Leave UI Validation and Error Messages

Summary

Client validation is limited and differs between ESS and the broader compatibility UI; server validation remains authoritative.

Employees, administrators, QA, support, and developers.

Area	Confirmed UI behavior	Maturity
Missing tenant	Protected/client request context blocks or redirects some cases; exact API feedback varies	Transitional
Missing/inactive employee	Broader form requires selection; server rules are authoritative	Partial
Date order	ESS toast and broader conflict text reject reversed dates	Implemented
Before joining date	Broader UI blocks using loaded joining date	Implemented
Zero calculated days	No client preview/check; server validation	Not implemented in UI
Attendance conflict	Broader UI shows confirmed conflict/check-failure text	Implemented in legacy UI
Approved overlap	Broader UI shows confirmed overlap text	Implemented in legacy UI
Invalid Leave type	No general client validation; server validation	Requires confirmation
Missing balance	Informational empty-account message; creation is not universally blocked	Transitional
Invalid transition	Client hides some actions; API remains authoritative	Transitional
Rejection reason	Modal requests a reason; client does not prove non-empty enforcement	Partial
Workflow restriction	No visible workflow-aware client state	Not implemented
Cancellation restriction	Client permits self-owned Pending cancellation only	Implemented in legacy UI
Network/server failure	Broader page errors; ESS query/submit presentation has gaps	Partial
Permission denied	ProtectedRoute renders Unauthorized; ESS maps query 403 but Leave page omits that error prop	Partial

Exact messages are documented only where they are literal source text. Do not treat client messages as stable API contracts.