@article {1796,
	title = {An in-depth study of the promises and perils of mining GitHub},
	journal = {Empirical Software Engineering},
	year = {2015},
	publisher = {Springer},
	abstract = {With over 10 million git repositories, GitHub is becoming one of the most important sources of software artifacts on the Internet. Researchers mine the information stored in GitHub{\textquoteright}s event logs to understand how its users employ the site to collaborate on software, but so far there have been no studies describing the quality and properties of the available GitHub data. We document the results of an empirical study aimed at understanding the characteristics of the repositories and users in GitHub; we see how users take advantage of GitHub{\textquoteright}s main features and how their activity is tracked on GitHub and related datasets to point out misalignment between the real and mined data. Our results indicate that while GitHub is a rich source of data on software development, mining GitHub for research purposes should take various potential perils into consideration. For example, we show that the majority of the projects are personal and inactive, and that almost 40\% of all pull requests do not appear as merged even though they were. Also, approximately half of GitHub{\textquoteright}s registered users do not have public activity, while the activity of GitHub users in repositories is not always easy to pinpoint. We use our identified perils to see if they can pose validity threats; we review selected papers from the MSR 2014 Mining Challenge and see if there are potential impacts to consider. We provide a set of recommendations for software engineering researchers on how to approach the data in GitHub.},
	keywords = {github},
	issn = {1573-7616},
	doi = {10.1007/s10664-015-9393-5},
	url = {http://www.gousios.gr/pub/promises-perils-github-extended.pdf},
	attachments = {https://flosshub.org/sites/flosshub.org/files/promises-perils-github-extended.pdf},
	author = {Kalliamvakou, Eirini and Gousios, Georgios and Blincoe, Kelly and Singer, Leif and Daniel M. German and Damian, Daniela}
}
@proceedings {1754,
	title = {Unveiling Exception Handling Bug Hazards in Android based on GitHub and Google Code Issues},
	year = {2015},
	month = {05/2015},
	abstract = {This paper reports on a study mining the exception
stack traces included in 159,048 issues reported on Android
projects hosted in GitHub (482 projects) and Google Code (157
projects). The goal of this study is to investigate whether stack
trace information can reveal bug hazards related to exception
handling code that may lead to a decrease in application robustness.
Overall 6,005 exception stack traces were extracted,
and subjected to source code and bytecode analysis. The outcomes
of this study include the identification of the following
bug hazards: (i) unexpected cross-type exception wrappings (for
instance, trying to handle an instance of OutOfMemoryError
{\textquotedblleft}hidden{\textquotedblright} in a checked exception) which can make the exceptionrelated
code more complex and negatively impact the application
robustness; (ii) undocumented runtime exceptions thrown by both
the Android platform and third party libraries; and (iii) undocumented
checked exceptions thrown by the Android Platform.
Such undocumented exceptions make difficult, and most of the
times infeasible for the client code to protect against {\textquotedblleft}unforeseen{\textquotedblright}
situations that may happen while calling third-party code. This
study provides further insights on such bug hazards and the
robustness threats they impose to Android apps as well as to
other systems based on the Java exception model.},
	keywords = {github, google code},
	url = {http://www.gousios.gr/pub/android-stacks.pdf},
	attachments = {https://flosshub.org/sites/flosshub.org/files/android-stacks.pdf},
	author = {Roberta Coelho and Lucas Almeida and Gousios, Georgios and van Deursen, Arie}
}
@conference {Gousios:2014:LGG:2597073.2597126,
	title = {Lean GHTorrent: GitHub Data on Demand},
	booktitle = {Proceedings of the 11th Working Conference on Mining Software Repositories},
	series = {MSR 2014},
	year = {2014},
	pages = {384{\textendash}387},
	publisher = {ACM},
	organization = {ACM},
	address = {New York, NY, USA},
	abstract = {In recent years, GitHub has become the largest code host in the world, with more than 5M developers collaborating across 10M repositories. Numerous popular open source projects (such as Ruby on Rails, Homebrew, Bootstrap, Django or jQuery) have chosen GitHub as their host and have migrated their code base to it. GitHub offers a tremendous research potential. For instance, it is a flagship for current open source development, a place for developers to showcase their expertise to peers or potential recruiters, and the platform where social coding features or pull requests emerged. However, GitHub data is, to date, largely underexplored. To facilitate studies of GitHub, we have created GHTorrent, a scalable, queriable, offline mirror of the data offered through the GitHub REST API. In this paper we present a novel feature of GHTorrent designed to offer customisable data dumps on demand. The new GHTorrent data-on-demand service offers users the possibility to request via a web form up-to-date GHTorrent data dumps for any collection of GitHub repositories. We hope that by offering customisable GHTorrent data dumps we will not only lower the "barrier for entry" even further for researchers interested in mining GitHub data (thus encourage researchers to intensify their mining efforts), but also enhance the replicability of GitHub studies (since a snapshot of the data on which the results were obtained can now easily accompany each study).
},
	keywords = {data on demand, dataset, github, msr data showcase},
	isbn = {978-1-4503-2863-0},
	doi = {10.1145/2597073.2597126},
	url = {http://doi.acm.org/10.1145/2597073.2597126},
	attachments = {https://flosshub.org/sites/flosshub.org/files/lean-ghtorrent_0.pdf},
	author = {Gousios, Georgios and Vasilescu, Bogdan and Serebrenik, Alexander and Zaidman, Andy}
}
@conference {Kalliamvakou:2014:PPM:2597073.2597074,
	title = {The Promises and Perils of Mining GitHub},
	booktitle = {Proceedings of the 11th Working Conference on Mining Software Repositories},
	series = {MSR 2014},
	year = {2014},
	pages = {92{\textendash}101},
	publisher = {ACM},
	organization = {ACM},
	address = {New York, NY, USA},
	abstract = {With over 10 million git repositories, GitHub is becoming one of the most important source of software artifacts on the Internet. Researchers are starting to mine the information stored in GitHub{\textquoteright}s event logs, trying to understand how its users employ the site to collaborate on software. However, so far there have been no studies describing the quality and properties of the data available from GitHub. We document the results of an empirical study aimed at understanding the characteristics of the repositories in GitHub and how users take advantage of GitHub{\textquoteright}s main features---namely commits, pull requests, and issues. Our results indicate that, while GitHub is a rich source of data on software development, mining GitHub for research purposes should take various potential perils into consideration. We show, for example, that the majority of the projects are personal and inactive; that GitHub is also being used for free storage and as a Web hosting service; and that almost 40\% of all pull requests do not appear as merged, even though they were. We provide a set of recommendations for software engineering researchers on how to approach the data in GitHub.
},
	keywords = {bias, code reviews, git, github, mining software repositories},
	isbn = {978-1-4503-2863-0},
	doi = {10.1145/2597073.2597074},
	url = {http://doi.acm.org/10.1145/2597073.2597074},
	attachments = {https://flosshub.org/sites/flosshub.org/files/perils.pdf},
	author = {Kalliamvakou, Eirini and Gousios, Georgios and Blincoe, Kelly and Singer, Leif and Daniel M. German and Damian, Daniela}
}
