[medusa-os-bot]

Summary

What — The Payment Module now works out a currency's rounding precision without depending on the server's locale. This fixes rounding for zero-decimal currencies and for servers running under locales that use a comma as the decimal separator.

Why — roundToCurrencyPrecision counted decimals by formatting a number with Intl.NumberFormat in the default locale and splitting the result on ".". That breaks in two cases:

• For JPY (and other zero-decimal currencies) there is no "." at all.
• Under locales like de-DE the separator is ",".

In both cases the split threw, the catch kept full precision, and capture checks compared unrounded amounts. Valid captures were then rejected with "You cannot capture more than the authorized amount...", and full-capture detection was also affected. Only servers running en-US-style locales with two-decimal currencies worked.

How — packages/modules/payment/src/services/payment-module.ts:177 now reads resolvedOptions().maximumFractionDigits from the formatter. That value comes from the currency's data, not the formatted string, so it doesn't depend on the locale. It gives 0 for JPY and 2 for EUR/USD under every locale. Unknown currencies still throw and keep full precision, as before.

Testing — I added two tests to packages/modules/payment/integration-tests/__tests__/services/payment-module/index.spec.ts:

• capturing 2000 JPY against an authorization of 1999.6 JPY
• capturing 200.13 EUR against an authorization of 200.129 EUR with Intl.NumberFormat forced to de-DE

Both failed before the fix with the "cannot capture more than the authorized amount" error, and both pass after it. The full spec (68 tests) and the package unit tests pass.

---

Checklist

• I have added a changeset for this PR
• The changes are covered by relevant tests
• I have verified the code works as intended locally
• I have linked the related issue(s) if applicable

---

Additional Context

The module integration runner loads the payment module from dist, and the package couldn't be rebuilt in this environment. So I ran the spec against src by temporarily passing resolve: <package>/src to moduleIntegrationTestRunner, then removed that change. CI builds before running integration tests, so the committed spec doesn't need it.

Fixes #16974

Opened automatically by the Fix Bug workflow. Review carefully before merging.

[changeset-bot]

🦋 Changeset detected

Latest commit: 41552a3

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 83 packages

Name	Type
@medusajs/payment	Patch
@medusajs/medusa	Patch
@medusajs/test-utils	Patch
@medusajs/loyalty-plugin	Patch
@medusajs/medusa-oas-cli	Patch
integration-tests-http	Patch
@medusajs/analytics	Patch
@medusajs/api-key	Patch
@medusajs/auth	Patch
@medusajs/caching	Patch
@medusajs/cart	Patch
@medusajs/currency	Patch
@medusajs/customer	Patch
@medusajs/file	Patch
@medusajs/fulfillment	Patch
@medusajs/index	Patch
@medusajs/inventory	Patch
@medusajs/link-modules	Patch
@medusajs/locking	Patch
@medusajs/notification	Patch
@medusajs/order	Patch
@medusajs/pricing	Patch
@medusajs/product	Patch
@medusajs/promotion	Patch
@medusajs/rbac	Patch
@medusajs/region	Patch
@medusajs/sales-channel	Patch
@medusajs/search	Patch
@medusajs/settings	Patch
@medusajs/stock-location	Patch
@medusajs/store	Patch
@medusajs/tax	Patch
@medusajs/translation	Patch
@medusajs/user	Patch
@medusajs/workflow-engine-inmemory	Patch
@medusajs/workflow-engine-redis	Patch
@medusajs/search-postgres	Patch
@medusajs/draft-order	Patch
@medusajs/oas-github-ci	Patch
@medusajs/cache-inmemory	Patch
@medusajs/cache-redis	Patch
@medusajs/event-bus-local	Patch
@medusajs/event-bus-redis	Patch
@medusajs/analytics-local	Patch
@medusajs/analytics-posthog	Patch
@medusajs/auth-emailpass	Patch
@medusajs/auth-github	Patch
@medusajs/auth-google	Patch
@medusajs/auth-oidc	Patch
@medusajs/caching-redis	Patch
@medusajs/file-local	Patch
@medusajs/file-s3	Patch
@medusajs/fulfillment-manual	Patch
@medusajs/locking-postgres	Patch
@medusajs/locking-redis	Patch
@medusajs/notification-local	Patch
@medusajs/notification-sendgrid	Patch
@medusajs/payment-stripe	Patch
@medusajs/core-flows	Patch
@medusajs/framework	Patch
@medusajs/instantsearch-adapter	Patch
@medusajs/js-sdk	Patch
@medusajs/modules-sdk	Patch
@medusajs/orchestration	Patch
@medusajs/query	Patch
@medusajs/types	Patch
@medusajs/utils	Patch
@medusajs/workflows-sdk	Patch
create-medusa-app	Patch
@medusajs/http-types-generator	Patch
@medusajs/cli	Patch
@medusajs/deps	Patch
@medusajs/eslint-plugin	Patch
@medusajs/telemetry	Patch
@medusajs/admin-bundler	Patch
@medusajs/admin-sdk	Patch
@medusajs/admin-shared	Patch
@medusajs/admin-vite-plugin	Patch
@medusajs/dashboard	Patch
@medusajs/icons	Patch
@medusajs/toolbox	Patch
@medusajs/ui-preset	Patch
@medusajs/ui	Patch

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[medusa-os-bot]

Thanks for the contribution! Initial automated review looks good.

Verdict: Looks good for initial approval.

Replaces the locale-dependent Intl.NumberFormat.format().split(".") approach in roundToCurrencyPrecision with resolvedOptions().maximumFractionDigits, which reads each currency's decimal count directly from the JS engine — correctly handling zero-decimal currencies (JPY) and servers running non-en locales.

Checked: security (no user-controlled input in the changed path), performance (no query or loop changes), correctness, conventions, changeset (patch bump, correct format), tests (two integration tests covering JPY and the de-DE locale mock).

Triggered by: new PR opened

[medusa-os-bot]

Thanks for the contribution! Initial automated review looks good.

Verdict: Looks good for a final review by the team.

Replaces the locale-sensitive Intl.NumberFormat.format().split(".") pattern in roundToCurrencyPrecision with resolvedOptions().maximumFractionDigits, which reads each currency's decimal count from the ICU data regardless of server locale. This correctly returns 0 for JPY and 2 for EUR/USD under every locale, fixing failed captures for zero-decimal currencies and non-en servers.

Checked: security (no user-controlled input in this path), performance (synchronous calculation, no query changes), correctness, conventions, changeset (patch bump for @medusajs/payment), tests (unit tests across 4 locales × 4 currencies; 4 integration tests covering JPY and de-DE locale mocking).

Triggered by: new commit pushed