document

Primers or Reminders?: The Effects of Existing Review Comments on Code Review

Spadini, D. (author), Calikli, Gul (author), Bacchelli, A. (author)

In contemporary code review, the comments put by reviewers on a specific code change are immediately visible to the other reviewers involved. Could this visibility prime new reviewers' attention (due to the human's proneness to availability bias), thus biasing the code review outcome In this study, we investigate this topic by conducting a...

conference paper 2020

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Investigating Severity Thresholds for Test Smells

Spadini, D. (author), Schvarcbacher, Martin (author), Oprescu, Ana (author), Bruntink, Magiel (author), Bacchelli, A. (author)

Test smells are poor design decisions implemented in test code, which can have an impact on the effectiveness and maintainability of unit tests. Even though test smell detection tools exist, how to rank the severity of the detected smells is an open research topic. In this work, we aim at investigating the severity rating for four test smells...

conference paper 2020

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The effects of change decomposition on code review—a controlled experiment

di Biase, M. (author), Bruntink, Magiel (author), van Deursen, A. (author), Bacchelli, A. (author)

Background: Code review is a cognitively demanding and time-consuming process. Previous qualitative studies hinted at how decomposing change sets into multiple yet internally coherent ones would improve the reviewing process. So far, literature provided no quantitative analysis of this hypothesis.<br/>Aims: (1) Quantitatively measure the effects...

journal article 2019

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PathMiner: A library for mining of path-based representations of code

Kovalenko, V.V. (author), Bogomolov, Egor (author), Bryksin, Timofey (author), Bacchelli, A. (author)

One recent, significant advance in modeling source code for machine learning algorithms has been the introduction of path-based representation - an approach consisting in representing a snippet of code as a collection of paths from its syntax tree. Such representation efficiently captures the structure of code, which, in turn, carries its...

conference paper 2019

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Fine-grained just-in-time defect prediction

Pascarella, L. (author), Palomba, F. (author), Bacchelli, A. (author)

Defect prediction models focus on identifying defect-prone code elements, for example to allow practitioners to allocate testing resources on specific subsystems and to provide assistance during code reviews. While the research community has been highly active in proposing metrics and methods to predict defects on long-term periods (i.e.,at...

journal article 2019

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Does reviewer recommendation help developers?

Kovalenko, V.V. (author), Tintarev, N. (author), Pasynkov, Evgeny (author), Bird, Christian (author), Bacchelli, A. (author)

Selecting reviewers for code changes is a critical step for an efficient code review process. Recent studies propose automated reviewer recommendation algorithms to support developers in this task. However, the evaluation of recommendation algorithms, when done apart from their target systems and users (i.e., code review tools and change...

journal article 2019

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Test-Driven Code Review: An Empirical Study

Spadini, D. (author), Palomba, F. (author), Baum, Tobias (author), Hanenberg, Stefan (author), Bruntink, Magiel (author), Bacchelli, A. (author)

Test-Driven Code Review (TDR) is a code review practice in which a reviewer inspects a patch by examining the changed test code before the changed production code. Although this practice has been mentioned positively by practitioners in informal literature and interviews, there is no systematic knowledge of its effects, prevalence, problems, and...

conference paper 2019

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Classifying code comments in Java software systems

Pascarella, L. (author), Bruntink, Magiel (author), Bacchelli, A. (author)

Code comments are a key software component containing information about the underlying implementation. Several studies have shown that code comments enhance the readability of the code. Nevertheless, not all the comments have the same goal and target audience. In this paper, we investigate how 14 diverse Java open and closed source software...

journal article 2019

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To react, or not to react: Patterns of reaction to API deprecation

Sawant, A.A. (author), Robbes, Romain (author), Bacchelli, A. (author)

Application Programming Interfaces (API) provide reusable functionality to aid developers in the development process. The features provided by these APIs might change over time as the API evolves. To allow API consumers to peacefully transition from older obsolete features to new features, API producers make use of the deprecation mechanism...

journal article 2019

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Information Needs in Contemporary Code Review

Pascarella, L. (author), Spadini, D. (author), Palomba, F. (author), Bruntink, Magiel (author), Bacchelli, A. (author)

Contemporary code review is a widespread practice used by software engineers to maintain high software quality and share project knowledge. However, conducting proper code review takes time and developers often have limited time for review. In this paper, we aim at investigating the information that reviewers need<br/>to conduct a proper code...

journal article 2018

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Why are features deprecated?: An investigation into the motivation behind deprecation

Sawant, A.A. (author), Huang, Guangzhe (author), Vilen, Gabriel (author), Stojkovski, Stefan (author), Bacchelli, A. (author)

In this study, we investigate why API producers deprecate features. Previous work has shown us that knowing the rationale behind deprecation of an API aids a consumer in deciding to react, thus hinting at a diversity of deprecation reasons. We manually analyze the Javadoc of 374 deprecated methods pertaining four mainstream Java APIs to see...

conference paper 2018

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Understanding Developers' Needs on Deprecation as a Language Feature

Sawant, A.A. (author), Aniche, Maurício (author), van Deursen, A. (author), Bacchelli, A. (author)

Deprecation is a language feature that allows API producers to mark a feature as obsolete. We aim to gain a deep understanding of the needs of API producers and consumers alike regarding deprecation. To that end, we investigate why API producers deprecate features, whether they remove deprecated features, how they expect consumers to react, and...

conference paper 2018

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Re-evaluating Method-Level Bug Prediction

Pascarella, L. (author), Palomba, F. (author), Bacchelli, A. (author)

Bug prediction is aimed at supporting developers in the identification of code artifacts more likely to be defective. Researchers have proposed prediction models to identify bug prone methods and provided promising evidence that it is possible to operate at this level of granularity. Particularly, models based on a mixture of product and process...

conference paper 2018

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When Testing Meets Code Review: Why and How Developers Review Tests

Spadini, D. (author), Aniche, Maurício (author), Storey, Margaret-Anne (author), Bruntink, Magiel (author), Bacchelli, A. (author)

Automated testing is considered an essential process for ensuring software quality. However, writing and maintaining high-quality test code is challenging and frequently considered of secondary importance. For production code, many open source and industrial software projects employ code review, a well-established software quality practice, but...

conference paper 2018

document

Investigating Type Declaration Mismatches in Python

Pascarella, L. (author), Keshav Ram, A.R. (author), Nadeem, Azqa (author), Bisesser, Dinesh (author), Knyazev, Norman (author), Bacchelli, A. (author)

Past research provided evidence that developers making code changes sometimes omit to update the related documentation, thus creating inconsistencies that may contribute to faults and crashes. In dynamically typed languages, such as Python, an inconsistency in the documentation may lead to a mismatch in type declarations only visible at runtime....

conference paper 2018

document

Code review for newcomers: Is it different?

Kovalenko, V.V. (author), Bacchelli, A. (author)

Onboarding is a critical stage in the tenure of software developers with a project, because meaningful contribution requires familiarity with the codebase. Some software teams employ practices, such as mentoring, to help new developers get accustomed faster. Code review, i.e., the manual inspection of code changes, is an opportunity for...

conference paper 2018

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Mining File Histories: Should we consider branches?

Kovalenko, V.V. (author), Palomba, F. (author), Bacchelli, A. (author)

Modern distributed version control systems, such as Git, offer support for branching — the possibility to develop parts of software outside the master trunk. Consideration of the repository structure in Mining Software Repository (MSR) studies requires a thorough approach to mining, but there is no well-documented, widespread methodology...

conference paper 2018

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Mock objects for testing java systems: Why and how developers use them, and how they evolve

Spadini, D. (author), Aniche, Maurício (author), Bruntink, Magiel (author), Bacchelli, A. (author)

When testing software artifacts that have several dependencies, one has the possibility of either instantiating these dependencies or using mock objects to simulate the dependencies’ expected behavior. Even though recent quantitative studies showed that mock objects are widely used both in open source and proprietary projects, scientific...

journal article 2018

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PyDriller: Python Framework for Mining Software Repositories

Spadini, D. (author), Aniche, Maurício (author), Bacchelli, A. (author)

Software repositories contain historical and valuable information about the overall development of software systems. Mining software repositories (MSR) is nowadays considered one of the most interesting growing fields within software engineering. MSR focuses on extracting and analyzing data available in software repositories to uncover...

conference paper 2018

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A Graph-based Dataset of Commit History of Real-World Android apps

Geiger, Franz-Xaver (author), Malavolta, Ivano (author), Pascarella, L. (author), Palomba, F. (author), Di Nucci, D. (author), Bacchelli, A. (author)

Obtaining a good dataset to conduct empirical studies on the engineering of Android apps is an open challenge. To start tackling this challenge, we present AndroidTimeMachine, the first, self-contained, publicly available dataset weaving spread-out data sources about real-world, open-source Android apps. Encoded as a graph-based database,...

conference paper 2018