I have a model which I would like to have a 'virtual' date column.
This column wouldn't exist in the database, but would exist for
validation, etc. The data would be provided in the form of a
date_select in the view. This produces a multiparameter attribute. My
problem is that the 'execute_callstack_for_multiparameter_attributes'
method in base.rb of ActiveRecord looks at the columns array to
determine the 'class' (klass) to use when doing the multiparameter
conversion. Since this column doesn't really exist nothing is found
and an exception is thrown when trying to evaluate nil.klass.
I'm willing to provide a patch, but I am not what would be the best
way to provide the type information. Any suggestions?