jenkinsci/jenkins — pull request #533 by cjo9900 (2012-08-03 12:44:20+00:00)
Title: Prevent processing hetero-list twice.

Check for null prototype occuring if we end up calling the function
multiple times on the list. the type error that it causes means other
behaviours are not applied to the rest of the container.
[FIXED JENKINS-14495]

Full details of investigation in the issue
https://issues.jenkins-ci.org/browse/JENKINS-14495