{"abstract":"Cascaded substitutions rewrite newly inserted text.","category":"Text processing","checks":4,"contract":"Simultaneously replace original a with b and original b with c, leaving other codepoints unchanged.","evaluation_group":"model-33fcb5e43194e896","failed_approach":"The attempted repair handles the primary example but still violates a separate boundary of the same contract.","family":"xp-simultaneous-replacement","id":"FA-3956","implementations":{"attempt":{"sha256":"1c0bce923fcc8c13d1ddc87e33af41cb9be21425848c242e50e86928670a45cb","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.replace('b','c').replace('a','b').replace('c','d')\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('ab'), 'bc')\ncheck('boundary 2', solve('a'), 'b')\ncheck('boundary 3', solve('bc'), 'cc')\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":"b3b854cf5ac2d623d1aaa5579a2041d1cb68fc7e4c4fe69f33b0c9a0c8191606","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.replace('a','b').replace('b','c')\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('ab'), 'bc')\ncheck('boundary 2', solve('a'), 'b')\ncheck('boundary 3', solve('bc'), 'cc')\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"},"fixed":{"sha256":"480b543cc7b838b4ad13b5012a5f3998c512dbe7eeadea234445a77b3533a90f","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.translate(str.maketrans({'a':'b','b':'c'}))\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('ab'), 'bc')\ncheck('boundary 2', solve('a'), 'b')\ncheck('boundary 3', solve('bc'), 'cc')\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-simultaneous-replacement","generated_at":"2026-09-29T14:37:33.569679+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: Simultaneously replace original a with b and original b with c, leaving other codepoints unchanged.","root_cause":"The implementation applies an operation whose text or grammar semantics violate this contract: Simultaneously replace original a with b and original b with c, leaving other codepoints unchanged.","sha256":"648ecfc9d5450b18ad305b8cecae2e9f407b7406750b5441501354d5a38495be","title":"Cascaded substitutions rewrite newly inserted text · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":161.999,"exit_code":1,"observations":[{"actual":"bd","check":"boundary 1","expected":"bc","passed":false},{"actual":"b","check":"boundary 2","expected":"b","passed":true},{"actual":"dd","check":"boundary 3","expected":"cc","passed":false},{"actual":"","check":"boundary 4","expected":"","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"bd\", \"expected\": \"bc\", \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": \"b\", \"expected\": \"b\", \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": \"dd\", \"expected\": \"cc\", \"passed\": false}, {\"check\": \"boundary 4\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":61.764,"exit_code":1,"observations":[{"actual":"cc","check":"boundary 1","expected":"bc","passed":false},{"actual":"c","check":"boundary 2","expected":"b","passed":false},{"actual":"cc","check":"boundary 3","expected":"cc","passed":true},{"actual":"","check":"boundary 4","expected":"","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"cc\", \"expected\": \"bc\", \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": \"c\", \"expected\": \"b\", \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": \"cc\", \"expected\": \"cc\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":65.03,"exit_code":0,"observations":[{"actual":"bc","check":"boundary 1","expected":"bc","passed":true},{"actual":"b","check":"boundary 2","expected":"b","passed":true},{"actual":"cc","check":"boundary 3","expected":"cc","passed":true},{"actual":"","check":"boundary 4","expected":"","passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"bc\", \"expected\": \"bc\", \"passed\": true}, {\"check\": \"boundary 2\", \"actual\": \"b\", \"expected\": \"b\", \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": \"cc\", \"expected\": \"cc\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}