{"abstract":"A structured table violates the declared record or column contract.","category":"Delimited text","checks":7,"contract":"Bind a parsed comma row to an exact schema [head, ..., tail] where the middle ... captures zero or more fields as a list. The first and last physical cells bind head and tail; at least two cells are required. The rest list preserves empty cells and order.","contract_signature":"data","evaluation_group":"s3-delimited-text-named-rest-column","failed_approach":"The alternate implementation still violates the same declared invariant: a variadic column consumes the trailing fixed field.","family":"s3-delimited-text-named-rest-column-rest-tail","id":"FA-48166","implementations":{"attempt":{"sha256":"095d09f819a9c9a80725d932747e203a1b05ab5932ebcf978ae271e366b36160","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    cells=data.split(',')\n    if len(cells)<2: return None\n    head=cells[0]\n    tail=cells[-1]\n    rest=cells[:-1]\n    return {'head':head,'rest':rest,'tail':tail}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('rest', solve(_vary('a,@,x,z')), _vary({'head': 'a', 'rest': ['@', 'x'], 'tail': 'z'}))\ncheck('none', solve(_vary('a,z')), _vary({'head': 'a', 'rest': [], 'tail': 'z'}))\ncheck('empty rest', solve(_vary('a,,z')), _vary({'head': 'a', 'rest': [''], 'tail': 'z'}))\ncheck('two empties', solve(_vary(',')), _vary({'head': '', 'rest': [], 'tail': ''}))\ncheck('short', solve(_vary('@')), _vary(None))\ncheck('one rest', solve(_vary('a,@,z')), _vary({'head': 'a', 'rest': ['@'], 'tail': 'z'}))\ncheck('trailing', solve(_vary('a,@,')), _vary({'head': 'a', 'rest': ['@'], 'tail': ''}))\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":"bc6b8f1e1053cfbdd78bccdf6546310ed30d0a784dd56df21eb88da9808b8c94","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    cells=data.split(',')\n    if len(cells)<2: return None\n    head=cells[0]\n    tail=cells[-1]\n    rest=cells[1:]\n    return {'head':head,'rest':rest,'tail':tail}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('rest', solve(_vary('a,@,x,z')), _vary({'head': 'a', 'rest': ['@', 'x'], 'tail': 'z'}))\ncheck('none', solve(_vary('a,z')), _vary({'head': 'a', 'rest': [], 'tail': 'z'}))\ncheck('empty rest', solve(_vary('a,,z')), _vary({'head': 'a', 'rest': [''], 'tail': 'z'}))\ncheck('two empties', solve(_vary(',')), _vary({'head': '', 'rest': [], 'tail': ''}))\ncheck('short', solve(_vary('@')), _vary(None))\ncheck('one rest', solve(_vary('a,@,z')), _vary({'head': 'a', 'rest': ['@'], 'tail': 'z'}))\ncheck('trailing', solve(_vary('a,@,')), _vary({'head': 'a', 'rest': ['@'], 'tail': ''}))\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-named-rest-column-rest-tail","generated_at":"2026-09-29T14:44:48.427737+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.","root_cause":"A variadic column consumes the trailing fixed field.","sha256":"857ca63e921d9debf34d66f47ed33e2444b50e34b35fc3746ced160babbda1a2","title":"A variadic column consumes the trailing fixed field · 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":41.241,"exit_code":1,"observations":[{"actual":{"head":"a","rest":["a","cell","x"],"tail":"z"},"check":"rest","expected":{"head":"a","rest":["cell","x"],"tail":"z"},"passed":false},{"actual":{"head":"a","rest":["a"],"tail":"z"},"check":"none","expected":{"head":"a","rest":[],"tail":"z"},"passed":false},{"actual":{"head":"a","rest":["a",""],"tail":"z"},"check":"empty rest","expected":{"head":"a","rest":[""],"tail":"z"},"passed":false},{"actual":{"head":"","rest":[""],"tail":""},"check":"two empties","expected":{"head":"","rest":[],"tail":""},"passed":false},{"actual":null,"check":"short","expected":null,"passed":true},{"actual":{"head":"a","rest":["a","cell"],"tail":"z"},"check":"one rest","expected":{"head":"a","rest":["cell"],"tail":"z"},"passed":false},{"actual":{"head":"a","rest":["a","cell"],"tail":""},"check":"trailing","expected":{"head":"a","rest":["cell"],"tail":""},"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"rest\", \"actual\": {\"head\": \"a\", \"rest\": [\"a\", \"cell\", \"x\"], \"tail\": \"z\"}, \"expected\": {\"head\": \"a\", \"rest\": [\"cell\", \"x\"], \"tail\": \"z\"}, \"passed\": false}, {\"check\": \"none\", \"actual\": {\"head\": \"a\", \"rest\": [\"a\"], \"tail\": \"z\"}, \"expected\": {\"head\": \"a\", \"rest\": [], \"tail\": \"z\"}, \"passed\": false}, {\"check\": \"empty rest\", \"actual\": {\"head\": \"a\", \"rest\": [\"a\", \"\"], \"tail\": \"z\"}, \"expected\": {\"head\": \"a\", \"rest\": [\"\"], \"tail\": \"z\"}, \"passed\": false}, {\"check\": \"two empties\", \"actual\": {\"head\": \"\", \"rest\": [\"\"], \"tail\": \"\"}, \"expected\": {\"head\": \"\", \"rest\": [], \"tail\": \"\"}, \"passed\": false}, {\"check\": \"short\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"one rest\", \"actual\": {\"head\": \"a\", \"rest\": [\"a\", \"cell\"], \"tail\": \"z\"}, \"expected\": {\"head\": \"a\", \"rest\": [\"cell\"], \"tail\": \"z\"}, \"passed\": false}, {\"check\": \"trailing\", \"actual\": {\"head\": \"a\", \"rest\": [\"a\", \"cell\"], \"tail\": \"\"}, \"expected\": {\"head\": \"a\", \"rest\": [\"cell\"], \"tail\": \"\"}, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":37.864,"exit_code":1,"observations":[{"actual":{"head":"a","rest":["cell","x","z"],"tail":"z"},"check":"rest","expected":{"head":"a","rest":["cell","x"],"tail":"z"},"passed":false},{"actual":{"head":"a","rest":["z"],"tail":"z"},"check":"none","expected":{"head":"a","rest":[],"tail":"z"},"passed":false},{"actual":{"head":"a","rest":["","z"],"tail":"z"},"check":"empty rest","expected":{"head":"a","rest":[""],"tail":"z"},"passed":false},{"actual":{"head":"","rest":[""],"tail":""},"check":"two empties","expected":{"head":"","rest":[],"tail":""},"passed":false},{"actual":null,"check":"short","expected":null,"passed":true},{"actual":{"head":"a","rest":["cell","z"],"tail":"z"},"check":"one rest","expected":{"head":"a","rest":["cell"],"tail":"z"},"passed":false},{"actual":{"head":"a","rest":["cell",""],"tail":""},"check":"trailing","expected":{"head":"a","rest":["cell"],"tail":""},"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"rest\", \"actual\": {\"head\": \"a\", \"rest\": [\"cell\", \"x\", \"z\"], \"tail\": \"z\"}, \"expected\": {\"head\": \"a\", \"rest\": [\"cell\", \"x\"], \"tail\": \"z\"}, \"passed\": false}, {\"check\": \"none\", \"actual\": {\"head\": \"a\", \"rest\": [\"z\"], \"tail\": \"z\"}, \"expected\": {\"head\": \"a\", \"rest\": [], \"tail\": \"z\"}, \"passed\": false}, {\"check\": \"empty rest\", \"actual\": {\"head\": \"a\", \"rest\": [\"\", \"z\"], \"tail\": \"z\"}, \"expected\": {\"head\": \"a\", \"rest\": [\"\"], \"tail\": \"z\"}, \"passed\": false}, {\"check\": \"two empties\", \"actual\": {\"head\": \"\", \"rest\": [\"\"], \"tail\": \"\"}, \"expected\": {\"head\": \"\", \"rest\": [], \"tail\": \"\"}, \"passed\": false}, {\"check\": \"short\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"one rest\", \"actual\": {\"head\": \"a\", \"rest\": [\"cell\", \"z\"], \"tail\": \"z\"}, \"expected\": {\"head\": \"a\", \"rest\": [\"cell\"], \"tail\": \"z\"}, \"passed\": false}, {\"check\": \"trailing\", \"actual\": {\"head\": \"a\", \"rest\": [\"cell\", \"\"], \"tail\": \"\"}, \"expected\": {\"head\": \"a\", \"rest\": [\"cell\"], \"tail\": \"\"}, \"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."}}