{"abstract":"Two base85 alphabets are confused.","category":"Encodings","checks":4,"contract":"Encode hex bytes using RFC-style Python b85, without Adobe delimiters.","contract_signature":"x","evaluation_group":"model-4839847fea887605","failed_approach":"The attempted repair handles the primary example but still violates a separate boundary of the same contract.","family":"xp-base85-vs-ascii85","id":"FA-3321","implementations":{"attempt":{"sha256":"21c1c472e2c48f296ec9a64ca9dc58e3b83664a3021f515db1ecfa2014a766a9","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 base64.a85encode(bytes.fromhex(x),adobe=True).decode()\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('00000000'), '00000')\ncheck('boundary 2', solve('61'), 'VE')\ncheck('boundary 3', solve('ffffffff'), '|NsC0')\ncheck('boundary 4', solve(''), '')\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":"28c374c5a960ed869012314093dc908a869a7f2c01612c017b9b0c6a6e37bc2a","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 base64.a85encode(bytes.fromhex(x)).decode()\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('00000000'), '00000')\ncheck('boundary 2', solve('61'), 'VE')\ncheck('boundary 3', solve('ffffffff'), '|NsC0')\ncheck('boundary 4', solve(''), '')\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-base85-vs-ascii85","generated_at":"2026-09-29T14:37:24.397980+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: Encode hex bytes using RFC-style Python b85, without Adobe delimiters.","sha256":"1603988a3cedc92413059db30157e7a1187fca871293c49f0526ff4a75d9f570","title":"Two base85 alphabets are confused · 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":52.66,"exit_code":1,"observations":[{"actual":"<~z~>","check":"boundary 1","expected":"00000","passed":false},{"actual":"<~@/~>","check":"boundary 2","expected":"VE","passed":false},{"actual":"<~s8W-!~>","check":"boundary 3","expected":"|NsC0","passed":false},{"actual":"<~~>","check":"boundary 4","expected":"","passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"<~z~>\", \"expected\": \"00000\", \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": \"<~@/~>\", \"expected\": \"VE\", \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": \"<~s8W-!~>\", \"expected\": \"|NsC0\", \"passed\": false}, {\"check\": \"boundary 4\", \"actual\": \"<~~>\", \"expected\": \"\", \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":121.778,"exit_code":1,"observations":[{"actual":"z","check":"boundary 1","expected":"00000","passed":false},{"actual":"@/","check":"boundary 2","expected":"VE","passed":false},{"actual":"s8W-!","check":"boundary 3","expected":"|NsC0","passed":false},{"actual":"","check":"boundary 4","expected":"","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"z\", \"expected\": \"00000\", \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": \"@/\", \"expected\": \"VE\", \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": \"s8W-!\", \"expected\": \"|NsC0\", \"passed\": false}, {\"check\": \"boundary 4\", \"actual\": \"\", \"expected\": \"\", \"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."}}