{"abstract":"A structured table violates the declared record or column contract.","category":"Delimited text","checks":10,"contract":"Decode a semicolon table row whose cells are either bare scalar text or bracketed pipe lists. Backslash has no special role. List elements may be empty; [] is an empty list. Brackets must occupy the whole cell; nested brackets reject. Return each cell as scalar text or a list.","contract_signature":"data","evaluation_group":"s3-delimited-text-field-list-cells","failed_approach":"Trimming list separators loses edge positions while retaining only interior empties.","family":"s3-delimited-text-field-list-cells-empty-elements","id":"FA-47896","implementations":{"attempt":{"sha256":"8b43d8d78b58d4525d06838f83d1ecc12a6cdbbb16c7c4eadeb9700ebc7e7662","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 = []\n    for cell in data.split(';'):\n        if cell.startswith('['):\n            if not cell.endswith(']'): return None\n            inner = cell[1:-1]\n            if '[' in inner or ']' in inner: return None\n            value = [] if inner == '' else inner.strip('|').split('|')\n        else:\n            if '[' in cell or ']' in cell: return None\n            value = cell\n        out.append(value)\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('mixed', solve(_vary('@;[a|b]')), _vary(['@', ['a', 'b']]))\ncheck('empty list', solve(_vary('[]')), _vary([[]]))\ncheck('empty elements', solve(_vary('[|a|]')), _vary([['', 'a', '']]))\ncheck('bare empty', solve(_vary('')), _vary(['']))\ncheck('unclosed', solve(_vary('[a')), _vary(None))\ncheck('suffix', solve(_vary('[a]tail')), _vary(None))\ncheck('nested', solve(_vary('[[a]]')), _vary(None))\ncheck('bare bracket', solve(_vary('a]')), _vary(None))\ncheck('pipe bare', solve(_vary('a|b')), _vary(['a|b']))\ncheck('three list', solve(_vary('[a|b|c]')), _vary([['a', 'b', 'c']]))\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":"11402d2bc8a43bc0b65c52bc52d7452f6f8c7217783a54466afc5a86fed83e4e","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 = []\n    for cell in data.split(';'):\n        if cell.startswith('['):\n            if not cell.endswith(']'): return None\n            inner = cell[1:-1]\n            if '[' in inner or ']' in inner: return None\n            value = [] if inner == '' else [x for x in inner.split('|') if x]\n        else:\n            if '[' in cell or ']' in cell: return None\n            value = cell\n        out.append(value)\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('mixed', solve(_vary('@;[a|b]')), _vary(['@', ['a', 'b']]))\ncheck('empty list', solve(_vary('[]')), _vary([[]]))\ncheck('empty elements', solve(_vary('[|a|]')), _vary([['', 'a', '']]))\ncheck('bare empty', solve(_vary('')), _vary(['']))\ncheck('unclosed', solve(_vary('[a')), _vary(None))\ncheck('suffix', solve(_vary('[a]tail')), _vary(None))\ncheck('nested', solve(_vary('[[a]]')), _vary(None))\ncheck('bare bracket', solve(_vary('a]')), _vary(None))\ncheck('pipe bare', solve(_vary('a|b')), _vary(['a|b']))\ncheck('three list', solve(_vary('[a|b|c]')), _vary([['a', 'b', 'c']]))\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-field-list-cells-empty-elements","generated_at":"2026-09-29T14:44:46.019674+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":"The list-cell parser filters empty members that have positional meaning.","sha256":"c5f0036698187a9da00f410c3c8522272af7e4b49b3a6474ca2fe05adeafa594","title":"Empty positions inside a list cell disappear · 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":42.263,"exit_code":1,"observations":[{"actual":["cell",["a","b"]],"check":"mixed","expected":["cell",["a","b"]],"passed":true},{"actual":[[]],"check":"empty list","expected":[[]],"passed":true},{"actual":[["a"]],"check":"empty elements","expected":[["","a",""]],"passed":false},{"actual":[""],"check":"bare empty","expected":[""],"passed":true},{"actual":null,"check":"unclosed","expected":null,"passed":true},{"actual":null,"check":"suffix","expected":null,"passed":true},{"actual":null,"check":"nested","expected":null,"passed":true},{"actual":null,"check":"bare bracket","expected":null,"passed":true},{"actual":["a|b"],"check":"pipe bare","expected":["a|b"],"passed":true},{"actual":[["a","b","c"]],"check":"three list","expected":[["a","b","c"]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"mixed\", \"actual\": [\"cell\", [\"a\", \"b\"]], \"expected\": [\"cell\", [\"a\", \"b\"]], \"passed\": true}, {\"check\": \"empty list\", \"actual\": [[]], \"expected\": [[]], \"passed\": true}, {\"check\": \"empty elements\", \"actual\": [[\"a\"]], \"expected\": [[\"\", \"a\", \"\"]], \"passed\": false}, {\"check\": \"bare empty\", \"actual\": [\"\"], \"expected\": [\"\"], \"passed\": true}, {\"check\": \"unclosed\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"suffix\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"nested\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"bare bracket\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"pipe bare\", \"actual\": [\"a|b\"], \"expected\": [\"a|b\"], \"passed\": true}, {\"check\": \"three list\", \"actual\": [[\"a\", \"b\", \"c\"]], \"expected\": [[\"a\", \"b\", \"c\"]], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":41.833,"exit_code":1,"observations":[{"actual":["cell",["a","b"]],"check":"mixed","expected":["cell",["a","b"]],"passed":true},{"actual":[[]],"check":"empty list","expected":[[]],"passed":true},{"actual":[["a"]],"check":"empty elements","expected":[["","a",""]],"passed":false},{"actual":[""],"check":"bare empty","expected":[""],"passed":true},{"actual":null,"check":"unclosed","expected":null,"passed":true},{"actual":null,"check":"suffix","expected":null,"passed":true},{"actual":null,"check":"nested","expected":null,"passed":true},{"actual":null,"check":"bare bracket","expected":null,"passed":true},{"actual":["a|b"],"check":"pipe bare","expected":["a|b"],"passed":true},{"actual":[["a","b","c"]],"check":"three list","expected":[["a","b","c"]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"mixed\", \"actual\": [\"cell\", [\"a\", \"b\"]], \"expected\": [\"cell\", [\"a\", \"b\"]], \"passed\": true}, {\"check\": \"empty list\", \"actual\": [[]], \"expected\": [[]], \"passed\": true}, {\"check\": \"empty elements\", \"actual\": [[\"a\"]], \"expected\": [[\"\", \"a\", \"\"]], \"passed\": false}, {\"check\": \"bare empty\", \"actual\": [\"\"], \"expected\": [\"\"], \"passed\": true}, {\"check\": \"unclosed\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"suffix\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"nested\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"bare bracket\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"pipe bare\", \"actual\": [\"a|b\"], \"expected\": [\"a|b\"], \"passed\": true}, {\"check\": \"three list\", \"actual\": [[\"a\", \"b\", \"c\"]], \"expected\": [[\"a\", \"b\", \"c\"]], \"passed\": true}], \"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."}}