rails/rails — pull request #6249 by bartvandendriessche (2012-05-10 11:30:22+00:00)
Title: Error message generation now supports more flexible error format lookup

When generating an error message, a format lookup is done for the
following keys:
errors.models.MODEL.attributes.ATTRIBUTE.format
errors.models.SUPERCLASS.attributes.ATTRIBUTE.format (if there's a superclass with I18n support)
errors.attributes.ATTRIBUTE.format
errors.format

If none of these keys are associated with an error format, the default
'%{attribute} %{message}' is used.