{"abstract":"A complemented byte mask includes unbounded high bits.","category":"Binary formats","checks":4,"contract":"Complement all eight bits of an octet and retain an octet result.","contract_signature":"x","evaluation_group":"model-d478cd87398b34b2","failed_approach":"The attempted repair handles the primary example but still violates a separate boundary of the same contract.","family":"xp-binary-ones-complement","id":"FA-3721","implementations":{"attempt":{"sha256":"5231476671d2950064fb9bcaff317b1aaa92f892161c01898151e66bba1d850f","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\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(0), 255)\ncheck('boundary 2', solve(255), 0)\ncheck('boundary 3', solve(128), 127)\ncheck('boundary 4', solve(1), 254)\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":"fed8d26bb70b825c9b3ef3b39a5b161acd927c91ac834ad1a2c3c7f9f9a93fe2","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\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(0), 255)\ncheck('boundary 2', solve(255), 0)\ncheck('boundary 3', solve(128), 127)\ncheck('boundary 4', solve(1), 254)\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-ones-complement","generated_at":"2026-09-29T14:37:30.059210+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: Complement all eight bits of an octet and retain an octet result.","sha256":"ff953822ed35688b6c1ddeda8f026c528bb3641532281a6ba3263f6ed4ac28dc","title":"A complemented byte mask includes unbounded high bits · 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":55.005,"exit_code":1,"observations":[{"actual":0,"check":"boundary 1","expected":255,"passed":false},{"actual":-255,"check":"boundary 2","expected":0,"passed":false},{"actual":-128,"check":"boundary 3","expected":127,"passed":false},{"actual":-1,"check":"boundary 4","expected":254,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": 0, \"expected\": 255, \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": -255, \"expected\": 0, \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": -128, \"expected\": 127, \"passed\": false}, {\"check\": \"boundary 4\", \"actual\": -1, \"expected\": 254, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":51.311,"exit_code":1,"observations":[{"actual":-1,"check":"boundary 1","expected":255,"passed":false},{"actual":-256,"check":"boundary 2","expected":0,"passed":false},{"actual":-129,"check":"boundary 3","expected":127,"passed":false},{"actual":-2,"check":"boundary 4","expected":254,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": -1, \"expected\": 255, \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": -256, \"expected\": 0, \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": -129, \"expected\": 127, \"passed\": false}, {\"check\": \"boundary 4\", \"actual\": -2, \"expected\": 254, \"passed\": false}], \"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."}}