Who's who in Gnome: Using LSA to merge software repository identities

Understanding an individual's contribution to an ecosystem often necessitates integrating information from multiple repositories corresponding to different projects within the ecosystem or different kinds of repositories (e.g., mail archives and version control systems). However, recognising that different contributions belong to the same contributor is challenging, since developers may use different aliases. It is known that existing identity merging algorithms are sensitive to large discrepancies between the aliases used by the same individual: the noisier the data, the worse their performance. To assess the scale of the problem for a large software ecosystem, we study all Gnome Git repositories, classify the differences in aliases, and discuss robustness of existing algorithms with respect to these types of differences. We then propose a new identity merging algorithm based on Latent Semantic Analysis (LSA), designed to be robust against more types of differences in aliases, and evaluate it empirically by means of cross-validation on Gnome Git authors. Our results show a clear improvement over existing algorithms in terms of precision and recall on worst-case input data.