rails/rails — pull request #6284 by acapilleri (2012-05-12 13:09:30+00:00)
Title: clean the erros if an object that includes validations errors is duped.

If an istance that include validation is duped it keep track of errors of this 'parent', because both errors instances point to the same ActiveModel::Errors instance. This happen when before to call dup, ``` save or valid?``` is called. This Fixes #5953 and it was discussed on the pull request https://github.com/rails/rails/pull/5958