After adding the item, an error undefined method `key?' for nil:NilClass


After adding the item, an error undefined method `key?’ for nil:NilClass

its my controller products:

GET /products/new

GET /products/new.json

def new
@product =

respond_to do |format|
  format.html # new.html.erb
  format.json { render json: @product }


model product:

lass Product < ActiveRecord::Base
has_many :line_items
before_destroy : ensure_not_referenced_by_any_line_item

attr_accessible :title, :description, :image_url, :price

validates :title, :description, :image_url, :price, presence: true
validates :price, numericality: {greater_than_or_equal_to: 0.01}
validates :title, uniqueness: true

validates :image_url, allow_blank: true, format: {

with: %r{ .(gif|jpg|png)$}i,

#message: 'gif, jpg png. '


def ensure_not_referenced_by_any_line_item
if line_items.empty?
return true
errors.add(:base, " существуют товарные позиции")
return false


class CreateProducts < ActiveRecord::Migration
def change
create_table :products do |t|
t.string :title
t.text :description
t.string :image_url
t.decimal :price



How solve this problem?

lass Product < ActiveRecord::Base

I don’t know if this typo is just here and occured when you copied your
source code, or you have ‘lass Product’ in your model. If second, that
be reason for error

, 18 2013 ., 11:46:48 UTC+4
User :

no, its easy copy. class Product < ActiveRecord::Base

why do you show code of Product controller, if you create new Line_Item?

, 18 2013 ., 11:46:48 UTC+4
User :

no i want add new product - http://localhost:3000/products/new

undefined method `key?’ for nil:NilClass

Rails.root: /home/dima/RubyOnRails/Projects/depot

its trace -

On 18 March 2013 07:46, Dmitrij B. [email protected] wrote:


After adding the item, an error undefined method `key?’ for nil:NilClass

That error means that something is nil when it should not be.
Unless I have missed it, you have not shown us which line is
generating the error. If you cannot work it out from the stack trace
post the complete trace here. If it refers to a line in your code
then tell us which that line is…

First, though, have a look at the Rails Guide on Debugging which will
show you techniques that you can use to debug the code yourself. It
is always better to work a problem out for yourself if possible.


This forum is not affiliated to the Ruby language, Ruby on Rails framework, nor any Ruby applications discussed here.

| Privacy Policy | Terms of Service | Remote Ruby Jobs