chore: post-1.0 upstream reproducibility audit backlog

[sokaluis]

Summary

After publishing @cyberlz/react-date-range@1.0.0, we audited upstream PRs/issues against the current fork codebase to avoid assuming old upstream bugs still reproduce after the modernization work.

This issue tracks the post-1.0 reproducibility classification:

• Reproducible bug → candidate for 1.0.1+
• Verified resolved / not reproducible → no immediate action
• Nice-to-have / feature → backlog only, requires separate proposal or design decision

Related index issue: #1

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Reproducible bugs in current code

Upstream	Classification	Current evidence	Recommended action
hypeserver/react-date-range#523	Reproducible bug	src/defaultRanges.js computes startOfWeek(new Date()) / endOfWeek(new Date()) at module load without weekStartsOn; DefinedRange static ranges therefore ignore runtime weekStartsOn.	Create 1.0.1 bugfix candidate. Refactor default ranges to accept week options or generate ranges from props.
hypeserver/react-date-range#353 / #504 / #575	Reproducible bug	src/utils.js::findNextRangeIndex(ranges, ...) calls ranges.findIndex(...) without guarding ranges; undefined, null, or non-array values crash.	High-priority low-risk fix. Add Array.isArray(ranges) guard and regression tests.
hypeserver/react-date-range#360 + hypeserver/react-date-range#402	Reproducible bug	src/components/DayCell/index.jsx marks days in range with `(!startDate

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Not reproducible / verified resolved

Upstream	Classification	Evidence
hypeserver/react-date-range#614	Not reproducible	No getAttribute calls exist in current src/ or dist/; keyboard navigation uses element.dataset.date.
hypeserver/react-date-range#454	Verified resolved	showMonthAndYearPickers?: boolean exists in src/index.d.ts; Calendar supports it; npm run type-check passes.
hypeserver/react-date-range#625	Verified resolved	Equivalent callback exists as onShownDateChange, typed and called in Calendar scroll/date navigation paths.
hypeserver/react-date-range#632	Verified resolved	Current scroll options are typed and implemented through virtualized scrolling config.
hypeserver/react-date-range#516	Verified resolved	Equivalent behavior exists as preventSnapRefocus, typed and implemented in Calendar focus logic.
hypeserver/react-date-range#443	Verified resolved	Disabled dates block interaction through Month → DayCell disabled propagation and DayCell.handleMouseEvent early return.
hypeserver/react-date-range#587	Not reproducible as reported	Current code uses startOfDay(endDate) in DayCell, not endOfDay; upstream report does not match current behavior. May still deserve a separate range-boundary semantics review later.

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Nice-to-have / requires proposal

Upstream	Classification	Notes
hypeserver/react-date-range#526	Nice-to-have accessibility	CSS suppresses focus outlines for nav/select/day controls without restoring visible focus rings. Keyboard behavior exists, but visual focus styling needs an a11y polish pass.
hypeserver/react-date-range#530	Needs investigation / feature	Current DefinedRange only gives color styling for selected static ranges. No explicit human-readable selected range label exists. Requires UX decision on placement/format.

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Proposed follow-up slices

1. 1.0.1 bugfix batch

   • findNextRangeIndex array guard (#353/#504/#575)
   • null range visual selection guard (#360/#402)
   • weekStartsOn propagation into DefinedRange static ranges (#523)

2. A11y polish backlog

   • visible focus rings for nav arrows, month/year selects, and day buttons (#526)

3. UX proposal backlog

   • selected range label behavior (#530)
   • optional separate review of single-day range boundary semantics (#587), because current behavior differs from the upstream report

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Verification performed during audit

• Current tests: 159 passing
• npm run type-check: passing
• npm run build: passing
• Source review of src/utils.js, src/defaultRanges.js, src/components/DayCell/index.jsx, src/components/Calendar/index.jsx, src/index.d.ts, and theme CSS