gem/oq-hazardlib — pull request #105 by larsbutler (2013-02-26 16:26:42+00:00)
Title: Rect mesh enclosing poly bug

This is handling for a special case has only consistently cropped up in our CI environment: http://ci.openquake.org/job/oq-engine/199/testReport/

Basically, this part of the code throws an exception when trying to create a cascading union of many polygons (resulting in a single polygon). This seems to happen only with VERY specific geometry AND when one of those very specific geometries is duplicated in the input list to `shapely.ops.cascading_union`.

Oh, it gets worse. The only machine on which I've been able to reproduce this error is the CI machine. No other machine can do it as far as I know.