mbostock/d3 — pull request #1501 by couchand (2013-09-02 17:27:57+00:00)
Title: fix voronoi degenerate polygon check

To be honest I'm not exactly sure what's going on here, but this does seem like a valid guard for the code below, and it sure seemed to clear up my problem.

Let me know if I can add anything else or if this isn't a valid fix.