* Use chrono for UTC/calendar conversion instead of hand-rolled copies
Replaces the hand-rolled civil_from_days / days_from_civil copies and the
is_leap / days_in_month calendar helpers with chrono as a workspace dependency
(default-features = false, std only, so wasm is unaffected). The spreadsheet
serial-date semantics are untouched: Excel's 1900 fictitious leap day (serial
60 = 1900-02-29), the 1899-12-30 / 1904-01-01 serial offsets, Excel's weekday
numbering and the 1900/1904 systems keep their explicit special cases in
serial_from_ymd / datetime_from_serial / days_in_month_in. chrono only backs
the plain proleptic-Gregorian day-number <-> date conversion and the
leap-year / month-length helpers those build on; a small fallback keeps the old
answer for dates outside chrono's NaiveDate range. The duplicate local is_leap
in the financial functions now uses the core one. Output is byte-identical and
pinned by the existing date, parse, financial and logging tests. AGENTS.md now
says time goes through chrono.
Follow-up to storytold/cadcraft#1785
* Never panic on out-of-range clocks or years; keep calendar results outside chrono's range
- logging::timestamp: chrono's From<SystemTime> unwraps, so a clock past year
262143 panicked inside the logger. Use the fallible DateTime::from_timestamp
and read such a clock as the epoch, like the old saturating code. Years past
9999 are written with {:04} (not %Y, which prefixes a '+').
- date::is_leap: restore the Gregorian leap-year rule for years outside chrono's
NaiveDate range (e.g. is_leap(400000) is true again) via direct arithmetic.
- date::days_in_month: compute the December boundary with checked_add so
days_in_month(i32::MAX, 12) no longer overflows, and compute month lengths
through days_from_civil's fallback so out-of-range years keep their real
lengths (e.g. days_in_month(400000, 2) is 29). Invalid months still return 0.
- civil_from_days: add missing docstring.
- AGENTS.md: note the narrow out-of-range fallback exception to the chrono rule.
* Don't build an unrepresentable SystemTime in the far-future test
UNIX_EPOCH + Duration::from_secs(u64::MAX / 2) overflows Windows'
SystemTime and panicked before timestamp() ran, failing the Windows
test job. Build it with checked_add and only assert where it exists.
* Route out-of-range dates through chrono's 400-year cycle, not hand-rolled copies
The PR kept hand-rolled Hinnant `days_from_civil_fallback`/`civil_from_days_fallback`
copies for dates outside chrono's ±262143-year range, plus a hand-rolled
Gregorian leap rule in `is_leap` and an i32::MAX special-case in `days_in_month`.
AGENTS.md carved a "narrow fallback" exception for them, which left calendar
arithmetic outside chrono after all.
Replace all of it with the Gregorian 400-year cycle (146_097 days): chrono
converts the day/year within one cycle and whole cycles are added back via i128
(so the i32/i64 extremes can't overflow). `is_leap` and `days_in_month` reduce
the year with `rem_euclid(400)` (leap years and month lengths repeat every 400
years), which also removes the December `i32::MAX` overflow special-case.
chrono is now the only calendar logic, and every output is unchanged: verified
the cycle result equals the old formula over wide ranges and at the i32/i64
extremes with a scratch chrono program. The Excel 1900 leap bug (serial 60 =
fictitious 1900-02-29) and 1904 semantics are untouched -- `serial_from_ymd`/
`datetime_from_serial` only ever hand the converters in-range years, so their
serials are byte-for-byte the pre-chrono ones (pinned by a new test).
New tests pin `days_from_civil`/`civil_from_days` past chrono's range on both
sides of the epoch, round-tripping, with values from the old formula; the
existing leap/month-length-beyond-range test still passes unchanged. Removed the
AGENTS.md "narrow fallback" exception.
Tested: cargo test -p gridcraft-core -p gridcraft-functions; fmt --check;
clippy --all-targets -D warnings.
* time: preserve out-of-range years in the log timestamp instead of the epoch
`DateTime::from_timestamp(..).unwrap_or_default()` changed the existing output: a
clock set far ahead (an input the old hand-rolled civil-from-days converted)
collapsed to `1970-01-01`. Restore the old conversion domain with a cycle-based
helper: reduce by whole 400-year Gregorian cycles (146_097 days), convert the
in-range remainder with chrono, and carry the year back as i128. Only the year
leaves chrono's range; month/day/time stay exact. Pre-1970 still clamps to the
epoch as before. chrono stays the only calendar logic (no new features).
apps/gridcraft logging.rs `timestamp` (SystemTime, u64 secs), pinned via a
platform-safe `UNIX_EPOCH.checked_add`:
u64::MAX/2 s → "292277026596-12-04T15:30:07.000Z" (was "1970-01-01..."),
10e12 s → "318857-05-20T17:46:40.000Z", 253_402_300_800 s → "10000-01-01...".
* Name the 400-year range extension as the one exception to the time rule
The rule said never to hand-roll calendar math, but the range fix
(shifting by whole 400-year Gregorian cycles so dates past chrono's year
range keep their old output) is cycle arithmetic, so the rule and the code
disagreed. The rule now names that exception: the library still computes
month, day and time, and only whole cycles are carried in the year.
* Say the library computes month and day; time-of-day is plain arithmetic
Narrows the range-extension wording: the date library computes the
calendar fields, and splitting seconds into hours, minutes and seconds
is ordinary arithmetic, which is what the code does.
serial_from_ymd worked out the real calendar date and then moved serials
up to 60 down by one. February 1900 has no 29th in the real calendar, so
DATE(1900,2,29) and DATEVALUE("2/29/1900") rolled over to 1 March (61),
and DATE(1900,3,0) gave 28 February (59). Excel's 1900 system keeps the
Lotus leap day: serial 60 is 29 February 1900, and DAY(60) already
said so.
The serial of the first of the month is now taken in Excel's calendar
(one lower up to February 1900), and the day, with any overflow, counts
on from there. So day and month overflow pass through serial 60 both
ways: DATE(1900,1,60), DATE(1900,4,-31) and DATE(1901,-10,29) are 60 too.
Month and day arithmetic is checked, so hostile values return None.
days_in_month_in gives February 1900 29 days in the 1900 system; EDATE
and EOMONTH use it, so EOMONTH(60,0) is 60 rather than the day before,
and the text parser uses it in place of its own special case. The 1904
system is unchanged (1900 is before its epoch).
Tests: serials around the leap day (overflow both ways, every serial
0-366 round-trips through its year, month and day), hostile months and
days, parsing 2/29/1900 and 1900-02-29, DATE/DATEVALUE/EDATE/EOMONTH
in the 1900 system and the 1904 system. The DATE, DATEVALUE and serial
cases fail before the fix.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Local clippy 1.96 flags pre-existing patterns the code has always had:
manual range-contains comparisons, a dead `|| true` filter and a
simplifiable boolean. None change behaviour; they only clear the lints
so `cargo xtask ci` passes on a current toolchain.
- ui-egui: title bar with QAT, full ribbon (Home/Insert/Draw/Page Layout/Formulas/Data/
Review/View/Automate + Table/Chart Design), formula bar with Name Box, virtualised grid
(frozen panes, overflow, borders, CF data bars/scales/icons, tables, sparklines, filter
buttons, charts/pictures/shapes), in-cell editor with point mode, reference colouring,
autocomplete and argument hints, sheet tabs, status bar, dialogs, control channel
- apps/sheetcraft: desktop app (control server, file dialogs, prefs, drag & drop)
- chart: toolkit-free chart layout/rendering for 25 chart kinds + sparklines + rasteriser
- mcp + sheetcraft-cli: MCP server (headless or bridged) and CLI (info/convert/eval/cat/run/mcp)
- xtask (ci/layers/assets/wasm/version/parity), release workflows, packaging, placeholder icon
- automatic row heights
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
