{"abstract":"Canonical hexadecimal output mixes letter case.","category":"Encodings","checks":4,"contract":"Encode integer byte values as uppercase two-nybble hex without separators.","evaluation_group":"model-24fe11c728f08d40","failed_approach":"The attempted repair handles the primary example but still violates a separate boundary of the same contract.","family":"xp-hex-uppercase-contract","id":"FA-3331","implementations":{"attempt":{"sha256":"bcbe2175ee33664c9b1bcf41e0bf20c06d4cd1f1401de563f1ed9415e7f157e8","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 ''.join(format(v,'X') for v 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([10, 255]), '0AFF')\ncheck('boundary 2', solve([0, 1]), '0001')\ncheck('boundary 3', solve([]), '')\ncheck('boundary 4', solve([16]), '10')\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":"b3efaac6aa2773a5f8ff8c020d053393c5ad918c14c6a205f4ec95cbe5dd31e9","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 bytes(x).hex()\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([10, 255]), '0AFF')\ncheck('boundary 2', solve([0, 1]), '0001')\ncheck('boundary 3', solve([]), '')\ncheck('boundary 4', solve([16]), '10')\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":"4f23d8f497b191ca0fc49a59463fdc29aff42868edd3f34038f9f49eb93bd922","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 bytes(x).hex().upper()\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([10, 255]), '0AFF')\ncheck('boundary 2', solve([0, 1]), '0001')\ncheck('boundary 3', solve([]), '')\ncheck('boundary 4', solve([16]), '10')\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-hex-uppercase-contract","generated_at":"2026-09-29T14:37:24.451582+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: Encode integer byte values as uppercase two-nybble hex without separators.","root_cause":"The implementation applies an operation whose text or grammar semantics violate this contract: Encode integer byte values as uppercase two-nybble hex without separators.","sha256":"9abc1f7c6cd62b5733bf5c9fdf87e126bb844b89a8fb628b79582b86665b8b90","title":"Canonical hexadecimal output mixes letter case · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":53.872,"exit_code":1,"observations":[{"actual":"AFF","check":"boundary 1","expected":"0AFF","passed":false},{"actual":"01","check":"boundary 2","expected":"0001","passed":false},{"actual":"","check":"boundary 3","expected":"","passed":true},{"actual":"10","check":"boundary 4","expected":"10","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"AFF\", \"expected\": \"0AFF\", \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": \"01\", \"expected\": \"0001\", \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"10\", \"expected\": \"10\", \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":53.037,"exit_code":1,"observations":[{"actual":"0aff","check":"boundary 1","expected":"0AFF","passed":false},{"actual":"0001","check":"boundary 2","expected":"0001","passed":true},{"actual":"","check":"boundary 3","expected":"","passed":true},{"actual":"10","check":"boundary 4","expected":"10","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"0aff\", \"expected\": \"0AFF\", \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": \"0001\", \"expected\": \"0001\", \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"10\", \"expected\": \"10\", \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":52.526,"exit_code":0,"observations":[{"actual":"0AFF","check":"boundary 1","expected":"0AFF","passed":true},{"actual":"0001","check":"boundary 2","expected":"0001","passed":true},{"actual":"","check":"boundary 3","expected":"","passed":true},{"actual":"10","check":"boundary 4","expected":"10","passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"0AFF\", \"expected\": \"0AFF\", \"passed\": true}, {\"check\": \"boundary 2\", \"actual\": \"0001\", \"expected\": \"0001\", \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"10\", \"expected\": \"10\", \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}