MPDX-9650 - Improve validation in Savings Fund Transfer

[zweatshirt]

Description

• Ensures the start and end date can't be the same date, since SAA has validation that raises in error for this case.
• Adds information text for the recurring end date
  https://jira.cru.org/browse/MPDX-9580

Testing

• Go to SavingsFundTransfer
• Ensure that the user cannot set the start date and the end date to be the same date.

Checklist:

• I have given my PR a title with the format "MPDX-(JIRA#) (summary sentence max 80 chars)"
• I have applied the appropriate labels (Add the label "Preview" to automatically create a preview environment)
• I have run the Claude Code /pr-review command locally and fixed any relevant suggestions
• I have requested a review from another person on the project
• I have tested my changes in preview or in staging
• I have cleaned up my commit history

[github-actions]

Bundle sizes [mpdx-react]

Compared against 8544dce

No significant changes found

[zweatshirt]

🤖 Multi-Agent Code Review — Verdict: ✅ CLEAN

Mode: standard · Risk: 1/10 (LOW) · Blockers: 0

Agents run: Architecture, UX/a11y, Financial (domain). Testing + Standards were verified inline (their key concerns are addressed below). This is a small, focused change — end-date validation now requires the end date to be strictly at least one calendar day after the transfer date (day-granular Luxon comparison), plus a permanent descriptive helper text on the End Date field, with 4 colocated tests.

Findings

Only two severity-3 suggestions (informational — do not block merge). See the inline comment for the first; the second is below.

Verified — concerns from skipped agents

• Type safety: Dropping the as string cast on errors.endDate is correct and type-safe. Because endDate is DateTime<boolean> | null, Formik's FormikErrors mapped type resolves it to string | undefined (the | null defeats the extends object branch). The sibling transferDate (non-nullable) resolves to a FormikErrors<DateTime> object — which is exactly why line 478 still needs its cast. tsc --noEmit is clean.
• Tests using past dates: 12/01/2024 also fails the recurring start-date rule, but each new test asserts only the end-date error's presence/absence, which is independent and correct in isolation. Suite passes. Minor smell — future dates would read cleaner — but not a defect.

Findings on Related Files (Not on Changed Lines)

[Suggestion] TransferModal.tsx:478 — Cast asymmetry between sibling date fields

• Severity: 3.0/10 · Flagged by: Architecture
• The End Date helper (this PR) now passes errors.endDate directly, while the adjacent Transfer Date helper at line 478 still uses (errors.transferDate as string). The new pattern is the better one; line 478 is the outlier and is out of scope here. Consider dropping that cast if the line is touched in a future PR.

Domain note (non-blocking, pre-existing)

The submit path sends recurringStart/recurringEnd as full toISO() timestamps with a local offset, while validation compares at day granularity. Not reachable as a bug here (both fields are local-midnight date-only values), but worth a one-line confirmation with the API team that the backend treats these as calendar dates, not raw UTC instants — to avoid a boundary day-shift. This concerns the pre-existing toISO() submission, not the lines this PR adds.

[zweatshirt]

[Suggestion] The `touched.endDate && errors.endDate ? errors.endDate : t(...)` expression is correct but slightly over-conditioned — the leading `touched.endDate &&` only gates the error branch, while the default helper text always renders in the false branch. Behavior is verified correct across all touched/error states, so this is optional polish, not a fix.

[github-actions]

AI Review Auto-Approval

Risk Level: LOW (1/10)
Verdict: CLEAN (no issues found)

This PR was auto-approved because:

• The multi-agent AI review determined it is low risk
• No blocking issues were found

If you believe this PR needs human review, dismiss this approval and request a review manually.

[github-actions]

Preview branch generated at https://MPDX-9650.d3dytjb8adxkk5.amplifyapp.com