silverstripe/sapphire — pull request #316 by mateusz (2012-04-13 04:25:13+00:00)
Title: Re: SiteTree ParentID information can occassionally generate infinite loops.

Ref: http://open.silverstripe.org/ticket/4339 , adds a validation hook for DataExtension and adds a check in Hierarchy for infinite loops.
Impact: on each write the hierarchy will be checked, and it will not be possible to save existing objects that are looping (will throw a ValidationException from write).