research-article

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DéjàVu: a map of code duplicates on GitHub

Authors:

Cristina V. Lopes,

Hitesh Sajnani,

Jan VitekAuthors Info & Claims

Proceedings of the ACM on Programming Languages, Volume 1, Issue OOPSLA

Article No.: 84, Pages 1 - 28

https://doi.org/10.1145/3133908

Published: 12 October 2017 Publication History

Abstract

Previous studies have shown that there is a non-trivial amount of duplication in source code. This paper analyzes a corpus of 4.5 million non-fork projects hosted on GitHub representing over 428 million files written in Java, C++, Python, and JavaScript. We found that this corpus has a mere 85 million unique files. In other words, 70% of the code on GitHub consists of clones of previously created files. There is considerable variation between language ecosystems. JavaScript has the highest rate of file duplication, only 6% of the files are distinct. Java, on the other hand, has the least duplication, 60% of files are distinct. Lastly, a project-level analysis shows that between 9% and 31% of the projects contain at least 80% of files that can be found elsewhere. These rates of duplication have implications for systems built on open source software as well as for researchers interested in analyzing large code bases. As a concrete artifact of this study, we have created DéjàVu, a publicly available map of code duplicates in GitHub repositories.

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Cited By

Zhang XXu ZYang SLi ZShi ZSun L(2024)Enhancing Function Name Prediction using Votes-Based Name Tokenization and Multi-task LearningProceedings of the ACM on Software Engineering10.1145/36607821:FSE(1679-1702)Online publication date: 12-Jul-2024
https://dl.acm.org/doi/10.1145/3660782
Jahanshahi MMockus ASpinellis DConstantinou EBacchelli A(2024)Dataset: Copy-based Reuse in Open Source SoftwareProceedings of the 21st International Conference on Mining Software Repositories10.1145/3643991.3644868(42-47)Online publication date: 15-Apr-2024
https://dl.acm.org/doi/10.1145/3643991.3644868
AlOmar EKnobloch BKain TKalish CMkaouer MOuni ARoychoudhury APaiva AAbreu RStorey M(2024)AntiCopyPaster 2.0: Whitebox just-in-time code duplicates extractionProceedings of the 2024 IEEE/ACM 46th International Conference on Software Engineering: Companion Proceedings10.1145/3639478.3640035(84-88)Online publication date: 14-Apr-2024
https://dl.acm.org/doi/10.1145/3639478.3640035
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Index Terms

DéjàVu: a map of code duplicates on GitHub
1. Information systems
  1. Information retrieval
    1. Retrieval tasks and goals
      1. Near-duplicate and plagiarism detection
2. Software and its engineering
  1. Software organization and properties
    1. Software system structures
      1. Ultra-large-scale systems

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Published In

cover image Proceedings of the ACM on Programming Languages

Proceedings of the ACM on Programming Languages Volume 1, Issue OOPSLA

October 2017

1786 pages

EISSN:2475-1421

DOI:10.1145/3152284

Issue’s Table of Contents

Copyright © 2017 Owner/Author.

This work is licensed under a Creative Commons Attribution International 4.0 License.

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Association for Computing Machinery

New York, NY, United States

Publication History

Published: 12 October 2017

Published in PACMPL Volume 1, Issue OOPSLA

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Cited By

Zhang XXu ZYang SLi ZShi ZSun L(2024)Enhancing Function Name Prediction using Votes-Based Name Tokenization and Multi-task LearningProceedings of the ACM on Software Engineering10.1145/36607821:FSE(1679-1702)Online publication date: 12-Jul-2024
https://dl.acm.org/doi/10.1145/3660782
Jahanshahi MMockus ASpinellis DConstantinou EBacchelli A(2024)Dataset: Copy-based Reuse in Open Source SoftwareProceedings of the 21st International Conference on Mining Software Repositories10.1145/3643991.3644868(42-47)Online publication date: 15-Apr-2024
https://dl.acm.org/doi/10.1145/3643991.3644868
AlOmar EKnobloch BKain TKalish CMkaouer MOuni ARoychoudhury APaiva AAbreu RStorey M(2024)AntiCopyPaster 2.0: Whitebox just-in-time code duplicates extractionProceedings of the 2024 IEEE/ACM 46th International Conference on Software Engineering: Companion Proceedings10.1145/3639478.3640035(84-88)Online publication date: 14-Apr-2024
https://dl.acm.org/doi/10.1145/3639478.3640035
Misu MAchar RLopes C(2024)SourcererJBF: A Java Build Framework For Large-Scale CompilationACM Transactions on Software Engineering and Methodology10.1145/363571033:3(1-35)Online publication date: 15-Mar-2024
https://dl.acm.org/doi/10.1145/3635710
OBrien DDyer RNguyen TRajan HRoychoudhury APaiva AAbreu RStorey M(2024)Data-Driven Evidence-Based Syntactic Sugar DesignProceedings of the IEEE/ACM 46th International Conference on Software Engineering10.1145/3597503.3639580(1-12)Online publication date: 20-May-2024
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Ahmed TPai KDevanbu PBarr ERoychoudhury APaiva AAbreu RStorey M(2024)Automatic Semantic Augmentation of Language Model Prompts (for Code Summarization)Proceedings of the IEEE/ACM 46th International Conference on Software Engineering10.1145/3597503.3639183(1-13)Online publication date: 20-May-2024
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Jiang LAn JHuang HTang QNie SWu SZhang YRoychoudhury APaiva AAbreu RStorey M(2024)BinaryAI: Binary Software Composition Analysis via Intelligent Binary Source Code MatchingProceedings of the IEEE/ACM 46th International Conference on Software Engineering10.1145/3597503.3639100(1-13)Online publication date: 20-May-2024
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He YWang YZhu SWang WZhang YLi QYu A(2024)Automatically Identifying CVE Affected Versions With Patches and Developer LogsIEEE Transactions on Dependable and Secure Computing10.1109/TDSC.2023.326456721:2(905-919)Online publication date: Mar-2024
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