{"abstract":"Dns rrset ttl uses lowest member ttl.","category":"DNS resolution","checks":4,"contract":"Bounded offline decision model: dns rrset ttl uses lowest member ttl. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.","evaluation_group":"xh-dns-rrset-ttl-uses-lowest-member-ttl","failed_approach":"The attempted repair uses `sum(ttls)//len(ttls) if ttls else 0` and still violates a separate fixture.","family":"xh-dns-rrset-ttl-uses-lowest-member-ttl","id":"FA-7356","implementations":{"attempt":{"sha256":"0f847387b455aa442e5c1394623554842900a5a594286c27546278a354b52921","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(ttls):\n    return sum(ttls)//len(ttls) if ttls else 0\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve([30, 60]), 30)\", \"check('fixture 2', solve([]), 0)\", \"check('fixture 3', solve([0, 30]), 0)\", \"check('fixture 4', solve([10]), 10)\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\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":"5440799591b4e2f5c7800153f379e5afa8baeb6c9b7f6043330dfe0483132a52","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(ttls):\n    return max(ttls) if ttls else 0\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve([30, 60]), 30)\", \"check('fixture 2', solve([]), 0)\", \"check('fixture 3', solve([0, 30]), 0)\", \"check('fixture 4', solve([10]), 10)\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\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":"912f1feab84660e59eddc054d44268cb5ebf4d828b67a10c65638147fd5b26c9","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(ttls):\n    return min(ttls) if ttls else 0\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve([30, 60]), 30)\", \"check('fixture 2', solve([]), 0)\", \"check('fixture 3', solve([0, 30]), 0)\", \"check('fixture 4', solve([10]), 10)\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\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":"Bounded deterministic policy model over validated inputs; not a complete protocol stack or an interoperability claim. The five variants rotate the same explicit fixture set. 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":"xh-dns-rrset-ttl-uses-lowest-member-ttl","generated_at":"2026-09-29T14:38:10.988467+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic dns resolution model isolates the dns-rrset-ttl-uses-lowest-member-ttl policy at a network component boundary.","repair":"Apply the explicit dns-rrset-ttl-uses-lowest-member-ttl contract, including the tested boundary and negative cases.","root_cause":"The faulty implementation uses `max(ttls) if ttls else 0` for the dns-rrset-ttl-uses-lowest-member-ttl decision.","sha256":"49e21741991fc39e4492ee9a98558edb41a26ecc919874eb7fc3fceff20cc2a2","title":"Dns rrset ttl uses lowest member ttl · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":48.406,"exit_code":1,"observations":[{"actual":0,"check":"fixture 2","expected":0,"passed":true},{"actual":15,"check":"fixture 3","expected":0,"passed":false},{"actual":10,"check":"fixture 4","expected":10,"passed":true},{"actual":45,"check":"fixture 1","expected":30,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": 15, \"expected\": 0, \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": 10, \"expected\": 10, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": 45, \"expected\": 30, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":43.963,"exit_code":1,"observations":[{"actual":0,"check":"fixture 2","expected":0,"passed":true},{"actual":30,"check":"fixture 3","expected":0,"passed":false},{"actual":10,"check":"fixture 4","expected":10,"passed":true},{"actual":60,"check":"fixture 1","expected":30,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": 30, \"expected\": 0, \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": 10, \"expected\": 10, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": 60, \"expected\": 30, \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":53.612,"exit_code":0,"observations":[{"actual":0,"check":"fixture 2","expected":0,"passed":true},{"actual":0,"check":"fixture 3","expected":0,"passed":true},{"actual":10,"check":"fixture 4","expected":10,"passed":true},{"actual":30,"check":"fixture 1","expected":30,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 10, \"expected\": 10, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": 30, \"expected\": 30, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}