{"abstract":"Merchant parking validations returns a wrong result when flat validations can drive the fee negative.","category":"Toll and parking fee computation","checks":8,"contract":"Input {minutes (single day), validations: [[free_min|pct|flat, value]], hourly, daily_max, max_free_min}. Free minutes from all validations are summed, capped at max_free_min and deducted from the stay before rating. The fee is started hours * hourly capped at daily_max. Only the largest percentage validation applies (discount floored to cents), then all flat validations are subtracted, never below zero.","contract_signature":"x","evaluation_group":"w2-toll_and_parking_fee_computation-merchant-validation","failed_approach":"Flooring before subtracting still returns negative amounts.","family":"w2-toll_and_parking_fee_computation-merchant-validation-zero-floor","id":"FA-68681","implementations":{"attempt":{"sha256":"30eea9e50bd34286f4e423e93a8583f499c89a433aee0720863e555e1c4622b1","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    free = min(x['max_free_min'], sum(v for k, v in x['validations'] if k == 'free_min'))\n    bill = max(0, x['minutes'] - free)\n    fee = min(x['daily_max'], -(-bill // 60) * x['hourly'])\n    pcts = [v for k, v in x['validations'] if k == 'pct']\n    if pcts:\n        fee -= fee * max(pcts) // 100\n    flat = sum(v for k, v in x['validations'] if k == 'flat')\n    return max(0, fee) - flat\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[({'minutes': 150, 'validations': [['free_min', 60], ['free_min', 60], ['free_min', 60]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 300), ({'minutes': 794, 'validations': [], 'hourly': 350, 'daily_max': 2400, 'max_free_min': 60}, 2400), ({'minutes': 754, 'validations': [['free_min', 30], ['free_min', 120], ['free_min', 30], ['pct', 25]], 'hourly': 300, 'daily_max': 1800, 'max_free_min': 180}, 1350), ({'minutes': 7, 'validations': [['flat', 250], ['free_min', 15], ['free_min', 60]], 'hourly': 350, 'daily_max': 1800, 'max_free_min': 120}, 0), ({'minutes': 27, 'validations': [['free_min', 90], ['flat', 500], ['free_min', 15]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 0), ({'minutes': 95, 'validations': [['free_min', 30]], 'hourly': 350, 'daily_max': 2400, 'max_free_min': 120}, 700), ({'minutes': 42, 'validations': [['pct', 10], ['flat', 500], ['flat', 500]], 'hourly': 200, 'daily_max': 2400, 'max_free_min': 120}, 0), ({'minutes': 200, 'validations': [['pct', 25], ['pct', 10], ['flat', 100], ['flat', 250]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 550)], [({'minutes': 27, 'validations': [['free_min', 90], ['free_min', 60], ['flat', 100], ['flat', 100]], 'hourly': 200, 'daily_max': 1800, 'max_free_min': 180}, 0), ({'minutes': 95, 'validations': [['free_min', 30]], 'hourly': 350, 'daily_max': 2400, 'max_free_min': 120}, 700), ({'minutes': 150, 'validations': [['free_min', 60], ['free_min', 60], ['free_min', 60]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 300), ({'minutes': 1012, 'validations': [['pct', 50], ['flat', 250], ['free_min', 30], ['pct', 50]], 'hourly': 300, 'daily_max': 1800, 'max_free_min': 120}, 650), ({'minutes': 42, 'validations': [['free_min', 60], ['flat', 500]], 'hourly': 200, 'daily_max': 2400, 'max_free_min': 60}, 0), ({'minutes': 1400, 'validations': [['free_min', 30], ['flat', 250], ['free_min', 90], ['free_min', 120]], 'hourly': 200, 'daily_max': 3000, 'max_free_min': 180}, 2750), ({'minutes': 200, 'validations': [['pct', 25], ['pct', 10], ['flat', 100], ['flat', 250]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 550), ({'minutes': 29, 'validations': [['flat', 250], ['free_min', 90], ['free_min', 30]], 'hourly': 350, 'daily_max': 3000, 'max_free_min': 60}, 0)], [({'minutes': 150, 'validations': [['free_min', 60], ['free_min', 60], ['free_min', 60]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 300), ({'minutes': 200, 'validations': [['pct', 25], ['pct', 10], ['flat', 100], ['flat', 250]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 550), ({'minutes': 259, 'validations': [['flat', 250], ['free_min', 60], ['free_min', 120], ['free_min', 120]], 'hourly': 350, 'daily_max': 3000, 'max_free_min': 180}, 450), ({'minutes': 420, 'validations': [['free_min', 120], ['free_min', 90], ['free_min', 90]], 'hourly': 300, 'daily_max': 1800, 'max_free_min': 180}, 1200), ({'minutes': 135, 'validations': [['free_min', 120], ['flat', 500], ['free_min', 30]], 'hourly': 200, 'daily_max': 3000, 'max_free_min': 180}, 0), ({'minutes': 95, 'validations': [['free_min', 30]], 'hourly': 350, 'daily_max': 2400, 'max_free_min': 120}, 700), ({'minutes': 94, 'validations': [['free_min', 60], ['flat', 500], ['pct', 25]], 'hourly': 300, 'daily_max': 1800, 'max_free_min': 120}, 0), ({'minutes': 87, 'validations': [['flat', 500], ['free_min', 120], ['flat', 250], ['free_min', 120]], 'hourly': 200, 'daily_max': 2400, 'max_free_min': 180}, 0)], [({'minutes': 209, 'validations': [['pct', 25], ['free_min', 30], ['flat', 500], ['pct', 50]], 'hourly': 300, 'daily_max': 1800, 'max_free_min': 60}, 0), ({'minutes': 19, 'validations': [['pct', 10], ['flat', 100], ['free_min', 120]], 'hourly': 200, 'daily_max': 2400, 'max_free_min': 180}, 0), ({'minutes': 95, 'validations': [['free_min', 30]], 'hourly': 350, 'daily_max': 2400, 'max_free_min': 120}, 700), ({'minutes': 568, 'validations': [['free_min', 60], ['free_min', 60], ['free_min', 30], ['free_min', 120]], 'hourly': 200, 'daily_max': 2400, 'max_free_min': 60}, 1800), ({'minutes': 200, 'validations': [['pct', 25], ['pct', 10], ['flat', 100], ['flat', 250]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 550), ({'minutes': 806, 'validations': [['pct', 50], ['free_min', 60], ['free_min', 60], ['flat', 500]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 700), ({'minutes': 56, 'validations': [['flat', 100], ['flat', 100], ['pct', 10], ['free_min', 90]], 'hourly': 350, 'daily_max': 3000, 'max_free_min': 60}, 0), ({'minutes': 150, 'validations': [['free_min', 60], ['free_min', 60], ['free_min', 60]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 300)], [({'minutes': 150, 'validations': [['free_min', 60], ['free_min', 60], ['free_min', 60]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 300), ({'minutes': 200, 'validations': [['pct', 25], ['pct', 10], ['flat', 100], ['flat', 250]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 550), ({'minutes': 95, 'validations': [['free_min', 30]], 'hourly': 350, 'daily_max': 2400, 'max_free_min': 120}, 700), ({'minutes': 485, 'validations': [['pct', 10], ['free_min', 60]], 'hourly': 350, 'daily_max': 3000, 'max_free_min': 120}, 2520), ({'minutes': 37, 'validations': [['free_min', 90], ['pct', 50], ['flat', 500]], 'hourly': 200, 'daily_max': 1800, 'max_free_min': 60}, 0), ({'minutes': 12, 'validations': [['flat', 500], ['flat', 500]], 'hourly': 350, 'daily_max': 3000, 'max_free_min': 180}, 0), ({'minutes': 1247, 'validations': [['flat', 250]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 180}, 2150), ({'minutes': 161, 'validations': [['free_min', 60], ['flat', 500], ['flat', 250]], 'hourly': 300, 'daily_max': 1800, 'max_free_min': 120}, 0)]]\nfor i, (args, expected) in enumerate(fixtures[N-1]):\n    check('fee oracle' + ' %d' % i, solve(args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"e86222e4554a5e24c4ebf64c33162aae8111bd68b14c92590b2be402de6d84dd","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    free = min(x['max_free_min'], sum(v for k, v in x['validations'] if k == 'free_min'))\n    bill = max(0, x['minutes'] - free)\n    fee = min(x['daily_max'], -(-bill // 60) * x['hourly'])\n    pcts = [v for k, v in x['validations'] if k == 'pct']\n    if pcts:\n        fee -= fee * max(pcts) // 100\n    flat = sum(v for k, v in x['validations'] if k == 'flat')\n    return fee - flat\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[({'minutes': 150, 'validations': [['free_min', 60], ['free_min', 60], ['free_min', 60]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 300), ({'minutes': 794, 'validations': [], 'hourly': 350, 'daily_max': 2400, 'max_free_min': 60}, 2400), ({'minutes': 754, 'validations': [['free_min', 30], ['free_min', 120], ['free_min', 30], ['pct', 25]], 'hourly': 300, 'daily_max': 1800, 'max_free_min': 180}, 1350), ({'minutes': 7, 'validations': [['flat', 250], ['free_min', 15], ['free_min', 60]], 'hourly': 350, 'daily_max': 1800, 'max_free_min': 120}, 0), ({'minutes': 27, 'validations': [['free_min', 90], ['flat', 500], ['free_min', 15]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 0), ({'minutes': 95, 'validations': [['free_min', 30]], 'hourly': 350, 'daily_max': 2400, 'max_free_min': 120}, 700), ({'minutes': 42, 'validations': [['pct', 10], ['flat', 500], ['flat', 500]], 'hourly': 200, 'daily_max': 2400, 'max_free_min': 120}, 0), ({'minutes': 200, 'validations': [['pct', 25], ['pct', 10], ['flat', 100], ['flat', 250]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 550)], [({'minutes': 27, 'validations': [['free_min', 90], ['free_min', 60], ['flat', 100], ['flat', 100]], 'hourly': 200, 'daily_max': 1800, 'max_free_min': 180}, 0), ({'minutes': 95, 'validations': [['free_min', 30]], 'hourly': 350, 'daily_max': 2400, 'max_free_min': 120}, 700), ({'minutes': 150, 'validations': [['free_min', 60], ['free_min', 60], ['free_min', 60]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 300), ({'minutes': 1012, 'validations': [['pct', 50], ['flat', 250], ['free_min', 30], ['pct', 50]], 'hourly': 300, 'daily_max': 1800, 'max_free_min': 120}, 650), ({'minutes': 42, 'validations': [['free_min', 60], ['flat', 500]], 'hourly': 200, 'daily_max': 2400, 'max_free_min': 60}, 0), ({'minutes': 1400, 'validations': [['free_min', 30], ['flat', 250], ['free_min', 90], ['free_min', 120]], 'hourly': 200, 'daily_max': 3000, 'max_free_min': 180}, 2750), ({'minutes': 200, 'validations': [['pct', 25], ['pct', 10], ['flat', 100], ['flat', 250]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 550), ({'minutes': 29, 'validations': [['flat', 250], ['free_min', 90], ['free_min', 30]], 'hourly': 350, 'daily_max': 3000, 'max_free_min': 60}, 0)], [({'minutes': 150, 'validations': [['free_min', 60], ['free_min', 60], ['free_min', 60]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 300), ({'minutes': 200, 'validations': [['pct', 25], ['pct', 10], ['flat', 100], ['flat', 250]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 550), ({'minutes': 259, 'validations': [['flat', 250], ['free_min', 60], ['free_min', 120], ['free_min', 120]], 'hourly': 350, 'daily_max': 3000, 'max_free_min': 180}, 450), ({'minutes': 420, 'validations': [['free_min', 120], ['free_min', 90], ['free_min', 90]], 'hourly': 300, 'daily_max': 1800, 'max_free_min': 180}, 1200), ({'minutes': 135, 'validations': [['free_min', 120], ['flat', 500], ['free_min', 30]], 'hourly': 200, 'daily_max': 3000, 'max_free_min': 180}, 0), ({'minutes': 95, 'validations': [['free_min', 30]], 'hourly': 350, 'daily_max': 2400, 'max_free_min': 120}, 700), ({'minutes': 94, 'validations': [['free_min', 60], ['flat', 500], ['pct', 25]], 'hourly': 300, 'daily_max': 1800, 'max_free_min': 120}, 0), ({'minutes': 87, 'validations': [['flat', 500], ['free_min', 120], ['flat', 250], ['free_min', 120]], 'hourly': 200, 'daily_max': 2400, 'max_free_min': 180}, 0)], [({'minutes': 209, 'validations': [['pct', 25], ['free_min', 30], ['flat', 500], ['pct', 50]], 'hourly': 300, 'daily_max': 1800, 'max_free_min': 60}, 0), ({'minutes': 19, 'validations': [['pct', 10], ['flat', 100], ['free_min', 120]], 'hourly': 200, 'daily_max': 2400, 'max_free_min': 180}, 0), ({'minutes': 95, 'validations': [['free_min', 30]], 'hourly': 350, 'daily_max': 2400, 'max_free_min': 120}, 700), ({'minutes': 568, 'validations': [['free_min', 60], ['free_min', 60], ['free_min', 30], ['free_min', 120]], 'hourly': 200, 'daily_max': 2400, 'max_free_min': 60}, 1800), ({'minutes': 200, 'validations': [['pct', 25], ['pct', 10], ['flat', 100], ['flat', 250]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 550), ({'minutes': 806, 'validations': [['pct', 50], ['free_min', 60], ['free_min', 60], ['flat', 500]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 700), ({'minutes': 56, 'validations': [['flat', 100], ['flat', 100], ['pct', 10], ['free_min', 90]], 'hourly': 350, 'daily_max': 3000, 'max_free_min': 60}, 0), ({'minutes': 150, 'validations': [['free_min', 60], ['free_min', 60], ['free_min', 60]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 300)], [({'minutes': 150, 'validations': [['free_min', 60], ['free_min', 60], ['free_min', 60]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 300), ({'minutes': 200, 'validations': [['pct', 25], ['pct', 10], ['flat', 100], ['flat', 250]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 120}, 550), ({'minutes': 95, 'validations': [['free_min', 30]], 'hourly': 350, 'daily_max': 2400, 'max_free_min': 120}, 700), ({'minutes': 485, 'validations': [['pct', 10], ['free_min', 60]], 'hourly': 350, 'daily_max': 3000, 'max_free_min': 120}, 2520), ({'minutes': 37, 'validations': [['free_min', 90], ['pct', 50], ['flat', 500]], 'hourly': 200, 'daily_max': 1800, 'max_free_min': 60}, 0), ({'minutes': 12, 'validations': [['flat', 500], ['flat', 500]], 'hourly': 350, 'daily_max': 3000, 'max_free_min': 180}, 0), ({'minutes': 1247, 'validations': [['flat', 250]], 'hourly': 300, 'daily_max': 2400, 'max_free_min': 180}, 2150), ({'minutes': 161, 'validations': [['free_min', 60], ['flat', 500], ['flat', 250]], 'hourly': 300, 'daily_max': 1800, 'max_free_min': 120}, 0)]]\nfor i, (args, expected) in enumerate(fixtures[N-1]):\n    check('fee oracle' + ' %d' % i, solve(args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"A deterministic, bounded toy model with a stipulated contract; it makes no claim of conformance to any agency manual or standard. 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.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w2-toll_and_parking_fee_computation-merchant-validation-zero-floor","generated_at":"2026-09-29T14:48:04.493512+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Fee engines bill customers in integer cents; a wrong boundary, rounding stage or cap scope silently over- or under-charges.","root_cause":"Flat validations larger than the fee produce a refund.","sha256":"66d92aff2bb58e293faca25338eb85ac6e66ea23c6249db26e7eb944a7cfbfc1","title":"Merchant parking validations: flat validations can drive the fee negative · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":44.043,"exit_code":1,"observations":[{"actual":300,"check":"fee oracle 0","expected":300,"passed":true},{"actual":2400,"check":"fee oracle 1","expected":2400,"passed":true},{"actual":1350,"check":"fee oracle 2","expected":1350,"passed":true},{"actual":-250,"check":"fee oracle 3","expected":0,"passed":false},{"actual":-500,"check":"fee oracle 4","expected":0,"passed":false},{"actual":700,"check":"fee oracle 5","expected":700,"passed":true},{"actual":-820,"check":"fee oracle 6","expected":0,"passed":false},{"actual":550,"check":"fee oracle 7","expected":550,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fee oracle 0\", \"actual\": 300, \"expected\": 300, \"passed\": true}, {\"check\": \"fee oracle 1\", \"actual\": 2400, \"expected\": 2400, \"passed\": true}, {\"check\": \"fee oracle 2\", \"actual\": 1350, \"expected\": 1350, \"passed\": true}, {\"check\": \"fee oracle 3\", \"actual\": -250, \"expected\": 0, \"passed\": false}, {\"check\": \"fee oracle 4\", \"actual\": -500, \"expected\": 0, \"passed\": false}, {\"check\": \"fee oracle 5\", \"actual\": 700, \"expected\": 700, \"passed\": true}, {\"check\": \"fee oracle 6\", \"actual\": -820, \"expected\": 0, \"passed\": false}, {\"check\": \"fee oracle 7\", \"actual\": 550, \"expected\": 550, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.943,"exit_code":1,"observations":[{"actual":300,"check":"fee oracle 0","expected":300,"passed":true},{"actual":2400,"check":"fee oracle 1","expected":2400,"passed":true},{"actual":1350,"check":"fee oracle 2","expected":1350,"passed":true},{"actual":-250,"check":"fee oracle 3","expected":0,"passed":false},{"actual":-500,"check":"fee oracle 4","expected":0,"passed":false},{"actual":700,"check":"fee oracle 5","expected":700,"passed":true},{"actual":-820,"check":"fee oracle 6","expected":0,"passed":false},{"actual":550,"check":"fee oracle 7","expected":550,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fee oracle 0\", \"actual\": 300, \"expected\": 300, \"passed\": true}, {\"check\": \"fee oracle 1\", \"actual\": 2400, \"expected\": 2400, \"passed\": true}, {\"check\": \"fee oracle 2\", \"actual\": 1350, \"expected\": 1350, \"passed\": true}, {\"check\": \"fee oracle 3\", \"actual\": -250, \"expected\": 0, \"passed\": false}, {\"check\": \"fee oracle 4\", \"actual\": -500, \"expected\": 0, \"passed\": false}, {\"check\": \"fee oracle 5\", \"actual\": 700, \"expected\": 700, \"passed\": true}, {\"check\": \"fee oracle 6\", \"actual\": -820, \"expected\": 0, \"passed\": false}, {\"check\": \"fee oracle 7\", \"actual\": 550, \"expected\": 550, \"passed\": true}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}