Use before_destroy to delete another model's entry?

Question

So I have a model, let's call it Notes. On the notes, you can but several posts. So the notes model has the line:

 has_many :posts

And the posts model has the line

 belongs_to :note

Now, when a User destroys a post, I want for the note to be destroyed IF it not longer has any other posts.

I thought i would write this code into the post model with before_destroy:

 def delete_note_if_last_post
    if self.note.posts.count == 1
      self.note.destroy
    end
  end

This doesn't work. It shuts down the server based on an "Illegal Instruction". Is there some way to accomplish what I am trying to do?

EDIT: changed the code, as I noticed an error, and now the problem is slightly different.

Answer 1

you can return false to prevent a model from destruction in before_destroy filter

before_destroy :has_no_post

then in has_no_post

def has_no_post
 #You can prevent this from deletion by using these options
 #Option1 return false on certain condition  
return false if posts.any?

#or add an error to errors
errors << "Can not delete note if it has post" if posts.any?
#raise an exception 
raise "Cant delete ..." if blah blah

end