Fixed: Discard rule for Shipping amount

[aasim110]

Root Cause
In processShippingAmount(), the original code combined getApplyToShipping() and canProcessRule() in a single condition with continue. When a rule had applyToShipping=false and stopRulesProcessing=true, the method would continue to the next rule instead of breaking, allowing subsequent lower-priority rules to incorrectly apply their shipping discounts

The FIx
The fix splits the condition so that getStopRulesProcessing() is checked before continuing past a non-shipping rule:

Description (*)

Related Pull Requests

Fixed Issues (if relevant)

1. Fixes Discard subsequent rules for shipping amount #37985

Manual testing scenarios (*)

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

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

[m2-assistant]

Hi @aasim110. Thank you for your contribution!
Here are some useful tips on how you can test your changes using Magento test environment.
❗ Automated tests can be triggered manually with an appropriate comment:

• @magento run all tests - run or re-run all required tests against the PR changes
• @magento run <test-build(s)> - run or re-run specific test build(s)
  For example: @magento run Unit Tests

<test-build(s)> is a comma-separated list of build names.

Allowed build names are:

1. Database Compare
2. Functional Tests CE
3. Functional Tests EE
4. Functional Tests B2B
5. Integration Tests
6. Magento Health Index
7. Sample Data Tests CE
8. Sample Data Tests EE
9. Sample Data Tests B2B
10. Static Tests
11. Unit Tests
12. WebAPI Tests
13. Semantic Version Checker

You can find more information about the builds here
ℹ️ Run only required test builds during development. Run all test builds before sending your pull request for review.

---

For more details, review the Code Contributions documentation.
Join Magento Community Engineering Slack and ask your questions in #github channel.

[ct-prd-pr-scan]

The security team has been informed about this pull request due to the presence of risky security keywords. For security vulnerability reports, please visit Adobe's vulnerability disclosure program on HackerOne or email psirt@adobe.com.

[aasim110]

@magento run all tests

[aasim110]

@engcom-Bravo Could you review this as WebAPI Tests failures are not related to this PR

[aasim110]

@magento run WebAPI Tests