I was recently tasked with converting a Rails app from Rails 2.3.x to 3.2.x.
“Shouldn’t be too difficult” I thought, but one of the first things that came out and bit me is that the
error_message_on helper method, which was previously used to display error messages next to the form fields that had caused them, has been deprecated.
It took me a little while to figure out how to reinstate this functionality. Here’s how I did it.