[Bug] Provider\RemainingTotalProvider meant to work by ShipmentRefund, but in practice works by shipment Adjustment

[diimpp]

Provider\RemainingTotalProvider is used to get available amount for refund for both OrderItemUnitRefund and ShipmentRefund.

That's the theory, in practice Validator\RefundAmountValidator expects to be working with Model\ShipmentRefund, which is correct, but order refund page _shipping.html.twig works with shipping Adjustments which is incorrect and source codes of Provider\RemainingTotalProvider were hacked for UI benefit.

    $shippingAdjustment = $this->adjustmentRepository->findOneBy([
            'id' => $id,
            'type' => AdjustmentInterface::SHIPPING_ADJUSTMENT,
        ]);
        Assert::notNull($shippingAdjustment);

So problem is public function getTotalLeftToRefund(int $id, RefundType $type): int expects one kind of $id and gets totally another and underling code was hacked to support adjustments usage.

Maybe this was conscious decision due to shipment and adjustments not being related in prior 1.9, but it should have been handled explicitly in such case.

Solution is to refactor UI to work with shipments directly.

Personally I've encountered this at non-standard use-case, while loading historical data in DB, so there might be no active bugs with standard usage.

[GSadee]

Hello @diimpp, thank you for opening an issue and your thoughts.

As you wrote, I guess this was a conscious decision due to shipment and adjustments not being related then. But I agree, that the current solution with using shipping adjustments instead of shipments doesn't seem to be the best one and it is certainly not the expected behaviour.

However, I'm not sure if it is a bug, or just sth for future improvement that could be quite difficult to refactor due to keeping backward compatibility.