{"abstract":"Http2 initial window change applies delta to existing streams.","category":"Multiplexed protocols","checks":4,"contract":"Bounded offline decision model: http2 initial window change applies delta to existing streams. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.","contract_signature":"current, old, new","evaluation_group":"xh-http2-initial-window-change-applies-delta-to-existing-streams","failed_approach":"The attempted repair uses `max(0,current+new-old)` and still violates a separate fixture.","family":"xh-http2-initial-window-change-applies-delta-to-existing-streams","id":"FA-7491","implementations":{"attempt":{"sha256":"03483de441276442eae1d23b91a74fc0b207a75eacd3b7d178518f134355b09e","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(current, old, new):\n    return max(0,current+new-old)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(3, 10, 5), -2)\", \"check('fixture 2', solve(7, 10, 20), 17)\", \"check('fixture 3', solve(0, 0, 0), 0)\", \"check('fixture 4', solve(4, 5, 5), 4)\"]\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":"41564783c8a9702bda31fff7250cf470a8712e8595203f9b11a875bad252c3a6","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(current, old, new):\n    return new\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(3, 10, 5), -2)\", \"check('fixture 2', solve(7, 10, 20), 17)\", \"check('fixture 3', solve(0, 0, 0), 0)\", \"check('fixture 4', solve(4, 5, 5), 4)\"]\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-http2-initial-window-change-applies-delta-to-existing-streams","generated_at":"2026-09-29T14:38:12.578487+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic multiplexed protocols model isolates the http2-initial-window-change-applies-delta-to-existing-streams policy at a network component boundary.","root_cause":"The faulty implementation uses `new` for the http2-initial-window-change-applies-delta-to-existing-streams decision.","sha256":"6a180c154dc283fd64bf2bc8004332f009ea0ae0029990beced6ef5d0a367fb6","title":"Http2 initial window change applies delta to existing streams · 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":43.83,"exit_code":1,"observations":[{"actual":17,"check":"fixture 2","expected":17,"passed":true},{"actual":0,"check":"fixture 3","expected":0,"passed":true},{"actual":4,"check":"fixture 4","expected":4,"passed":true},{"actual":0,"check":"fixture 1","expected":-2,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 17, \"expected\": 17, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 4, \"expected\": 4, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": 0, \"expected\": -2, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.661,"exit_code":1,"observations":[{"actual":20,"check":"fixture 2","expected":17,"passed":false},{"actual":0,"check":"fixture 3","expected":0,"passed":true},{"actual":5,"check":"fixture 4","expected":4,"passed":false},{"actual":5,"check":"fixture 1","expected":-2,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 20, \"expected\": 17, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 5, \"expected\": 4, \"passed\": false}, {\"check\": \"fixture 1\", \"actual\": 5, \"expected\": -2, \"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."}}