FAILURE MAP
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FA-67716 / Elevator dispatch scheduling / Open access

Double-deck car stop planning: deck parity convention · case 01

Buildings with even-floor lower decks send passengers to the wrong deck.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The parity rule ignores the lower_odd setting.

THE FAILURE

The parity rule ignores the lower_odd setting.

Unsuccessful approach: Inverting the parity comparison swaps the decks for every building.

Case contract

A double-deck car has a lower deck and an upper deck one floor above it; the car position is the lower deck floor. With lower_odd the lower deck serves odd destinations and the upper deck even ones (reversed otherwise). A destination served by the upper deck needs car position dest-1. Positions must lie in 1..top-1 (the lower deck never reaches the top floor); unreachable destinations are rejected. Return sorted unique stop positions, deck per destination and rejected destinations in input order.

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.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    stops = set()
    deck = {}
    rejected = []
    for d in x['dests']:
        lower = d % 2 == 1
        pos = d if lower else d - 1
        if pos < 1 or pos > x['top'] - 1:
            rejected.append(d)
            continue
        deck[str(d)] = 'lower' if lower else 'upper'
        stops.add(pos)
    return {'stops': sorted(stops), 'deck_of': deck, 'rejected': rejected}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: even-lower convention', {'top': 20, 'lower_odd': False, 'dests': [6, 7]}, {'stops': [6], 'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': []}), ('boundary: odd and even floors share a stop', {'top': 20, 'lower_odd': True, 'dests': [5, 6]}, {'stops': [5], 'deck_of': {'5': 'lower', '6': 'upper'}, 'rejected': []}), ('sampled regression 7', {'top': 21, 'lower_odd': False, 'dests': [9, 10, 3, 4, 7]}, {'stops': [2, 4, 6, 8, 10], 'deck_of': {'9': 'upper', '10': 'lower', '3': 'upper', '4': 'lower', '7': 'upper'}, 'rejected': []}), ('boundary: top floor by the upper deck', {'top': 20, 'lower_odd': True, 'dests': [20]}, {'stops': [19], 'deck_of': {'20': 'upper'}, 'rejected': []}), ('boundary: top floor by the lower deck', {'top': 21, 'lower_odd': True, 'dests': [21]}, {'stops': [], 'deck_of': {}, 'rejected': [21]}), ('control 1', {'top': 30, 'lower_odd': True, 'dests': [0]}, {'stops': [], 'deck_of': {}, 'rejected': [0]}), ('sampled regression 4', {'top': 20, 'lower_odd': False, 'dests': [19, 3]}, {'stops': [2, 18], 'deck_of': {'19': 'upper', '3': 'upper'}, 'rejected': []}), ('sampled regression 10', {'top': 20, 'lower_odd': False, 'dests': [10, 11, 15, 13]}, {'stops': [10, 12, 14], 'deck_of': {'10': 'lower', '11': 'upper', '15': 'upper', '13': 'upper'}, 'rejected': []})], [('regression: floor one by the upper deck', {'top': 20, 'lower_odd': False, 'dests': [1]}, {'stops': [], 'deck_of': {}, 'rejected': [1]}), ('regression: even-lower convention', {'top': 20, 'lower_odd': False, 'dests': [6, 7]}, {'stops': [6], 'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': []}), ('sampled regression 19', {'top': 20, 'lower_odd': False, 'dests': [4, 9, 11]}, {'stops': [4, 8, 10], 'deck_of': {'4': 'lower', '9': 'upper', '11': 'upper'}, 'rejected': []}), ('control 2', {'top': 21, 'lower_odd': True, 'dests': [21, 20, 0, 16, 19, 7]}, {'stops': [7, 15, 19], 'deck_of': {'20': 'upper', '16': 'upper', '19': 'lower', '7': 'lower'}, 'rejected': [21, 0]}), ('boundary: top floor by the upper deck', {'top': 20, 'lower_odd': True, 'dests': [20]}, {'stops': [19], 'deck_of': {'20': 'upper'}, 'rejected': []}), ('control 12', {'top': 21, 'lower_odd': True, 'dests': [7, 16, 15, 14, 18, 5]}, {'stops': [5, 7, 13, 15, 17], 'deck_of': {'7': 'lower', '16': 'upper', '15': 'lower', '14': 'upper', '18': 'upper', '5': 'lower'}, 'rejected': []}), ('sampled regression 15', {'top': 21, 'lower_odd': False, 'dests': [2]}, {'stops': [2], 'deck_of': {'2': 'lower'}, 'rejected': []}), ('control 18', {'top': 30, 'lower_odd': True, 'dests': [1, 2, 16, 17, 9, 14]}, {'stops': [1, 9, 13, 15, 17], 'deck_of': {'1': 'lower', '2': 'upper', '16': 'upper', '17': 'lower', '9': 'lower', '14': 'upper'}, 'rejected': []})], [('regression: even-lower convention', {'top': 20, 'lower_odd': False, 'dests': [6, 7]}, {'stops': [6], 'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': []}), ('boundary: top floor by the upper deck', {'top': 20, 'lower_odd': True, 'dests': [20]}, {'stops': [19], 'deck_of': {'20': 'upper'}, 'rejected': []}), ('sampled regression 31', {'top': 21, 'lower_odd': False, 'dests': [10, 8, 21, 15, 13]}, {'stops': [8, 10, 12, 14, 20], 'deck_of': {'10': 'lower', '8': 'lower', '21': 'upper', '15': 'upper', '13': 'upper'}, 'rejected': []}), ('sampled regression 7', {'top': 21, 'lower_odd': False, 'dests': [9, 10, 3, 4, 7]}, {'stops': [2, 4, 6, 8, 10], 'deck_of': {'9': 'upper', '10': 'lower', '3': 'upper', '4': 'lower', '7': 'upper'}, 'rejected': []}), ('regression: floor one by the upper deck', {'top': 20, 'lower_odd': False, 'dests': [1]}, {'stops': [], 'deck_of': {}, 'rejected': [1]}), ('control 23', {'top': 20, 'lower_odd': True, 'dests': [11, 6, 9, 18, 10, 19]}, {'stops': [5, 9, 11, 17, 19], 'deck_of': {'11': 'lower', '6': 'upper', '9': 'lower', '18': 'upper', '10': 'upper', '19': 'lower'}, 'rejected': []}), ('control 26', {'top': 20, 'lower_odd': True, 'dests': [0, 7, 4, 8, 20]}, {'stops': [3, 7, 19], 'deck_of': {'7': 'lower', '4': 'upper', '8': 'upper', '20': 'upper'}, 'rejected': [0]}), ('sampled regression 29', {'top': 21, 'lower_odd': False, 'dests': [3, 12, 13, 19, 1]}, {'stops': [2, 12, 18], 'deck_of': {'3': 'upper', '12': 'lower', '13': 'upper', '19': 'upper'}, 'rejected': [1]})], [('regression: floor one by the upper deck', {'top': 20, 'lower_odd': False, 'dests': [1]}, {'stops': [], 'deck_of': {}, 'rejected': [1]}), ('boundary: top floor by the lower deck', {'top': 21, 'lower_odd': True, 'dests': [21]}, {'stops': [], 'deck_of': {}, 'rejected': [21]}), ('sampled regression 41', {'top': 30, 'lower_odd': False, 'dests': [19, 10]}, {'stops': [10, 18], 'deck_of': {'19': 'upper', '10': 'lower'}, 'rejected': []}), ('control 12', {'top': 21, 'lower_odd': True, 'dests': [7, 16, 15, 14, 18, 5]}, {'stops': [5, 7, 13, 15, 17], 'deck_of': {'7': 'lower', '16': 'upper', '15': 'lower', '14': 'upper', '18': 'upper', '5': 'lower'}, 'rejected': []}), ('boundary: odd and even floors share a stop', {'top': 20, 'lower_odd': True, 'dests': [5, 6]}, {'stops': [5], 'deck_of': {'5': 'lower', '6': 'upper'}, 'rejected': []}), ('control 34', {'top': 20, 'lower_odd': True, 'dests': [5, 0]}, {'stops': [5], 'deck_of': {'5': 'lower'}, 'rejected': [0]}), ('sampled regression 37', {'top': 30, 'lower_odd': False, 'dests': [18, 28, 28]}, {'stops': [18, 28], 'deck_of': {'18': 'lower', '28': 'lower'}, 'rejected': []}), ('sampled regression 40', {'top': 20, 'lower_odd': False, 'dests': [11, 14, 12, 8, 0, 4]}, {'stops': [4, 8, 10, 12, 14], 'deck_of': {'11': 'upper', '14': 'lower', '12': 'lower', '8': 'lower', '4': 'lower'}, 'rejected': [0]})], [('regression: even-lower convention', {'top': 20, 'lower_odd': False, 'dests': [6, 7]}, {'stops': [6], 'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': []}), ('regression: floor one by the upper deck', {'top': 20, 'lower_odd': False, 'dests': [1]}, {'stops': [], 'deck_of': {}, 'rejected': [1]}), ('sampled regression 61', {'top': 30, 'lower_odd': False, 'dests': [1]}, {'stops': [], 'deck_of': {}, 'rejected': [1]}), ('control 17', {'top': 30, 'lower_odd': True, 'dests': [19, 5, 2, 23, 16]}, {'stops': [1, 5, 15, 19, 23], 'deck_of': {'19': 'lower', '5': 'lower', '2': 'upper', '23': 'lower', '16': 'upper'}, 'rejected': []}), ('boundary: top floor by the upper deck', {'top': 20, 'lower_odd': True, 'dests': [20]}, {'stops': [19], 'deck_of': {'20': 'upper'}, 'rejected': []}), ('sampled regression 45', {'top': 30, 'lower_odd': False, 'dests': [1, 11, 0, 7, 22]}, {'stops': [6, 10, 22], 'deck_of': {'11': 'upper', '7': 'upper', '22': 'lower'}, 'rejected': [1, 0]}), ('control 48', {'top': 20, 'lower_odd': True, 'dests': [7, 1, 12, 15, 14, 20]}, {'stops': [1, 7, 11, 13, 15, 19], 'deck_of': {'7': 'lower', '1': 'lower', '12': 'upper', '15': 'lower', '14': 'upper', '20': 'upper'}, 'rejected': []}), ('control 51', {'top': 21, 'lower_odd': True, 'dests': [22, 5, 13]}, {'stops': [5, 13], 'deck_of': {'5': 'lower', '13': 'lower'}, 'rejected': [22]})]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
regression: even-lower convention{'deck_of': {'6': 'upper', '7': 'lower'}, 'rejected': [], 'stops': [5, 7]}{'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': [], 'stops': [6]}Failed
boundary: odd and even floors share a stop{'deck_of': {'5': 'lower', '6': 'upper'}, 'rejected': [], 'stops': [5]}{'deck_of': {'5': 'lower', '6': 'upper'}, 'rejected': [], 'stops': [5]}Passed
sampled regression 7{'deck_of': {'10': 'upper', '3': 'lower', '4': 'upper', '7': 'lower', '9': 'lower'}, 'rejected': [], 'stops': [3, 7, 9]}{'deck_of': {'10': 'lower', '3': 'upper', '4': 'lower', '7': 'upper', '9': 'upper'}, 'rejected': [], 'stops': [2, 4, 6, 8, 10]}Failed
boundary: top floor by the upper deck{'deck_of': {'20': 'upper'}, 'rejected': [], 'stops': [19]}{'deck_of': {'20': 'upper'}, 'rejected': [], 'stops': [19]}Passed
boundary: top floor by the lower deck{'deck_of': {}, 'rejected': [21], 'stops': []}{'deck_of': {}, 'rejected': [21], 'stops': []}Passed
control 1{'deck_of': {}, 'rejected': [0], 'stops': []}{'deck_of': {}, 'rejected': [0], 'stops': []}Passed
sampled regression 4{'deck_of': {'19': 'lower', '3': 'lower'}, 'rejected': [], 'stops': [3, 19]}{'deck_of': {'19': 'upper', '3': 'upper'}, 'rejected': [], 'stops': [2, 18]}Failed
sampled regression 10{'deck_of': {'10': 'upper', '11': 'lower', '13': 'lower', '15': 'lower'}, 'rejected': [], 'stops': [9, 11, 13, 15]}{'deck_of': {'10': 'lower', '11': 'upper', '13': 'upper', '15': 'upper'}, 'rejected': [], 'stops': [10, 12, 14]}Failed

SHA-256 / 52cc6aa1ec25a915176c29d5fe646232a69c29163e9b7310c082a17549afeea3

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    stops = set()
    deck = {}
    rejected = []
    for d in x['dests']:
        lower = (d % 2 == 0) == x['lower_odd']
        pos = d if lower else d - 1
        if pos < 1 or pos > x['top'] - 1:
            rejected.append(d)
            continue
        deck[str(d)] = 'lower' if lower else 'upper'
        stops.add(pos)
    return {'stops': sorted(stops), 'deck_of': deck, 'rejected': rejected}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: even-lower convention', {'top': 20, 'lower_odd': False, 'dests': [6, 7]}, {'stops': [6], 'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': []}), ('boundary: odd and even floors share a stop', {'top': 20, 'lower_odd': True, 'dests': [5, 6]}, {'stops': [5], 'deck_of': {'5': 'lower', '6': 'upper'}, 'rejected': []}), ('sampled regression 7', {'top': 21, 'lower_odd': False, 'dests': [9, 10, 3, 4, 7]}, {'stops': [2, 4, 6, 8, 10], 'deck_of': {'9': 'upper', '10': 'lower', '3': 'upper', '4': 'lower', '7': 'upper'}, 'rejected': []}), ('boundary: top floor by the upper deck', {'top': 20, 'lower_odd': True, 'dests': [20]}, {'stops': [19], 'deck_of': {'20': 'upper'}, 'rejected': []}), ('boundary: top floor by the lower deck', {'top': 21, 'lower_odd': True, 'dests': [21]}, {'stops': [], 'deck_of': {}, 'rejected': [21]}), ('control 1', {'top': 30, 'lower_odd': True, 'dests': [0]}, {'stops': [], 'deck_of': {}, 'rejected': [0]}), ('sampled regression 4', {'top': 20, 'lower_odd': False, 'dests': [19, 3]}, {'stops': [2, 18], 'deck_of': {'19': 'upper', '3': 'upper'}, 'rejected': []}), ('sampled regression 10', {'top': 20, 'lower_odd': False, 'dests': [10, 11, 15, 13]}, {'stops': [10, 12, 14], 'deck_of': {'10': 'lower', '11': 'upper', '15': 'upper', '13': 'upper'}, 'rejected': []})], [('regression: floor one by the upper deck', {'top': 20, 'lower_odd': False, 'dests': [1]}, {'stops': [], 'deck_of': {}, 'rejected': [1]}), ('regression: even-lower convention', {'top': 20, 'lower_odd': False, 'dests': [6, 7]}, {'stops': [6], 'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': []}), ('sampled regression 19', {'top': 20, 'lower_odd': False, 'dests': [4, 9, 11]}, {'stops': [4, 8, 10], 'deck_of': {'4': 'lower', '9': 'upper', '11': 'upper'}, 'rejected': []}), ('control 2', {'top': 21, 'lower_odd': True, 'dests': [21, 20, 0, 16, 19, 7]}, {'stops': [7, 15, 19], 'deck_of': {'20': 'upper', '16': 'upper', '19': 'lower', '7': 'lower'}, 'rejected': [21, 0]}), ('boundary: top floor by the upper deck', {'top': 20, 'lower_odd': True, 'dests': [20]}, {'stops': [19], 'deck_of': {'20': 'upper'}, 'rejected': []}), ('control 12', {'top': 21, 'lower_odd': True, 'dests': [7, 16, 15, 14, 18, 5]}, {'stops': [5, 7, 13, 15, 17], 'deck_of': {'7': 'lower', '16': 'upper', '15': 'lower', '14': 'upper', '18': 'upper', '5': 'lower'}, 'rejected': []}), ('sampled regression 15', {'top': 21, 'lower_odd': False, 'dests': [2]}, {'stops': [2], 'deck_of': {'2': 'lower'}, 'rejected': []}), ('control 18', {'top': 30, 'lower_odd': True, 'dests': [1, 2, 16, 17, 9, 14]}, {'stops': [1, 9, 13, 15, 17], 'deck_of': {'1': 'lower', '2': 'upper', '16': 'upper', '17': 'lower', '9': 'lower', '14': 'upper'}, 'rejected': []})], [('regression: even-lower convention', {'top': 20, 'lower_odd': False, 'dests': [6, 7]}, {'stops': [6], 'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': []}), ('boundary: top floor by the upper deck', {'top': 20, 'lower_odd': True, 'dests': [20]}, {'stops': [19], 'deck_of': {'20': 'upper'}, 'rejected': []}), ('sampled regression 31', {'top': 21, 'lower_odd': False, 'dests': [10, 8, 21, 15, 13]}, {'stops': [8, 10, 12, 14, 20], 'deck_of': {'10': 'lower', '8': 'lower', '21': 'upper', '15': 'upper', '13': 'upper'}, 'rejected': []}), ('sampled regression 7', {'top': 21, 'lower_odd': False, 'dests': [9, 10, 3, 4, 7]}, {'stops': [2, 4, 6, 8, 10], 'deck_of': {'9': 'upper', '10': 'lower', '3': 'upper', '4': 'lower', '7': 'upper'}, 'rejected': []}), ('regression: floor one by the upper deck', {'top': 20, 'lower_odd': False, 'dests': [1]}, {'stops': [], 'deck_of': {}, 'rejected': [1]}), ('control 23', {'top': 20, 'lower_odd': True, 'dests': [11, 6, 9, 18, 10, 19]}, {'stops': [5, 9, 11, 17, 19], 'deck_of': {'11': 'lower', '6': 'upper', '9': 'lower', '18': 'upper', '10': 'upper', '19': 'lower'}, 'rejected': []}), ('control 26', {'top': 20, 'lower_odd': True, 'dests': [0, 7, 4, 8, 20]}, {'stops': [3, 7, 19], 'deck_of': {'7': 'lower', '4': 'upper', '8': 'upper', '20': 'upper'}, 'rejected': [0]}), ('sampled regression 29', {'top': 21, 'lower_odd': False, 'dests': [3, 12, 13, 19, 1]}, {'stops': [2, 12, 18], 'deck_of': {'3': 'upper', '12': 'lower', '13': 'upper', '19': 'upper'}, 'rejected': [1]})], [('regression: floor one by the upper deck', {'top': 20, 'lower_odd': False, 'dests': [1]}, {'stops': [], 'deck_of': {}, 'rejected': [1]}), ('boundary: top floor by the lower deck', {'top': 21, 'lower_odd': True, 'dests': [21]}, {'stops': [], 'deck_of': {}, 'rejected': [21]}), ('sampled regression 41', {'top': 30, 'lower_odd': False, 'dests': [19, 10]}, {'stops': [10, 18], 'deck_of': {'19': 'upper', '10': 'lower'}, 'rejected': []}), ('control 12', {'top': 21, 'lower_odd': True, 'dests': [7, 16, 15, 14, 18, 5]}, {'stops': [5, 7, 13, 15, 17], 'deck_of': {'7': 'lower', '16': 'upper', '15': 'lower', '14': 'upper', '18': 'upper', '5': 'lower'}, 'rejected': []}), ('boundary: odd and even floors share a stop', {'top': 20, 'lower_odd': True, 'dests': [5, 6]}, {'stops': [5], 'deck_of': {'5': 'lower', '6': 'upper'}, 'rejected': []}), ('control 34', {'top': 20, 'lower_odd': True, 'dests': [5, 0]}, {'stops': [5], 'deck_of': {'5': 'lower'}, 'rejected': [0]}), ('sampled regression 37', {'top': 30, 'lower_odd': False, 'dests': [18, 28, 28]}, {'stops': [18, 28], 'deck_of': {'18': 'lower', '28': 'lower'}, 'rejected': []}), ('sampled regression 40', {'top': 20, 'lower_odd': False, 'dests': [11, 14, 12, 8, 0, 4]}, {'stops': [4, 8, 10, 12, 14], 'deck_of': {'11': 'upper', '14': 'lower', '12': 'lower', '8': 'lower', '4': 'lower'}, 'rejected': [0]})], [('regression: even-lower convention', {'top': 20, 'lower_odd': False, 'dests': [6, 7]}, {'stops': [6], 'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': []}), ('regression: floor one by the upper deck', {'top': 20, 'lower_odd': False, 'dests': [1]}, {'stops': [], 'deck_of': {}, 'rejected': [1]}), ('sampled regression 61', {'top': 30, 'lower_odd': False, 'dests': [1]}, {'stops': [], 'deck_of': {}, 'rejected': [1]}), ('control 17', {'top': 30, 'lower_odd': True, 'dests': [19, 5, 2, 23, 16]}, {'stops': [1, 5, 15, 19, 23], 'deck_of': {'19': 'lower', '5': 'lower', '2': 'upper', '23': 'lower', '16': 'upper'}, 'rejected': []}), ('boundary: top floor by the upper deck', {'top': 20, 'lower_odd': True, 'dests': [20]}, {'stops': [19], 'deck_of': {'20': 'upper'}, 'rejected': []}), ('sampled regression 45', {'top': 30, 'lower_odd': False, 'dests': [1, 11, 0, 7, 22]}, {'stops': [6, 10, 22], 'deck_of': {'11': 'upper', '7': 'upper', '22': 'lower'}, 'rejected': [1, 0]}), ('control 48', {'top': 20, 'lower_odd': True, 'dests': [7, 1, 12, 15, 14, 20]}, {'stops': [1, 7, 11, 13, 15, 19], 'deck_of': {'7': 'lower', '1': 'lower', '12': 'upper', '15': 'lower', '14': 'upper', '20': 'upper'}, 'rejected': []}), ('control 51', {'top': 21, 'lower_odd': True, 'dests': [22, 5, 13]}, {'stops': [5, 13], 'deck_of': {'5': 'lower', '13': 'lower'}, 'rejected': [22]})]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
regression: even-lower convention{'deck_of': {'6': 'upper', '7': 'lower'}, 'rejected': [], 'stops': [5, 7]}{'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': [], 'stops': [6]}Failed
boundary: odd and even floors share a stop{'deck_of': {'5': 'upper', '6': 'lower'}, 'rejected': [], 'stops': [4, 6]}{'deck_of': {'5': 'lower', '6': 'upper'}, 'rejected': [], 'stops': [5]}Failed
sampled regression 7{'deck_of': {'10': 'upper', '3': 'lower', '4': 'upper', '7': 'lower', '9': 'lower'}, 'rejected': [], 'stops': [3, 7, 9]}{'deck_of': {'10': 'lower', '3': 'upper', '4': 'lower', '7': 'upper', '9': 'upper'}, 'rejected': [], 'stops': [2, 4, 6, 8, 10]}Failed
boundary: top floor by the upper deck{'deck_of': {}, 'rejected': [20], 'stops': []}{'deck_of': {'20': 'upper'}, 'rejected': [], 'stops': [19]}Failed
boundary: top floor by the lower deck{'deck_of': {'21': 'upper'}, 'rejected': [], 'stops': [20]}{'deck_of': {}, 'rejected': [21], 'stops': []}Failed
control 1{'deck_of': {}, 'rejected': [0], 'stops': []}{'deck_of': {}, 'rejected': [0], 'stops': []}Passed
sampled regression 4{'deck_of': {'19': 'lower', '3': 'lower'}, 'rejected': [], 'stops': [3, 19]}{'deck_of': {'19': 'upper', '3': 'upper'}, 'rejected': [], 'stops': [2, 18]}Failed
sampled regression 10{'deck_of': {'10': 'upper', '11': 'lower', '13': 'lower', '15': 'lower'}, 'rejected': [], 'stops': [9, 11, 13, 15]}{'deck_of': {'10': 'lower', '11': 'upper', '13': 'upper', '15': 'upper'}, 'rejected': [], 'stops': [10, 12, 14]}Failed

SHA-256 / 7c671134a6716b3b96b354714c27141d7bc7bfe4c548cf5cfc3eaa5af6e488e8

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 8 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

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Verification & scope

Stipulated toy lift-control contract for a bounded teaching model; it makes no claim of conformance to any lift code or vendor dispatcher and omits real safety cases. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:47:55.475137+00:00.

Case digest / e39663b76344134c168e512c35e33087b12c5ba1822ef5ef8ab440b8e01eb5f1