Mining frequent bug-fix code changes

Osman, Haidar; Lungu, Mircea; Nierstrasz, Oscar

doi:10.1109/csmr-wcre.2014.6747191

Cited by 35 publications

(21 citation statements)

References 10 publications

(12 reference statements)

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“…The answer implies that bug fixes affect fewer lines of code than tasks that implement new functionality. Osman et al have shown that, indeed, most bug fixes concern only one line of code [40]. It is intuitive that a single line of code change cannot cause as many review objections as the development of a full-blown new feature.…”

Section: Influences On the Number Of Changesmentioning

confidence: 99%

Modern code reviews in open-source projects: which problems do they fix?

Beller

Bacchelli

Zaidman

et al. 2014

Proceedings of the 11th Working Conference on Mining Software Repositories

197

140

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Code review is the manual assessment of source code by humans, mainly intended to identify defects and quality problems. Modern Code Review (MCR), a lightweight variant of the code inspections investigated since the 1970s, prevails today both in industry and open-source software (OSS) systems. The objective of this paper is to increase our understanding of the practical benefits that the MCR process produces on reviewed source code. To that end, we empirically explore the problems fixed through MCR in OSS systems. We manually classified over 1,400 changes taking place in reviewed code from two OSS projects into a validated categorization scheme. Surprisingly, results show that the types of changes due to the MCR process in OSS are strikingly similar to those in the industry and academic systems from literature, featuring the similar 75:25 ratio of maintainability-related to functional problems. We also reveal that 7-35% of review comments are discarded and that 10-22% of the changes are not triggered by an explicit review comment. Patterns emerged in the review data; we investigated them revealing the technical factors that influence the number of changes due to the MCR process. We found that bug-fixing tasks lead to fewer changes and tasks with more altered files and a higher code churn have more changes. Contrary to intuition, the person of the reviewer had no impact on the number of changes.

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Section: Influences On the Number Of Changesmentioning

confidence: 99%

Modern code reviews in open-source projects: which problems do they fix?

Beller

Bacchelli

Zaidman

et al. 2014

Proceedings of the 11th Working Conference on Mining Software Repositories

197

140

View full text Add to dashboard Cite

show abstract

“…Missing null checks are the most recurrent bug pattern in Java systems [7]. This bug manifests itself as the Java NullPointerException.…”

Section: Motivationmentioning

confidence: 99%

“…For our experiment, we used the same software corpus from a previous study [7]. This corpus was built using a crawler that queries Github 2 for Java projects that have more than 5 stars (popular) and are more than 100KB in size (relatively large).…”

Section: A Experimental Corpusmentioning

confidence: 99%

“…Interestingly, the if -related bug category is dominant [4], and more particularly, missing null check is the most frequent pattern of bugs in Java systems [7]. These results suggest that null dereferencing is a major source of bugs in Java programs, forcing developers to add guards (null checks) on objects before using them.…”

Section: Introductionmentioning

confidence: 95%

“…Recent studies show that a considerable number of bug fixes are recurrent [4][5] [6] [7]. Interestingly, the if -related bug category is dominant [4], and more particularly, missing null check is the most frequent pattern of bugs in Java systems [7].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Tracking Null Checks in Open-Source Java Systems

Osman

Leuenberger

Lungu

et al. 2016

2016 IEEE 23rd International Conference on Software Analysis, Evolution, and Reengineering (SANER)

Self Cite

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It is widely acknowledged that null values should be avoided if possible or carefully used when necessary in Java code. The careless use of null has negative effects on maintainability, code readability, and software performance. However, a study on understanding null usage is still missing.In this paper we analyze null checks in 810 open-source Java systems and manually inspect 100 code samples to understand when and why developers use null. We find that 35% of all conditional statements contain null checks. A deeper investigation reveals many questionable practices with respect to using null. Uninitialized member variables, returning null in methods, and passing null as a method parameter are among the most recurrent reasons for introducing null checks. Developers often return null in methods to signal errors instead of throwing a proper exception. As a result, 71% of the values checked for null are returned from method calls.Our study provides a novel evidence of an overuse of null checks and of the null value itself in Java, and at the same time, reveals actionable recommendations to reduce this null usage.

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Do Null-Type Mutation Operators Help Prevent Null-Type Faults?

Parsai

Demeyer

2019

SOFSEM 2019: Theory and Practice of Computer Science

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Mining frequent bug-fix code changes

Cited by 35 publications

References 10 publications

Modern code reviews in open-source projects: which problems do they fix?

Modern code reviews in open-source projects: which problems do they fix?

Tracking Null Checks in Open-Source Java Systems

Do Null-Type Mutation Operators Help Prevent Null-Type Faults?

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