Numerous tools exist for mining source code and software development process metrics. However, very few publicly available tools focus on source code comments, a crucial software artifact. This paper presents SoCCMiner (Source Code-Comments and Comment-Context Miner), a tool that offers multiple mining pipelines. It is the first readily available (plug-and-play) and customizable open-source tool for mining source code contextual information of comments at different granularities (Class comments, Method comments, Interface comments, and other granular comments). Mining comments at different source code granularities can aid researchers and practitioners working in a host of applications that focus on source code comments, such as Self-Admitted Technical Debt, Program Comprehension, and other applications. Furthermore, SoCCMiner is highly adaptable and extendable to include additional attributes and support other programming languages. This prototype supports the Java programming language.

A high imbalance exists between technical debt and non-technical debt source code comments. Such imbalance affects Self-Admitted Technical Debt (SATD) detection performance, and existing literature lacks empirical evidence on the choice of balancing technique. In this work, we evaluate the impact of multiple balancing techniques, including Data level, Classifier level, and Hybrid, for SATD detection in Within-Project and Cross-Project setup. Our results show that the Data level balancing technique SMOTE or Classifier level Ensemble approaches Random Forest or XGBoost are reasonable choices depending on whether the goal is to maximize Precision, Recall, F1, or AUC-ROC. We compared our best-performing model with the previous SATD detection benchmark (cost-sensitive Convolution Neural Network). Interestingly the top-performing XGBoost with SMOTE sampling improved the Within-project F1 score by 10% but fell short in Cross-Project set up by 9%. This supports the higher generalization capability of deep learning in Cross-Project SATD detection, yet while working within individual projects, classical machine learning algorithms can deliver better performance. We also evaluate and quantify the impact of duplicate source code comments in SATD detection performance. Finally, we employ SHAP and discuss the interpreted SATD features. We have included the replication package1and shared a web-based SATD prediction tool2with the balancing techniques in this study.

Data of long-lived and high profile projects is valuable for research on successful software engineering in the wild. Having a dataset with different linked software repositories of such projects, enables deeper diving investigations. This paper presents 20-MAD, a dataset linking the commit and issue data of Mozilla and Apache projects. It includes over 20 years of information about 765 projects, 3.4M commits, 2.3M issues, and 17.3M issue comments, and its compressed size is over 6 GB. The data contains all the typical information about source code commits (e.g., lines added and removed, message and commit time) and issues (status, severity, votes, and summary). The issue comments have been pre-processed for natural language processing and sentiment analysis. This includes emoticons and valence and arousal scores. Linking code repository and issue tracker information, allows studying individuals in two types of repositories and provide more accurate time zone information for issue trackers as well. To our knowledge, this the largest linked dataset in size and in project lifetime that is not based on GitHub.

Open source development contains contributions from both hired and volunteer software developers. Identification of this status is important when we consider the transferability of research results to the closed source software industry, as they include no volunteer developers. While many studies have taken the employment status of developers into account, this information is often gathered manually due to the lack of accurate automatic methods. In this paper, we present an initial step towards predicting paid and unpaid open source development using machine learning and compare our results with automatic techniques used in prior work. By relying on code source repository meta-data from Mozilla, and manually collected employment status, we built a dataset of the most active developers, both volunteer and hired by Mozilla. We define a set of metrics based on developers' usual commit time pattern and use different classification methods (logistic regression, classification tree, and random forest). The results show that our proposed method identify paid and unpaid commits with an AUC of 0.75 using random forest, which is higher than the AUC of 0.64 obtained with the best of the previously used automatic methods.

The use of natural language processing (NLP) is gaining popularity in software engineering. In order to correctly perform NLP, we must pre-process the textual information to separate natural language from other information, such as log messages, that are often part of the communication in software engineering. We present a simple approach for classifying whether some textual input is natural language or not. Although our NLoN package relies on only 11 language features and character tri-grams, we are able to achieve an area under the ROC curve performances between 0.976-0.987 on three different data sources, with Lasso regression from Glmnet as our learner and two human raters for providing ground truth. Cross-source prediction performance is lower and has more fluctuation with top ROC performances from 0.913 to 0.980. Compared with prior work, our approach offers similar performance but is considerably more lightweight, making it easier to apply in software engineering text mining pipelines. Our source code and data are provided as an R-package for further improvements.

During the past years, overload at work leading to psychological diseases, such as burnouts, have drawn more public attention. This paper is a preliminary step toward an analysis of the work patterns and possible indicators of overload and time pressure on software developers with mining software repositories approach. We explore the working pattern of developers in the context of Mozilla Firefox, a large and long-lived open source project. To that end we investigate the impact of the move from traditional to rapid release cycle on work pattern. Moreover we compare Mozilla Firefox work pattern with another Mozilla product, Firefox OS, which has a different release cycle than Firefox. We find that both projects exhibit healthy working patterns, i.e. lower activity during the weekends and outside of office hours. Firefox experiences proportionally more activity on weekends than Firefox OS (Cohen's d = 0.94). We find that switching to rapid releases has reduced weekend work (Cohen's d = 1.43) and working during the night (Cohen's d = 0.45). This result holds even when we limit the analyzes on the hired resources, i.e. considering only individuals with Mozilla foundation email address, although, the effect sizes are smaller for weekends (Cohen's d = 0.64) and nights (Cohen's d = 0.23). Moreover, we use dissimilarity word clouds and find that work during the weekend is more technical while work during the week expresses more positive sentiment with words like "good" and "nice". Our results suggest that moving to rapid releases have positive impact on the work health and work-life-balance of software engineers. However, caution is needed as our results are based on a limited set of quantitative data from a single organization.

Emotional arousal increases activation and performance but may also lead to burnout in software development. We present the first version of a Software Engineering Arousal lexicon (SEA) that is specifically designed to address the problem of emotional arousal in the software developer ecosystem. SEA is built using a bootstrapping approach that combines word embedding model trained on issue-tracking data and manual scoring of items in the lexicon. We show that our lexicon is able to differentiate between issue priorities, which are a source of emotional activation and then act as a proxy for arousal. The best performance is obtained by combining SEA (428 words) with a previously created general purpose lexicon by Warriner et al. (13,915 words) and it achieves Cohen's d effect sizes up to 0.5.

Users and developers of software distributions are often confronted with installation problems due to conflicting packages. A prototypical example of this are the Linux distributions such as Debian. Conflicts between packages have been studied under different points of view in the literature, in particular for the Debian operating system, but little is known about how these package conflicts evolve over time. This article presents an extensive analysis of the evolution of package incompatibilities, spanning a decade of the life of the Debian stable and testing distributions for its most popular architecture, i386. Using the technique of survival analysis, this empirical study sheds some light on the origin and evolution of package incompatibilities, and provides the basis for building indicators that may be used to improve the quality of package-based distributions.

We present a dataset of the open source software ecosystem Gnome from a social point of view. We have collected historical data about the contributors to all Gnome projects stored on git.gnome.org, taking into account the problem of identity matching, and associating different activity types to the contributors. This type of information is very useful to complement the traditional, source-code related information one can obtain by mining and analyzing the actual source code. The dataset can be obtained at https://bitbucket.org/mgoeminne/sgl-flossmetric-dbmerge.