As a fundamental component of software documentation, code comments could help developers comprehend and maintain programs. Several datasets of method header comments have been proposed in previous studies for machine learning-based code comment generation. As part of code comments, inline code comments are also crucial for code understanding activities. However, unlike method header comments written in a standard format and describing the whole method code, inline comments are often written in arbitrary formats by developers due to timelines pressures and different aspects of code snippets in the method are described. Currently, there is no large-scale dataset used for inline comments generation considering these. Hence, this naturally inspires us to explore whether we can construct a dataset to foster machine learning research that not only performs fine-grained noise-cleaning but conducts a taxonomy of inline comments. To this end, we first collect inline comments and code snippets from 8000 Java projects on GitHub. Then, we conduct a manual review to obtain heuristic rules, which could be used to clean the data noise in a fine-grained manner. As a result, we construct a large-scale benchmark dataset named ICG with 5,740,770 pairs of inline comments and code snippets. We then build a comprehensive taxonomy and conduct a statistical and manual analysis to explore the performances of different categories of inline comments, such as helpfulness in code understanding. After that, we provide and compare several baseline models to automatically generate inline comments, such as CodeBERT, to enhance the usability of the benchmark for researchers. The availability of our benchmark and baselines can help develop and validate new inline comment generation methods, which would also further facilitate code understanding activities.

Abstract Issue tracking systems are now prevalent in software development, which would help developers submit and discuss issues to solve development problems on software projects. Most previous studies have been conducted to analyze issue relations within projects, such as recommending similar or duplicate bug issues. However, along with the popularization of co‐developing through multiple projects, many issues are cross‐project correlated (CPC), that is, one issue is associated with another issue in a different project. When developers meet with CPC issues, it may primarily increase the difficulties of solving them because they need information from not only their projects but also other related projects that developers are not familiar with. Identifying a CPC issue as early as possible is a fundamental challenge for both managers and developers to allocate the resources for software maintenance and estimate the effort to solve it. This paper proposes 11 issue metrics of two groups to describe textual summary and reporters' activity, which can be extracted just after the issue was reported. We employ these 11 issue metrics to construct just‐in‐time (JIT) prediction models to identify CPC issues. To evaluate the effect of CPC issue prediction models, we conduct experiments on 16 open‐source data science and deep learning projects and compare our prediction model with two baseline models based on textual features (i.e., Term Frequency‐Inverse Document Frequency [TF‐IDF] and Word Embedding), which are commonly adopted by previous studies on issue prediction. The results show that the JIT prediction model based on issue metrics has significantly improved the performance of CPC issue prediction under two evaluation indicators, Matthew's correlation coefficient (MCC) and F1. In addition, we find that the prediction model is more suitable for large‐scale complex core projects in the open‐source ecosystem.

The calling relationship between projects becomes complicated as the number of open-source projects increases. Different issues across projects can also be related, referred to as cross-project correlated issues (CPCIs), and bring new challenges for developers to fix these issues. When solving these CPCIs, developers have to accurately locate the source code that causes it in the current project and also needs to know the related issues in other projects. However, few studies have proposed specific methods to help developers effectively address these CPCIs, i.e., find related issues for CPCIs.

Blocking bugs are a severe type of bugs that prevent other bugs from being fixed. As software becomes increasingly complex and large, blocking bugs occur in many large-scale software, especially in software ecosystems. Blocking bugs may have a high negative impact on software development and maintenance. Usually, blocking bugs preventing more bugs should be more concerned. In this paper, we focus on a special type of blocking bugs that block at least two bugs, which we call Critical Blocking Bugs (CBBs).