{"abstract":"Removing outer brackets strips unrelated nested delimiters.","category":"Parsing","checks":4,"contract":"Remove one outer round-parenthesis pair only if it encloses the entire balanced expression.","evaluation_group":"model-f7a231b8880782b2","failed_approach":"The attempted repair handles the primary example but still violates a separate boundary of the same contract.","family":"xp-strip-balanced-outer","id":"FA-3851","implementations":{"attempt":{"sha256":"b1c54eb629aca4cd6916b38f8de2ffd6509c7e2e757668b119143f4b405bcdfb","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 x[1:-1] if x.startswith('(') and x.endswith(')') else x\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('((a))'), '(a)')\ncheck('boundary 2', solve('(a)+(b)'), '(a)+(b)')\ncheck('boundary 3', solve('(a+b)'), 'a+b')\ncheck('boundary 4', solve('a'), 'a')\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":"e028cdc42965e4943c4d8a1d2df66a5c43012cc8506f37648d6b29b5e4f28962","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 x.strip('()')\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('((a))'), '(a)')\ncheck('boundary 2', solve('(a)+(b)'), '(a)+(b)')\ncheck('boundary 3', solve('(a+b)'), 'a+b')\ncheck('boundary 4', solve('a'), 'a')\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":"124b4047ae344b4698c83bf06ebfd01dd6a0d155fc0d2a994f6492ef83716f16","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        if not x.startswith('(') or not x.endswith(')'): return x\n        depth=0\n        for i,c in enumerate(x):\n            depth+=int(c=='(')-int(c==')')\n            if depth==0 and i<len(x)-1: return x\n        return x[1:-1]\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('((a))'), '(a)')\ncheck('boundary 2', solve('(a)+(b)'), '(a)+(b)')\ncheck('boundary 3', solve('(a+b)'), 'a+b')\ncheck('boundary 4', solve('a'), 'a')\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-strip-balanced-outer","generated_at":"2026-09-29T14:37:31.790402+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: Remove one outer round-parenthesis pair only if it encloses the entire balanced expression.","root_cause":"The implementation applies an operation whose text or grammar semantics violate this contract: Remove one outer round-parenthesis pair only if it encloses the entire balanced expression.","sha256":"c1811d65b45dd2292b21f430382ab17a2421116511136fde7e25c7c39d621fbd","title":"Removing outer brackets strips unrelated nested delimiters · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":52.464,"exit_code":1,"observations":[{"actual":"(a)","check":"boundary 1","expected":"(a)","passed":true},{"actual":"a)+(b","check":"boundary 2","expected":"(a)+(b)","passed":false},{"actual":"a+b","check":"boundary 3","expected":"a+b","passed":true},{"actual":"a","check":"boundary 4","expected":"a","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"(a)\", \"expected\": \"(a)\", \"passed\": true}, {\"check\": \"boundary 2\", \"actual\": \"a)+(b\", \"expected\": \"(a)+(b)\", \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": \"a+b\", \"expected\": \"a+b\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"a\", \"expected\": \"a\", \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":54.238,"exit_code":1,"observations":[{"actual":"a","check":"boundary 1","expected":"(a)","passed":false},{"actual":"a)+(b","check":"boundary 2","expected":"(a)+(b)","passed":false},{"actual":"a+b","check":"boundary 3","expected":"a+b","passed":true},{"actual":"a","check":"boundary 4","expected":"a","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"a\", \"expected\": \"(a)\", \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": \"a)+(b\", \"expected\": \"(a)+(b)\", \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": \"a+b\", \"expected\": \"a+b\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"a\", \"expected\": \"a\", \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":59.049,"exit_code":0,"observations":[{"actual":"(a)","check":"boundary 1","expected":"(a)","passed":true},{"actual":"(a)+(b)","check":"boundary 2","expected":"(a)+(b)","passed":true},{"actual":"a+b","check":"boundary 3","expected":"a+b","passed":true},{"actual":"a","check":"boundary 4","expected":"a","passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"(a)\", \"expected\": \"(a)\", \"passed\": true}, {\"check\": \"boundary 2\", \"actual\": \"(a)+(b)\", \"expected\": \"(a)+(b)\", \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": \"a+b\", \"expected\": \"a+b\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"a\", \"expected\": \"a\", \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}