NoMethodError in Orders#show , undefined method `grand

I'm want to show the grand_total to the show page and i have do a partial file to put in the table, in inside i want to grab the orderproduct data and show to front , but it show me this error. It seem like i didn't define method grand_total, but not sure how to solve it.

Orders controller

class OrdersController < ApplicationController

 def supplier
  @supplier = Supplier.find(params[:id])
 end

 def outlet
  @outlet = Outlet.find(params[:id])
 end

 def index
  @orders = Order.all
 end

 def show
  @orders = Order.all
  @order_products = OrderProduct.all
 end

def new
 @order = Order.new
 @supplier = Supplier.all
 @outlet = Outlet.all
 @products = Product.all
end

def create
 @order = Order.new(order_params)
 @supplier_id = Supplier.all
 @outlet_id = Outlet.all
 if @order.save
  product_ids = params[:product_ids]
  product_ids.each do |product_id|
    OrderProduct.create(order_id: @order.id, product_id: product_id)
  end
   flash[:success] = "Succesful create!"
   redirect_to @order
 else
   render 'new'
 end
end

private

def order_params
  params.require(:order).permit(:supplier_id,:quantity, :grand_total, :order_date,
                                :delivery_date, :delivery_address, :outlet_id)
 end
end

_orderproduct.html.erb

<div >
 <ul >
  <li >
   <div >Product</div>
   <div >Price</div>
   <div >Grand_total</div>
  </li>
  <% @order_products.each do |order_product| %>
  <li >
   <div  data-label="Product"><%= order_product.product.name %></div>
   <div  data-label="Price"><%= order_product.product.price %></div>
   <div  data-label="Grand_total"><%= order_product.order.grand_total %></div>
  <% end %>
 </ul>
</div>

show.html.erb

<% provide(:title)%>

<h2 >Order details</h2>

<div >
 <aside >
  <section >
   <%= render 'shared/stats' %>
  </section>
  <%= render 'orders/orderproduct' %>
  <div >
   <button ><%= link_to "Back to home", home_path %></button>
  </div>
 </aside>
</div>

Error show in website

CodePudding user response：

The only place in your examples on which you call grant_total is this:

<%= order_product.order.grand_total %>

The error message tells that there is a NoMethodError in Orders#show, undefined method grand_total for nil:NilClass. This means you are calling grant_total on something that is nil and not the type of object you expect. This can only happen when order_product.order returned nil. And that means you have an order_product in your database that doesn't have an order assigned.

There are several ways to fix that, depending on what you want to achieve:

add a validation that ensures that all order_products have an order assigned.
backfill missing orders in the database
exclude order products without associated order when loading or
checking if there is an order and only then outputting its grant total

CodePudding user response：

you can use debugger to see which variable is returning nil value. Check and work from there.