Discard subsequent rules for shipping amount

[aleneapen]

Preconditions and environment

• Magento version: 2.4.x
• Anything else that would help a developer reproduce the bug:

Steps to reproduce

1. Create the first cart price rule:
   Rule Information:
   Active: Yes
   Coupon: Specific Coupon
   Coupon Code: 50OFF
   Priority: 0
   Condition: None
   Actions
   Apply: Percent of product price discount
   Discount Amount: 50%
   Maximum Qty Discount is Applied To: 0
   Discount Qty Step (Buy X): 0
   Apply to Shipping Amount: No
   Discard subsequent rules: Yes

2. Create the second cart price rule
   Rule Information:
   Active: Yes
   Coupon: No Coupon
   Priority: 1
   Condition:
   If trial SKU is in cart
   Actions
   Apply: Percent of product price discount
   Discount Amount: 100%
   Maximum Qty Discount is Applied To: 1
   Discount Qty Step (Buy X): 0
   Apply to Shipping Amount: Yes
   Discard subsequent rules: Yes

3. Add to cart 2 products: first product = trial SKU, second product = non-trial SKU.
   The second rule applies
   Trial SKU price: $20
   Non-trial SKU price: $100
   Shipping: $10
   Subtotal: $130
   Discount: -$30.00

4. Apply Discount Code: 50OFF
   The first rule is applied correctly but the second rule's shipping discount is applied incorrectly
   Trial SKU price: $20
   Non-trial SKU price: $100
   Shipping: $10
   Subtotal: $130
   Discount: -$70

Expected result

Discount in step 4 should be $60

Actual result

Discount in step 4 is incorrect: $70

Additional information

This seems to be a problem in Magento\SalesRule\Model\Validator::processShippingAmount

Changing lines 334

    foreach ($this->getRules($address) as $rule) {
        /* @var Rule $rule */
        if (!$rule->getApplyToShipping() || !$this->validatorUtility->canProcessRule($rule, $address)) {
            continue;
        }

to

    foreach ($this->getRules($address) as $rule) {
        /* @var Rule $rule */
        if (!$rule->getApplyToShipping()) {
            if ($rule->getStopRulesProcessing()) {
                break;
            }
            continue;
        }
        
        if (!$this->validatorUtility->canProcessRule($rule, $address)) {
            continue;
        }

seems to fix the issue.

Release note

Discard subsequent cart price rules for shipping amount discounts

Triage and priority

• Severity: S0 - Affects critical data or functionality and leaves users without workaround.
• Severity: S2 - Affects non-critical data or functionality and forces users to employ a workaround.
• Severity: S1 - Affects 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 @aleneapen. 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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[aleneapen]

@magento give me 2.4-develop instance

[magento-deployment-service]

Hi @aleneapen. Thank you for your request. I'm working on Magento instance for you.

[magento-deployment-service]

Hi @aleneapen, here is your Magento Instance: https://f8fd22f80ea4faaa323e4d586df0fa8c.instances-prod.magento-community.engineering
Admin access: https://f8fd22f80ea4faaa323e4d586df0fa8c.instances-prod.magento-community.engineering/admin_fdb3
Login: 8e65dffe
Password: 68751eaaf747

[engcom-Bravo]

@magento give me 2.4-develop instance

[magento-deployment-service]

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

[magento-deployment-service]

Hi @engcom-Bravo, here is your Magento Instance: https://f8fd22f80ea4faaa323e4d586df0fa8c.instances-prod.magento-community.engineering
Admin access: https://f8fd22f80ea4faaa323e4d586df0fa8c.instances-prod.magento-community.engineering/admin_53ef
Login: 301ba636
Password: 20786fa664a5

[engcom-Bravo]

Hi @aleneapen,

Thank you for reporting and collaboration.

Verified the issue on Magento 2.4-develop instance and the issue is not reproducible.Kindly refer the screenshots.

Steps to reproduce

Create the first cart price rule:
Rule Information:
Active: Yes
Coupon: Specific Coupon
Coupon Code: 50OFF
Priority: 0
Condition: None
Actions
Apply: Percent of product price discount
Discount Amount: 50%
Maximum Qty Discount is Applied To: 0
Discount Qty Step (Buy X): 0
Apply to Shipping Amount: No
Discard subsequent rules: Yes

Create the second cart price rule
Rule Information:
Active: Yes
Coupon: No Coupon
Priority: 1
Condition:
If trial SKU is in cart
Actions
Apply: Percent of product price discount
Discount Amount: 100%
Maximum Qty Discount is Applied To: 1
Discount Qty Step (Buy X): 0
Apply to Shipping Amount: Yes
Discard subsequent rules: Yes

Add to cart 2 products: first product = trial SKU, second product = non-trial SKU.
The second rule applies
Trial SKU price: $20
Non-trial SKU price: $100
Shipping: $10
Subtotal: $130
Discount: -$30.00

It is working fine here.

Apply Discount Code: 50OFF
The first rule is applied correctly but the second rule's shipping discount is applied incorrectly
Trial SKU price: $20
Non-trial SKU price: $100
Shipping: $10
Subtotal: $130
Discount: -$70

Here discount $70 is getting applied Could you please elaborate how discount should be $60.

Thanks.

[aleneapen]

Hi @engcom-Bravo,
here is my thinking:
the discount should be $60 because the second rule shipping discount shouldn't apply.

Since the first rule had priority = 0 and Discard subsequent rules: Yes, and Apply to shipping Amount = No
so the second rule shouldn't apply.

Is that the intended behaviour?