Jesus M. Gonzalez-Barahona

• Doctor Engineer
• Rey Juan Carlos University

Python, one of the most prevalent programming languages today, is widely utilized in various domains, including web development, data science, machine learning, and DevOps. Recent scholarly efforts have proposed a methodology to assess Python competence levels, similar to how proficiency in natural languages is evaluated. This method involves assig...

Building past snapshots of a software project has shown to be of interest both for researchers and practitioners. However, little attention has been devoted specifically to tests available in those past snapshots, which are fundamental for the maintenance of old versions still in production. The aim of this study is to determine to which extent tes...

Context Current data visualization interfaces predominantly rely on 2-D screens. However, the emergence of virtual reality (VR) devices capable of immersive data visualization has sparked interest in exploring their suitability for visualizing software development data. Despite this, there is a lack of detailed investigation into the effectiveness...

Context When software is released publicly, it is common to include with it either the full text of the license or licenses under which it is published, or a detailed reference to them. Therefore public licenses, including FOSS (free, open source software) licenses, are usually publicly available in source code repositories Objective To compile a...

Context: When software is released publicly, it is common to include with it either the full text of the license or licenses under which it is published, or a detailed reference to them. Therefore public licenses, including FOSS (free, open source software) licenses, are usually publicly available in source code repositories.Objective: To compile a...

Context Over the past decades, researchers proposed numerous approaches to visualize source code. A popular one is CodeCity, an interactive 3D software visualization representing software system as cities: buildings represent classes (or files) and districts represent packages (or folders). Building dimensions represent values of software metrics,...

Effort estimation models are a fundamental tool in software management, and used as a forecast for resources, constraints and costs associated to software development. For Free/Open Source Software (FOSS) projects, effort estimation is especially complex: professional developers work alongside occasional, volunteer developers, so the overall effort...

Context Building past source code snapshots of a software product is necessary both for research (analyzing the past state of a program) and industry (increasing trustability by reproducibility of past versions, finding bugs by bisecting, backporting bug fixes, among others). A study by Tufano et al. showed in 2016 that many past snapshots cannot b...

A new generation of toolsets that are flexible enough to adapt to the data analytics needs of a given scenario is emerging to analyze free, open source software (FOSS). GrimoireLab is one such toolset that meets many of the needs of foundations, developers, and companies.

Python is known to be a versatile language, well suited both for beginners and advanced users. Some elements of the language are easier to understand than others: some are found in any kind of code, while some others are used only by experienced programmers. The use of these elements lead to different ways to code, depending on the experience with...

Effort estimation models are a fundamental tool in software management, and used as a forecast for resources, constraints and costs associated to software development. For Free/Open Source Software (FOSS) projects, effort estimation is especially complex: professional developers work alongside occasional, volunteer developers, so the overall effort...

Background/Context: Currently, the usual interface for visualizing data is based on 2-D screens. Recently, devices capable of visualizing data while immersed in VR scenes are becoming common. However, it has not been studied in detail to which extent these devices are suitable for interacting with data visualizations in the specific case of data ab...

Software repositories contain information about source code, software development processes, and team interactions. We combine the provenance of development processes with code security analysis results to provide fast feedback on the software’s design and security issues. Results from queries of the provenance graph drives the security analysis, w...

Background After many years of research on software repositories, the knowledge for building mature, reusable tools that perform data retrieval, storage and basic analytics is readily available. However, there is still room to improvement in the area of reusable tools implementing this knowledge. Goal To produce a reusable toolset supporting the m...

Software repositories contain information about source code, software development processes, and team interactions. We combine the provenance of development processes with code security analysis results to provide fast feedback on the software’s design and security issues. Results from queries of the provenance graph drives the security analysis, w...

Container-based solutions, such as Docker, have become increasingly relevant in the software industry to facilitate deploying and maintaining software systems. Little is known, however, about how outdated such containers are at the moment of their release or when used in production. This article addresses this question, by measuring and comparing f...

Free, open source software (FOSS) has a long history, beginning with the origins of software itself, when the terms free software and open source software were not yet defined. Learning about the milestones of this history may help to understand FOSS today.

Software repositories contain information about source code, software development processes, and team interactions. We combine provenance of the development process with code security analysis to automatically discover insights. This provides fast feedback on the software's design and security issues, which we evaluate on projects that are develope...

Diversity in software development teams has been identified as one of the main ingredients of a more productive and healthy software community. Thus, the interest in identifying who is contributing to a project has increased in the last years. In the software domain , although other types of diversity exist, the case of gender is particularly impor...

When identifying the origin of software bugs, many studies assume that “a bug was introduced by the lines of code that were modified to fix it”. However, this assumption does not always hold and at least in some cases, these modified lines are not responsible for introducing the bug. For example, when the bug was caused by a change in an external A...

Nowadays, software projects and in particular open source ones heavily rely on a plethora of tools (e.g., Git, GitHub) to support and coordinate development activities. Despite their paramount value, they foster to fragment members' contribution , since members can access them with different identities (e.g., email, username). Thus, researchers and...

Reusable Open Source Software (OSS) components for major programming languages are available in package repositories. Developers rely on package management tools to automate deployments, specifying which package releases satisfy the needs of their applications. However, these specifications may lead to deploying package releases that are outdated,...

Containerized applications, and in particular Docker images, are becoming a common solution in cloud environments to meet ever-increasing demands in terms of portability, reliability and fast deployment. A Docker image includes all environmental dependencies required to run it, such as specific versions of system and third-party packages. Leveragin...

Software systems often leverage on open source software libraries to reuse functionalities. Such libraries are readily available through software package managers like npm for JavaScript. Due to the huge amount of packages available in such package distributions, developers often decide to rely on or contribute to a software package based on its po...

Packaging software into containers is becoming a common practice when deploying services in cloud and other environments. Docker images are one of the most popular container technologies for building and deploying containers. A container image usually includes a collection of software packages, that can have bugs and security vulnerabilities that a...

Background: Many studies in the software research literature on bug fixing are built upon the assumption that "a given bug was introduced by the lines of code that were modified to fix it", or variations of it. Although this assumption seems very reasonable at first glance, there is little empirical evidence supporting it. A careful examination sur...

Source code analysis tools are designed to analyze code artifacts with different intents, which span from improving the quality and security of the software to easing refactoring and reverse engineering activities. However, most tools do not come with features to periodically schedule their analysis or to be executed on a battery of repositories, a...

Source code analysis tools are designed to analyze code artifacts with different intents, which span from improving the quality and security of the software to easing refactoring and reverse engineering activities. However, most tools do not come with features to periodically schedule their analysis or to be executed on a battery of repositories, a...

Xen is one of the most popular technologies for virtualization. It is produced and maintained by a software ecosystem with the participation of several large IT companies. Some years ago they decided to use software development analytics to better understand some problems they had with code review. Since them, they collect and publish several metri...

Software development projects, in particular open source ones, heavily rely on the use of tools to support, coordinate and promote development activities. Despite their paramount value, they contribute to fragment the project data, thus challenging practitioners and researchers willing to derive insightful analytics about software projects. In this...

Software library packages are constantly evolving and increasing in number. Not updating to the latest available release of dependent libraries may negatively affect software development by not benefiting from new functionality, vulnerability and bug fixes available in more recent versions. On the other hand, automatically updating to the latest re...

Context Reproducibility of Empirical Software Engineering (ESE) studies is an essential part for improving their credibility, as it offers the opportunity to the research community to verify, evaluate and improve their research outcomes. Objective We aim to study reproducibility and credibility in ESE with a case study, by investigating how they h...

In today's world, management often rely on FLOSS (Free/Libre/Open Source Software) systems to run their organizations. However, the nature of FLOSS is different from the software they have been using in the last decades. Its development model is distributed, and its authors are diverse as many volunteers and companies may collaborate in the project...

During 2015, some members of the Xen Project Advisory Board became worried about the performance of their code review process. The Xen Project is a free, open source software project developing one of the most popular virtualization platforms in the industry. They use a pre-commit peer review process similar to that in the Linux kernel, based on em...

Large software compilations based on free, open source software (FOSS) packages are the basis for many software systems. When they are deployed in production, specific versions of the packages in the compilation are selected for installation. Over time, those versions become outdated with respect to the upstream software from which they are produce...

Researchers working with software repositories, often when building performance or quality models, need to recover traceability links between bug reports in issue tracking repositories and reviews in code review systems. However, too often the information stored in bug tracking repositories is not explicitly tagged or linked to the issues reviewing...

Free/libre/open source software projects are usually developed by a geographically distributed community of developers and contributors. In contrast to traditional corporate environments, it is hard to obtain information about how the community is geographically distributed, mainly because participation is open to volunteers and in many cases it is...

Issue tracking systems are used, in most software projects, but in particular in almost all free open source software, to record many different kinds of issues: bug reports, feature requests, maintenance tickets and even design discussions. Identifying which of those issues are bug reports is not a trivial task. When researchers want to conduct stu...

Women are underrepresented in the IT sector. But the situation in FLOSS (free, libre, open source software) development is really extreme in this respect: past publications and studies show a female participation of around 2% to 5% and have shed some light into this problem. In this paper, we give an update the state of knowledge to the current sit...

Many software development projects have introduced mandatory code review for every change to the code. This means that the project needs to devote a significant effort to review all proposed changes, and that their merging into the code base may get considerably delayed. Therefore, all those projects need to understand how code review is working, a...

Many software projects are no longer done in-house by a single organization. Instead, we are in a new age where software is developed by a networked community of individuals and organizations, which base their relations to each other on mutual interest. Paradoxically, recent research suggests that software development can actually be jointly-develo...

This is a report from the Free/Libre/Open Source (FLOSS) research track at the 10th International Symposium on Open Collaboration (OpenSym 2014), which took place in Berlin, Germany, August 27-29. As part of a broader community interested in "everything open", including open access, open data, open educational resources, Wikipedia, wikis and open c...

Welcome to the proceedings of OpenSym 2014, the 10th international symposium on open collaboration! Open collaboration is collaboration that is egalitarian (everyone can join, no principled or artificial barriers to participation exist), meritocratic (decisions and status are merit-based rather than imposed) and self-organizing (processes adapt to...

O desenvolvimento de software é uma atividade intensive em esforço humano. Assim, a forma como os desenvolvedores encaram suas tarefas é de suam importância. Em um ambiente como o usual em projetos de FOSS (free/open source software) em que profissionais (desenvolvedores pagos) compartilham os esforços de desenvolvimento com voluntários, a moral da...

SUMMARY Some free, open-source software projects have been around for quite a long time, the longest living ones dating from the early 1980s. For some of them, detailed information about their evolution is available in source code management systems tracking all their code changes for periods of more than 15 years. This paper examines in detail the...

In this data paper we describe a data set obtained by means of performing an on-line survey to over 2,000 Free Libre Open Source Software (FLOSS) contributors. The survey includes questions related to personal characteristics (gender, age, civil status, nationality, etc.), education and level of English, professional status, dedication to FLOSS pro...

Because of the distributed and collaborative nature of free / open source software (FOSS) projects, the development effort invested in a project is usually unknown, even after the software has been released. However, this information is becoming of major interest, especially —but not only— because of the growth in the number of companies for which...

Free software has gained importance over the last few years, and can be found in almost any sphere in which ‘software processes’ are important. However, even when universities and higher education establishments include subjects concerning free programming and technologies in their curriculums, their graduates tend to attain limited technological,...

During the last years, most of the large free / open source software projects have included code review as an usual, or even mandatory practice for changes to their code. In many cases it is implemented as a process in which a developer proposing some change needs to ask for a review by another developer before it can enter the code base. Code revi...

This paper presents Free/Libre/Open Source Software (FLOSS) Projects as early Massive Online Open Courses (MOOCs). Being software development a process where learning and collaboration is of major importance, FLOSS projects have in common many characteristics with MOOCs. This is because many FLOSS projects (such as Linux, Apache, GNOME or KDE, amon...

Code review is becoming a common practice in large scale software development projects. In the case of free, open source software projects, many of them are selecting Gerrit as the system to support the code review process. Therefore, the analysis of the information produced by Gerrit allows for the detailed tracking of the code review process in t...

After more than 40 years of life, software evolution should be considered as a mature field. However, despite such a long history, many research questions still remain open, and controversial studies about the validity of the laws of software evolution are common. During the first part of these 40 years the laws themselves evolved to adapt to chang...

Zusammenfassung Die ersten „Free-, Libre-, und Open-Source- Software“-Gemeinschaften (FLOSS) bestanden fast durchgängig aus Freiwilligen. Diese Personen trugen zu den Projekten unabhängig von ihrem Arbeitgeber bei. Auch wenn gelegentlich Unternehmen Interesse an den Open- Source-Aktivitäten ihrer Mitarbeiter hatten, war doch deren aktive Beteiligun...

Free, open source software development communities can become large and complex. They can also be a focus of interest for competing companies relying on their outcomes, with employees joining the development and maintenance effort. In those cases, it's especially important for both companies and communities to understand how this collaboration is w...

Software is more than just source code. There is a myriad of elements that compose a software project, among others documentation, translations, multimedia, artwork, marketing. In this paper, we focus on the translation efforts that free, libre, open source software (FLOSS) projects undergo to provide their software in multiple languages. We have t...

Based on the empirical evidence that the ratio of email messages in public mailing lists to versioning system commits has remained relatively constant along the history of the Apache Software Foundation (ASF), this paper has as goal to study what can be inferred from such a metric for projects of the ASF. We have found that the metric seems to be a...

This paper presents an empirical study about the temporal patterns char-acterizing the requests submitted by users to Wikipedia. The study is based on the analysis of the log lines registered by the Wikimedia Foundation Squid servers af-ter having sent the appropriate content in response to users' requests. The analysis has been conducted regarding...

Engineering students often have to deliver small computer programs in many engineering courses. Instructors have to evaluate these assignments according to the learning goals and their quality, but ensure as well that there is no plagiarism. In this paper, we report the experience of using mining software repositories techniques in a multimedia net...

The process of fixing software bugs plays a key role in the maintenance activities of a software project. Ideally, code ownership and responsibility should be enforced among developers working on the same artifacts, so that those introducing buggy code could also contribute to its fix. However, especially in FLOSS projects, this mechanism is not cl...

In general it is assumed that a software product evolves within the authoring company or group of developers that develop the project. However, in some cases different groups of developers make the software evolve in different directions, a situation which is commonly known as a fork. In the case of free software, although forking is a practice tha...

Developer experience is a common matter of study in the software maintenance and evolution research literature. However it is still not well understood if less experienced developers are more prone to introduce errors in the source code than their more experienced colleagues. This paper aims to study the relationships between experience and the bug...

Learning in any environment has undergone major changes in recent times. Many of these changes are closely related or are similar to processes or solutions found traditionally in Free/Libre and Open Source (FLOSS) environments: peer to peer relationships, telematic support, use of new technologies, etc. [1] The purpose of this workshop is to bring...

In this paper we describe a competitive way to learn and review concepts: a championship based on quizzes. Students will compete in “duels” against other students in an instant messaging channel where a program will be launching questions; the student that answers first will get the point. And the first to reach a series of points will win the game...

The GSyC/LibreSoft research group at the Universidad Rey Juan Carlos has been investigating serious games with smartphones. In our approach, platform developers and educators do not need to create complete virtual worlds, which are in general very time and effort consuming. In the games that have been developed, participants are provided through a...

Among empirical software engineering studies, those based on data retrieved from development repositories (such as those of source code management, issue tracking or communication systems) are specially suitable for reproduction. However their reproducibility status can vary a lot, from easy to almost impossible to reproduce. This paper explores wh...

Thanks to the open nature of libre (free, open source) software projects, researchers have gained access to a rich set of data related to various aspects of software development. Although it is usually publicly available on the Internet, obtaining and analyzing the data in a convenient way is not an easy task, and many considerations have to be tak...

El software libre es cada vez más habitual en casi cualquier entorno informático. Sin embargo, es también un gran desconocido. En este artículo se exponen las condiciones que tiene que cumplir un programa para ser considerado como software libre, compiladas en varias definiciones. A partir de ellas se repasa brevemente su historia y se exploran alg...

The process of fixing software bugs plays a key role in the maintenance activities of a software project. Ideally, code ownership and responsibility should be enforced among developers working on the same artifacts, so that those introducing buggy code could also contribute to its fix. However, especially in FLOSS projects, this mechanism is not cl...

This paper presents an empirical study on the impact of featured articles on the attention that Wikipedia’s articles attract, and how this behavior differs in different editions of Wikipedia. The study is based on the analysis of the log lines registered by the Wikimedia Foundation Squid servers after having sent the appropriate content in response...

Thanks to the open nature of libre (free, open source) software projects, researchers have gained access to a rich set of data related to various aspects of software development. Although it is usually publicly available on the Internet, obtaining and analyzing the data in a convenient way is not an easy task, and many considerations have to be tak...

Què és el programari lliure? Què és i quines implicacions té la llicència d¿un programa lliure? Com es desenvolupa el programari lliure? Com es financen els projectes de programari lliure, quins models de negoci s¿experimenten relacionats amb aquests projectes? Què motiva els desenvolupadors, especialment els voluntaris, a involucrar-se en projecte...

Quality models for software products and processes help both to developers and users to better understand their characteristics. In the specific case of libre (free, open source) software, the availability of a mature and reliable development community is an important factor to be considered, since in most cases both the evolvability and future fit...

This paper presents an empirical study on the impact of featured articles on the attention that Wikipedia's articles attract, and how this behavior differs in different editions of Wikipedia. The study is based on the analysis of the log lines registered by the Wikimedia Foundation Squid servers after having sent the appropriate content in respo...