Error 500 - Customer viewing an edited order from which all items were removed

[filipefurtad0]

Description

After placement and payment capture of an order - but before shipment - the hub manager can edit the order and change the number of items, or remove all of them. If this is done and the customer attempts to view the order an error 500 become visible to the user, i.e., in /orders/Rxxxxxxxx. Looking at /transactions shows an error in the column Shipping status (pics below).

Expected Behavior

Clicking on the edited order should not show the snail and:

• perhaps lead show the order with zero items, and zero amounts, with the corresponding Outstanding balance (would this be a paper cut?)
• the error message under Shipping Status should be improved rather than display the error message

Actual Behaviour

• error 500 when visiting the edited order (from which nr. of items is now zero)
• [missing "en.spree.shipment_states.null" translation] error appears

Steps to Reproduce

1. Customer - Place an order
2. Admin - edit the order, removing all items
3. Customer - go to /orders and click on the order -> snail 500
4. Customer - go to /transactions and observe the error

Animated Gif/Screenshot

Workaround

Deleting an order, instead of reducing it's numbers to zero.

Severity

Placing as bug-s4. An argument for upgrading this to s3 would be that the user sees snail.

Your Environment

• Version used: v2.9.9
• Browser name and version: Firefox 75
• Operating System and version (desktop or mobile): Desktop

[filipefurtad0]

I think we can close this, as the only path to generating empty orders is by removing all items from orders, which cancels them automatically, and resuming the order.

However, resumed orders don't appear to the customer, so as of now, this bug does not occur.