{"abstract":"Dns edns payload negotiation respects both peer and local cap.","category":"DNS resolution","checks":4,"contract":"Bounded offline decision model: dns edns payload negotiation respects both peer and local cap. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.","contract_signature":"advertised, local","evaluation_group":"xh-dns-edns-payload-negotiation-respects-both-peer-and-local-cap","failed_approach":"The attempted repair uses `max(advertised,local)` and still violates a separate fixture.","family":"xh-dns-edns-payload-negotiation-respects-both-peer-and-local-cap","id":"FA-7426","implementations":{"attempt":{"sha256":"cd238b99ebad786fd8c7c98b4eec6adb557d412d90bea0d0d8777e5676fd6582","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(advertised, local):\n    return max(advertised,local)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(4096, 1232), 1232)\", \"check('fixture 2', solve(100, 1232), 512)\", \"check('fixture 3', solve(512, 1232), 512)\", \"check('fixture 4', solve(1232, 1232), 1232)\"]\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":"b730a78492972fa60bd9b9f69bb7c466a23f1cf3c4db1a00474316c47ca03200","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(advertised, local):\n    return advertised\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(4096, 1232), 1232)\", \"check('fixture 2', solve(100, 1232), 512)\", \"check('fixture 3', solve(512, 1232), 512)\", \"check('fixture 4', solve(1232, 1232), 1232)\"]\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-edns-payload-negotiation-respects-both-peer-and-local-cap","generated_at":"2026-09-29T14:38:11.810472+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic dns resolution model isolates the dns-edns-payload-negotiation-respects-both-peer-and-local-cap policy at a network component boundary.","root_cause":"The faulty implementation uses `advertised` for the dns-edns-payload-negotiation-respects-both-peer-and-local-cap decision.","sha256":"1fda83124427ecb6c97f11758423309afc56e650ecee503f615f6c7e5b4736e5","title":"Dns edns payload negotiation respects both peer and local cap · 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":53.001,"exit_code":1,"observations":[{"actual":1232,"check":"fixture 2","expected":512,"passed":false},{"actual":1232,"check":"fixture 3","expected":512,"passed":false},{"actual":1232,"check":"fixture 4","expected":1232,"passed":true},{"actual":4096,"check":"fixture 1","expected":1232,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 1232, \"expected\": 512, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": 1232, \"expected\": 512, \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": 1232, \"expected\": 1232, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": 4096, \"expected\": 1232, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":43.198,"exit_code":1,"observations":[{"actual":100,"check":"fixture 2","expected":512,"passed":false},{"actual":512,"check":"fixture 3","expected":512,"passed":true},{"actual":1232,"check":"fixture 4","expected":1232,"passed":true},{"actual":4096,"check":"fixture 1","expected":1232,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 100, \"expected\": 512, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": 512, \"expected\": 512, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 1232, \"expected\": 1232, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": 4096, \"expected\": 1232, \"passed\": false}], \"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."}}