FAILURE MAP
← Case archive

FA-67721 / Elevator dispatch scheduling / Open access

Double-deck car stop planning: upper deck position · case 01

The car stops a floor off for upper-deck passengers.

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

ROOT CAUSE

The upper-deck position is computed above instead of below the destination.

THE FAILURE

The upper-deck position is computed above instead of below the destination.

Unsuccessful approach: Using the destination itself leaves the upper deck a floor too high.

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) == 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: odd and even floors share a stop', {'top': 20, 'lower_odd': True, 'dests': [5, 6]}, {'stops': [5], 'deck_of': {'5': 'lower', '6': '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': []}), ('regression: 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]}), ('sampled regression 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 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: even-lower convention', {'top': 20, 'lower_odd': False, 'dests': [6, 7]}, {'stops': [6], 'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': []}), ('sampled regression 6', {'top': 20, 'lower_odd': True, 'dests': [21, 13, 16, 2]}, {'stops': [1, 13, 15], 'deck_of': {'13': 'lower', '16': 'upper', '2': 'upper'}, 'rejected': [21]}), ('sampled regression 3', {'top': 20, 'lower_odd': True, 'dests': [1, 17, 15, 8, 5, 7]}, {'stops': [1, 5, 7, 15, 17], 'deck_of': {'1': 'lower', '17': 'lower', '15': 'lower', '8': 'upper', '5': 'lower', '7': 'lower'}, 'rejected': []}), ('regression: 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]}), ('sampled regression 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': []}), ('control 15', {'top': 21, 'lower_odd': False, 'dests': [2]}, {'stops': [2], 'deck_of': {'2': 'lower'}, 'rejected': []}), ('sampled regression 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: top floor by the upper deck', {'top': 20, 'lower_odd': True, 'dests': [20]}, {'stops': [19], 'deck_of': {'20': 'upper'}, 'rejected': []}), ('sampled regression 13', {'top': 30, 'lower_odd': False, 'dests': [25, 12, 4, 16]}, {'stops': [4, 12, 16, 24], 'deck_of': {'25': 'upper', '12': 'lower', '4': 'lower', '16': 'lower'}, 'rejected': []}), ('sampled regression 8', {'top': 30, 'lower_odd': True, 'dests': [26]}, {'stops': [25], 'deck_of': {'26': 'upper'}, 'rejected': []}), ('regression: floor one by the upper deck', {'top': 20, 'lower_odd': False, 'dests': [1]}, {'stops': [], 'deck_of': {}, 'rejected': [1]}), ('regression: repeated destinations', {'top': 20, 'lower_odd': True, 'dests': [9, 9, 10]}, {'stops': [9], 'deck_of': {'9': 'lower', '10': 'upper'}, 'rejected': []}), ('sampled regression 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': []}), ('sampled regression 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]}), ('sampled regression 21', {'top': 21, 'lower_odd': False, 'dests': [12, 5, 13, 0, 20]}, {'stops': [4, 12, 20], 'deck_of': {'12': 'lower', '5': 'upper', '13': 'upper', '20': 'lower'}, 'rejected': [0]}), ('sampled regression 13', {'top': 30, 'lower_odd': False, 'dests': [25, 12, 4, 16]}, {'stops': [4, 12, 16, 24], 'deck_of': {'25': 'upper', '12': 'lower', '4': 'lower', '16': 'lower'}, 'rejected': []}), ('regression: odd and even floors share a stop', {'top': 20, 'lower_odd': True, 'dests': [5, 6]}, {'stops': [5], 'deck_of': {'5': 'lower', '6': 'upper'}, 'rejected': []}), ('regression: even-lower convention', {'top': 20, 'lower_odd': False, 'dests': [6, 7]}, {'stops': [6], 'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': []}), ('sampled regression 34', {'top': 20, 'lower_odd': True, 'dests': [5, 0]}, {'stops': [5], 'deck_of': {'5': 'lower'}, 'rejected': [0]}), ('control 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: repeated destinations', {'top': 20, 'lower_odd': True, 'dests': [9, 9, 10]}, {'stops': [9], 'deck_of': {'9': 'lower', '10': 'upper'}, 'rejected': []}), ('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]}), ('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': []}), ('regression: 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]}), ('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]}), ('sampled regression 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: odd and even floors share a stop{'deck_of': {'5': 'lower', '6': 'upper'}, 'rejected': [], 'stops': [5, 7]}{'deck_of': {'5': 'lower', '6': 'upper'}, 'rejected': [], 'stops': [5]}Failed
regression: floor one by the upper deck{'deck_of': {'1': 'upper'}, 'rejected': [], 'stops': [2]}{'deck_of': {}, 'rejected': [1], 'stops': []}Failed
regression: even-lower convention{'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': [], 'stops': [6, 8]}{'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': [], 'stops': [6]}Failed
regression: 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': {}, 'rejected': [21], 'stops': []}{'deck_of': {}, 'rejected': [21], 'stops': []}Passed
sampled regression 1{'deck_of': {'0': 'upper'}, 'rejected': [], 'stops': [1]}{'deck_of': {}, 'rejected': [0], 'stops': []}Failed
sampled regression 4{'deck_of': {'3': 'upper'}, 'rejected': [19], 'stops': [4]}{'deck_of': {'19': 'upper', '3': 'upper'}, 'rejected': [], 'stops': [2, 18]}Failed
sampled regression 7{'deck_of': {'10': 'lower', '3': 'upper', '4': 'lower', '7': 'upper', '9': 'upper'}, 'rejected': [], 'stops': [4, 8, 10]}{'deck_of': {'10': 'lower', '3': 'upper', '4': 'lower', '7': 'upper', '9': 'upper'}, 'rejected': [], 'stops': [2, 4, 6, 8, 10]}Failed

SHA-256 / 96ab04bdea752a96a2d4b169f1034c623f2e6b4d7a0f0ba09d8386a4d22c8ac7

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 == 1) == x['lower_odd']
        pos = d
        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: odd and even floors share a stop', {'top': 20, 'lower_odd': True, 'dests': [5, 6]}, {'stops': [5], 'deck_of': {'5': 'lower', '6': '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': []}), ('regression: 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]}), ('sampled regression 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 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: even-lower convention', {'top': 20, 'lower_odd': False, 'dests': [6, 7]}, {'stops': [6], 'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': []}), ('sampled regression 6', {'top': 20, 'lower_odd': True, 'dests': [21, 13, 16, 2]}, {'stops': [1, 13, 15], 'deck_of': {'13': 'lower', '16': 'upper', '2': 'upper'}, 'rejected': [21]}), ('sampled regression 3', {'top': 20, 'lower_odd': True, 'dests': [1, 17, 15, 8, 5, 7]}, {'stops': [1, 5, 7, 15, 17], 'deck_of': {'1': 'lower', '17': 'lower', '15': 'lower', '8': 'upper', '5': 'lower', '7': 'lower'}, 'rejected': []}), ('regression: 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]}), ('sampled regression 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': []}), ('control 15', {'top': 21, 'lower_odd': False, 'dests': [2]}, {'stops': [2], 'deck_of': {'2': 'lower'}, 'rejected': []}), ('sampled regression 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: top floor by the upper deck', {'top': 20, 'lower_odd': True, 'dests': [20]}, {'stops': [19], 'deck_of': {'20': 'upper'}, 'rejected': []}), ('sampled regression 13', {'top': 30, 'lower_odd': False, 'dests': [25, 12, 4, 16]}, {'stops': [4, 12, 16, 24], 'deck_of': {'25': 'upper', '12': 'lower', '4': 'lower', '16': 'lower'}, 'rejected': []}), ('sampled regression 8', {'top': 30, 'lower_odd': True, 'dests': [26]}, {'stops': [25], 'deck_of': {'26': 'upper'}, 'rejected': []}), ('regression: floor one by the upper deck', {'top': 20, 'lower_odd': False, 'dests': [1]}, {'stops': [], 'deck_of': {}, 'rejected': [1]}), ('regression: repeated destinations', {'top': 20, 'lower_odd': True, 'dests': [9, 9, 10]}, {'stops': [9], 'deck_of': {'9': 'lower', '10': 'upper'}, 'rejected': []}), ('sampled regression 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': []}), ('sampled regression 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]}), ('sampled regression 21', {'top': 21, 'lower_odd': False, 'dests': [12, 5, 13, 0, 20]}, {'stops': [4, 12, 20], 'deck_of': {'12': 'lower', '5': 'upper', '13': 'upper', '20': 'lower'}, 'rejected': [0]}), ('sampled regression 13', {'top': 30, 'lower_odd': False, 'dests': [25, 12, 4, 16]}, {'stops': [4, 12, 16, 24], 'deck_of': {'25': 'upper', '12': 'lower', '4': 'lower', '16': 'lower'}, 'rejected': []}), ('regression: odd and even floors share a stop', {'top': 20, 'lower_odd': True, 'dests': [5, 6]}, {'stops': [5], 'deck_of': {'5': 'lower', '6': 'upper'}, 'rejected': []}), ('regression: even-lower convention', {'top': 20, 'lower_odd': False, 'dests': [6, 7]}, {'stops': [6], 'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': []}), ('sampled regression 34', {'top': 20, 'lower_odd': True, 'dests': [5, 0]}, {'stops': [5], 'deck_of': {'5': 'lower'}, 'rejected': [0]}), ('control 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: repeated destinations', {'top': 20, 'lower_odd': True, 'dests': [9, 9, 10]}, {'stops': [9], 'deck_of': {'9': 'lower', '10': 'upper'}, 'rejected': []}), ('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]}), ('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': []}), ('regression: 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]}), ('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]}), ('sampled regression 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: odd and even floors share a stop{'deck_of': {'5': 'lower', '6': 'upper'}, 'rejected': [], 'stops': [5, 6]}{'deck_of': {'5': 'lower', '6': 'upper'}, 'rejected': [], 'stops': [5]}Failed
regression: floor one by the upper deck{'deck_of': {'1': 'upper'}, 'rejected': [], 'stops': [1]}{'deck_of': {}, 'rejected': [1], 'stops': []}Failed
regression: even-lower convention{'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': [], 'stops': [6, 7]}{'deck_of': {'6': 'lower', '7': 'upper'}, 'rejected': [], 'stops': [6]}Failed
regression: 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': {}, 'rejected': [21], 'stops': []}{'deck_of': {}, 'rejected': [21], 'stops': []}Passed
sampled regression 1{'deck_of': {}, 'rejected': [0], 'stops': []}{'deck_of': {}, 'rejected': [0], 'stops': []}Passed
sampled regression 4{'deck_of': {'19': 'upper', '3': 'upper'}, 'rejected': [], 'stops': [3, 19]}{'deck_of': {'19': 'upper', '3': 'upper'}, 'rejected': [], 'stops': [2, 18]}Failed
sampled regression 7{'deck_of': {'10': 'lower', '3': 'upper', '4': 'lower', '7': 'upper', '9': 'upper'}, 'rejected': [], 'stops': [3, 4, 7, 9, 10]}{'deck_of': {'10': 'lower', '3': 'upper', '4': 'lower', '7': 'upper', '9': 'upper'}, 'rejected': [], 'stops': [2, 4, 6, 8, 10]}Failed

SHA-256 / 1911722f7cae74cb3822da289ed8e41f44ef638656e8a36c2a4d7eb396c3c3a9

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.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

Sign in to the archive ↗

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 2026-09-29T14:47:55.555001+00:00.

Case digest / b357cb6ac9a32ee4d3b2d07a18810ed93ddd9f6632d03fd4a9ec8098a6a7442c