Refunding Doesn't Update Credit Owed

[gmacdougall]

When a refund is given, the "Credit Owed" in the admin and order payment state are not correctly updated.

Steps to Reproduce

Start up a Solidus Sandbox

1. Purchase 3 items
2. Go to the admin page for that order
3. Capture the payment for the order
4. Cancel one of the three items ordered
5. Go to the payment page and see that credit is owed
6. Refund the amount owed to the customer

Expected Results

The order should move into a paid state and balance due/credit owed should be $0

Actual Results

The order's payment state is still credit owed, with -$20.99 showing as credit owed at the top of the page.

Example

[DanielePalombo]

My and @mtylty started to investigate this issue and we found these related issues: #1254, #1107, spree/spree#6229 , spree/spree#5907

[skukx]

The reason this is happening is because of this line:
https://github.com/solidusio/solidus/blob/v2.1/core/app/models/spree/order.rb#L355

    def outstanding_balance
      # If reimbursement has happened add it back to total to prevent balance_due payment state
      # See: https://github.com/spree/spree/issues/6229
      adjusted_payment_total = payment_total + refund_total

      if state == 'canceled'
        -1 * adjusted_payment_total
      else
        total - adjusted_payment_total
      end
    end

After a Spree::Refund is created perform! is called
https://github.com/solidusio/solidus/blob/master/core/app/models/spree/refund.rb#L16

In turn, this method calls payment.order.updater.update Which updates the payment_total column on the Spree::Order. This update already accounts for refunds when calculating payment_total.

See https://github.com/solidusio/solidus/blob/master/core/app/models/spree/order_updater.rb#L141

def update_payment_total
    order.payment_total = payments.completed.includes(:refunds).map { |payment| payment.amount - payment.refunds.sum(:amount) }.sum
end

So TLDR; Get rid of adjusted_payment_total because payment_total is already adjusted.

Edit

I'm realizing that this method may be used at times when the payment total has not been updated. So the question stands on what is the best way to fix this?

[jhawthorn]

I believe this is fixed by #2002