Previous studies have shown that there is a non-trivial amount of duplication in source code. This paper analyzes a corpus of 2.6 million non-fork projects hosted on GitHub representing over 258 million files written in Java, C++ Python and JavaScript. We found that this corpus has a mere 54 million unique files. In other words, 79% 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 7% of the files are distinct. Java, on the other hand, has the least duplication, 65% of files are distinct. Focusing on files that have some differences, we found between 31% and 43% of files with strong similarities. Lastly, we made a project-level analysis, and found that between 10% and 20% of the projects contain at least 80% of files that can be found elsewhere. These surprisingly high 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.
Thu 26 Oct
13:30 - 15:00: OOPSLA - Mining Software Repositories and Parsing at Regency A Chair(s): Wolfgang De MeuterVrije Universiteit Brussel | ||||||||||||||||||||||||||||||||||||||||||
| 13:30 - 13:52 Talk | Samantha Syeda KhairunnesaIowa State University, Hoan Anh NguyenIowa State University, USA, Tien N. NguyenUniversity of Texas at Dallas, Hridesh RajanIowa State University DOI | |||||||||||||||||||||||||||||||||||||||||
| 13:52 - 14:15 Talk | Crista LopesUniversity of California, Irvine, Petr MajReactorLabs, Pedro MartinsUniversity of California at Irvine, USA, Vaibhav SainiUniversity of California at Irvine, USA, Di YangUniversity of California at Irvine, USA, Jakub ZitnyCzech Technical University, Czechia, Hitesh SajnaniMicrosoft , Jan VitekNortheastern University, USA DOI | |||||||||||||||||||||||||||||||||||||||||
| 14:15 - 14:37 Talk | Davood MazinanianConcordia University, Canada, Ameya KetkarOregon State University, USA, Nikolaos TsantalisConcordia University, Canada, Danny DigSchool of EECS at Oregon State University DOI | |||||||||||||||||||||||||||||||||||||||||
| 14:37 - 15:00 Talk | DOI | |||||||||||||||||||||||||||||||||||||||||