In software engineering, it is not enough to simply write code that only works as intended, even if it is free from vulnerabilities and bugs. Every programming language has a style guide and a set of best practices defined by its community, which help practitioners to build solutions that have a clear structure and therefore are easy to read and maintain. To introduce assessment of code quality into the educational process, we developed a tool called Hyperstyle. To make it reflect the needs of the programming community and at the same time be easily extendable, we built it upon several existing professional linters and code checkers. Hyperstyle supports four programming languages (Python, Java, Kotlin, and Javascript) and can be used as a standalone tool or integrated into a MOOC platform. We have integrated the tool into two educational platforms, Stepik and JetBrains Academy, and it has been used to process about one million submissions every week since May 2021.

Inspection of code changes is a time-consuming task that constitutes a big part of everyday work of software engineers. Existing IDEs provide little information about the semantics of code changes within the file editor view. Therefore developers have to track changes across multiple files, which is a hard task with large codebases.In this paper, we present REFACTORINSIGHT, a plugin for IntelliJ IDEA that introduces a smart diff for code changes in Java and Kotlin where refactorings are auto-folded and provided with their description, thus allowing users to focus on changes that modify the code behavior like bug fixes and new features. REFACTORINSIGHT supports three usage scenarios: viewing smart diffs with auto-folded refactorings and hints, inspecting refactorings in pull requests and in any specific commit in the project change history, and exploring the refactoring history of methods and classes. The evaluation shows that commit processing time is acceptable: on median it is less than 0.2 seconds, which delay does not disrupt developers’ IDE workflows.Refactorinsight is available at https://github.com/JetBrains-Research/RefactorInsight. The demonstration video is available at https://youtu.be/-6L2AKQ66nA.

Many code changes that developers make in their projects are repeated and constitute recurrent change patterns. It is of interest to collect such patterns from the version history of open-source repositories and suggest the most useful of them as quick fixes. In this paper, we present Revizor—a tool aimed to build custom plugins for PyCharm, a popular Python IDE. A Revizor-based plugin can take change patterns and highlight potential places for their application in the developer’s code editor. If the developer accepts the quick fix, the plugin automatically performs the edit. Our approach uses a graph-based representation of code changes, which allows it to support complex distributed code patterns. Experienced developers have also rated the usability and the performance of such Revizor-based plugin positively.The source code of the tool and test plugin prototype are available on GitHub: https://github.com/JetBrains-Research/revizor. A demonstration video with a short tool description can be found on YouTube: https://youtu.be/5eLs14nco7E.