A Comprehensive Study of Software Forks: Dates, Reasons and Outcomes

  • Gregorio Robles
  • Jesús M. González-Barahona
Part of the IFIP Advances in Information and Communication Technology book series (IFIPAICT, volume 378)


In general it is assumed that a software product evolves within the authoring company or group of developers that develop the project. However, in some cases different groups of developers make the software evolve in different directions, a situation which is commonly known as a fork. In the case of free software, although forking is a practice that is considered as a last resort, it is inherent to the four freedoms. This paper tries to shed some light on the practice of forking. Therefore, we have identified significant forks, several hundreds in total, and have studied them in depth. Among the issues that have been analyzed for each fork is the date when the forking occurred, the reason of the fork, and the outcome of the fork, i.e., if the original or the forking project are still developed. Our investigation shows, among other results, that forks occur in every software domain, that they have become more frequent in recent years, and that very few forks merge with the original project.


free software open source forks forking social legal sustainability software evolution 


  1. 1.
    Bezroukov, N.: A second look at the Cathedral and The Bazar. First Monday 4(12) (1997)Google Scholar
  2. 2.
    Capiluppi, A., Boldyreff, C., Stol, K.-J.: Successful reuse of software components: A report from the open source perspective. In: International Conference on Open Source Software Systems, pp. 159–176 (2011)Google Scholar
  3. 3.
    Deshpande, A., Riehle, D.: The Total Growth of Open Source. In: Proceedings of the Fourth Conference on Open Source Systems, pp. 197–209. Springer (2008)Google Scholar
  4. 4.
    DiBona, C., Ockman, S., Stone, M.: Introduction. In: DiBona, C., Ockman, S., Stone, M. (eds.) Open Sources. Voices from the Open Source Revolution, pp. 1–17. O’Reilly (1999)Google Scholar
  5. 5.
    Ernst, N.A., Easterbrook, S.M., Mylopoulos, J.: Code forking in open-source software: a requirements perspective. CoRR, abs/1004.2889 (2010)Google Scholar
  6. 6.
    Feller, J., Fitzgerald, B.: A Framework Analysis of the Open Source Software Development Paradigm. In: 21st International Conference of Information Systems, Brisbane, Australia, pp. 58–69 (2010)Google Scholar
  7. 7.
    Fischer, M., Oberleitner, J., Ratzinger, J., Gall, H.: Mining evolution data of a product family. ACM SIGSOFT Software Engineering Notes 30(4), 1–5 (2005)CrossRefGoogle Scholar
  8. 8.
    Fogel, K.: Producing Open Source Software - How to run a successful free software project. O’Reilly (2005)Google Scholar
  9. 9.
    Germán, D.M.: The GNOME project: a case study of open source, global software development. Journal of Software Process: Improvement and Practice 8(4), 201–215 (2004)CrossRefGoogle Scholar
  10. 10.
    Germán, D.M., Di Penta, M., Guéhéneuc, Y.-G., Antoniol, G.: Code siblings: Technical and legal implications of copying code between applications. In: International Working Conference on Mining Software Repositories (MSR), pp. 81–90. IEEE (2009)Google Scholar
  11. 11.
    Karpf, D.: What Can Wikipedia Tell Us about Open Source Politics?. In: Conference Proceedings of JITP 2010: The Politics of Open Source, pp. 2–31 (2010)Google Scholar
  12. 12.
    Kogut, B., Metiu, A.: Open-source software development and distributed innovation. Oxford Review of Economic Policy 17(2) (2001)Google Scholar
  13. 13.
    Lehman, M.M., Belady, L.A. (eds.): Program evolution: Processes of software change. Academic Press Professional, Inc., San Diego (1985)Google Scholar
  14. 14.
    Lerner, J., Tirole, J.: Some simple economics of open source. Journal of Industrial Economics 50(2), 197–234 (2002)CrossRefGoogle Scholar
  15. 15.
    Mockus, A.: Amassing and indexing a large sample of version control systems: Towards the census of public source code history. In: MSR 2009: Proceedings of the 2009 International Working Conference on Mining Software Repositories, pp. 11–20 (2009)Google Scholar
  16. 16.
    Neville-Neil, G.V.: Think before you fork. Commun. ACM 54, 34–35 (2011)Google Scholar
  17. 17.
    Raymond, E.S.: The New Hacker’s Dictionary, 3rd edn. MIT Press, Cambridge (1996)Google Scholar
  18. 18.
    Raymond, E.S.: The Cathedral and the Bazaar. In: Raymond, E.S. (ed.) Musings on Linux and Open Source by an Accidental Revolutionary pp. 79–135. O’Reilly (1999)Google Scholar
  19. 19.
    Scacchi, W.: Computer game mods, modders, modding, and the mod scene. First Monday 15(5) (2010)Google Scholar
  20. 20.
    Schweik, C.M., English, R., Paienjton, Q., Haire, S.: Success and Abandonment in Open Source Commons: Selected Findings from an Empirical Study of Projects. In: Proceedings of the Sixth International Conference on Open Source Systems 2010, pp. 91–101 (2010)Google Scholar
  21. 21.
    Weber, S.: The Success of Open Source. Harvard University Press (April 2004)Google Scholar
  22. 22.
    Xie, G., Chen, J., Neamtiu, I.: Towards a better understanding of software evolution: An empirical study on open source software. In: Proceedings of the Internacional Conference on Software Maintenance, pp. 51–60. IEEE (2009)Google Scholar
  23. 23.
    Yamamoto, T., Matsushita, M., Kamiya, T., Inoue, K.: Measuring Similarity of Large Software Systems Based on Source Code Correspondence. In: Bomarius, F., Komi-Sirviö, S. (eds.) PROFES 2005. LNCS, vol. 3547, pp. 530–544. Springer, Heidelberg (2005)CrossRefGoogle Scholar
  24. 24.
    Yu, L., Schach, S.R., Chen, K., Heller, G.Z., Offutt, A.J.: Maintainability of the kernels of open-source operating systems: A comparison of Linux with FreeBSD, NetBSD, and OpenBSD. Journal of Systems and Software 79(6), 807–815 (2006)CrossRefGoogle Scholar

Copyright information

© IFIP International Federation for Information Processing 2012

Authors and Affiliations

  • Gregorio Robles
    • 1
  • Jesús M. González-Barahona
    • 1
  1. 1.GSyC/LibresoftUniversidad Rey Juan CarlosSpain

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