Deming Ding, Shichun Liu, Enhui Yang, Jiahang Lin, Ziying Chen, Shihan Dou, Honglin Guo, Weiyu Cheng, Pengyu Zhao, Chengjun Xiao, Qunhong Zeng, Qi Zhang, Xuanjing Huang, Qidi Xu, Tao Gui. Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers). 2026.

Open source software (OSS) development widely adopts modern code review to identify issues and guarantee code quality. As reported repeatedly, maintainers are under heavy workloads when reviewing code changes. Meanwhile, we notice that some code reviews were overlooked by the authors of the code changes, i.e., neither causing code modification nor being replied to. These code reviews, if requiring responses but not receiving any, might represent a significant inefficiency, risk of overlooking critical issues, and problematic social exchange. Moreover, leaving code reviews publicly unanswered may cause a negative impression on both the corresponding OSS contributors and the OSS projects. Existing literature on code review mainly focuses on the usefulness of code reviews, reviewer recommendations, factors affecting PR acceptance, and review comment generation; the nature of overlooked reviews has not been explored. To this end, we focus on a widely-used modern code review mechanism, i.e., reviewing Pull Request (PR) code before merge, and conduct the first empirical study on 80 Java OSS projects to explore the prevalence, characteristics, rationales, and possible impact of the overlooked code reviews. We find that approximately 7.5% of PRs have at least one review comment being ignored. We further show that pull requests containing no-response comments are significantly associated with longer review lifecycles and lower acceptance rates, indicating measurable negative outcomes beyond their modest prevalence. Then, we categorize these no-response comments through thematic analysis and find two main categories with seven subcategories: Review inquiry and PR management. We also extract four subcategories in Review inquiry, e.g., Give suggestions about code implementation, Point out implementation issues, and Additional task requests. PR management consists of three subcategories, i.e., PR status checks, PR merge conflict notifications, and Reject PR with uncertain reasons. To better understand the existence of no-response comments, we surveyed developers and received 45 responses. We found that the reasons for the existence of no-response comments are diverse, such as prolonged review times and a lack of consensus on opinions. Developers also hold the consensus that ignored reviews will have negative effects on software projects. These findings emphasize the need for attention from both academia and industry to the responses to review comments and optimization of the reminder mechanism.

Modern distributed software development relies on commits to control system versions. Commit classification plays a vital role in both industry and academia. The widely-used commit classification framework was proposed in 1976 by Swanson and includes three base classes: perfective, corrective, and adaptive. With the increasing complexity of software development, the industry has shifted towards a more fine-grained commit category, i.e., adopting Conventional Commits Specification (CCS) for delicacy management. The new commit framework requires developers to classify commits into ten distinct categories, such as “feat”, “fix”, and “docs”. However, existing studies mainly focus on the three-category classification, leaving the definition and application of the fine-grained commit categories as knowledge gaps. This paper reports a preliminary study on this mechanism from its application status and problems. We also explore ways to address these identified problems. We find that a growing number of projects on GitHub are adopting CCS. By qualitatively analyzing 194 issues from GitHub and 100 questions from Stack Overflow about the CCS application, we categorized four main challenges developers encountered when using CCS. The most common one is CCS-type confusion. To address these challenges, we propose a clear definition of CCS types based on existing variants. Further, we designed an approach to automatically classify commits into CCS types, and the evaluation results demonstrate a promising performance. Our work facilitates a deeper comprehension of the present fine-grained commit categorization and holds the potential to alleviate application challenges significantly.

Commit classification for maintenance activities is of critical importance for both industry and academia. State-of-the-art approaches either treat code changes as plain text or rely on manually identified features. Directly applying the most advanced model of code change representation into commit classification faces two limitations: (1) coarse-grained diff comparison neglects the distance of modified code lines; (2) missing key context information of hunk modification and file categories. This study proposes a novel classification model, COLARE, which compares code changes at the hunk level, takes fine-grained features based on categories of changed files, and aggregates with the representation of commit messages. The evaluation results show that our model outperforms state-of-the-art techniques by 7.24% and 7.35% in accuracy and macro F1 score, respectively. We also manually labeled a multi-language dataset and evaluated our approach, The results further confirm that our approach achieves the best performance over three baselines, including ChatGPT (3.5). The evaluation of the ablation study demonstrates the effectiveness of the major components in our technique.