Creditmemo creation error - Forgotten shipping discount tax compensation in creditmemo calculation ?

[Nuranto]

Preconditions and environment

• Magento version 2.4.6-p2

Steps to reproduce

It's kind hard to say how to reproduce step by step because it's a very very rare rounding issue on shipping amounts. But I'll try anyway, and then give the order details :

1. Place an order*, with a discount (not sure if the discount is mandatory)
2. Invoice & Ship order
3. Create a creditmemo (via invoice) to refund shipping amount
4. try to create another creditmemo (via invoice)

(*) Here is some order detail that might be relevant :

• grand_total = 780.26
• subtotal = 710.77
• subtotal_incl_tax = 770.90
• total_refunded = 125
• tax_amount = 62.48
• tax_invoiced = 62.48
• tax_refunded = 11.36
• discount_tax_compensation_amount = 9.01
• discount_amount = -115.64
• shipping_amount = 113.63
• shipping_invoiced = 113.63
• shipping_refunded = 113.63
• shipping_tax_amount = 11.36
• shipping_tax_refunded = 11.36
• shipping_discount_tax_compensation_amount = 0.01
• shipping_incl_tax = 125
• shipping_discount_amount = 0

Expected result

We can create another creditmemo

Actual result

We can not create another creditmemo, and have an error message : Maximum shipping amount allowed to refund is: 0,00 €

Additional information

desiredAmount is 0.01 in

magento2/app/code/Magento/Sales/Model/Order/Creditmemo/Total/Shipping.php

Lines 71 to 98 in 2b3ad2e

	$desiredAmount = $this->priceCurrency->round($creditmemo->getBaseShippingAmount());
	$maxAllowedAmount = ($useAmountsWithTax ? $baseAllowedAmountInclTax : $baseAllowedAmount);
	$originalTotalAmount = ($useAmountsWithTax ? $orderBaseShippingInclTax : $orderBaseShippingAmount);
	// Note: ($x < $y + 0.0001) means ($x <= $y) for floats
	if ($desiredAmount < $this->priceCurrency->round($maxAllowedAmount) + 0.0001) {
	// since the admin is returning less than the allowed amount, compute the ratio being returned
	$ratio = 0;
	if ($originalTotalAmount > 0) {
	$ratio = $desiredAmount / $originalTotalAmount;
	}
	// capture amounts without tax
	// Note: ($x > $y - 0.0001) means ($x >= $y) for floats
	if ($desiredAmount > $maxAllowedAmount - 0.0001) {
	$shippingAmount = $allowedAmount;
	$baseShippingAmount = $baseAllowedAmount;
	} else {
	$shippingAmount = $this->priceCurrency->round($orderShippingAmount * $ratio);
	$baseShippingAmount = $this->priceCurrency->round($orderBaseShippingAmount * $ratio);
	}
	$shippingInclTax = $this->priceCurrency->round($orderShippingInclTax * $ratio);
	$baseShippingInclTax = $this->priceCurrency->round($orderBaseShippingInclTax * $ratio);
	} else {
	$maxAllowedAmount = $order->getBaseCurrency()->format($maxAllowedAmount, null, false);
	throw new \Magento\Framework\Exception\LocalizedException(
	__('Maximum shipping amount allowed to refund is: %1', $maxAllowedAmount)
	);
	}

So $desiredAmount < [..]$allowedAmount gives 0.01 < 0 which causes the exception. That 0.01 seems to correspond to shipping_discount_tax_compensation_amount field.

DesiredAmount is set previously here :

magento2/app/code/Magento/Sales/Model/Order/CreditmemoFactory.php

Lines 151 to 154 in 2b3ad2e

	if (!isset($data['shipping_amount'])) {
	$baseAllowedAmount = $this->getShippingAmount($invoice);
	$creditmemo->setBaseShippingAmount($baseAllowedAmount);
	}

and calculated here :

magento2/app/code/Magento/Sales/Model/Order/CreditmemoFactory.php

Lines 326 to 340 in 2b3ad2e

	private function getShippingAmount(Invoice $invoice): float
	{
	$order = $invoice->getOrder();
	$isShippingInclTax = $this->taxConfig->displaySalesShippingInclTax($order->getStoreId());
	if ($isShippingInclTax) {
	$amount = $order->getBaseShippingInclTax() -
	$order->getBaseShippingRefunded() -
	$order->getBaseShippingTaxRefunded();
	} else {
	$amount = $order->getBaseShippingAmount() - $order->getBaseShippingRefunded();
	$amount = min($amount, $invoice->getBaseShippingAmount());
	}
	return (float)$amount;
	}

As you can see, if we apply my order numbers in that code, it gives :

$amount = 125 - 113.63 - 11.36 = 0.01 => So I guess the calculation is forgetting about shipping_discount_tax_compensation_amount

And a fix would be :

$amount = $order->getBaseShippingInclTax() -
                $order->getBaseShippingRefunded() -
                $order->getBaseShippingTaxRefunded() -
                $order->getBaseShippingDiscountTaxCompensationAmnt();

However, tax calculation is so complex in Magento 2 that I won't try to make a PR for this. It would be safer if someone used to such calculations can have a look. However, this fix seems to fix the issue.

EDIT : This fix was not OK, and it seems unrelated from shipping_discount_tax_compensation_amount after all.

Release note

No response

Triage and priority

• Severity: S0 - Affects critical data or functionality and leaves users without workaround.
• Severity: S1 - Affects critical data or functionality and forces users to employ a workaround.
• Severity: S2 - Affects non-critical data or functionality and forces users to employ a workaround.
• Severity: S3 - Affects non-critical data or functionality and does not force users to employ a workaround.
• Severity: S4 - Affects aesthetics, professional look and feel, “quality” or “usability”.

[m2-assistant]

Hi @Nuranto. Thank you for your report.
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[m2-assistant]

Hi @engcom-Bravo. Thank you for working on this issue.
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[m2-assistant]

Hi @engcom-Dash. Thank you for working on this issue.
In order to make sure that issue has enough information and ready for development, please read and check the following instruction: 👇

• 1. Verify that issue has all the required information. (Preconditions, Steps to reproduce, Expected result, Actual result).
• 2. Verify that issue has a meaningful description and provides enough information to reproduce the issue.
• 3. Add Area: XXXXX label to the ticket, indicating the functional areas it may be related to.
• 4. Verify that the issue is reproducible on 2.4-develop branch
     Details

     - Add the comment @magento give me 2.4-develop instance to deploy test instance on Magento infrastructure.
     - If the issue is reproducible on 2.4-develop branch, please, add the label Reproduced on 2.4.x.
     - If the issue is not reproducible, add your comment that issue is not reproducible and close the issue and stop verification process here!

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[engcom-Dash]

@magento give me 2.4-develop instance

[magento-deployment-service]

Hi @engcom-Dash. Thank you for your request. I'm working on Magento instance for you.

[magento-deployment-service]

Hi @engcom-Dash, here is your Magento Instance: https://553a183d014e02ad841c505fd4fefbce.instances-prod.magento-community.engineering
Admin access: https://553a183d014e02ad841c505fd4fefbce.instances-prod.magento-community.engineering/admin_05e8
Login: 4ef431e2
Password: bb147afe901a

[engcom-Dash]

Hi @Nuranto
Thanks for reporting and collaboration. verified in magento 2.4 develop instance
and able to create another credit memo. Not able to reproduce the issue. Please refer the screenshots below.

Creditmemos:

Creditmemo1:

Creditmemo2:

[Nuranto]

As I said, it is a very rare issue (we got 1 case for thousands of orders). It happened on a big order (douzens of products), with a cart discount. However, I don't know how to reproduce for sure I'm afraid.

[engcom-Dash]

Hi @Nuranto
Thanks for reporting and collaboration.
We have tested with number of products.Sometimes the issue depends on the operating system.Can you please let us know the operating system you are using?
Thanks.

[Nuranto]

We're running on docker php:8.1-apache-bullseye image.

Note : If you refunded Shipping fees on first creditmemo, why do you have 10.03 proposed in second creditmemo creation ? First creditmemo should refund 100% of shipping fees

[engcom-Dash]

@magento give me 2.4-develop instance

[magento-deployment-service]

Hi @engcom-Dash. Thank you for your request. I'm working on Magento instance for you.

[magento-deployment-service]

Hi @engcom-Dash, here is your Magento Instance: https://553a183d014e02ad841c505fd4fefbce.instances-prod.magento-community.engineering
Admin access: https://553a183d014e02ad841c505fd4fefbce.instances-prod.magento-community.engineering/admin_d8ae
Login: 48c7b232
Password: 874b1ca678ab

[engcom-Dash]

Hi @Nuranto

Thanks for reporting and collaboration.

we can divide the shipping fee into two creditmemos

We followed the steps to reproduce but not able to reproduce the issue.

1.Place an order*, with a discount (not sure if the discount is mandatory)
2.Invoice & Ship order
3.Create a creditmemo (via invoice) to refund shipping amount
4.try to create another creditmemo (via invoice)

Please let us know the detailed steps to reproduce the issue.

[engcom-Dash]

Hi @Nuranto

We have noticed that this issue has not been updated since long time.
Hence we assume that this issue is fixed now, so we are closing it. Please feel to raise a fresh ticket or reopen this ticket if you need more assistance on this.

Thanks.

[Nuranto]

(related to #38134)

[Nuranto]

Workaround Fix proposal, for those who have the issue, or if the issue is reopened one day :

Replace :

if ($desiredAmount < $this->priceCurrency->round($maxAllowedAmount) + 0.0001) { 
     // since the admin is returning less than the allowed amount, compute the ratio being returned 
     $ratio = 0; 
     if ($originalTotalAmount > 0) { 
         $ratio = $desiredAmount / $originalTotalAmount; 
     } 
     // capture amounts without tax 
     // Note: ($x > $y - 0.0001) means ($x >= $y) for floats 
     if ($desiredAmount > $maxAllowedAmount - 0.0001) { 
         $shippingAmount = $allowedAmount; 
         $baseShippingAmount = $baseAllowedAmount; 
     } else { 
         $shippingAmount = $this->priceCurrency->round($orderShippingAmount * $ratio); 
         $baseShippingAmount = $this->priceCurrency->round($orderBaseShippingAmount * $ratio); 
     } 
     $shippingInclTax = $this->priceCurrency->round($orderShippingInclTax * $ratio); 
     $baseShippingInclTax = $this->priceCurrency->round($orderBaseShippingInclTax * $ratio); 
 } else { 
     $maxAllowedAmount = $order->getBaseCurrency()->format($maxAllowedAmount, null, false); 
     throw new \Magento\Framework\Exception\LocalizedException( 
         __('Maximum shipping amount allowed to refund is: %1', $maxAllowedAmount) 
     ); 
 } 

With

if ($desiredAmount >= $this->priceCurrency->round($maxAllowedAmount) + 0.0001) { 
  $desiredAmount = $maxAllowedAmount;
}
     // since the admin is returning less than the allowed amount, compute the ratio being returned 
     $ratio = 0; 
     if ($originalTotalAmount > 0) { 
         $ratio = $desiredAmount / $originalTotalAmount; 
     } 
     // capture amounts without tax 
     // Note: ($x > $y - 0.0001) means ($x >= $y) for floats 
     if ($desiredAmount > $maxAllowedAmount - 0.0001) { 
         $shippingAmount = $allowedAmount; 
         $baseShippingAmount = $baseAllowedAmount; 
     } else { 
         $shippingAmount = $this->priceCurrency->round($orderShippingAmount * $ratio); 
         $baseShippingAmount = $this->priceCurrency->round($orderBaseShippingAmount * $ratio); 
     } 
     $shippingInclTax = $this->priceCurrency->round($orderShippingInclTax * $ratio); 
     $baseShippingInclTax = $this->priceCurrency->round($orderBaseShippingInclTax * $ratio); 

This doesn't fix the underlaying issue that I did not identified yet. But that will prevent the exception to be thrown without damaging creditmemo data.