Cookbook2 tutorial error: The error occured while evaluatin

Ruby
1

I am following the Cookbook2 tutorial on the InstantRails website (
http://instantrails.rubyforge.org/tutorial/index.html ). I am almost
finshed with the tutorial but have started getting the following error:

NoMethodError in Recipe#list

Showing app/views/recipe/list.rhtml where line #24 raised:

You have a nil object when you didn’t expect it!
The error occured while evaluating nil.name

Extracted source (around line #24):

21: :confirm => “Really delete #{recipe.title}?” %>
22:
23:
24: <%= recipe.category.name %>
25: <%= recipe.date %>
26:
27: <% end %>

RAILS_ROOT: ./script/…/config/…
Application Trace | Framework Trace | Full Trace

#{RAILS_ROOT}/app/views/recipe/list.rhtml:24
#{RAILS_ROOT}/app/views/recipe/list.rhtml:11

And here are the first three lines of the Full Trace:

C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/actionpack-1.11.2/lib/action_view/base.rb:268:in
compile_and_render_template' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/actionpack-1.11.2/lib/action_view/base.rb:244:in render_template’
C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/actionpack-1.11.2/lib/action_view/base.rb:205:in
`render_file’

I have attempted double checking the code throughout the tutorial, but
I am just not seeing what is causing the error. I figure it is a small
typing error, but I do not know how to isolate which section of code it
is in. Any suggestions would be welcomed.

Thank you for your time.

John

2

I forgot to mention I am getting the error when I attempt to “add a
new recipe like the one shown in Figure 56.”.

Thanks,
John

3

Well I figured it out in case anyone searches for this same problem…
The receipe table had a row with a category_id of 0. Note that the
category table does not have a row for 0.

Not sure how this wound up in the DB like that, but I manually fixed it
by changing the 0 to a 1.

Hope this helps someone else learning ruby!

4

Thanks, I’ll see if we can get something added to the tutorial about
this.

Curt