{"abstract":"A structured table violates the declared record or column contract.","category":"Delimited text","checks":8,"contract":"Decode TSV fields with exactly four escapes: backslash-t, backslash-n, backslash-r, backslash-backslash. Raw tabs split fields, raw newlines are forbidden; unknown and dangling escapes reject the row. Empty input is one empty field.","evaluation_group":"s3-delimited-text-escaped-tsv-reader","failed_approach":"Resetting except after a literal backslash incorrectly treats its following t as another escape.","family":"s3-delimited-text-escaped-tsv-reader-escape-reset","id":"FA-47396","implementations":{"attempt":{"sha256":"decadf6fa6fa2e26f3406d41dd8b2161679e5b51442ff66c56fa945587fa5e48","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\ndef _vary(value):\n    if value == '@END': return 3 + 4*N\n    if isinstance(value, str): return value.replace('@', 'cell' * N)\n    if isinstance(value, list): return [_vary(x) for x in value]\n    if isinstance(value, dict): return {_vary(k): _vary(v) for k,v in value.items()}\n    return value\nN = 1\nobservations = []\ndef solve(data):\n    out, field, escaped = [], [], False\n    for ch in data:\n        if escaped:\n            if ch not in 'tnr\\\\': return None\n            field.append({'t':'\\t','n':'\\n','r':'\\r','\\\\':'\\\\'}[ch])\n            escaped = ch == '\\\\'\n        elif ch == '\\\\': escaped = True\n        elif ch == '\\t':\n            out.append(''.join(field))\n            field = []\n        elif ch in '\\r\\n': return None\n        else: field.append(ch)\n    if escaped: return None\n    out.append(''.join(field))\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('mapped escapes', solve(_vary('@\\\\tA\\\\nB\\\\rC\\\\\\\\D')), _vary(['@\\tA\\nB\\rC\\\\D']))\ncheck('separators', solve(_vary('@\\t\\tZ')), _vary(['@', '', 'Z']))\ncheck('escaped backslash then t', solve(_vary('\\\\\\\\t')), _vary(['\\\\t']))\ncheck('unknown', solve(_vary('\\\\q')), _vary(None))\ncheck('dangling', solve(_vary('@\\\\')), _vary(None))\ncheck('raw newline', solve(_vary('@\\nZ')), _vary(None))\ncheck('empty', solve(_vary('')), _vary(['']))\ncheck('leading trailing', solve(_vary('\\t@\\t')), _vary(['', '@', '']))\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":"e0d23961ca98473ee9eeaae5e7e947ac560ed0ca60b3be8c90fd65d675fa4740","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\ndef _vary(value):\n    if value == '@END': return 3 + 4*N\n    if isinstance(value, str): return value.replace('@', 'cell' * N)\n    if isinstance(value, list): return [_vary(x) for x in value]\n    if isinstance(value, dict): return {_vary(k): _vary(v) for k,v in value.items()}\n    return value\nN = 1\nobservations = []\ndef solve(data):\n    out, field, escaped = [], [], False\n    for ch in data:\n        if escaped:\n            if ch not in 'tnr\\\\': return None\n            field.append({'t':'\\t','n':'\\n','r':'\\r','\\\\':'\\\\'}[ch])\n            escaped = True\n        elif ch == '\\\\': escaped = True\n        elif ch == '\\t':\n            out.append(''.join(field))\n            field = []\n        elif ch in '\\r\\n': return None\n        else: field.append(ch)\n    if escaped: return None\n    out.append(''.join(field))\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('mapped escapes', solve(_vary('@\\\\tA\\\\nB\\\\rC\\\\\\\\D')), _vary(['@\\tA\\nB\\rC\\\\D']))\ncheck('separators', solve(_vary('@\\t\\tZ')), _vary(['@', '', 'Z']))\ncheck('escaped backslash then t', solve(_vary('\\\\\\\\t')), _vary(['\\\\t']))\ncheck('unknown', solve(_vary('\\\\q')), _vary(None))\ncheck('dangling', solve(_vary('@\\\\')), _vary(None))\ncheck('raw newline', solve(_vary('@\\nZ')), _vary(None))\ncheck('empty', solve(_vary('')), _vary(['']))\ncheck('leading trailing', solve(_vary('\\t@\\t')), _vary(['', '@', '']))\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":"98c681e1d643b08c156bd53a4503ea6ecd2ea6bf8f46c1fef0a558a502918826","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\ndef _vary(value):\n    if value == '@END': return 3 + 4*N\n    if isinstance(value, str): return value.replace('@', 'cell' * N)\n    if isinstance(value, list): return [_vary(x) for x in value]\n    if isinstance(value, dict): return {_vary(k): _vary(v) for k,v in value.items()}\n    return value\nN = 1\nobservations = []\ndef solve(data):\n    out, field, escaped = [], [], False\n    for ch in data:\n        if escaped:\n            if ch not in 'tnr\\\\': return None\n            field.append({'t':'\\t','n':'\\n','r':'\\r','\\\\':'\\\\'}[ch])\n            escaped = False\n        elif ch == '\\\\': escaped = True\n        elif ch == '\\t':\n            out.append(''.join(field))\n            field = []\n        elif ch in '\\r\\n': return None\n        else: field.append(ch)\n    if escaped: return None\n    out.append(''.join(field))\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('mapped escapes', solve(_vary('@\\\\tA\\\\nB\\\\rC\\\\\\\\D')), _vary(['@\\tA\\nB\\rC\\\\D']))\ncheck('separators', solve(_vary('@\\t\\tZ')), _vary(['@', '', 'Z']))\ncheck('escaped backslash then t', solve(_vary('\\\\\\\\t')), _vary(['\\\\t']))\ncheck('unknown', solve(_vary('\\\\q')), _vary(None))\ncheck('dangling', solve(_vary('@\\\\')), _vary(None))\ncheck('raw newline', solve(_vary('@\\nZ')), _vary(None))\ncheck('empty', solve(_vary('')), _vary(['']))\ncheck('leading trailing', solve(_vary('\\t@\\t')), _vary(['', '@', '']))\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":"Deterministic bounded in-memory model. No claim of complete CSV or external format conformance. 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":"s3-delimited-text-escaped-tsv-reader-escape-reset","generated_at":"2026-09-29T14:44:41.084317+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Delimited interchange needs explicit framing, schema and field semantics at ingestion and emission boundaries.","repair":"Preserve the named invariant at the faulty decision: escaped = False","root_cause":"Escape state remains armed after consuming its payload.","sha256":"a57f3815a1ab60ed3f014814fadeb71d663a8dbb33faeed399613b7a3790430a","title":"One TSV escape captures the following ordinary character · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":45.783,"exit_code":1,"observations":[{"actual":null,"check":"mapped escapes","expected":["cell\tA\nB\rC\\D"],"passed":false},{"actual":["cell","","Z"],"check":"separators","expected":["cell","","Z"],"passed":true},{"actual":["\\\t"],"check":"escaped backslash then t","expected":["\\t"],"passed":false},{"actual":null,"check":"unknown","expected":null,"passed":true},{"actual":null,"check":"dangling","expected":null,"passed":true},{"actual":null,"check":"raw newline","expected":null,"passed":true},{"actual":[""],"check":"empty","expected":[""],"passed":true},{"actual":["","cell",""],"check":"leading trailing","expected":["","cell",""],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"mapped escapes\", \"actual\": null, \"expected\": [\"cell\\tA\\nB\\rC\\\\D\"], \"passed\": false}, {\"check\": \"separators\", \"actual\": [\"cell\", \"\", \"Z\"], \"expected\": [\"cell\", \"\", \"Z\"], \"passed\": true}, {\"check\": \"escaped backslash then t\", \"actual\": [\"\\\\\\t\"], \"expected\": [\"\\\\t\"], \"passed\": false}, {\"check\": \"unknown\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"dangling\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"raw newline\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"empty\", \"actual\": [\"\"], \"expected\": [\"\"], \"passed\": true}, {\"check\": \"leading trailing\", \"actual\": [\"\", \"cell\", \"\"], \"expected\": [\"\", \"cell\", \"\"], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.569,"exit_code":1,"observations":[{"actual":null,"check":"mapped escapes","expected":["cell\tA\nB\rC\\D"],"passed":false},{"actual":["cell","","Z"],"check":"separators","expected":["cell","","Z"],"passed":true},{"actual":null,"check":"escaped backslash then t","expected":["\\t"],"passed":false},{"actual":null,"check":"unknown","expected":null,"passed":true},{"actual":null,"check":"dangling","expected":null,"passed":true},{"actual":null,"check":"raw newline","expected":null,"passed":true},{"actual":[""],"check":"empty","expected":[""],"passed":true},{"actual":["","cell",""],"check":"leading trailing","expected":["","cell",""],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"mapped escapes\", \"actual\": null, \"expected\": [\"cell\\tA\\nB\\rC\\\\D\"], \"passed\": false}, {\"check\": \"separators\", \"actual\": [\"cell\", \"\", \"Z\"], \"expected\": [\"cell\", \"\", \"Z\"], \"passed\": true}, {\"check\": \"escaped backslash then t\", \"actual\": null, \"expected\": [\"\\\\t\"], \"passed\": false}, {\"check\": \"unknown\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"dangling\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"raw newline\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"empty\", \"actual\": [\"\"], \"expected\": [\"\"], \"passed\": true}, {\"check\": \"leading trailing\", \"actual\": [\"\", \"cell\", \"\"], \"expected\": [\"\", \"cell\", \"\"], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":42.66,"exit_code":0,"observations":[{"actual":["cell\tA\nB\rC\\D"],"check":"mapped escapes","expected":["cell\tA\nB\rC\\D"],"passed":true},{"actual":["cell","","Z"],"check":"separators","expected":["cell","","Z"],"passed":true},{"actual":["\\t"],"check":"escaped backslash then t","expected":["\\t"],"passed":true},{"actual":null,"check":"unknown","expected":null,"passed":true},{"actual":null,"check":"dangling","expected":null,"passed":true},{"actual":null,"check":"raw newline","expected":null,"passed":true},{"actual":[""],"check":"empty","expected":[""],"passed":true},{"actual":["","cell",""],"check":"leading trailing","expected":["","cell",""],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"mapped escapes\", \"actual\": [\"cell\\tA\\nB\\rC\\\\D\"], \"expected\": [\"cell\\tA\\nB\\rC\\\\D\"], \"passed\": true}, {\"check\": \"separators\", \"actual\": [\"cell\", \"\", \"Z\"], \"expected\": [\"cell\", \"\", \"Z\"], \"passed\": true}, {\"check\": \"escaped backslash then t\", \"actual\": [\"\\\\t\"], \"expected\": [\"\\\\t\"], \"passed\": true}, {\"check\": \"unknown\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"dangling\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"raw newline\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"empty\", \"actual\": [\"\"], \"expected\": [\"\"], \"passed\": true}, {\"check\": \"leading trailing\", \"actual\": [\"\", \"cell\", \"\"], \"expected\": [\"\", \"cell\", \"\"], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}