feat: persist user input values when selected payment method is changed

[Shivam25092001]

Type of Change.

• Bugfix
• New feature
• Enhancement
• Refactoring
• Dependency updates
• Documentation
• CI/CD

Description

Persists user-entered dynamic field values when the selected payment method type changes, so a shopper who types into shared fields (name, email, phone, address, etc.) doesn't lose that input after switching payment methods.

Why this happens:

In PaymentElement.res the payment-method subtree is rendered under <ErrorBoundary key={selectedOption} ...>. Switching the payment method type changes the key and remounts the whole subtree (DynamicFields → ReactFinalForm.Form), destroying all form state. Previously only Country survived, because it round-trips through the persistent userCountry atom.

Changes:

• New Recoil atom userDynamicFieldsValues : Dict.t<string> in RecoilAtoms.res, keyed by confirmRequestWritePath. It lives above the remount boundary, so its contents survive the payment-method switch.
• Persist on change — in FormBody's onFormChange, the typed values of persistable fields are written into the atom every time the form updates.
• Restore on remount — a new initialValuesWithUserInputOverride memo seeds the form's initialValues from the cached atom (layered on top of the existing billing-details override), and the ReactFinalForm.Form now consumes this override.
• New persistableFields set — the fields whose values we persist. Unlike missingRequiredFieldsFiltered (which dedups Email/CardHolderName down to the single visible input), this keeps both name paths (first_name + last_name) and every email path, since the combined name/email inputs write all of them into RFF. It excludes self-managed fields (Country / PhoneCountryCode), which own their value outside RFF and are seeded through their own atom/local-state path.
• Refactor — extracted the shared "does this field render a visible input?" logic out of the missingRequiredFieldsFiltered filter into a single rendersVisibleInput helper, reused by both missingRequiredFieldsFiltered and persistableFields.

No change to the '/confirm' payload shape — seeding stays restricted to the current payment method's rendered fields.

How did you test it?

Manually verified in the SDK: entered values into shared dynamic fields (name / email / phone / address), switched between payment method types, and confirmed the previously typed values are restored on the re-rendered form instead of being wiped.

Screen.Recording.2026-08-06.at.6.18.32.PM.mov

Checklist

• I ran npm run re:build
• I reviewed submitted code
• I added unit tests for my changes where possible

[semanticdiff-com]

Review changes with  

[XyneSpaces]

[should-fix] Recompute initialValuesWithUserInputOverride when the persisted dynamic-field cache or persistableFields changes. With the current dependency list, updates to userDynamicFieldsValues can re-render this component but keep the memoized initial values stale, so a payment-method switch can still remount the form without the latest typed values.

  }, [initialValuesWithBillingDataOverride, cachedUserDynamicFieldsValues, persistableFields])