FA-60089 / Inventory cost layering / Member archive

First-expired-first-out lot picking: pick quantity cap · case 04

Whole lots are picked even when the order needs only part of the lot.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

Input {lots:[[lot,qty,expiry_day,unit_cost]], today, order_qty, min_shelf}. A lot is eligible when expiry_day - today >= min_shelf. Eligible lots are picked by earliest expiry, ties by lot id ascending. If eligible stock < order_qty return {"error":"insufficient","available":eligible qty}. Return {picks:[[lot,qty]], cost}.

Why this case matters

Inventory valuation and cost-of-goods decisions depend on this rule.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
earliest expiry	`{"cost": 155, "picks": [["L1", 5], ["L3", 5], ["L2", 5]]}`	`{"cost": 80, "picks": [["L1", 5], ["L3", 2]]}`	Failed

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