FA-299 / Time representation / Member archive

Truncating a negative epoch fraction selects the next second · case 04

An instant just before the Unix epoch is assigned to second zero, or rounding moves a positive fraction into a later second.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

Convert an integer count of milliseconds since the Unix epoch to the integer second s satisfying 1000*s <= milliseconds < 1000*(s+1). Do not round to the nearest second and do not pass through floating point.

Why this case matters

Pre-epoch timestamps and high-magnitude archival timestamps reveal a distinction hidden by common positive, whole-second fixtures.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
negative fractional second	`-4`	`-5`	Failed

MEMBER ARCHIVE

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This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

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