{"abstract":"A folded text header is treated as a separate field.","category":"Parsing","checks":4,"contract":"Unfold each LF followed by space/tab into a single space; preserve other LF.","evaluation_group":"model-068c6b27b4ab8e56","failed_approach":"The attempted repair handles the primary example but still violates a separate boundary of the same contract.","family":"xp-comment-header-folding","id":"FA-3891","implementations":{"attempt":{"sha256":"6cfb111b4e8effa493ca1fb2af9d2c0e365f8023004628a2942624ca66f6beef","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('\\n ',' ')\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('a\\n\\tb'), 'a b')\ncheck('boundary 2', solve('a\\n b'), 'a b')\ncheck('boundary 3', solve('a\\nb'), 'a\\nb')\ncheck('boundary 4', solve('a\\n   b'), 'a b')\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":"436c886482f134c41418773a0978fec337c48e3a44ef720221bda9bf5631c82f","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('\\n',' ')\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('a\\n\\tb'), 'a b')\ncheck('boundary 2', solve('a\\n b'), 'a b')\ncheck('boundary 3', solve('a\\nb'), 'a\\nb')\ncheck('boundary 4', solve('a\\n   b'), 'a b')\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":"a6f92766249857b53a0779b448fb7d32d8b1c83ec082b2216104024ff55877c4","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 re.sub(r'\\n[ \\x09]+',' ',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('a\\n\\tb'), 'a b')\ncheck('boundary 2', solve('a\\n b'), 'a b')\ncheck('boundary 3', solve('a\\nb'), 'a\\nb')\ncheck('boundary 4', solve('a\\n   b'), 'a b')\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-comment-header-folding","generated_at":"2026-09-29T14:37:32.419111+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: Unfold each LF followed by space/tab into a single space; preserve other LF.","root_cause":"The implementation applies an operation whose text or grammar semantics violate this contract: Unfold each LF followed by space/tab into a single space; preserve other LF.","sha256":"53e6215b64bad2113ad310bfa8b4ca9041b9ff3305833d086833855d6725555d","title":"A folded text header is treated as a separate field · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":55.488,"exit_code":1,"observations":[{"actual":"a\n\tb","check":"boundary 1","expected":"a b","passed":false},{"actual":"a b","check":"boundary 2","expected":"a b","passed":true},{"actual":"a\nb","check":"boundary 3","expected":"a\nb","passed":true},{"actual":"a   b","check":"boundary 4","expected":"a b","passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"a\\n\\tb\", \"expected\": \"a b\", \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": \"a b\", \"expected\": \"a b\", \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": \"a\\nb\", \"expected\": \"a\\nb\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"a   b\", \"expected\": \"a b\", \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":54.638,"exit_code":1,"observations":[{"actual":"a \tb","check":"boundary 1","expected":"a b","passed":false},{"actual":"a  b","check":"boundary 2","expected":"a b","passed":false},{"actual":"a b","check":"boundary 3","expected":"a\nb","passed":false},{"actual":"a    b","check":"boundary 4","expected":"a b","passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"a \\tb\", \"expected\": \"a b\", \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": \"a  b\", \"expected\": \"a b\", \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": \"a b\", \"expected\": \"a\\nb\", \"passed\": false}, {\"check\": \"boundary 4\", \"actual\": \"a    b\", \"expected\": \"a b\", \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":65.772,"exit_code":0,"observations":[{"actual":"a b","check":"boundary 1","expected":"a b","passed":true},{"actual":"a b","check":"boundary 2","expected":"a b","passed":true},{"actual":"a\nb","check":"boundary 3","expected":"a\nb","passed":true},{"actual":"a b","check":"boundary 4","expected":"a b","passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"a b\", \"expected\": \"a b\", \"passed\": true}, {\"check\": \"boundary 2\", \"actual\": \"a b\", \"expected\": \"a b\", \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": \"a\\nb\", \"expected\": \"a\\nb\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"a b\", \"expected\": \"a b\", \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}