{"abstract":"Send window is minimum of peer and congestion windows.","category":"Transport flow control","checks":4,"contract":"Bounded offline decision model: send window is minimum of peer and congestion windows. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.","evaluation_group":"xh-send-window-is-minimum-of-peer-and-congestion-windows","failed_approach":"The attempted repair uses `min(peer,congestion)` and still violates a separate fixture.","family":"xh-send-window-is-minimum-of-peer-and-congestion-windows","id":"FA-7206","implementations":{"attempt":{"sha256":"613125f8a16fe331a505e954b0795c0f0957e293e5e3dba33613488937322e98","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(peer, congestion, flight):\n    return min(peer,congestion)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(10, 5, 2), 3)\", \"check('fixture 2', solve(3, 10, 4), 0)\", \"check('fixture 3', solve(10, 10, 0), 10)\", \"check('fixture 4', solve(0, 10, 0), 0)\"]\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":"4ec5fe44e1434e5d02759bbfc19b3d6c90b2263ccaa9d28e3df6af680c32cfd4","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(peer, congestion, flight):\n    return max(0,max(peer,congestion)-flight)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(10, 5, 2), 3)\", \"check('fixture 2', solve(3, 10, 4), 0)\", \"check('fixture 3', solve(10, 10, 0), 10)\", \"check('fixture 4', solve(0, 10, 0), 0)\"]\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":"e5c752f903245c17b2754a3a1330f2b92fc7fc81bae53665bb95c565deca2040","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(peer, congestion, flight):\n    return max(0,min(peer,congestion)-flight)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(10, 5, 2), 3)\", \"check('fixture 2', solve(3, 10, 4), 0)\", \"check('fixture 3', solve(10, 10, 0), 10)\", \"check('fixture 4', solve(0, 10, 0), 0)\"]\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-send-window-is-minimum-of-peer-and-congestion-windows","generated_at":"2026-09-29T14:38:09.396561+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic transport flow control model isolates the send-window-is-minimum-of-peer-and-congestion-windows policy at a network component boundary.","repair":"Apply the explicit send-window-is-minimum-of-peer-and-congestion-windows contract, including the tested boundary and negative cases.","root_cause":"The faulty implementation uses `max(0,max(peer,congestion)-flight)` for the send-window-is-minimum-of-peer-and-congestion-windows decision.","sha256":"1ecf385bef23756cd6f2237efea2c32d9eb6a2880f26db8e8f38609cee165d30","title":"Send window is minimum of peer and congestion windows · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":45.722,"exit_code":1,"observations":[{"actual":3,"check":"fixture 2","expected":0,"passed":false},{"actual":10,"check":"fixture 3","expected":10,"passed":true},{"actual":0,"check":"fixture 4","expected":0,"passed":true},{"actual":5,"check":"fixture 1","expected":3,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 3, \"expected\": 0, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": 10, \"expected\": 10, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": 5, \"expected\": 3, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":45.781,"exit_code":1,"observations":[{"actual":6,"check":"fixture 2","expected":0,"passed":false},{"actual":10,"check":"fixture 3","expected":10,"passed":true},{"actual":10,"check":"fixture 4","expected":0,"passed":false},{"actual":8,"check":"fixture 1","expected":3,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 6, \"expected\": 0, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": 10, \"expected\": 10, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 10, \"expected\": 0, \"passed\": false}, {\"check\": \"fixture 1\", \"actual\": 8, \"expected\": 3, \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":43.942,"exit_code":0,"observations":[{"actual":0,"check":"fixture 2","expected":0,"passed":true},{"actual":10,"check":"fixture 3","expected":10,"passed":true},{"actual":0,"check":"fixture 4","expected":0,"passed":true},{"actual":3,"check":"fixture 1","expected":3,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": 10, \"expected\": 10, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": 3, \"expected\": 3, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}