Pg 111: Error regarding StoreController #add_to_cart

When I try to add something to my cart, I get this error:

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.<<

app/models/cart.rb:9:in `add_product’
app/controllers/store_controller.rb:10:in `add_to_cart’

—

What exactly is the problem?

Make sure that cart.rb looks exactly like this href=”http://media.pragprog.com/titles/rails3/code/depot_f/app/models/cart.rb”>http://media.pragprog.com/titles/rails3/code/de…

Line 9 is

@items << product

The message indicates that @items has not been initialized. This should have been done on line 5:

@items = []

Check both lines, for spelling mistakes, missing @ signs or the like.

Thank you for responding, Mr. Ruby. It is very comforting as a reader to know that you are so available and outgoing.

I can’t find and errors with my cart.rb. I’ve pasted it up here:

code font
class Cart attr_reader :items

def initialize
    @items = []
end

def add_product(product)
    @items << product
end
end
code font

That code appears to be correct. My next guess is that somehow you created a Cart without setting @items correctly, and then subsequently fixed the code, but the original Cart is still captured and stored in your session.

Try

rake db:sessions:clear

It worked! Thank you!

Hi,
I am getting the same error as Max except rake db:sessions:clear isn’t fixing it. I have tried clearing the browser cache, restarting the server and clearing sessions but I still have problems. Is there anything beside cart.rb that could be causing these problems? I have triple checked that cart.rb is not the problem and copy-pasted the code you provided above but nothing is working. Thanks for any help.