{"abstract":"Lowercasing misses multi-character caseless matches.","category":"Unicode","checks":4,"contract":"Return the Unicode casefold without normalization.","evaluation_group":"model-09db5e98b3333cd4","failed_approach":"The attempted repair handles the primary example but still violates a separate boundary of the same contract.","family":"xp-casefold-expansion","id":"FA-2851","implementations":{"attempt":{"sha256":"032b8edd847acfa3bca60a538329456a965a8c5ef23e73b2427a35c74a8a1901","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.lower().replace('ß','ss')\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('Straße'), 'strasse')\ncheck('boundary 2', solve('ς'), 'σ')\ncheck('boundary 3', solve('İ'), 'i̇')\ncheck('boundary 4', solve('Ab'), 'ab')\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":"dfa05ab3d86904928d75da026fea3f436fce70c2cbeef2043dd3b66f53c5df99","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.lower()\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('Straße'), 'strasse')\ncheck('boundary 2', solve('ς'), 'σ')\ncheck('boundary 3', solve('İ'), 'i̇')\ncheck('boundary 4', solve('Ab'), 'ab')\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":"94fc80071930ff2e46ce69397004f263ec6fcedf6061e18c6385934380d1973c","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.casefold()\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('Straße'), 'strasse')\ncheck('boundary 2', solve('ς'), 'σ')\ncheck('boundary 3', solve('İ'), 'i̇')\ncheck('boundary 4', solve('Ab'), 'ab')\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-casefold-expansion","generated_at":"2026-09-29T14:37:18.020711+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: Return the Unicode casefold without normalization.","root_cause":"The implementation applies an operation whose text or grammar semantics violate this contract: Return the Unicode casefold without normalization.","sha256":"b3ccc6a7ea52878a5717e3b3357bf5d2264f270b65180368f3edb8970b0cc4a1","title":"Lowercasing misses multi-character caseless matches · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":126.834,"exit_code":1,"observations":[{"actual":"strasse","check":"boundary 1","expected":"strasse","passed":true},{"actual":"ς","check":"boundary 2","expected":"σ","passed":false},{"actual":"i̇","check":"boundary 3","expected":"i̇","passed":true},{"actual":"ab","check":"boundary 4","expected":"ab","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"strasse\", \"expected\": \"strasse\", \"passed\": true}, {\"check\": \"boundary 2\", \"actual\": \"ς\", \"expected\": \"σ\", \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": \"i̇\", \"expected\": \"i̇\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"ab\", \"expected\": \"ab\", \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":60.452,"exit_code":1,"observations":[{"actual":"straße","check":"boundary 1","expected":"strasse","passed":false},{"actual":"ς","check":"boundary 2","expected":"σ","passed":false},{"actual":"i̇","check":"boundary 3","expected":"i̇","passed":true},{"actual":"ab","check":"boundary 4","expected":"ab","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"straße\", \"expected\": \"strasse\", \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": \"ς\", \"expected\": \"σ\", \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": \"i̇\", \"expected\": \"i̇\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"ab\", \"expected\": \"ab\", \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":49.322,"exit_code":0,"observations":[{"actual":"strasse","check":"boundary 1","expected":"strasse","passed":true},{"actual":"σ","check":"boundary 2","expected":"σ","passed":true},{"actual":"i̇","check":"boundary 3","expected":"i̇","passed":true},{"actual":"ab","check":"boundary 4","expected":"ab","passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"strasse\", \"expected\": \"strasse\", \"passed\": true}, {\"check\": \"boundary 2\", \"actual\": \"σ\", \"expected\": \"σ\", \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": \"i̇\", \"expected\": \"i̇\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"ab\", \"expected\": \"ab\", \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}