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

Journal Article (2019)
Author(s)

M. di Biase (Software Improvement Group, TU Delft - Software Engineering)

Magiel Bruntink (Software Improvement Group)

A. van Deursen (TU Delft - Software Technology)

Alberto Bacchelli (Universitat Zurich)

Research Group
Software Engineering
Copyright
© 2019 M. di Biase, Magiel Bruntink, A. van Deursen, A. Bacchelli
DOI related publication
https://doi.org/10.7717/peerj-cs.193
More Info
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Publication Year
2019
Language
English
Copyright
© 2019 M. di Biase, Magiel Bruntink, A. van Deursen, A. Bacchelli
Research Group
Software Engineering
Volume number
5
Pages (from-to)
1-25
Reuse Rights

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Abstract

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.
Aims: (1) Quantitatively measure the effects of change decomposition on the outcome of code review (in terms of number of found defects, wrongly reported issues, suggested improvements, time, and understanding); (2) Qualitatively analyze how subjects approach the review and navigate the code, building knowledge and addressing existing issues, in large vs. decomposed changes.
Method: Controlled experiment using the pull-based development model involving 28 software developers among professionals and graduate students.
Results: Change decomposition leads to fewer wrongly reported issues, influences how subjects approach and conduct the review activity (by increasing context- seeking), yet impacts neither understanding the change rationale nor the number of found defects.
Conclusions: Change decomposition reduces the noise for subsequent data analyses but also significantly supports the tasks of the developers in charge of reviewing the changes. As such, commits belonging to different concepts should be separated, adopting this as a best practice in software engineering.