Getting nicely formated error page for associated models.

I have a question regarding reporting of errors for models which contain other models.

For example, if I have a User model which contains a Comments collection, and I am not able to see any errors encountered when validating the comments.

So if I do something like the following to append a new comment:

user = User.find(id)

comment = Comment.new(:comment => params[:comment_text],                     :user_id => id)

user.comments << comment user.save!

When I do this, with an empty :comment_text string, I get an exception (coming from a validates_length_if associated with the Comment model).

My question is, how can I get this to show on the form via <%= error_messages_for... %>, nicely formated instead of an application exception error message?

At the moment I have a <%= error_messages_for :user %>, which results in a nicely formated page showing any validation errors for User. But not if an empty comment is added to the user's comments collection.

Any help would be greatly appreciated.

Cheers, Diego

Nick, thanks for the reply. Appreciate it.