{"abstract":"Multipart response type carries a boundary rather than the object media type.","category":"HTTP ranges","checks":6,"contract":"Return the stipulated ASCII top-level type multipart/byteranges; boundary=\"value\". Boundary has only letters/digits and may be empty in this framing-unit test.","contract_signature":"boundary, object_type","evaluation_group":"s3-http_ranges-multipart","failed_approach":"The partial repair uses return \"multipart/byteranges\", which still violates the stated contract.","family":"s3-http_ranges-multipart-top-content-type","id":"FA-26456","implementations":{"attempt":{"sha256":"e6f03a9c2f0f5b8ddd311cf51af46a1489e49f917a1f74cded29db52b76402ad","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(boundary, object_type):\n    return \"multipart/byteranges\"\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('multipart-top-content-type fixture 0', solve(\"b\"+str(N),\"text/plain\"), \"multipart/byteranges; boundary=\\\"b\"+str(N)+\"\\\"\")\ncheck('multipart-top-content-type fixture 1', solve(\"x\",\"image/png\"), 'multipart/byteranges; boundary=\"x\"')\ncheck('multipart-top-content-type fixture 2', solve(\"\",\"x/y\"), 'multipart/byteranges; boundary=\"\"')\ncheck('multipart-top-content-type fixture 3', solve(\"abc\",\"\"), 'multipart/byteranges; boundary=\"abc\"')\ncheck('multipart-top-content-type fixture 4', solve(\"Z\",\"application/octet-stream\"), 'multipart/byteranges; boundary=\"Z\"')\ncheck('multipart-top-content-type fixture 5', solve(\"ab12\",\"text/plain\"), 'multipart/byteranges; boundary=\"ab12\"')\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":"33f075e5d44f5832b89ec93ec3116885206e6dc9196485604016c4ba53ec1e22","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(boundary, object_type):\n    return object_type\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('multipart-top-content-type fixture 0', solve(\"b\"+str(N),\"text/plain\"), \"multipart/byteranges; boundary=\\\"b\"+str(N)+\"\\\"\")\ncheck('multipart-top-content-type fixture 1', solve(\"x\",\"image/png\"), 'multipart/byteranges; boundary=\"x\"')\ncheck('multipart-top-content-type fixture 2', solve(\"\",\"x/y\"), 'multipart/byteranges; boundary=\"\"')\ncheck('multipart-top-content-type fixture 3', solve(\"abc\",\"\"), 'multipart/byteranges; boundary=\"abc\"')\ncheck('multipart-top-content-type fixture 4', solve(\"Z\",\"application/octet-stream\"), 'multipart/byteranges; boundary=\"Z\"')\ncheck('multipart-top-content-type fixture 5', solve(\"ab12\",\"text/plain\"), 'multipart/byteranges; boundary=\"ab12\"')\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":"Deterministic simplified range service, with stipulated local policies and already parsed trusted inputs; not a complete HTTP implementation. 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":"s3-http_ranges-multipart-top-content-type","generated_at":"2026-09-29T14:41:16.253557+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Range responses combine representation identity, conditional requests, framing, and partial-object state.","root_cause":"The multipart-top-content-type decision uses return object_type.","sha256":"6ed10667287d7590707f27f7c0feea777b938d9d91bfbf98f20aaa99caba1227","title":"Multipart response type carries a boundary rather than the object media type · 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":40.828,"exit_code":1,"observations":[{"actual":"multipart/byteranges","check":"multipart-top-content-type fixture 0","expected":"multipart/byteranges; boundary=\"b1\"","passed":false},{"actual":"multipart/byteranges","check":"multipart-top-content-type fixture 1","expected":"multipart/byteranges; boundary=\"x\"","passed":false},{"actual":"multipart/byteranges","check":"multipart-top-content-type fixture 2","expected":"multipart/byteranges; boundary=\"\"","passed":false},{"actual":"multipart/byteranges","check":"multipart-top-content-type fixture 3","expected":"multipart/byteranges; boundary=\"abc\"","passed":false},{"actual":"multipart/byteranges","check":"multipart-top-content-type fixture 4","expected":"multipart/byteranges; boundary=\"Z\"","passed":false},{"actual":"multipart/byteranges","check":"multipart-top-content-type fixture 5","expected":"multipart/byteranges; boundary=\"ab12\"","passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"multipart-top-content-type fixture 0\", \"actual\": \"multipart/byteranges\", \"expected\": \"multipart/byteranges; boundary=\\\"b1\\\"\", \"passed\": false}, {\"check\": \"multipart-top-content-type fixture 1\", \"actual\": \"multipart/byteranges\", \"expected\": \"multipart/byteranges; boundary=\\\"x\\\"\", \"passed\": false}, {\"check\": \"multipart-top-content-type fixture 2\", \"actual\": \"multipart/byteranges\", \"expected\": \"multipart/byteranges; boundary=\\\"\\\"\", \"passed\": false}, {\"check\": \"multipart-top-content-type fixture 3\", \"actual\": \"multipart/byteranges\", \"expected\": \"multipart/byteranges; boundary=\\\"abc\\\"\", \"passed\": false}, {\"check\": \"multipart-top-content-type fixture 4\", \"actual\": \"multipart/byteranges\", \"expected\": \"multipart/byteranges; boundary=\\\"Z\\\"\", \"passed\": false}, {\"check\": \"multipart-top-content-type fixture 5\", \"actual\": \"multipart/byteranges\", \"expected\": \"multipart/byteranges; boundary=\\\"ab12\\\"\", \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.247,"exit_code":1,"observations":[{"actual":"text/plain","check":"multipart-top-content-type fixture 0","expected":"multipart/byteranges; boundary=\"b1\"","passed":false},{"actual":"image/png","check":"multipart-top-content-type fixture 1","expected":"multipart/byteranges; boundary=\"x\"","passed":false},{"actual":"x/y","check":"multipart-top-content-type fixture 2","expected":"multipart/byteranges; boundary=\"\"","passed":false},{"actual":"","check":"multipart-top-content-type fixture 3","expected":"multipart/byteranges; boundary=\"abc\"","passed":false},{"actual":"application/octet-stream","check":"multipart-top-content-type fixture 4","expected":"multipart/byteranges; boundary=\"Z\"","passed":false},{"actual":"text/plain","check":"multipart-top-content-type fixture 5","expected":"multipart/byteranges; boundary=\"ab12\"","passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"multipart-top-content-type fixture 0\", \"actual\": \"text/plain\", \"expected\": \"multipart/byteranges; boundary=\\\"b1\\\"\", \"passed\": false}, {\"check\": \"multipart-top-content-type fixture 1\", \"actual\": \"image/png\", \"expected\": \"multipart/byteranges; boundary=\\\"x\\\"\", \"passed\": false}, {\"check\": \"multipart-top-content-type fixture 2\", \"actual\": \"x/y\", \"expected\": \"multipart/byteranges; boundary=\\\"\\\"\", \"passed\": false}, {\"check\": \"multipart-top-content-type fixture 3\", \"actual\": \"\", \"expected\": \"multipart/byteranges; boundary=\\\"abc\\\"\", \"passed\": false}, {\"check\": \"multipart-top-content-type fixture 4\", \"actual\": \"application/octet-stream\", \"expected\": \"multipart/byteranges; boundary=\\\"Z\\\"\", \"passed\": false}, {\"check\": \"multipart-top-content-type fixture 5\", \"actual\": \"text/plain\", \"expected\": \"multipart/byteranges; boundary=\\\"ab12\\\"\", \"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."}}