{"abstract":"Tabs expand without considering current column.","category":"Text processing","checks":4,"contract":"Expand tabs to tab stops of width four, resetting column at line boundaries.","evaluation_group":"model-f54e407ae051a61c","failed_approach":"The attempted repair handles the primary example but still violates a separate boundary of the same contract.","family":"xp-tab-column-reset","id":"FA-3016","implementations":{"attempt":{"sha256":"4e46fdbee1354db642a5755cdfe09cea52a12316da2a7f49a8eca112c1cc96e7","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 ''.join(' '*(4-i%4) if c=='\\x09' else c for i,c in enumerate(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\\tb'), 'a   b')\ncheck('boundary 2', solve('\\t\\tx'), '        x')\ncheck('boundary 3', solve('abc\\n\\tx'), 'abc\\n    x')\ncheck('boundary 4', solve('abcd\\t'), 'abcd    ')\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":"b289f3a5304fa1c9b47f6e5b1e0ffc8399ac5b9d9ccaba2225761bf3ff36450d","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('\\x09','    ')\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\\tb'), 'a   b')\ncheck('boundary 2', solve('\\t\\tx'), '        x')\ncheck('boundary 3', solve('abc\\n\\tx'), 'abc\\n    x')\ncheck('boundary 4', solve('abcd\\t'), 'abcd    ')\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":"6c0d28d7f90f209a720f8628d11d98a5a53b8f388cc034714b8aff7946f69376","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.expandtabs(4)\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\\tb'), 'a   b')\ncheck('boundary 2', solve('\\t\\tx'), '        x')\ncheck('boundary 3', solve('abc\\n\\tx'), 'abc\\n    x')\ncheck('boundary 4', solve('abcd\\t'), 'abcd    ')\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-tab-column-reset","generated_at":"2026-09-29T14:37:20.461221+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: Expand tabs to tab stops of width four, resetting column at line boundaries.","root_cause":"The implementation applies an operation whose text or grammar semantics violate this contract: Expand tabs to tab stops of width four, resetting column at line boundaries.","sha256":"c2dcb6e0bc45e5a50596eb97934b5a44ede09708cecfe1c44c7cf6b674213e8b","title":"Tabs expand without considering current column · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":55.793,"exit_code":1,"observations":[{"actual":"a   b","check":"boundary 1","expected":"a   b","passed":true},{"actual":"       x","check":"boundary 2","expected":"        x","passed":false},{"actual":"abc\n    x","check":"boundary 3","expected":"abc\n    x","passed":true},{"actual":"abcd    ","check":"boundary 4","expected":"abcd    ","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"a   b\", \"expected\": \"a   b\", \"passed\": true}, {\"check\": \"boundary 2\", \"actual\": \"       x\", \"expected\": \"        x\", \"passed\": false}, {\"check\": \"boundary 3\", \"actual\": \"abc\\n    x\", \"expected\": \"abc\\n    x\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"abcd    \", \"expected\": \"abcd    \", \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":55.67,"exit_code":1,"observations":[{"actual":"a    b","check":"boundary 1","expected":"a   b","passed":false},{"actual":"        x","check":"boundary 2","expected":"        x","passed":true},{"actual":"abc\n    x","check":"boundary 3","expected":"abc\n    x","passed":true},{"actual":"abcd    ","check":"boundary 4","expected":"abcd    ","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"a    b\", \"expected\": \"a   b\", \"passed\": false}, {\"check\": \"boundary 2\", \"actual\": \"        x\", \"expected\": \"        x\", \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": \"abc\\n    x\", \"expected\": \"abc\\n    x\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"abcd    \", \"expected\": \"abcd    \", \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":53.968,"exit_code":0,"observations":[{"actual":"a   b","check":"boundary 1","expected":"a   b","passed":true},{"actual":"        x","check":"boundary 2","expected":"        x","passed":true},{"actual":"abc\n    x","check":"boundary 3","expected":"abc\n    x","passed":true},{"actual":"abcd    ","check":"boundary 4","expected":"abcd    ","passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary 1\", \"actual\": \"a   b\", \"expected\": \"a   b\", \"passed\": true}, {\"check\": \"boundary 2\", \"actual\": \"        x\", \"expected\": \"        x\", \"passed\": true}, {\"check\": \"boundary 3\", \"actual\": \"abc\\n    x\", \"expected\": \"abc\\n    x\", \"passed\": true}, {\"check\": \"boundary 4\", \"actual\": \"abcd    \", \"expected\": \"abcd    \", \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}