{"abstract":"Quic final size cannot change after fin.","category":"Multiplexed protocols","checks":4,"contract":"Bounded offline decision model: quic final size cannot change after fin. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.","contract_signature":"known, proposed","evaluation_group":"xh-quic-final-size-cannot-change-after-fin","failed_approach":"The attempted repair uses `bool(known) and known == proposed` and still violates a separate fixture.","family":"xh-quic-final-size-cannot-change-after-fin","id":"FA-7561","implementations":{"attempt":{"sha256":"31482d82c388a94e53c1d3bcdde13be69815b3ea2bf140e8624cf500503f8c6d","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(known, proposed):\n    return bool(known) and known == proposed\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(10, 11), False)\", \"check('fixture 2', solve(None, 10), True)\", \"check('fixture 3', solve(0, 0), True)\", \"check('fixture 4', solve(10, 10), True)\"]\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":"ae58cfbdc1b323f64b285bcc19ec85b7ef02397f6b089a2808a3bdeceab0e38d","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(known, proposed):\n    return proposed >= (known or 0)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(10, 11), False)\", \"check('fixture 2', solve(None, 10), True)\", \"check('fixture 3', solve(0, 0), True)\", \"check('fixture 4', solve(10, 10), True)\"]\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-quic-final-size-cannot-change-after-fin","generated_at":"2026-09-29T14:38:13.196969+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic multiplexed protocols model isolates the quic-final-size-cannot-change-after-fin policy at a network component boundary.","root_cause":"The faulty implementation uses `proposed >= (known or 0)` for the quic-final-size-cannot-change-after-fin decision.","sha256":"e102ee7cb3b5b9ba511dd8051c28a3d7dff517a3f4e9d4b8c79fef10721c3cec","title":"Quic final size cannot change after fin · 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":40.741,"exit_code":1,"observations":[{"actual":false,"check":"fixture 2","expected":true,"passed":false},{"actual":false,"check":"fixture 3","expected":true,"passed":false},{"actual":true,"check":"fixture 4","expected":true,"passed":true},{"actual":false,"check":"fixture 1","expected":false,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": false, \"expected\": true, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": false, \"expected\": true, \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": false, \"expected\": false, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.78,"exit_code":1,"observations":[{"actual":true,"check":"fixture 2","expected":true,"passed":true},{"actual":true,"check":"fixture 3","expected":true,"passed":true},{"actual":true,"check":"fixture 4","expected":true,"passed":true},{"actual":true,"check":"fixture 1","expected":false,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": true, \"expected\": false, \"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."}}