{"abstract":"The multipart terminator closes the boundary exactly once.","category":"HTTP ranges","checks":6,"contract":"Return serialized preframed chunks followed by --boundary-- CRLF, including an empty multipart body.","contract_signature":"boundary, chunks","evaluation_group":"s3-http_ranges-multipart","failed_approach":"The partial repair uses return \"\".join(chunks)+(\"--\"+boundary+\"--\\r\\n\" if chunks else \"\"), which still violates the stated contract.","family":"s3-http_ranges-multipart-closing-delimiter","id":"FA-26446","implementations":{"attempt":{"sha256":"047c03488c25938ceeb54fd1cfb21244b086db888559e98c029b8f3c04433c48","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(boundary, chunks):\n    return \"\".join(chunks)+(\"--\"+boundary+\"--\\r\\n\" if chunks else \"\")\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('multipart-closing-delimiter fixture 0', solve(\"b\"+str(N),[]), \"--b\"+str(N)+\"--\\r\\n\")\ncheck('multipart-closing-delimiter fixture 1', solve(\"b\",[\"a\",\"c\"]), \"ac--b--\\r\\n\")\ncheck('multipart-closing-delimiter fixture 2', solve(\"b\",[\"\"]), \"--b--\\r\\n\")\ncheck('multipart-closing-delimiter fixture 3', solve(\"x\",[\"abc\"]), \"abc--x--\\r\\n\")\ncheck('multipart-closing-delimiter fixture 4', solve(\"z\",[\"\\r\\n\"]), \"\\r\\n--z--\\r\\n\")\ncheck('multipart-closing-delimiter fixture 5', solve(\"b\",[\"a\"*N]), \"a\"*N+\"--b--\\r\\n\")\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":"d50e48d8a7597c7308e74e8c1ece8da396f8692ccb38579333146726becede00","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(boundary, chunks):\n    return \"\".join(chunks)+\"--\"+boundary+\"\\r\\n\"\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('multipart-closing-delimiter fixture 0', solve(\"b\"+str(N),[]), \"--b\"+str(N)+\"--\\r\\n\")\ncheck('multipart-closing-delimiter fixture 1', solve(\"b\",[\"a\",\"c\"]), \"ac--b--\\r\\n\")\ncheck('multipart-closing-delimiter fixture 2', solve(\"b\",[\"\"]), \"--b--\\r\\n\")\ncheck('multipart-closing-delimiter fixture 3', solve(\"x\",[\"abc\"]), \"abc--x--\\r\\n\")\ncheck('multipart-closing-delimiter fixture 4', solve(\"z\",[\"\\r\\n\"]), \"\\r\\n--z--\\r\\n\")\ncheck('multipart-closing-delimiter fixture 5', solve(\"b\",[\"a\"*N]), \"a\"*N+\"--b--\\r\\n\")\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-closing-delimiter","generated_at":"2026-09-29T14:41:16.113874+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-closing-delimiter decision uses return \"\".join(chunks)+\"--\"+boundary+\"\\r\\n\".","sha256":"0ce1723643bc79a5f333b4efa64b9a41c67f25cdc26895928960679716f51b57","title":"The multipart terminator closes the boundary exactly once · 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":41.541,"exit_code":1,"observations":[{"actual":"","check":"multipart-closing-delimiter fixture 0","expected":"--b1--\r\n","passed":false},{"actual":"ac--b--\r\n","check":"multipart-closing-delimiter fixture 1","expected":"ac--b--\r\n","passed":true},{"actual":"--b--\r\n","check":"multipart-closing-delimiter fixture 2","expected":"--b--\r\n","passed":true},{"actual":"abc--x--\r\n","check":"multipart-closing-delimiter fixture 3","expected":"abc--x--\r\n","passed":true},{"actual":"\r\n--z--\r\n","check":"multipart-closing-delimiter fixture 4","expected":"\r\n--z--\r\n","passed":true},{"actual":"a--b--\r\n","check":"multipart-closing-delimiter fixture 5","expected":"a--b--\r\n","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"multipart-closing-delimiter fixture 0\", \"actual\": \"\", \"expected\": \"--b1--\\r\\n\", \"passed\": false}, {\"check\": \"multipart-closing-delimiter fixture 1\", \"actual\": \"ac--b--\\r\\n\", \"expected\": \"ac--b--\\r\\n\", \"passed\": true}, {\"check\": \"multipart-closing-delimiter fixture 2\", \"actual\": \"--b--\\r\\n\", \"expected\": \"--b--\\r\\n\", \"passed\": true}, {\"check\": \"multipart-closing-delimiter fixture 3\", \"actual\": \"abc--x--\\r\\n\", \"expected\": \"abc--x--\\r\\n\", \"passed\": true}, {\"check\": \"multipart-closing-delimiter fixture 4\", \"actual\": \"\\r\\n--z--\\r\\n\", \"expected\": \"\\r\\n--z--\\r\\n\", \"passed\": true}, {\"check\": \"multipart-closing-delimiter fixture 5\", \"actual\": \"a--b--\\r\\n\", \"expected\": \"a--b--\\r\\n\", \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.394,"exit_code":1,"observations":[{"actual":"--b1\r\n","check":"multipart-closing-delimiter fixture 0","expected":"--b1--\r\n","passed":false},{"actual":"ac--b\r\n","check":"multipart-closing-delimiter fixture 1","expected":"ac--b--\r\n","passed":false},{"actual":"--b\r\n","check":"multipart-closing-delimiter fixture 2","expected":"--b--\r\n","passed":false},{"actual":"abc--x\r\n","check":"multipart-closing-delimiter fixture 3","expected":"abc--x--\r\n","passed":false},{"actual":"\r\n--z\r\n","check":"multipart-closing-delimiter fixture 4","expected":"\r\n--z--\r\n","passed":false},{"actual":"a--b\r\n","check":"multipart-closing-delimiter fixture 5","expected":"a--b--\r\n","passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"multipart-closing-delimiter fixture 0\", \"actual\": \"--b1\\r\\n\", \"expected\": \"--b1--\\r\\n\", \"passed\": false}, {\"check\": \"multipart-closing-delimiter fixture 1\", \"actual\": \"ac--b\\r\\n\", \"expected\": \"ac--b--\\r\\n\", \"passed\": false}, {\"check\": \"multipart-closing-delimiter fixture 2\", \"actual\": \"--b\\r\\n\", \"expected\": \"--b--\\r\\n\", \"passed\": false}, {\"check\": \"multipart-closing-delimiter fixture 3\", \"actual\": \"abc--x\\r\\n\", \"expected\": \"abc--x--\\r\\n\", \"passed\": false}, {\"check\": \"multipart-closing-delimiter fixture 4\", \"actual\": \"\\r\\n--z\\r\\n\", \"expected\": \"\\r\\n--z--\\r\\n\", \"passed\": false}, {\"check\": \"multipart-closing-delimiter fixture 5\", \"actual\": \"a--b\\r\\n\", \"expected\": \"a--b--\\r\\n\", \"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."}}