FA-67578 / Elevator dispatch scheduling / Member archive

Fire service phase I recall: shaft end clipping · case 03

A car moving away at the top or bottom is sent to a floor that does not exist.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

The recall floor is the designated floor unless smoke is detected there and not at the alternate floor. Each car: stationary at the recall floor -> open; stationary elsewhere -> travel to recall; moving towards the recall floor (strictly) -> nonstop to it; otherwise (moving away, or passing the recall floor) -> reverse after stopping at the next floor in its direction, clipped to 0..top.

Why this case matters

Lift group controllers make these decisions many times per minute; a wrong answer strands passengers, wastes trips or overrides a safety rule.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression: passing the recall floor	`{"cars": {"L1": ["reverse", -1]}, "recall": 0}`	`{"cars": {"L1": ["reverse", 0]}, "recall": 0}`	Failed

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