NoMethodError in Spree::UserSessionsController#create

[nefarianblack]

NoMethodError in Spree::UserSessionsController#create undefined method `quantity' for true:TrueClass

How to reproduce:

1. disable checkout without registration
2. add Spree Login as Existing form in registration.html.erb (so that existing users can login right in the checkout process)
3. select a product -> add to cart -> checkout -> registration page
4. try logging in with a registered account
5. error shows up

Resolution: file: order_decorator.rb line no. 4 current_item = contains?(variant, ad_hoc_option_value_ids, product_customizations)

change this to: current_item = find_line_item_by_variant(variant, ad_hoc_option_value_ids, product_customizations)

Note: I have created a pull request for the issue (https://github.com/jsqu99/spree_flexi_variants/pull/100).