undefined method 'model_name' for NilClass:Class

Question

the browser returned me the following error in Locals#show:

undefined method 'model_name' for NilClass:Class

51: <%= form_for(@food) do |f| %>
52:   <%= render 'shared/error_messages', object: f.object %>
53:   <div class="field">
54:     <%= f.label :nome %>

Here is my locals_controller.rb (the show action)

 def show
   @local = Local.find(params[:id])
   @foods = @local.foods.paginate(page: params[:page])
   respond_to do |format|
   format.html # show.html.erb
   format.json { render json: @local }
end

end

And here foods_controller.rb (the create action)

def create
@food = @local.foods.build(params[:food])
if @food.save
  flash[:success] = "Food created!"
  redirect_to '/locals'
else
  flash[:error] = "Error on creating food"
  render '/locals'
end
end

Food model and Local model are related with :has_many and belongs_to

What's the issue? Thank you

Solution 1

Then change your view code as:

<%= form_for :food, :url => {:action => :create} do |f| %>

Solution 2

Check by adding following code (I assumed that your model is Local)
@food = Local.new
In your new action

Comments

[Trip]

What is @local ? That sounds undefined.

[bugman]

@local = Local.find(params[:id])

[bugman]

you mean the scope of that variable is wrong?

[Casper]

You have @food in one controller action and @foods in another, yet the form is for @food (singular), and you say the error is for Locals#show where you use @foods (plural). Something doesn't match up there in your code.

[bugman]

i have @foods because i want to show in show.html.erb also a list of foods but the form is for a singular food so i don't understand

[bugman]

in form i have @ food (singular for one food) in show i have @foods in order to display a list of foods that belongs to a local (in italian a synonim of "bar"). The <%= form_for :food, :url => {:action => :create} do |f| %> solution seems to be working but raise another issue when i try to create a new food by filling fields and click on submit button i've been redirected to new Local path and no food has been created

[bugman]

wait i have 2 model one is Local (that has_many :foods) and the other is Food (that belongs_to :local) so you mean @food = Food.new ? However unfortunately it doesn't work

[bugman]

I've no more the error when page is displayed but when i try to create a new food by filling fields and click on submit button i've been redirected to new Local path and no food has been created, do you know why?

[bugman]

when i try to post the debugger writes the following : food: !ruby/hash:ActiveSupport::HashWithIndifferentAccess nome: a descrizione: '' prezzo: '10' commit: Post action: create controller: locals ...How can i change the controller from locals to foods ?

[Salil]

You need to add this code in your 'show' action. Did you understand that your '@food' instance variable is not set in show action and that is why you are getting this error?