Fix bugs in algorithms ported from Howard Hinnant's date_algorithms#50
Merged
rockorager merged 1 commit intorockorager:mainfrom Nov 26, 2025
Merged
Fix bugs in algorithms ported from Howard Hinnant's date_algorithms#50rockorager merged 1 commit intorockorager:mainfrom
rockorager merged 1 commit intorockorager:mainfrom
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This PR fixes several issues in the Zig port of the algorithms from https://howardhinnant.github.io/date_algorithms.html.
The original C++ algorithms use workarounds for truncated division with negative numerators. These workarounds are unnecessary (actually incorrect) when porting to Zig using floored division. The added range assertions will trigger for negative
Daysor negative years, catching these cases.Similar issue affect
weekdayFromDayswhen called with negative Days values. The previous implementation also caused panics for allDays< -4 (except Saturdays).The errors in
civilFromDayswere previously masked because subsequent calculations compensated for them. I've added expectations in tests that trigger the new range assertions because of the lack of better tests possibilities in this case.