FA-18220 / Time representation / Member archive

Timestamp migration treats legacy milliseconds as seconds or reverses fractional part · case 05

The decoded time state disagrees with the explicit regression oracle for nanoseconds.

Member previewVariant 5 · 3 implementations · 15 checks per implementation

Case contract

Controlled timestamp migration from version 1 milliseconds or version 2 split seconds/nanos into exact nanoseconds. A separate presence bit distinguishes missing from epoch zero. Version 2 fraction must be 0..999999999; timezone offsets are forbidden because payload is already UTC. Preserve uncertainty in matching units and emit canonical seconds/remainder with precision and provenance. Negative uncertainty is invalid; zero means exact.

Why this case matters

Clock transfer and timestamp consumers require preserved coordinate, phase, validity and elapsed-time semantics.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
fixture 3	`["ok", [1234, 0, 3000000, 1000000]]`	`["ok", [1, 234000000, 3000000, 1000000]]`	Failed

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

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