Question

I am trying to implement the following code in index.html.erb on rails and the following error appears on the server:

NoMethodError in Users#index
You have a nil object when you didn’t expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.each

Extracted source (around line #2)

<div id="users">  
  <% @users.each do |user| %>  
<div id="user">  
      <% if user.username != current_user.username %>  
        <%=h user.username %>  
        <%= link_to "Add Friend", friendships_path(:friend_id => user), :method => :post %>  
      <% end %>  
    </div>  

  <% end %>  
</div>  

Controller code:

    class UsersController < ApplicationController

  def new
    @user = User.new
  end

  def create
    @user = User.new(params[:user])
    if @user.save
      session[:user_id] = @user.id
      redirect_to root_url, :notice => "Thank you for signing up! You are now logged in."
    else
      render :action => 'new'
    end
  end
  end

  def edit
    @user = current_user
  end

  def update
    @user = current_user
    if @user.update_attributes(params[:user])
      redirect_to root_url, :notice => "Your profile has been updated."
    else
      render :action => 'edit'
    end
  end

Answer 1

You’ll get this a lot with rails.
To explain:
The method does exist so the error message is confusing. The problem is that the variable (@users) doesn’t have any value. It’s nil rather than a valid object. So when you try to call that method on ‘nil’ you get that error message.
So look in your controller and make sure that the query e.g. @users = User.all does actually return records and you can also check that in the console (script/console or script/rails console)