Deleted products crash the wishlist view

[brchristian]

My app uses wished_products.count to tell the user in the head of the page how many items are in their Wish List.

After upgrading Spree to 2-0-master, I saw "Wish List (1)" but upon clicking, my application crashed, citing:

undefined method `product' for nil:NilClass

at the line product = variant.product.

As you can see at the source, the default scoping of the Variant model (which itself comes from acts_as_paranoid) will create these types of nil variants, with the potential to crash spree_wishlist.

I'm not sure what the solution is in this case. Namely, I'm not sure whether we should have a way to purge wishlist items that refer to deleted objects as we find them, or whether we should have a subtler way of determining the logical size of the wishlist (scoped to not deleted products/variants), or what exactly is the conceptual approach to this.

I'd be happy to suggest a PR if someone from the spree team (@radar?) wants to comment on how best to address it.

Personally I think the cleanest would be to create a railties migration that deletes at migration time any WishedProducts with nil Variants, and then to prevent future problems by using an after_destroy hook to the Variant model.

[Ryan Bigg]

Yes, you're on the right track with the migration and the after_destroy hook.

I think we should just have a class decorator for the Variant model which defines this:

Spree::Variant.class_eval do
  has_many :wished_products, :dependent => :destroy
end

[brchristian]

@radar This issue appears to have been successfully addressed by the pull request #66 and so I'm going to go ahead and close this issue.

[Ryan Bigg]

Ok, great :)