oerpub/github-bookeditor — pull request #110 by izak (2013-11-04 13:02:53+00:00)
Title: Avoid the exception where two updaters run at the same time

This is technically not possible, only one updater can ever run at a time, the error merely says that a new poll started before the previous one was marked as done. This happened for many reasons, one was a possible race condition (you switch repos in the middle of a poll), the other was that poll completion was not properly marked if it failed.