fix: sequence from_chars pointer advances in to_time_point#17
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from_chars(++p, p+N, ...) unsequenced the increment with the end-pointer read, which is undefined behavior and silently parsed the wrong digits on common compilers (e.g. month from one character). Advance p between calls so ISO-8601 round-trips stay exact. Co-authored-by: Kaius Ruokonen <ruoka@users.noreply.github.com>
Default ostream precision (6 significant digits) silently corrupted JSON number_type values on stringify/parse (e.g. 123456789.123… became 123457000). Emit max_digits10 via to_chars and reject non-finite values. Co-authored-by: Kaius Ruokonen <ruoka@users.noreply.github.com>
Lengths other than YYYY-MM-DD / YYYY-MM-DDTHH:MM:SS.sssZ used to parse the date only and silently drop a present time (e.g. …T12:00:00Z → midnight). Failed from_chars left zero fields and built unspecified dates. Require exact forms, separators, full-width digits, and valid ranges. Co-authored-by: Kaius Ruokonen <ruoka@users.noreply.github.com>
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* fix: sequence from_chars pointer advances in to_time_point from_chars(++p, p+N, ...) unsequenced the increment with the end-pointer read, which is undefined behavior and silently parsed the wrong digits on common compilers (e.g. month from one character). Advance p between calls so ISO-8601 round-trips stay exact. Co-authored-by: Kaius Ruokonen <ruoka@users.noreply.github.com> * fix: stringify doubles with max_digits10 precision Default ostream precision (6 significant digits) silently corrupted JSON number_type values on stringify/parse (e.g. 123456789.123… became 123457000). Emit max_digits10 via to_chars and reject non-finite values. Co-authored-by: Kaius Ruokonen <ruoka@users.noreply.github.com> * fix: reject truncated/corrupt ISO-8601 in to_time_point Lengths other than YYYY-MM-DD / YYYY-MM-DDTHH:MM:SS.sssZ used to parse the date only and silently drop a present time (e.g. …T12:00:00Z → midnight). Failed from_chars left zero fields and built unspecified dates. Require exact forms, separators, full-width digits, and valid ranges. Co-authored-by: Kaius Ruokonen <ruoka@users.noreply.github.com> --------- Co-authored-by: Cursor Agent <cursoragent@cursor.com> Co-authored-by: Kaius Ruokonen <ruoka@users.noreply.github.com>
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Summary
xson::to_time_pointusedstd::from_chars(++p, p+N, ...), which unsequences a write and read ofp(undefined behavior). On common right-to-left evaluation (e.g. g++), that silently parsed the wrong digit spans so every valid ISO-8601 string could decode to the wrongtime_point.Trigger
xson::to_time_point("1970-01-01T00:00:00.000Z")should be epoch (0 ms); on g++ it returned a far-from-epoch value. Same for pre-epoch and modern dates.Fix
Advance
pbetweenfrom_charscalls; returntimestamp_type; add round-trip and known-value regression tests.Test plan
./tools/CB.sh debug test --tags='\[xson\]'— 415/415 passed