{"abstract":"Fixed text padding removal destroys embedded zero bytes.","category":"Binary formats","checks":4,"contract":"Strip only trailing zero bytes from a fixed-width binary field.","evaluation_group":"model-be577e444f9d2e31","failed_approach":"The attempted repair handles the primary example but still violates a separate boundary of the same contract.","family":"xp-binary-fixed-padding","id":"FA-3671","implementations":{"attempt":{"sha256":"05da5a86a8478b62458c3999e5f57ee7cc02edfd25300fa1943f2a5453eb8c59","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[:x.index(0)] if 0 in x 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([65, 0, 66, 0]), [65, 0, 66])\ncheck('boundary 2', solve([0, 0]), [])\ncheck('boundary 3', solve([0, 65]), [0, 65])\ncheck('boundary 4', solve([65]), [65])\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":"271fda879ef7e2a96a63b28907b01938e2f99ad116648014df03cd6a2d54dd87","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 [v for v in x if v]\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([65, 0, 66, 0]), [65, 0, 66])\ncheck('boundary 2', solve([0, 0]), [])\ncheck('boundary 3', solve([0, 65]), [0, 65])\ncheck('boundary 4', solve([65]), [65])\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":"0d302c5621db8d068fe43756d0720b7fa2c10122e5414ef980abd047e179d320","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 list(bytes(x).rstrip(b'\\x00'))\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([65, 0, 66, 0]), [65, 0, 66])\ncheck('boundary 2', solve([0, 0]), [])\ncheck('boundary 3', solve([0, 65]), [0, 65])\ncheck('boundary 4', solve([65]), [65])\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-binary-fixed-padding","generated_at":"2026-09-29T14:37:29.300023+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: Strip only trailing zero bytes from a fixed-width binary field.","root_cause":"The implementation applies an operation whose text or grammar semantics violate this contract: Strip only trailing zero bytes from a fixed-width binary field.","sha256":"5482d79440e29573cf16628558df4d9f881da2d449d23b88f3a9ddefe3b2fc62","title":"Fixed text padding removal destroys embedded zero bytes · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":62.701,"exit_code":1,"observations":[{"actual":[65],"check":"boundary 1","expected":[65,0,66],"passed":false},{"actual":[],"check":"boundary 2","expected":[],"passed":true},{"actual":[],"check":"boundary 3","expected":[0,65],"passed":false},{"actual":[65],"check":"boundary 4","expected":[65],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": [65], \"expected\": [65, 0, 66], \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": [], \"expected\": [0, 65], \"passed\": false}, {\"check\": \"boundary 4\", \"actual\": [65], \"expected\": [65], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":53.32,"exit_code":1,"observations":[{"actual":[65,66],"check":"boundary 1","expected":[65,0,66],"passed":false},{"actual":[],"check":"boundary 2","expected":[],"passed":true},{"actual":[65],"check":"boundary 3","expected":[0,65],"passed":false},{"actual":[65],"check":"boundary 4","expected":[65],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": [65, 66], \"expected\": [65, 0, 66], \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": [65], \"expected\": [0, 65], \"passed\": false}, {\"check\": \"boundary 4\", \"actual\": [65], \"expected\": [65], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":61.404,"exit_code":0,"observations":[{"actual":[65,0,66],"check":"boundary 1","expected":[65,0,66],"passed":true},{"actual":[],"check":"boundary 2","expected":[],"passed":true},{"actual":[0,65],"check":"boundary 3","expected":[0,65],"passed":true},{"actual":[65],"check":"boundary 4","expected":[65],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": [65, 0, 66], \"expected\": [65, 0, 66], \"passed\": true}, {\"check\": \"boundary 2\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": [0, 65], \"expected\": [0, 65], \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": [65], \"expected\": [65], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}