{"abstract":"An odd trailing byte is silently dropped from a word array.","category":"Binary formats","checks":4,"contract":"Decode consecutive big-endian 16-bit words; reject odd byte length.","contract_signature":"x","evaluation_group":"model-d7401f2219b7741f","failed_approach":"The attempted repair handles the primary example but still violates a separate boundary of the same contract.","family":"xp-binary-u16-array-alignment","id":"FA-3686","implementations":{"attempt":{"sha256":"ecc25e7977fc87786ad06595bf9dd8311e8dd912b1657f4765497a24ca4c74fa","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[i]+x[i+1]*256 for i in range(0,len(x)-1,2)]\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([1]), None)\ncheck('boundary 2', solve([0, 1, 0, 2]), [1, 2])\ncheck('boundary 3', solve([]), [])\ncheck('boundary 4', solve([255, 0]), [65280])\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":"ab3a6f4458a17ab355545e56111cde3e2d030707d45148dc576f17801fc603cf","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[i]*256+x[i+1] for i in range(0,len(x)-1,2)]\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([1]), None)\ncheck('boundary 2', solve([0, 1, 0, 2]), [1, 2])\ncheck('boundary 3', solve([]), [])\ncheck('boundary 4', solve([255, 0]), [65280])\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-u16-array-alignment","generated_at":"2026-09-29T14:37:29.511002+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: Decode consecutive big-endian 16-bit words; reject odd byte length.","sha256":"cf1e0f9b8ca11c1adc598c32928477b040e7710da2cbc1386f4917ca8426903a","title":"An odd trailing byte is silently dropped from a word array · 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":155.819,"exit_code":1,"observations":[{"actual":[],"check":"boundary 1","expected":null,"passed":false},{"actual":[256,512],"check":"boundary 2","expected":[1,2],"passed":false},{"actual":[],"check":"boundary 3","expected":[],"passed":true},{"actual":[255],"check":"boundary 4","expected":[65280],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": [], \"expected\": null, \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": [256, 512], \"expected\": [1, 2], \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": [255], \"expected\": [65280], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":61.508,"exit_code":1,"observations":[{"actual":[],"check":"boundary 1","expected":null,"passed":false},{"actual":[1,2],"check":"boundary 2","expected":[1,2],"passed":true},{"actual":[],"check":"boundary 3","expected":[],"passed":true},{"actual":[65280],"check":"boundary 4","expected":[65280],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": [], \"expected\": null, \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": [1, 2], \"expected\": [1, 2], \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": [65280], \"expected\": [65280], \"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."}}