Masanari Kondo

Zhao Tian, Zifan Zhang, Tao Xiao et al.

Recent advances in coding agents have shown remarkable progress in software issue resolution. In practice, real-world issues are typically bug fixes or feature requests in which human developers naturally incorporate refactoring as part of the resolution process, resulting in tangled refactoring. Since LLMs are trained on large-scale open-source repositories, coding agents may inherit such behaviors. In this paper, we conduct an empirical study on Multi-SWE-bench, analyzing 3,691 valid patches generated by three agent frameworks with 12 LLMs. We find that coding agents introduce tangled refactorings less frequently (21.43% vs. 36.72%) and with lower intensity (0.66 vs. 1.75) than human developers, although they exhibit a broader diversity of refactoring types. Logistic regression analysis further shows that tangled refactorings are strongly associated with reduced compilability, while exhibiting no significant association with functional correctness. Based on these findings, we propose a refactoring-aware refinement approach that assesses the necessity and safety of tangled refactorings and selectively removes or repairs problematic operations. Our approach improves compilability from 19.34% to 38.33%, and additionally resolves 2.79% previously unresolved issues. Overall, this work presents the first step towards understanding tangled refactoring practices in agentic issue resolution and opens up avenues for future work.

Kazuki Kusama, Honglin Shu, Masanari Kondo et al.

Log statements capture critical information for software maintenance activities such as testing, debugging, and failure analysis. Because of this importance, developers must carefully design log statements, which requires significant effort. To support developers, various end-to-end automated log statement generation approaches have been proposed, whereas these approaches have mainly been evaluated within a single programming language environment and their effectiveness in multilingual environments remains underexplored. In this paper, we therefore comparatively evaluate three state-of-the-art log statement generation approaches and five large language models (LLMs) across multiple programming languages. For this purpose, we constructed a multilingual benchmark comprising 150,000 instances across five programming languages. Our empirical results demonstrate that UniLog, a state-of-the-art approach, achieves the best overall performance, maintaining high effectiveness even in multilingual environments. We also observe substantial variance in the difficulty of log generation across languages: Python presents a greater challenge, whereas JavaScript yields comparatively better performance. Detailed analysis reveals that these disparities stem from variations in log insertion distributions and language-specific logging idioms. Our findings indicate that simply scaling model size or the volume of training data is insufficient for multilingual log generation; rather, designing approaches tailored to the specific characteristics of target languages is crucial. These findings suggest that future automated logging techniques should explicitly account for language-specific logging characteristics to achieve robust performance in multilingual software development environments.