{"abstract":"Arabic-Indic digit strings are scored as valid or invalid instead of malformed.","category":"Check-digit algorithms","checks":8,"contract":"Input a card-style number that may contain spaces or hyphens as group separators. After removing them the text must be 2..19 ASCII digits, otherwise \"malformed\". Doubling applies to every second digit counting from the rightmost (check) digit, doubled values above 9 lose 9, and the number is \"valid\" when the sum is a multiple of 10, else \"invalid\".","contract_signature":"s","evaluation_group":"w2-check_digit_algorithms-luhn-validate","failed_approach":"Switching to isdecimal still admits every Unicode decimal digit.","family":"w2-check_digit_algorithms-luhn-validate-ascii-digit-gate","id":"FA-72361","implementations":{"attempt":{"sha256":"386e83b82b84894eb3d522d6525138a17d2b234511241dade2f1954029d96592","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(s):\n    t = s.replace(' ', '').replace('-', '')\n    if not t.isdecimal() or len(t) < 2 or len(t) > 19:\n        return 'malformed'\n    total = 0\n    for i, ch in enumerate(reversed(t)):\n        d = ord(ch) - 48\n        if i % 2 == 1:\n            d *= 2\n            if d > 9:\n                d -= 9\n        total += d\n    return 'valid' if total % 10 == 0 else 'invalid'\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[['regression [\"١٨\"]', ['١٨'], 'malformed'], ['regression [\"٣٤٥\"]', ['٣٤٥'], 'malformed'], ['control [\"59\"]', ['59'], 'valid'], ['control [\"182\"]', ['182'], 'valid'], ['control [\"97956\"]', ['97956'], 'valid'], ['control [\"60866456\"]', ['60866456'], 'valid'], ['control [\"49717735275\"]', ['49717735275'], 'valid'], ['control [\"9207919074163\"]', ['9207919074163'], 'valid']], [['regression [\"٣٤٥\"]', ['٣٤٥'], 'malformed'], ['regression [\"١٨\"]', ['١٨'], 'malformed'], ['control [\"9207919074163\"]', ['9207919074163'], 'valid'], ['control [\"470663048070284\"]', ['470663048070284'], 'valid'], ['control [\"2300017738893848\"]', ['2300017738893848'], 'valid'], ['control [\"7985145013991721\"]', ['7985145013991721'], 'valid'], ['control [\"067122965057139178\"]', ['067122965057139178'], 'valid'], ['control [\"1513156399001929628\"]', ['1513156399001929628'], 'valid']], [['regression [\"١٨\"]', ['١٨'], 'malformed'], ['regression [\"٣٤٥\"]', ['٣٤٥'], 'malformed'], ['control [\"1513156399001929628\"]', ['1513156399001929628'], 'valid'], ['control [\"9505094299844733505\"]', ['9505094299844733505'], 'valid'], ['control [\"0906050370970\"]', ['0906050370970'], 'valid'], ['control [\"3165356977\"]', ['3165356977'], 'valid'], ['control [\"91\"]', ['91'], 'valid'], ['control [\"992\"]', ['992'], 'valid']], [['regression [\"٣٤٥\"]', ['٣٤٥'], 'malformed'], ['regression [\"١٨\"]', ['١٨'], 'malformed'], ['control [\"992\"]', ['992'], 'valid'], ['control [\"5553\"]', ['5553'], 'valid'], ['control [\"77777779\"]', ['77777779'], 'valid'], ['control [\"52\"]', ['52'], 'invalid'], ['control [\"185\"]', ['185'], 'invalid'], ['control [\"97959\"]', ['97959'], 'invalid']], [['regression [\"١٨\"]', ['١٨'], 'malformed'], ['regression [\"٣٤٥\"]', ['٣٤٥'], 'malformed'], ['control [\"97959\"]', ['97959'], 'invalid'], ['control [\"60866459\"]', ['60866459'], 'invalid'], ['control [\"49717735278\"]', ['49717735278'], 'invalid'], ['control [\"9207919074166\"]', ['9207919074166'], 'invalid'], ['control [\"470663048070287\"]', ['470663048070287'], 'invalid'], ['control [\"2300017738893841\"]', ['2300017738893841'], 'invalid']]]\nfor label, args, expected in fixtures[N - 1]:\n    check(label, 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":"2ef937e169432a71370ee16916dca4a8478be29f48412b7796e6423270b43b47","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(s):\n    t = s.replace(' ', '').replace('-', '')\n    if not t.isdigit() or len(t) < 2 or len(t) > 19:\n        return 'malformed'\n    total = 0\n    for i, ch in enumerate(reversed(t)):\n        d = ord(ch) - 48\n        if i % 2 == 1:\n            d *= 2\n            if d > 9:\n                d -= 9\n        total += d\n    return 'valid' if total % 10 == 0 else 'invalid'\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[['regression [\"١٨\"]', ['١٨'], 'malformed'], ['regression [\"٣٤٥\"]', ['٣٤٥'], 'malformed'], ['control [\"59\"]', ['59'], 'valid'], ['control [\"182\"]', ['182'], 'valid'], ['control [\"97956\"]', ['97956'], 'valid'], ['control [\"60866456\"]', ['60866456'], 'valid'], ['control [\"49717735275\"]', ['49717735275'], 'valid'], ['control [\"9207919074163\"]', ['9207919074163'], 'valid']], [['regression [\"٣٤٥\"]', ['٣٤٥'], 'malformed'], ['regression [\"١٨\"]', ['١٨'], 'malformed'], ['control [\"9207919074163\"]', ['9207919074163'], 'valid'], ['control [\"470663048070284\"]', ['470663048070284'], 'valid'], ['control [\"2300017738893848\"]', ['2300017738893848'], 'valid'], ['control [\"7985145013991721\"]', ['7985145013991721'], 'valid'], ['control [\"067122965057139178\"]', ['067122965057139178'], 'valid'], ['control [\"1513156399001929628\"]', ['1513156399001929628'], 'valid']], [['regression [\"١٨\"]', ['١٨'], 'malformed'], ['regression [\"٣٤٥\"]', ['٣٤٥'], 'malformed'], ['control [\"1513156399001929628\"]', ['1513156399001929628'], 'valid'], ['control [\"9505094299844733505\"]', ['9505094299844733505'], 'valid'], ['control [\"0906050370970\"]', ['0906050370970'], 'valid'], ['control [\"3165356977\"]', ['3165356977'], 'valid'], ['control [\"91\"]', ['91'], 'valid'], ['control [\"992\"]', ['992'], 'valid']], [['regression [\"٣٤٥\"]', ['٣٤٥'], 'malformed'], ['regression [\"١٨\"]', ['١٨'], 'malformed'], ['control [\"992\"]', ['992'], 'valid'], ['control [\"5553\"]', ['5553'], 'valid'], ['control [\"77777779\"]', ['77777779'], 'valid'], ['control [\"52\"]', ['52'], 'invalid'], ['control [\"185\"]', ['185'], 'invalid'], ['control [\"97959\"]', ['97959'], 'invalid']], [['regression [\"١٨\"]', ['١٨'], 'malformed'], ['regression [\"٣٤٥\"]', ['٣٤٥'], 'malformed'], ['control [\"97959\"]', ['97959'], 'invalid'], ['control [\"60866459\"]', ['60866459'], 'invalid'], ['control [\"49717735278\"]', ['49717735278'], 'invalid'], ['control [\"9207919074166\"]', ['9207919074166'], 'invalid'], ['control [\"470663048070287\"]', ['470663048070287'], 'invalid'], ['control [\"2300017738893841\"]', ['2300017738893841'], 'invalid']]]\nfor label, args, expected in fixtures[N - 1]:\n    check(label, 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 teaching model of the named scheme under the stated contract; not a certified validator. 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-check_digit_algorithms-luhn-validate-ascii-digit-gate","generated_at":"2026-09-29T14:48:37.810974+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Payment-card, loyalty and account numbers are screened with the Luhn mod-10 check before any lookup.","root_cause":"The gate relies on str.isdigit without isascii, so Unicode digits pass and ord(ch) - 48 yields huge values.","sha256":"0b7b03ad2cf7f7eac0c25ffa7fb8c9a7b19a19432b7d302faed032b8220ca35f","title":"Luhn gate accepts non-ASCII decimal digits · 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":38.276,"exit_code":1,"observations":[{"actual":"invalid","check":"regression [\"١٨\"]","expected":"malformed","passed":false},{"actual":"invalid","check":"regression [\"٣٤٥\"]","expected":"malformed","passed":false},{"actual":"valid","check":"control [\"59\"]","expected":"valid","passed":true},{"actual":"valid","check":"control [\"182\"]","expected":"valid","passed":true},{"actual":"valid","check":"control [\"97956\"]","expected":"valid","passed":true},{"actual":"valid","check":"control [\"60866456\"]","expected":"valid","passed":true},{"actual":"valid","check":"control [\"49717735275\"]","expected":"valid","passed":true},{"actual":"valid","check":"control [\"9207919074163\"]","expected":"valid","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression [\\\"١٨\\\"]\", \"actual\": \"invalid\", \"expected\": \"malformed\", \"passed\": false}, {\"check\": \"regression [\\\"٣٤٥\\\"]\", \"actual\": \"invalid\", \"expected\": \"malformed\", \"passed\": false}, {\"check\": \"control [\\\"59\\\"]\", \"actual\": \"valid\", \"expected\": \"valid\", \"passed\": true}, {\"check\": \"control [\\\"182\\\"]\", \"actual\": \"valid\", \"expected\": \"valid\", \"passed\": true}, {\"check\": \"control [\\\"97956\\\"]\", \"actual\": \"valid\", \"expected\": \"valid\", \"passed\": true}, {\"check\": \"control [\\\"60866456\\\"]\", \"actual\": \"valid\", \"expected\": \"valid\", \"passed\": true}, {\"check\": \"control [\\\"49717735275\\\"]\", \"actual\": \"valid\", \"expected\": \"valid\", \"passed\": true}, {\"check\": \"control [\\\"9207919074163\\\"]\", \"actual\": \"valid\", \"expected\": \"valid\", \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":36.048,"exit_code":1,"observations":[{"actual":"invalid","check":"regression [\"١٨\"]","expected":"malformed","passed":false},{"actual":"invalid","check":"regression [\"٣٤٥\"]","expected":"malformed","passed":false},{"actual":"valid","check":"control [\"59\"]","expected":"valid","passed":true},{"actual":"valid","check":"control [\"182\"]","expected":"valid","passed":true},{"actual":"valid","check":"control [\"97956\"]","expected":"valid","passed":true},{"actual":"valid","check":"control [\"60866456\"]","expected":"valid","passed":true},{"actual":"valid","check":"control [\"49717735275\"]","expected":"valid","passed":true},{"actual":"valid","check":"control [\"9207919074163\"]","expected":"valid","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression [\\\"١٨\\\"]\", \"actual\": \"invalid\", \"expected\": \"malformed\", \"passed\": false}, {\"check\": \"regression [\\\"٣٤٥\\\"]\", \"actual\": \"invalid\", \"expected\": \"malformed\", \"passed\": false}, {\"check\": \"control [\\\"59\\\"]\", \"actual\": \"valid\", \"expected\": \"valid\", \"passed\": true}, {\"check\": \"control [\\\"182\\\"]\", \"actual\": \"valid\", \"expected\": \"valid\", \"passed\": true}, {\"check\": \"control [\\\"97956\\\"]\", \"actual\": \"valid\", \"expected\": \"valid\", \"passed\": true}, {\"check\": \"control [\\\"60866456\\\"]\", \"actual\": \"valid\", \"expected\": \"valid\", \"passed\": true}, {\"check\": \"control [\\\"49717735275\\\"]\", \"actual\": \"valid\", \"expected\": \"valid\", \"passed\": true}, {\"check\": \"control [\\\"9207919074163\\\"]\", \"actual\": \"valid\", \"expected\": \"valid\", \"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."}}