FA-61977 / Currency rounding and FX conversion / Member archive

A rate exactly at the maximum age is declared stale · case 02

A tick exactly max_age old is rejected.

Member previewVariant 2 · 3 implementations · 8 checks per implementation

Case contract

solve(ticks, trade_ts, max_age): ticks is the published rate feed [[ts, rate], ...] in publication order. Use the tick with the greatest ts <= trade_ts; among ticks with equal ts the later-published one is a correction and wins. No eligible tick returns 'ERR:no-rate'. If max_age is not None and trade_ts - ts > max_age the rate is 'ERR:stale' (max_age 0 accepts only a same-instant tick). Return [ts, rate].

Why this case matters

Currency amounts must be rounded at the right stage and in the right unit, or ledgers, quotes and settlements drift by minor units.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression staleness-boundary 1	`"ERR:stale"`	`[3, "1.1605"]`	Failed

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