Ruby: Getting Active Record validation errors twice
I managed to create an interesting problem for myself while playing around with some code whereby I was ending up with validation errors appearing twice every time I called ‘valid?’ on a specific model.
I figured I was probably doing something stupid and in fact a few replies by Aaron Baldwin on a mailing list thread on ‘rubyonrails-talk’ helped explain exactly what I’d done:
Are you calling require 'employee' anywhere? If so you are likely causing the model to load twice which causes duplicate errors because the validates_presence_of method gets called twice.
I’d put the following code into a controller elsewhere somewhat unnecessarily since it didn’t seem to be picking up the location of my model at the time:
require 'models/code_submission' class CodeSubmissionsController < ApplicationController def new CodeSubmission.new end end
require doesn’t load a file if it’s already been included but Aaron points out why it does on this occasion:
You are right that "require" will only load the file once. But if you load the class another way calling "require" will load it again.
As I understand it that controller code would also implicitly require ‘code_submission’ by the convention of inserting an underscore between the ‘CodeSubmission’ constant’s names.
We therefore effectively have the following two requires:
require 'code_submission' require 'models/code_submission'
Which explain how the file gets loaded twice and therefore why the validation method fires twice and therefore creates two errors!