{"abstract":"An open byte range clips at representation length and rejects starts beyond it.","category":"HTTP ranges","checks":4,"contract":"An open byte range clips at representation length and rejects starts beyond it: return the result specified by the explicit input/output boundary fixtures.","contract_signature":"start, length","evaluation_group":"xh-range-open","failed_approach":"The attempted repair uses `(min(start,length-1),length-1) if length else None` and still violates a separate fixture.","family":"xh-range-open","id":"FA-6686","implementations":{"attempt":{"sha256":"85d912a6f96750ededf09e29f15e67c4feb7d709c3c5fbbcb4fc880c77b9fd25","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(start, length):\n    return (min(start,length-1),length-1) if length else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(2, 5), (2, 4))\", \"check('fixture 2', solve(5, 5), None)\", \"check('fixture 3', solve(0, 1), (0, 0))\", \"check('fixture 4', solve(0, 0), None)\"]\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":"d024c69121a87cda074fc77a6dbd58e18ceb0cccf53c1633b2656f14e7a2c41f","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(start, length):\n    return (start, length)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(2, 5), (2, 4))\", \"check('fixture 2', solve(5, 5), None)\", \"check('fixture 3', solve(0, 1), (0, 0))\", \"check('fixture 4', solve(0, 0), None)\"]\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-range-open","generated_at":"2026-09-29T14:38:04.341491+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic http ranges model isolates the range-open policy at a network component boundary.","root_cause":"The faulty implementation uses `(start, length)` for the range-open decision.","sha256":"518472553a15980c8371d9e2574c6d358222caab642cd3ed70de925c12d8290e","title":"An open byte range clips at representation length and rejects starts beyond it · 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":35.164,"exit_code":1,"observations":[{"actual":[4,4],"check":"fixture 2","expected":null,"passed":false},{"actual":[0,0],"check":"fixture 3","expected":[0,0],"passed":true},{"actual":null,"check":"fixture 4","expected":null,"passed":true},{"actual":[2,4],"check":"fixture 1","expected":[2,4],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": [4, 4], \"expected\": null, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [0, 0], \"expected\": [0, 0], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": [2, 4], \"expected\": [2, 4], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.035,"exit_code":1,"observations":[{"actual":[5,5],"check":"fixture 2","expected":null,"passed":false},{"actual":[0,1],"check":"fixture 3","expected":[0,0],"passed":false},{"actual":[0,0],"check":"fixture 4","expected":null,"passed":false},{"actual":[2,5],"check":"fixture 1","expected":[2,4],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": [5, 5], \"expected\": null, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [0, 1], \"expected\": [0, 0], \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": [0, 0], \"expected\": null, \"passed\": false}, {\"check\": \"fixture 1\", \"actual\": [2, 5], \"expected\": [2, 4], \"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."}}