{"abstract":"Overlapping fragments must agree on their bytes.","category":"HTTP ranges","checks":6,"contract":"Fragments are [absolute-offset,ASCII-body]. Return sorted [offset,char] cells; reject conflicting bytes with None. Identical overlap is permitted.","evaluation_group":"s3-http_ranges-cache-assembly","failed_approach":"The partial repair uses seen={}\nfor s,b in fragments:\n    for i,c in enumerate(b):\n        if s+i in seen: return None\n        seen[s+i]=c\nreturn sorted(seen.items()), which still violates the stated contract.","family":"s3-http_ranges-cache-overlap-byte-conflict","id":"FA-26496","implementations":{"attempt":{"sha256":"83b31375f5cf1108fd51a277b07f5ae48fec66a3a080dc6fbf8726f6cabec04d","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(fragments):\n    seen={}\n    for s,b in fragments:\n        for i,c in enumerate(b):\n            if s+i in seen: return None\n            seen[s+i]=c\n    return sorted(seen.items())\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('cache-overlap-byte-conflict fixture 0', solve([[N,\"ab\"],[N+1,\"x\"]]), None)\ncheck('cache-overlap-byte-conflict fixture 1', solve([[N,\"ab\"],[N+1,\"b\"]]), [(N,\"a\"),(N+1,\"b\")])\ncheck('cache-overlap-byte-conflict fixture 2', solve([]), [])\ncheck('cache-overlap-byte-conflict fixture 3', solve([[0,\"a\"]]), [(0,\"a\")])\ncheck('cache-overlap-byte-conflict fixture 4', solve([[1,\"b\"],[0,\"a\"]]), [(0,\"a\"),(1,\"b\")])\ncheck('cache-overlap-byte-conflict fixture 5', solve([[0,\"\"]]), [])\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":"7f901776c0d5fe91ee9d5a62245624f6c78ae4dad9e99a6df67ceb1a0d41b265","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(fragments):\n    return sorted({s+i:c for s,b in fragments for i,c in enumerate(b)}.items())\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('cache-overlap-byte-conflict fixture 0', solve([[N,\"ab\"],[N+1,\"x\"]]), None)\ncheck('cache-overlap-byte-conflict fixture 1', solve([[N,\"ab\"],[N+1,\"b\"]]), [(N,\"a\"),(N+1,\"b\")])\ncheck('cache-overlap-byte-conflict fixture 2', solve([]), [])\ncheck('cache-overlap-byte-conflict fixture 3', solve([[0,\"a\"]]), [(0,\"a\")])\ncheck('cache-overlap-byte-conflict fixture 4', solve([[1,\"b\"],[0,\"a\"]]), [(0,\"a\"),(1,\"b\")])\ncheck('cache-overlap-byte-conflict fixture 5', solve([[0,\"\"]]), [])\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":"cfd0e152f08b15419c8342d0b893b80cf9554c54febdc37d2060fd12bb9740d0","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(fragments):\n    seen={}\n    for s,b in fragments:\n        for i,c in enumerate(b):\n            if s+i in seen and seen[s+i]!=c: return None\n            seen[s+i]=c\n    return sorted(seen.items())\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('cache-overlap-byte-conflict fixture 0', solve([[N,\"ab\"],[N+1,\"x\"]]), None)\ncheck('cache-overlap-byte-conflict fixture 1', solve([[N,\"ab\"],[N+1,\"b\"]]), [(N,\"a\"),(N+1,\"b\")])\ncheck('cache-overlap-byte-conflict fixture 2', solve([]), [])\ncheck('cache-overlap-byte-conflict fixture 3', solve([[0,\"a\"]]), [(0,\"a\")])\ncheck('cache-overlap-byte-conflict fixture 4', solve([[1,\"b\"],[0,\"a\"]]), [(0,\"a\"),(1,\"b\")])\ncheck('cache-overlap-byte-conflict fixture 5', solve([[0,\"\"]]), [])\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-cache-overlap-byte-conflict","generated_at":"2026-09-29T14:41:16.452122+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.","repair":"Apply the bounded decision exactly: seen={}\nfor s,b in fragments:\n    for i,c in enumerate(b):\n        if s+i in seen and seen[s+i]!=c: return None\n        seen[s+i]=c\nreturn sorted(seen.items())","root_cause":"The cache-overlap-byte-conflict decision uses return sorted({s+i:c for s,b in fragments for i,c in enumerate(b)}.items()).","sha256":"f3ff9c0c2f65cd2abd3cdbddf5f6b41299833a09f757186497b8a2c4547765b4","title":"Overlapping fragments must agree on their bytes · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":38.418,"exit_code":1,"observations":[{"actual":null,"check":"cache-overlap-byte-conflict fixture 0","expected":null,"passed":true},{"actual":null,"check":"cache-overlap-byte-conflict fixture 1","expected":[[1,"a"],[2,"b"]],"passed":false},{"actual":[],"check":"cache-overlap-byte-conflict fixture 2","expected":[],"passed":true},{"actual":[[0,"a"]],"check":"cache-overlap-byte-conflict fixture 3","expected":[[0,"a"]],"passed":true},{"actual":[[0,"a"],[1,"b"]],"check":"cache-overlap-byte-conflict fixture 4","expected":[[0,"a"],[1,"b"]],"passed":true},{"actual":[],"check":"cache-overlap-byte-conflict fixture 5","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"cache-overlap-byte-conflict fixture 0\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"cache-overlap-byte-conflict fixture 1\", \"actual\": null, \"expected\": [[1, \"a\"], [2, \"b\"]], \"passed\": false}, {\"check\": \"cache-overlap-byte-conflict fixture 2\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"cache-overlap-byte-conflict fixture 3\", \"actual\": [[0, \"a\"]], \"expected\": [[0, \"a\"]], \"passed\": true}, {\"check\": \"cache-overlap-byte-conflict fixture 4\", \"actual\": [[0, \"a\"], [1, \"b\"]], \"expected\": [[0, \"a\"], [1, \"b\"]], \"passed\": true}, {\"check\": \"cache-overlap-byte-conflict fixture 5\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.009,"exit_code":1,"observations":[{"actual":[[1,"a"],[2,"x"]],"check":"cache-overlap-byte-conflict fixture 0","expected":null,"passed":false},{"actual":[[1,"a"],[2,"b"]],"check":"cache-overlap-byte-conflict fixture 1","expected":[[1,"a"],[2,"b"]],"passed":true},{"actual":[],"check":"cache-overlap-byte-conflict fixture 2","expected":[],"passed":true},{"actual":[[0,"a"]],"check":"cache-overlap-byte-conflict fixture 3","expected":[[0,"a"]],"passed":true},{"actual":[[0,"a"],[1,"b"]],"check":"cache-overlap-byte-conflict fixture 4","expected":[[0,"a"],[1,"b"]],"passed":true},{"actual":[],"check":"cache-overlap-byte-conflict fixture 5","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"cache-overlap-byte-conflict fixture 0\", \"actual\": [[1, \"a\"], [2, \"x\"]], \"expected\": null, \"passed\": false}, {\"check\": \"cache-overlap-byte-conflict fixture 1\", \"actual\": [[1, \"a\"], [2, \"b\"]], \"expected\": [[1, \"a\"], [2, \"b\"]], \"passed\": true}, {\"check\": \"cache-overlap-byte-conflict fixture 2\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"cache-overlap-byte-conflict fixture 3\", \"actual\": [[0, \"a\"]], \"expected\": [[0, \"a\"]], \"passed\": true}, {\"check\": \"cache-overlap-byte-conflict fixture 4\", \"actual\": [[0, \"a\"], [1, \"b\"]], \"expected\": [[0, \"a\"], [1, \"b\"]], \"passed\": true}, {\"check\": \"cache-overlap-byte-conflict fixture 5\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":36.671,"exit_code":0,"observations":[{"actual":null,"check":"cache-overlap-byte-conflict fixture 0","expected":null,"passed":true},{"actual":[[1,"a"],[2,"b"]],"check":"cache-overlap-byte-conflict fixture 1","expected":[[1,"a"],[2,"b"]],"passed":true},{"actual":[],"check":"cache-overlap-byte-conflict fixture 2","expected":[],"passed":true},{"actual":[[0,"a"]],"check":"cache-overlap-byte-conflict fixture 3","expected":[[0,"a"]],"passed":true},{"actual":[[0,"a"],[1,"b"]],"check":"cache-overlap-byte-conflict fixture 4","expected":[[0,"a"],[1,"b"]],"passed":true},{"actual":[],"check":"cache-overlap-byte-conflict fixture 5","expected":[],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"cache-overlap-byte-conflict fixture 0\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"cache-overlap-byte-conflict fixture 1\", \"actual\": [[1, \"a\"], [2, \"b\"]], \"expected\": [[1, \"a\"], [2, \"b\"]], \"passed\": true}, {\"check\": \"cache-overlap-byte-conflict fixture 2\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"cache-overlap-byte-conflict fixture 3\", \"actual\": [[0, \"a\"]], \"expected\": [[0, \"a\"]], \"passed\": true}, {\"check\": \"cache-overlap-byte-conflict fixture 4\", \"actual\": [[0, \"a\"], [1, \"b\"]], \"expected\": [[0, \"a\"], [1, \"b\"]], \"passed\": true}, {\"check\": \"cache-overlap-byte-conflict fixture 5\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}