{"abstract":"Calendar quarters ignore the fiscal start month.","category":"Calendar arithmetic","checks":4,"contract":"Valid ISO Gregorian dates in years 1 through 9999; generated dates must remain in that range. Month is 1 through 12 and zero-based weekday is Monday 0 through Sunday 6 unless the output convention says otherwise. month,start are 1..12; fiscal quarter one starts at start and lasts three months. Exact operational definition: ((month-start)%12)//3+1","evaluation_group":"model-7bd072c926277705","failed_approach":"Absolute month distance loses year wrap direction.","family":"xn-fiscal-quarter-offset-start-month","id":"FA-6511","implementations":{"attempt":{"sha256":"51b97aff4f569c6d7584a7b8b8cf6e7c4212a03737f39084184e06708ba2d5b6","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nimport calendar\nimport statistics\nimport itertools\nfrom fractions import Fraction\nfrom datetime import date, datetime, timedelta, timezone\nfrom decimal import Decimal, ROUND_HALF_UP, ROUND_DOWN, ROUND_CEILING, ROUND_FLOOR\n\nN = 1\nobservations = []\ndef solve(month, start):\n    return abs(month-start)//3+1\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: (4, 4)', solve(*(4, 4)), 1)\ncheck('fixture 2: (3, 4)', solve(*(3, 4)), 4)\ncheck('fixture 3: (1, 10)', solve(*(1, 10)), 2)\ncheck('fixture 4: (12, 10)', solve(*(12, 10)), 1)\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":"7156f64e304f3811fb9530bc5a95ccd5686701d2986b34a442340cc8f83ffc29","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nimport calendar\nimport statistics\nimport itertools\nfrom fractions import Fraction\nfrom datetime import date, datetime, timedelta, timezone\nfrom decimal import Decimal, ROUND_HALF_UP, ROUND_DOWN, ROUND_CEILING, ROUND_FLOOR\n\nN = 1\nobservations = []\ndef solve(month, start):\n    return (month-1)//3+1\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: (4, 4)', solve(*(4, 4)), 1)\ncheck('fixture 2: (3, 4)', solve(*(3, 4)), 4)\ncheck('fixture 3: (1, 10)', solve(*(1, 10)), 2)\ncheck('fixture 4: (12, 10)', solve(*(12, 10)), 1)\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"},"fixed":{"sha256":"a5bf196c64676d4c31d84731fd888e5b89849261a9f0a5d5fc2910f100446ae6","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nimport calendar\nimport statistics\nimport itertools\nfrom fractions import Fraction\nfrom datetime import date, datetime, timedelta, timezone\nfrom decimal import Decimal, ROUND_HALF_UP, ROUND_DOWN, ROUND_CEILING, ROUND_FLOOR\n\nN = 1\nobservations = []\ndef solve(month, start):\n    return ((month-start)%12)//3+1\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1: (4, 4)', solve(*(4, 4)), 1)\ncheck('fixture 2: (3, 4)', solve(*(3, 4)), 4)\ncheck('fixture 3: (1, 10)', solve(*(1, 10)), 2)\ncheck('fixture 4: (12, 10)', solve(*(12, 10)), 1)\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":" 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":"xn-fiscal-quarter-offset-start-month","generated_at":"2026-09-29T14:38:02.719474+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Small exact fixtures expose this error without platform timing, external services, or probabilistic observations. Calendar conventions results depend on the stated convention.","repair":"Apply the specified mathematical contract directly, preserving all terms and boundary cases: return ((month-start)%12)//3+1","root_cause":"Calendar quarters ignore the fiscal start month.","sha256":"9a98ad5be32a1b01dd6a7b530506db8168c2cf4095329130704ae83bf24d0a1b","title":"Fiscal quarter offset start month · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":40.514,"exit_code":1,"observations":[{"actual":1,"check":"fixture 1: (4, 4)","expected":1,"passed":true},{"actual":1,"check":"fixture 2: (3, 4)","expected":4,"passed":false},{"actual":4,"check":"fixture 3: (1, 10)","expected":2,"passed":false},{"actual":1,"check":"fixture 4: (12, 10)","expected":1,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: (4, 4)\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"fixture 2: (3, 4)\", \"actual\": 1, \"expected\": 4, \"passed\": false}, {\"check\": \"fixture 3: (1, 10)\", \"actual\": 4, \"expected\": 2, \"passed\": false}, {\"check\": \"fixture 4: (12, 10)\", \"actual\": 1, \"expected\": 1, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.811,"exit_code":1,"observations":[{"actual":2,"check":"fixture 1: (4, 4)","expected":1,"passed":false},{"actual":1,"check":"fixture 2: (3, 4)","expected":4,"passed":false},{"actual":1,"check":"fixture 3: (1, 10)","expected":2,"passed":false},{"actual":4,"check":"fixture 4: (12, 10)","expected":1,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: (4, 4)\", \"actual\": 2, \"expected\": 1, \"passed\": false}, {\"check\": \"fixture 2: (3, 4)\", \"actual\": 1, \"expected\": 4, \"passed\": false}, {\"check\": \"fixture 3: (1, 10)\", \"actual\": 1, \"expected\": 2, \"passed\": false}, {\"check\": \"fixture 4: (12, 10)\", \"actual\": 4, \"expected\": 1, \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":41.298,"exit_code":0,"observations":[{"actual":1,"check":"fixture 1: (4, 4)","expected":1,"passed":true},{"actual":4,"check":"fixture 2: (3, 4)","expected":4,"passed":true},{"actual":2,"check":"fixture 3: (1, 10)","expected":2,"passed":true},{"actual":1,"check":"fixture 4: (12, 10)","expected":1,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1: (4, 4)\", \"actual\": 1, \"expected\": 1, \"passed\": true}, {\"check\": \"fixture 2: (3, 4)\", \"actual\": 4, \"expected\": 4, \"passed\": true}, {\"check\": \"fixture 3: (1, 10)\", \"actual\": 2, \"expected\": 2, \"passed\": true}, {\"check\": \"fixture 4: (12, 10)\", \"actual\": 1, \"expected\": 1, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}