eventmachine/eventmachine — pull request #287 by lgierth (2011-12-29 03:08:06+00:00)
Title: Don't overwrite @deferrable_status

Use Case: #succeed a Deferrable, later #fail it. Both the callbacks _and_ errbacks will be executed. This is a problem if you have the same Proc once in callbacks and once in errbacks, e.g. with EM::Synchrony.sync. It also contradicts the documentation of #set_deferred_status which states that the role-model is Twisted, which "only allows status to be set once".