{"abstract":"Nested JSON arrays lose structure.","category":"Serialization","checks":4,"contract":"Decode JSON retaining arbitrary list nesting and nulls.","contract_signature":"x","evaluation_group":"model-cba6aabbde1f7dff","failed_approach":"The attempted repair handles the primary example but still violates a separate boundary of the same contract.","family":"xp-json-array-flatten","id":"FA-3151","implementations":{"attempt":{"sha256":"8bdb4bccc6ee52dcb2f7e469661a8073998a3e79dafeccb52d43855c1f878bd1","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport re, unicodedata, json, csv, io, html, base64, binascii, codecs, struct\nfrom urllib.parse import quote, unquote, unquote_to_bytes, urlencode, parse_qsl, urlsplit, urlunsplit\nfrom email.header import decode_header, make_header\nfrom email.utils import getaddresses\nfrom xml.etree import ElementTree as ET\nimport shlex, string, textwrap\n\nN = 1\nobservations = []\ndef solve(x):\n    try:\n        return [v for row in json.loads(x) for v in (row if isinstance(row,list) else [row])]\n    except Exception as exc:\n        return {\"error\": type(exc).__name__}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('boundary 1', solve('[[1,2],[3]]'), [[1, 2], [3]])\ncheck('boundary 2', solve('[null,[]]'), [None, []])\ncheck('boundary 3', solve('[]'), [])\ncheck('boundary 4', solve('[1]'), [1])\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":"5d95fe80262f38918ec4c4af43647a9d3c25f08af6a6e510ab7dfc551b89099f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport re, unicodedata, json, csv, io, html, base64, binascii, codecs, struct\nfrom urllib.parse import quote, unquote, unquote_to_bytes, urlencode, parse_qsl, urlsplit, urlunsplit\nfrom email.header import decode_header, make_header\nfrom email.utils import getaddresses\nfrom xml.etree import ElementTree as ET\nimport shlex, string, textwrap\n\nN = 1\nobservations = []\ndef solve(x):\n    try:\n        return str(x).strip('[]').split(',')\n    except Exception as exc:\n        return {\"error\": type(exc).__name__}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('boundary 1', solve('[[1,2],[3]]'), [[1, 2], [3]])\ncheck('boundary 2', solve('[null,[]]'), [None, []])\ncheck('boundary 3', solve('[]'), [])\ncheck('boundary 4', solve('[1]'), [1])\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":" 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":"xp-json-array-flatten","generated_at":"2026-09-29T14:37:22.138004+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A local executable model for consumers of structured text; oracle values are authored literals, not outputs copied from the repaired implementation.","root_cause":"The implementation applies an operation whose text or grammar semantics violate this contract: Decode JSON retaining arbitrary list nesting and nulls.","sha256":"c85d166f0e8e01bf2933702b46acbb709470162bbd147445acd8753f6cc57b65","title":"Nested JSON arrays lose structure · 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":55.234,"exit_code":1,"observations":[{"actual":[1,2,3],"check":"boundary 1","expected":[[1,2],[3]],"passed":false},{"actual":[null],"check":"boundary 2","expected":[null,[]],"passed":false},{"actual":[],"check":"boundary 3","expected":[],"passed":true},{"actual":[1],"check":"boundary 4","expected":[1],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": [1, 2, 3], \"expected\": [[1, 2], [3]], \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": [null], \"expected\": [null, []], \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": [1], \"expected\": [1], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":53.32,"exit_code":1,"observations":[{"actual":["1","2]","[3"],"check":"boundary 1","expected":[[1,2],[3]],"passed":false},{"actual":["null",""],"check":"boundary 2","expected":[null,[]],"passed":false},{"actual":[""],"check":"boundary 3","expected":[],"passed":false},{"actual":["1"],"check":"boundary 4","expected":[1],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": [\"1\", \"2]\", \"[3\"], \"expected\": [[1, 2], [3]], \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": [\"null\", \"\"], \"expected\": [null, []], \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": [\"\"], \"expected\": [], \"passed\": false}, {\"check\": \"boundary 4\", \"actual\": [\"1\"], \"expected\": [1], \"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."}}