fix(checkout): guard billing_zip_code v-if against undefined uses_postal_code

[superdav42]

Summary

The billing_zip_code checkout field's Vue v-if expression references uses_postal_code without a guard. When older or minified checkout bundles render before the Vue data key has been registered, the expression throws a ReferenceError and the entire checkout form fails to render.

This change wraps the symbol with typeof X === 'undefined' so the form falls back to showing the ZIP field instead of crashing.

The bug

inc/checkout/signup-fields/class-signup-field-billing-address.php:355 (before):

$field['wrapper_html_attr']['v-if'] = "(order === false || order.should_collect_payment) && !($self_billing_gateways) && uses_postal_code";

If the Vue instance attempts to evaluate this expression before uses_postal_code has been registered as a data key, Vue throws ReferenceError: uses_postal_code is not defined and the surrounding <div v-if> collapses — taking the entire billing block with it on some renderings.

The fix

$field['wrapper_html_attr']['v-if'] = "(order === false || order.should_collect_payment) && !($self_billing_gateways) && (typeof uses_postal_code === 'undefined' || uses_postal_code)";

Defaulting to visible when the symbol is undefined is the safe choice:

• The ZIP field still validates and submits correctly.
• The symbol becomes defined on subsequent re-renders (data registration is eventual).
• Countries that genuinely don't use postal codes (Hong Kong, UAE, Angola — see Country_Default) hide the field once uses_postal_code is defined and falsy, so the previous behaviour is preserved in steady state.

The alternative — defaulting to hidden when undefined — would prevent users from filling in the ZIP at all on the first render, which is a worse failure mode than showing a field that may not strictly be required.

Test

Adds test_zip_visibility_guards_uses_postal_code_symbol to tests/WP_Ultimo/Checkout/Signup_Fields/Signup_Field_Billing_Address_Test.php:

public function test_zip_visibility_guards_uses_postal_code_symbol(): void {
    $fields = $this->field->to_fields_array(
        array(
            'id'              => 'billing_address',
            'zip_and_country' => true,
            'element_classes' => '',
        )
    );

    $this->assertArrayHasKey( 'billing_zip_code', $fields );
    $this->assertArrayHasKey( 'v-if', $fields['billing_zip_code']['wrapper_html_attr'] );
    $this->assertStringContainsString( "typeof uses_postal_code === 'undefined'", $fields['billing_zip_code']['wrapper_html_attr']['v-if'] );
}

This asserts the guard is present in the generated wrapper attribute so future refactors don't quietly drop it.

Verification

• vendor/bin/phpcs --standard=.phpcs.xml.dist <both files> → clean (0 errors, 0 warnings).
• vendor/bin/phpstan analyse <both files> → clean (No errors).
• vendor/bin/phpunit --filter test_zip_visibility_guards_uses_postal_code_symbol … → OK (1 test, 3 assertions).

Scope

Pure defensive guard against a JS runtime error. No behaviour change in steady state. No new dependencies, no schema change, no migration.

Files touched:

• inc/checkout/signup-fields/class-signup-field-billing-address.php — 1 line changed (the v-if string), 3 lines added (docblock explanation).
• tests/WP_Ultimo/Checkout/Signup_Fields/Signup_Field_Billing_Address_Test.php — 1 new test method (19 lines including docblock and arrange/act/assert).

Total: +23 / −1.

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Summary by CodeRabbit

Release Notes

• Bug Fixes

  • Enhanced stability of the billing zip code field in checkout by adding protective guards to the visibility logic, ensuring compatibility with older or minified checkout bundles and preventing potential rendering errors.

• Tests

  • Added regression test to verify the billing zip code field visibility guard functions correctly across different bundle versions and configurations.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 24c1db9a-6a76-48ee-b660-29cc511e3159

📥 Commits

Reviewing files that changed from the base of the PR and between f1b5ab6 and 0e96172.

📒 Files selected for processing (2)

• inc/checkout/signup-fields/class-signup-field-billing-address.php
• tests/WP_Ultimo/Checkout/Signup_Fields/Signup_Field_Billing_Address_Test.php

---

📝 Walkthrough

Walkthrough

The PR adds a safety guard to prevent ReferenceError when the uses_postal_code Vue data key is unavailable in older checkout bundles. The billing_zip_code field's v-if condition now checks typeof uses_postal_code === 'undefined' before evaluating the symbol, with a corresponding regression test validating the guard's presence.

Changes

Billing Zip Code Visibility Guard

Layer / File(s)	Summary
Vue v-if safety guard for postal code availability inc/checkout/signup-fields/class-signup-field-billing-address.php, tests/WP_Ultimo/Checkout/Signup_Fields/Signup_Field_Billing_Address_Test.php	The billing_zip_code field's v-if expression is updated to wrap uses_postal_code with a typeof guard, and a new regression test verifies the guard is correctly generated in the wrapper's html attributes.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Suggested labels

review-feedback-scanned, origin:worker

Poem

🐰 A guard on the postal key so bright,
Checks if it exists before the sight,
No more errors in bundles of old,
Vue renders safely, as planned is told! 📮

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The pull request title accurately and specifically describes the main change: adding a guard against undefined uses_postal_code in the billing_zip_code v-if condition.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/checkout-zip-uses-postal-code-guard

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[github-actions]

🔨 Build Complete - Ready for Testing!

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[github-actions]

🔨 Build Complete - Ready for Testing!

📦 Download Build Artifact (Recommended)

Download the zip build, upload to WordPress and test:

• Build: ultimate-multisite
• ⬇️ Download from GitHub Actions
• ⬇️ Download without Github Account (nightly.link)

🌐 Test in WordPress Playground (Very Experimental)

Click the link below to instantly test this PR in your browser - no installation needed!
Playground support for multisite is very limitied, hopefully it will get better in the future.

🚀 Launch in Playground

Login credentials: admin / password

[github-actions]

🔨 Build Complete - Ready for Testing!

📦 Download Build Artifact (Recommended)

Download the zip build, upload to WordPress and test:

• Build: ultimate-multisite
• ⬇️ Download from GitHub Actions
• ⬇️ Download without Github Account (nightly.link)

🌐 Test in WordPress Playground (Very Experimental)

Click the link below to instantly test this PR in your browser - no installation needed!
Playground support for multisite is very limitied, hopefully it will get better in the future.

🚀 Launch in Playground

Login credentials: admin / password