{"abstract":"A decoder accepts a second trailing JSON value.","category":"Serialization","checks":4,"contract":"Accept exactly one complete JSON value surrounded by whitespace; malformed documents return None.","evaluation_group":"model-3cb81c69e9db8a43","failed_approach":"The attempted repair handles the primary example but still violates a separate boundary of the same contract.","family":"xp-json-trailing-document","id":"FA-3166","implementations":{"attempt":{"sha256":"d29e72c7a0bb166027c00899b7a6d363de972d3a6de2f0247f1bf0ae26bd7e07","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 json.JSONDecoder().raw_decode(x.strip().splitlines()[0])[0]\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'), None)\ncheck('boundary 2', solve('1\\n2'), None)\ncheck('boundary 3', solve('  [1] \\n'), [1])\ncheck('boundary 4', solve('0'), 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":"356d011f131d1b5b3b99cc6c2a5235bc192ccf00542e1f76aedbc70bff219b38","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 json.JSONDecoder().raw_decode(x.lstrip())[0]\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'), None)\ncheck('boundary 2', solve('1\\n2'), None)\ncheck('boundary 3', solve('  [1] \\n'), [1])\ncheck('boundary 4', solve('0'), 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":"ca93e3d8e4a17232558310391f7848e3cfb72e8c46fca3e3a1ed201a29d0d726","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        try:\n            return json.loads(x)\n        except ValueError:\n            return None\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'), None)\ncheck('boundary 2', solve('1\\n2'), None)\ncheck('boundary 3', solve('  [1] \\n'), [1])\ncheck('boundary 4', solve('0'), 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":" 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-trailing-document","generated_at":"2026-09-29T14:37:22.200345+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.","repair":"Implement the complete stated contract, including the boundary fixtures: Accept exactly one complete JSON value surrounded by whitespace; malformed documents return None.","root_cause":"The implementation applies an operation whose text or grammar semantics violate this contract: Accept exactly one complete JSON value surrounded by whitespace; malformed documents return None.","sha256":"5d9e6d5aee55966da889058c069ea99c39e9d5fe6f4815cfb41f1ab48e1f180a","title":"A decoder accepts a second trailing JSON value · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":52.732,"exit_code":1,"observations":[{"actual":1,"check":"boundary 1","expected":null,"passed":false},{"actual":1,"check":"boundary 2","expected":null,"passed":false},{"actual":[1],"check":"boundary 3","expected":[1],"passed":true},{"actual":0,"check":"boundary 4","expected":0,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": 1, \"expected\": null, \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": 1, \"expected\": null, \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": [1], \"expected\": [1], \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": 0, \"expected\": 0, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":52.693,"exit_code":1,"observations":[{"actual":1,"check":"boundary 1","expected":null,"passed":false},{"actual":1,"check":"boundary 2","expected":null,"passed":false},{"actual":[1],"check":"boundary 3","expected":[1],"passed":true},{"actual":0,"check":"boundary 4","expected":0,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": 1, \"expected\": null, \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": 1, \"expected\": null, \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": [1], \"expected\": [1], \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": 0, \"expected\": 0, \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":55.812,"exit_code":0,"observations":[{"actual":null,"check":"boundary 1","expected":null,"passed":true},{"actual":null,"check":"boundary 2","expected":null,"passed":true},{"actual":[1],"check":"boundary 3","expected":[1],"passed":true},{"actual":0,"check":"boundary 4","expected":0,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"boundary 2\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": [1], \"expected\": [1], \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": 0, \"expected\": 0, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}