Rails "undefined method 'name' for nil:NilClass" error when adding @article.comments.size

Question

I am following Jumpstartlab's Blogger Rails tutorial.

I am using Ruby 2.2.1 and Rails 4.0.0.

The "undefined method 'name' for nil:NilClass" error is raised when I add

(<%= @article.comments.size %>)

to

<h3>Comments</h3>

in ~/show.html.erb.

If I swap this line with

<%= render partial: 'articles/comment', collection: @article.comments %>

I get no error and everything displays correctly (except that the header displays in the wrong spot - after the comments, rather than before).

I tried git hard reset to restore the entire comments section and redo all of it, but I got the same error.

Here is my code for ~/show.html.erb when it raises the error:

<h1><%= @article.title %></h1>
<p><%= @article.body %></p>
<h3>Comments (<%= @article.comments.size %>)</h3>
<%= render partial: 'articles/comment', collection: @article.comments %>
<%= render partial: 'comments/form' %>
<%= link_to '<< Back to Articles List >>', articles_path %>
<%= link_to 'edit', edit_article_path(@article) %>
<%= link_to 'delete', article_path(@article), method: :delete, data: {confirm: "Really delete the article?"} %>

I am using...

articles.rb:

class Article < ActiveRecord::Base
  has_many :comments
end

comment.rb:

class Comment < ActiveRecord::Base
  belongs_to :article
end

My fix is to swap

<h3>Comments (<%= @article.comments.size %>)</h3>

with

<%= render partial: 'articles/comment', collection: @article.comments %>

but this displays the header at the wrong place. It also doesn't make any sense to me why this works. Note that there are no errors if I do not include

(<%= @article.comments.size %>)` in `<h3>Comments

The solution to "NoMethodError undefined method `name' for nil:NilClass)" led me to check my databases for missing ids, but there were no problems there.

Answer 1

You could try using .count or .length instead of .size.

<h3>Comments (<%= @article.comments.count %>)</h3>

I'm using ruby 2.3 and rails 4.0.0.