{"abstract":"A valid null is confused with parse failure.","category":"Serialization","checks":4,"contract":"Return an ok/value envelope on JSON success, and ok false for malformed input.","contract_signature":"x","evaluation_group":"model-c8a75982b5abbd4b","failed_approach":"The attempted repair handles the primary example but still violates a separate boundary of the same contract.","family":"xp-json-top-level-null","id":"FA-3161","implementations":{"attempt":{"sha256":"17fe854bb648e233d2d0aae6c4b253edd20196aec0412bdd6d26547f574fa5b2","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            v=json.loads(x)\n            return {'ok':v is not None,'value':v}\n        except ValueError:\n            return {'ok':False}\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('null'), {'ok': True, 'value': None})\ncheck('boundary 2', solve('0'), {'ok': True, 'value': 0})\ncheck('boundary 3', solve('false'), {'ok': True, 'value': False})\ncheck('boundary 4', solve('{'), {'ok': False})\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":"4d850e992f6d7451ffdf28d9b298425fcc0d16aceab7c4fdbd58add772eb90bb","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            v=json.loads(x)\n            return {'ok':bool(v),'value':v}\n        except ValueError:\n            return {'ok':False}\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('null'), {'ok': True, 'value': None})\ncheck('boundary 2', solve('0'), {'ok': True, 'value': 0})\ncheck('boundary 3', solve('false'), {'ok': True, 'value': False})\ncheck('boundary 4', solve('{'), {'ok': False})\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-top-level-null","generated_at":"2026-09-29T14:37:22.196081+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: Return an ok/value envelope on JSON success, and ok false for malformed input.","sha256":"3e1ae600ac0e3e110f0f9bced0e85efc90bab618ff1e7220f5d0c0bfad833aaf","title":"A valid null is confused with parse failure · 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":54.505,"exit_code":1,"observations":[{"actual":{"ok":false,"value":null},"check":"boundary 1","expected":{"ok":true,"value":null},"passed":false},{"actual":{"ok":true,"value":0},"check":"boundary 2","expected":{"ok":true,"value":0},"passed":true},{"actual":{"ok":true,"value":false},"check":"boundary 3","expected":{"ok":true,"value":false},"passed":true},{"actual":{"ok":false},"check":"boundary 4","expected":{"ok":false},"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": {\"ok\": false, \"value\": null}, \"expected\": {\"ok\": true, \"value\": null}, \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": {\"ok\": true, \"value\": 0}, \"expected\": {\"ok\": true, \"value\": 0}, \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": {\"ok\": true, \"value\": false}, \"expected\": {\"ok\": true, \"value\": false}, \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": {\"ok\": false}, \"expected\": {\"ok\": false}, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":53.055,"exit_code":1,"observations":[{"actual":{"ok":false,"value":null},"check":"boundary 1","expected":{"ok":true,"value":null},"passed":false},{"actual":{"ok":false,"value":0},"check":"boundary 2","expected":{"ok":true,"value":0},"passed":false},{"actual":{"ok":false,"value":false},"check":"boundary 3","expected":{"ok":true,"value":false},"passed":false},{"actual":{"ok":false},"check":"boundary 4","expected":{"ok":false},"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": {\"ok\": false, \"value\": null}, \"expected\": {\"ok\": true, \"value\": null}, \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": {\"ok\": false, \"value\": 0}, \"expected\": {\"ok\": true, \"value\": 0}, \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": {\"ok\": false, \"value\": false}, \"expected\": {\"ok\": true, \"value\": false}, \"passed\": false}, {\"check\": \"boundary 4\", \"actual\": {\"ok\": false}, \"expected\": {\"ok\": false}, \"passed\": true}], \"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."}}