fix(ui5-date-picker): LocaleData._getDeep crash causes all DatePicker Cypress tests to fail in CI

[nnaydenow]

Summary

All DatePicker Cypress tests are currently skipped via describe.skip in packages/main/cypress/specs/DatePicker.cy.tsx due to a recurring CI failure that is not reproducible locally.

Error

TypeError at LocaleData._getDeep (LocaleData.js:141)
  at LocaleData._get (LocaleData.js:95)
  at LocaleData.getFirstDayOfWeek (LocaleData.js:1299)
  at DayPicker._getFirstDayOfWeek (DayPicker.ts:704)
  at DayPicker._buildWeeks (DayPicker.ts:90)
  at DayPicker.onBeforeRendering (DayPicker.ts:77)
  at DayPicker._render (UI5Element.ts:638)
  at renderImmediately (Render.ts:24)
  at DayPicker.connectedCallback (UI5Element.ts:198)

Root Cause Hypothesis

CLDR locale data may not be fully loaded/resolved when DayPicker.onBeforeRendering runs during Cypress test setup, causing _getDeep to walk into an undefined path.

Steps to Fix

• Investigate locale data initialization timing in the Cypress test environment
• Ensure CLDR data for the active locale is available before the first render of DayPicker
• Remove describe.skip in packages/main/cypress/specs/DatePicker.cy.tsx once fixed and verify all tests pass in CI

Related

Skipped in: packages/main/cypress/specs/DatePicker.cy.tsx (branch skip-flaky-tests)

[kgogov]

Hello @UI5/ui5-team-ctr-bal, please take a look at this.

DatePicker Cypress tests crash in CI with LocaleData._getDeep TypeError on DayPicker's first render — looks like a CLDR locale-timing race. I ran the full spec locally on main and all 87 tests pass, so this reproduces only in CI (consistent with a setup/timing race).

Regards,
Konstantin Gogov