A Dataset for GitHub Repository Deduplication: Replication Package

This is the replication package for creating a dataset of GitHub projects that are copies of other. GitHub projects can be easily replicated through the site’s fork process or through a Git clone-push sequence. This is a problem for empirical software engineering, because it can lead to skewed results or mistrained machine learning models. We provide a dataset of 10.6 million GitHub projects that are copies of others, and link each record with the project’s ultimate parent. The ultimate parents were derived from a ranking along six metrics. The related projects were calculated as the connected components of an 18.2 million node and 12 million edge denoised graph created by directing edges to ultimate parents. The graph was created by filtering out more than 30 hand-picked and 2.3 million pattern-matched clumping projects. Projects that introduced unwanted clumping were identified by repeatedly visualizing shortest path distances between unrelated important projects. Our dataset identified 30 thousand duplicate projects in an existing popular reference dataset of 1.8 million projects. An evaluation of our dataset against another created independently with different methods found a significant overlap, but also differences attributed to the operational definition of what projects are considered as related.

The creation process is documented through rules in src/Makefile and the files residing in that directory. An installed version of the GHTorrent dataset in a PostgreSQL database is required for running the queries. The name of the database and access credentials can be adjusted through Makefile variables. The running of the SQL queries is automated through the simple-rolap system, which is installed automatically. For running the tests (with make test) and installation of the relational database unit test system rdbunit is required.

In addition, the directory diagrams contains in SVG and PDF format the various diagrams referenced from the text.