{"abstract":"An identifier rejects underscores and admits leading digits.","category":"Lexical grammars","checks":4,"contract":"Validate Python Unicode identifiers, including keywords as lexical identifiers.","evaluation_group":"model-877aeddf7edc0c8f","failed_approach":"The attempted repair handles the primary example but still violates a separate boundary of the same contract.","family":"xp-identifier-not-alnum","id":"FA-2881","implementations":{"attempt":{"sha256":"76aa54116c5b3f28da1cbe38c958b21e0d37f9f11b74f869579251b4153cefc5","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 bool(x) and (x[0].isalpha() or x[0]=='_') and all(c.isalnum() or c=='_' for c in 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'), True)\ncheck('boundary 2', solve('1a'), False)\ncheck('boundary 3', solve('á'), True)\ncheck('boundary 4', solve('class'), True)\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":"e9eb96f83099a97e1bdc44fbd3a3fce9264778c1d923c58922675d919becc834","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.isalnum()\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'), True)\ncheck('boundary 2', solve('1a'), False)\ncheck('boundary 3', solve('á'), True)\ncheck('boundary 4', solve('class'), True)\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":"65d0e6d07ae251b4587e488e0afdd4a734456321613fb67ba1e2ed1aed9417d6","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.isidentifier()\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'), True)\ncheck('boundary 2', solve('1a'), False)\ncheck('boundary 3', solve('á'), True)\ncheck('boundary 4', solve('class'), True)\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-identifier-not-alnum","generated_at":"2026-09-29T14:37:18.516399+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: Validate Python Unicode identifiers, including keywords as lexical identifiers.","root_cause":"The implementation applies an operation whose text or grammar semantics violate this contract: Validate Python Unicode identifiers, including keywords as lexical identifiers.","sha256":"073c69ef0d26ce75564e4aaf436c54fc1aac147b18578d55ee04bc40f2beec42","title":"An identifier rejects underscores and admits leading digits · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":54.815,"exit_code":1,"observations":[{"actual":true,"check":"boundary 1","expected":true,"passed":true},{"actual":false,"check":"boundary 2","expected":false,"passed":true},{"actual":false,"check":"boundary 3","expected":true,"passed":false},{"actual":true,"check":"boundary 4","expected":true,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"boundary 2\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": false, \"expected\": true, \"passed\": false}, {\"check\": \"boundary 4\", \"actual\": true, \"expected\": true, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":55.368,"exit_code":1,"observations":[{"actual":false,"check":"boundary 1","expected":true,"passed":false},{"actual":true,"check":"boundary 2","expected":false,"passed":false},{"actual":false,"check":"boundary 3","expected":true,"passed":false},{"actual":true,"check":"boundary 4","expected":true,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": false, \"expected\": true, \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": true, \"expected\": false, \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": false, \"expected\": true, \"passed\": false}, {\"check\": \"boundary 4\", \"actual\": true, \"expected\": true, \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":56.481,"exit_code":0,"observations":[{"actual":true,"check":"boundary 1","expected":true,"passed":true},{"actual":false,"check":"boundary 2","expected":false,"passed":true},{"actual":true,"check":"boundary 3","expected":true,"passed":true},{"actual":true,"check":"boundary 4","expected":true,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"boundary 2\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": true, \"expected\": true, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}