes that frequently change together. They are proposed as an alternative modular view, which can be used to assess the traditional decomposition of systems in packages. To investigate developer's perception of co-change clusters, we report in this paper a study with experts on six systems, implemented in two languages. We mine 102 co-change clusters from the version history of such systems, which are classified in three patterns regarding their projection to the package structure: Encapsulated, Crosscutting, and Octopus. We then collect the perception of expert developers on such clusters, aiming to ask two central questions: (a) what concerns and changes are captured by the extracted clusters? (b) do the extracted clusters reveal design anomalies? We conclude that Encapsulated Clusters are often viewed as healthy designs and that Crosscutting Clusters tend to be associated to design anomalies. Octopus Clusters are normally associated to expected class distributions, which are not easy to implement in an encapsulated way, according to the interviewed developers.

Open online courses are a method of online lecturing whose application in education is not bounded by space and location constraints. The successful implementation of open courses requires conceptual changes in how instructors and students behave in open unbounded education environment. There are some emerging open courses for teaching specific topics of Software Engineering. However, it is still limited the knowledge about the best practices for learning Software Engineering processes, methods, and tools in such an open environment. To address this limitation, this paper presents and evaluates an open course for Introduction to Software Engineering. The presented open course has over 250 online students registered and is based on a face-to-face equivalent. The online course is currently composed of 44 video lectures, 160 questions in 16 quizzes, and several discussion topics. We evaluate this course by comparing the students' performance in online vs. face-to-face equivalent courses. Our results indicated that students who had access to online content achieve similar or better performance than students taking only the face-to-face course.