{"abstract":"Nested list decoding ignores child validity.","category":"Data systems","checks":7,"contract":"Gather selected list rows from offset-based child storage. Parent nullness hides child storage; empty valid lists remain []; child nulls remain None. Preserve repeated selected rows and list element order.","evaluation_group":"s3-data-systems-list-offset-slice","failed_approach":"Filtering null children shortens the list.","family":"s3-data-systems-list-offset-slice-child-validity","id":"FA-44446","implementations":{"attempt":{"sha256":"6f794e4eb84f82871fbcee35bd02ca3e19803818cc061b3026a9fd1b7f619ece","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(d):\n    try:\n        offsets,child,parents,valid,selection=d\n        out=[]\n        for row in selection:\n            lo=offsets[row]\n            hi=offsets[row+1]\n            items=[child[i] for i in range(lo,hi) if valid[i]]\n            out.append(items if parents[row] else None)\n        return out\n    except (IndexError, KeyError, ValueError, StopIteration) as exc:\n        return {\"representation_error\": type(exc).__name__}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nif N == 1:\n    check('shared child offsets', solve([[0, 2, 3], [1, 2, 3], [True, True], [True, True, True], [1, 0]]), [[3], [1, 2]])\n    check('null child', solve([[0, 2], [1, 2], [True], [False, True], [0]]), [[None, 2]])\n    check('hidden null list', solve([[0, 2], [1, 2], [False], [True, True], [0]]), [None])\n    check('empty valid list', solve([[0, 0, 1], [1], [True, True], [True], [0, 1]]), [[], [1]])\n    check('repeated list', solve([[0, 1, 2], [1, 2], [True, True], [True, True], [1, 1]]), [[2], [2]])\n    check('no rows', solve([[0], [], [], [], []]), [])\n    check('nonzero physical origin', solve([[1, 3], [0, 1, 2], [True], [True, True, True], [0]]), [[1, 2]])\nelif N == 2:\n    check('shared child offsets', solve([[0, 2, 3], [2, 3, 4], [True, True], [True, True, True], [1, 0]]), [[4], [2, 3]])\n    check('null child', solve([[0, 2], [2, 3], [True], [False, True], [0]]), [[None, 3]])\n    check('hidden null list', solve([[0, 2], [2, 3], [False], [True, True], [0]]), [None])\n    check('empty valid list', solve([[0, 0, 1], [2], [True, True], [True], [0, 1]]), [[], [2]])\n    check('repeated list', solve([[0, 1, 2], [2, 3], [True, True], [True, True], [1, 1]]), [[3], [3]])\n    check('no rows', solve([[0], [], [], [], []]), [])\n    check('nonzero physical origin', solve([[1, 3], [0, 2, 3], [True], [True, True, True], [0]]), [[2, 3]])\nelif N == 3:\n    check('shared child offsets', solve([[0, 2, 3], [3, 4, 5], [True, True], [True, True, True], [1, 0]]), [[5], [3, 4]])\n    check('null child', solve([[0, 2], [3, 4], [True], [False, True], [0]]), [[None, 4]])\n    check('hidden null list', solve([[0, 2], [3, 4], [False], [True, True], [0]]), [None])\n    check('empty valid list', solve([[0, 0, 1], [3], [True, True], [True], [0, 1]]), [[], [3]])\n    check('repeated list', solve([[0, 1, 2], [3, 4], [True, True], [True, True], [1, 1]]), [[4], [4]])\n    check('no rows', solve([[0], [], [], [], []]), [])\n    check('nonzero physical origin', solve([[1, 3], [0, 3, 4], [True], [True, True, True], [0]]), [[3, 4]])\nelif N == 4:\n    check('shared child offsets', solve([[0, 2, 3], [4, 5, 6], [True, True], [True, True, True], [1, 0]]), [[6], [4, 5]])\n    check('null child', solve([[0, 2], [4, 5], [True], [False, True], [0]]), [[None, 5]])\n    check('hidden null list', solve([[0, 2], [4, 5], [False], [True, True], [0]]), [None])\n    check('empty valid list', solve([[0, 0, 1], [4], [True, True], [True], [0, 1]]), [[], [4]])\n    check('repeated list', solve([[0, 1, 2], [4, 5], [True, True], [True, True], [1, 1]]), [[5], [5]])\n    check('no rows', solve([[0], [], [], [], []]), [])\n    check('nonzero physical origin', solve([[1, 3], [0, 4, 5], [True], [True, True, True], [0]]), [[4, 5]])\nelif N == 5:\n    check('shared child offsets', solve([[0, 2, 3], [5, 6, 7], [True, True], [True, True, True], [1, 0]]), [[7], [5, 6]])\n    check('null child', solve([[0, 2], [5, 6], [True], [False, True], [0]]), [[None, 6]])\n    check('hidden null list', solve([[0, 2], [5, 6], [False], [True, True], [0]]), [None])\n    check('empty valid list', solve([[0, 0, 1], [5], [True, True], [True], [0, 1]]), [[], [5]])\n    check('repeated list', solve([[0, 1, 2], [5, 6], [True, True], [True, True], [1, 1]]), [[6], [6]])\n    check('no rows', solve([[0], [], [], [], []]), [])\n    check('nonzero physical origin', solve([[1, 3], [0, 5, 6], [True], [True, True, True], [0]]), [[5, 6]])\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":"06132e90ab44d4989fd47be8365622c9677e728e2187902a584f48c93d65dbf4","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(d):\n    try:\n        offsets,child,parents,valid,selection=d\n        out=[]\n        for row in selection:\n            lo=offsets[row]\n            hi=offsets[row+1]\n            items=[child[i] for i in range(lo,hi)]\n            out.append(items if parents[row] else None)\n        return out\n    except (IndexError, KeyError, ValueError, StopIteration) as exc:\n        return {\"representation_error\": type(exc).__name__}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nif N == 1:\n    check('shared child offsets', solve([[0, 2, 3], [1, 2, 3], [True, True], [True, True, True], [1, 0]]), [[3], [1, 2]])\n    check('null child', solve([[0, 2], [1, 2], [True], [False, True], [0]]), [[None, 2]])\n    check('hidden null list', solve([[0, 2], [1, 2], [False], [True, True], [0]]), [None])\n    check('empty valid list', solve([[0, 0, 1], [1], [True, True], [True], [0, 1]]), [[], [1]])\n    check('repeated list', solve([[0, 1, 2], [1, 2], [True, True], [True, True], [1, 1]]), [[2], [2]])\n    check('no rows', solve([[0], [], [], [], []]), [])\n    check('nonzero physical origin', solve([[1, 3], [0, 1, 2], [True], [True, True, True], [0]]), [[1, 2]])\nelif N == 2:\n    check('shared child offsets', solve([[0, 2, 3], [2, 3, 4], [True, True], [True, True, True], [1, 0]]), [[4], [2, 3]])\n    check('null child', solve([[0, 2], [2, 3], [True], [False, True], [0]]), [[None, 3]])\n    check('hidden null list', solve([[0, 2], [2, 3], [False], [True, True], [0]]), [None])\n    check('empty valid list', solve([[0, 0, 1], [2], [True, True], [True], [0, 1]]), [[], [2]])\n    check('repeated list', solve([[0, 1, 2], [2, 3], [True, True], [True, True], [1, 1]]), [[3], [3]])\n    check('no rows', solve([[0], [], [], [], []]), [])\n    check('nonzero physical origin', solve([[1, 3], [0, 2, 3], [True], [True, True, True], [0]]), [[2, 3]])\nelif N == 3:\n    check('shared child offsets', solve([[0, 2, 3], [3, 4, 5], [True, True], [True, True, True], [1, 0]]), [[5], [3, 4]])\n    check('null child', solve([[0, 2], [3, 4], [True], [False, True], [0]]), [[None, 4]])\n    check('hidden null list', solve([[0, 2], [3, 4], [False], [True, True], [0]]), [None])\n    check('empty valid list', solve([[0, 0, 1], [3], [True, True], [True], [0, 1]]), [[], [3]])\n    check('repeated list', solve([[0, 1, 2], [3, 4], [True, True], [True, True], [1, 1]]), [[4], [4]])\n    check('no rows', solve([[0], [], [], [], []]), [])\n    check('nonzero physical origin', solve([[1, 3], [0, 3, 4], [True], [True, True, True], [0]]), [[3, 4]])\nelif N == 4:\n    check('shared child offsets', solve([[0, 2, 3], [4, 5, 6], [True, True], [True, True, True], [1, 0]]), [[6], [4, 5]])\n    check('null child', solve([[0, 2], [4, 5], [True], [False, True], [0]]), [[None, 5]])\n    check('hidden null list', solve([[0, 2], [4, 5], [False], [True, True], [0]]), [None])\n    check('empty valid list', solve([[0, 0, 1], [4], [True, True], [True], [0, 1]]), [[], [4]])\n    check('repeated list', solve([[0, 1, 2], [4, 5], [True, True], [True, True], [1, 1]]), [[5], [5]])\n    check('no rows', solve([[0], [], [], [], []]), [])\n    check('nonzero physical origin', solve([[1, 3], [0, 4, 5], [True], [True, True, True], [0]]), [[4, 5]])\nelif N == 5:\n    check('shared child offsets', solve([[0, 2, 3], [5, 6, 7], [True, True], [True, True, True], [1, 0]]), [[7], [5, 6]])\n    check('null child', solve([[0, 2], [5, 6], [True], [False, True], [0]]), [[None, 6]])\n    check('hidden null list', solve([[0, 2], [5, 6], [False], [True, True], [0]]), [None])\n    check('empty valid list', solve([[0, 0, 1], [5], [True, True], [True], [0, 1]]), [[], [5]])\n    check('repeated list', solve([[0, 1, 2], [5, 6], [True, True], [True, True], [1, 1]]), [[6], [6]])\n    check('no rows', solve([[0], [], [], [], []]), [])\n    check('nonzero physical origin', solve([[1, 3], [0, 5, 6], [True], [True, True, True], [0]]), [[5, 6]])\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":"8b82b4b1704df7570994e3cdfa1520cd2e8d47c877862c456aa26cb0a9a578b7","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(d):\n    try:\n        offsets,child,parents,valid,selection=d\n        out=[]\n        for row in selection:\n            lo=offsets[row]\n            hi=offsets[row+1]\n            items=[child[i] if valid[i] else None for i in range(lo,hi)]\n            out.append(items if parents[row] else None)\n        return out\n    except (IndexError, KeyError, ValueError, StopIteration) as exc:\n        return {\"representation_error\": type(exc).__name__}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nif N == 1:\n    check('shared child offsets', solve([[0, 2, 3], [1, 2, 3], [True, True], [True, True, True], [1, 0]]), [[3], [1, 2]])\n    check('null child', solve([[0, 2], [1, 2], [True], [False, True], [0]]), [[None, 2]])\n    check('hidden null list', solve([[0, 2], [1, 2], [False], [True, True], [0]]), [None])\n    check('empty valid list', solve([[0, 0, 1], [1], [True, True], [True], [0, 1]]), [[], [1]])\n    check('repeated list', solve([[0, 1, 2], [1, 2], [True, True], [True, True], [1, 1]]), [[2], [2]])\n    check('no rows', solve([[0], [], [], [], []]), [])\n    check('nonzero physical origin', solve([[1, 3], [0, 1, 2], [True], [True, True, True], [0]]), [[1, 2]])\nelif N == 2:\n    check('shared child offsets', solve([[0, 2, 3], [2, 3, 4], [True, True], [True, True, True], [1, 0]]), [[4], [2, 3]])\n    check('null child', solve([[0, 2], [2, 3], [True], [False, True], [0]]), [[None, 3]])\n    check('hidden null list', solve([[0, 2], [2, 3], [False], [True, True], [0]]), [None])\n    check('empty valid list', solve([[0, 0, 1], [2], [True, True], [True], [0, 1]]), [[], [2]])\n    check('repeated list', solve([[0, 1, 2], [2, 3], [True, True], [True, True], [1, 1]]), [[3], [3]])\n    check('no rows', solve([[0], [], [], [], []]), [])\n    check('nonzero physical origin', solve([[1, 3], [0, 2, 3], [True], [True, True, True], [0]]), [[2, 3]])\nelif N == 3:\n    check('shared child offsets', solve([[0, 2, 3], [3, 4, 5], [True, True], [True, True, True], [1, 0]]), [[5], [3, 4]])\n    check('null child', solve([[0, 2], [3, 4], [True], [False, True], [0]]), [[None, 4]])\n    check('hidden null list', solve([[0, 2], [3, 4], [False], [True, True], [0]]), [None])\n    check('empty valid list', solve([[0, 0, 1], [3], [True, True], [True], [0, 1]]), [[], [3]])\n    check('repeated list', solve([[0, 1, 2], [3, 4], [True, True], [True, True], [1, 1]]), [[4], [4]])\n    check('no rows', solve([[0], [], [], [], []]), [])\n    check('nonzero physical origin', solve([[1, 3], [0, 3, 4], [True], [True, True, True], [0]]), [[3, 4]])\nelif N == 4:\n    check('shared child offsets', solve([[0, 2, 3], [4, 5, 6], [True, True], [True, True, True], [1, 0]]), [[6], [4, 5]])\n    check('null child', solve([[0, 2], [4, 5], [True], [False, True], [0]]), [[None, 5]])\n    check('hidden null list', solve([[0, 2], [4, 5], [False], [True, True], [0]]), [None])\n    check('empty valid list', solve([[0, 0, 1], [4], [True, True], [True], [0, 1]]), [[], [4]])\n    check('repeated list', solve([[0, 1, 2], [4, 5], [True, True], [True, True], [1, 1]]), [[5], [5]])\n    check('no rows', solve([[0], [], [], [], []]), [])\n    check('nonzero physical origin', solve([[1, 3], [0, 4, 5], [True], [True, True, True], [0]]), [[4, 5]])\nelif N == 5:\n    check('shared child offsets', solve([[0, 2, 3], [5, 6, 7], [True, True], [True, True, True], [1, 0]]), [[7], [5, 6]])\n    check('null child', solve([[0, 2], [5, 6], [True], [False, True], [0]]), [[None, 6]])\n    check('hidden null list', solve([[0, 2], [5, 6], [False], [True, True], [0]]), [None])\n    check('empty valid list', solve([[0, 0, 1], [5], [True, True], [True], [0, 1]]), [[], [5]])\n    check('repeated list', solve([[0, 1, 2], [5, 6], [True, True], [True, True], [1, 1]]), [[6], [6]])\n    check('no rows', solve([[0], [], [], [], []]), [])\n    check('nonzero physical origin', solve([[1, 3], [0, 5, 6], [True], [True, True, True], [0]]), [[5, 6]])\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":"Offline stipulated semantics over valid small inputs; no performance, concurrency, or production-engine conformance claim. 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-data-systems-list-offset-slice-child-validity","generated_at":"2026-09-29T14:44:12.384025+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A bounded deterministic data engine model makes representation and changelog faults reproducible.","repair":"Preserve the stated physical representation and operation order: Gather selected list rows from offset-based child storage. Parent nullness hides child storage; empty valid lists remain []; child nulls remain None. Preserve repeated selected rows and list element order.","root_cause":"list-offset-slice: Nested list decoding ignores child validity.","sha256":"9f9f5ffd3ced78432809a25f849fb22663459a384112f6aefaea7a9e77c8dd9c","title":"Nested list decoding ignores child validity · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":45.428,"exit_code":1,"observations":[{"actual":[[3],[1,2]],"check":"shared child offsets","expected":[[3],[1,2]],"passed":true},{"actual":[[2]],"check":"null child","expected":[[null,2]],"passed":false},{"actual":[null],"check":"hidden null list","expected":[null],"passed":true},{"actual":[[],[1]],"check":"empty valid list","expected":[[],[1]],"passed":true},{"actual":[[2],[2]],"check":"repeated list","expected":[[2],[2]],"passed":true},{"actual":[],"check":"no rows","expected":[],"passed":true},{"actual":[[1,2]],"check":"nonzero physical origin","expected":[[1,2]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"shared child offsets\", \"actual\": [[3], [1, 2]], \"expected\": [[3], [1, 2]], \"passed\": true}, {\"check\": \"null child\", \"actual\": [[2]], \"expected\": [[null, 2]], \"passed\": false}, {\"check\": \"hidden null list\", \"actual\": [null], \"expected\": [null], \"passed\": true}, {\"check\": \"empty valid list\", \"actual\": [[], [1]], \"expected\": [[], [1]], \"passed\": true}, {\"check\": \"repeated list\", \"actual\": [[2], [2]], \"expected\": [[2], [2]], \"passed\": true}, {\"check\": \"no rows\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"nonzero physical origin\", \"actual\": [[1, 2]], \"expected\": [[1, 2]], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":42.316,"exit_code":1,"observations":[{"actual":[[3],[1,2]],"check":"shared child offsets","expected":[[3],[1,2]],"passed":true},{"actual":[[1,2]],"check":"null child","expected":[[null,2]],"passed":false},{"actual":[null],"check":"hidden null list","expected":[null],"passed":true},{"actual":[[],[1]],"check":"empty valid list","expected":[[],[1]],"passed":true},{"actual":[[2],[2]],"check":"repeated list","expected":[[2],[2]],"passed":true},{"actual":[],"check":"no rows","expected":[],"passed":true},{"actual":[[1,2]],"check":"nonzero physical origin","expected":[[1,2]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"shared child offsets\", \"actual\": [[3], [1, 2]], \"expected\": [[3], [1, 2]], \"passed\": true}, {\"check\": \"null child\", \"actual\": [[1, 2]], \"expected\": [[null, 2]], \"passed\": false}, {\"check\": \"hidden null list\", \"actual\": [null], \"expected\": [null], \"passed\": true}, {\"check\": \"empty valid list\", \"actual\": [[], [1]], \"expected\": [[], [1]], \"passed\": true}, {\"check\": \"repeated list\", \"actual\": [[2], [2]], \"expected\": [[2], [2]], \"passed\": true}, {\"check\": \"no rows\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"nonzero physical origin\", \"actual\": [[1, 2]], \"expected\": [[1, 2]], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":41.553,"exit_code":0,"observations":[{"actual":[[3],[1,2]],"check":"shared child offsets","expected":[[3],[1,2]],"passed":true},{"actual":[[null,2]],"check":"null child","expected":[[null,2]],"passed":true},{"actual":[null],"check":"hidden null list","expected":[null],"passed":true},{"actual":[[],[1]],"check":"empty valid list","expected":[[],[1]],"passed":true},{"actual":[[2],[2]],"check":"repeated list","expected":[[2],[2]],"passed":true},{"actual":[],"check":"no rows","expected":[],"passed":true},{"actual":[[1,2]],"check":"nonzero physical origin","expected":[[1,2]],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"shared child offsets\", \"actual\": [[3], [1, 2]], \"expected\": [[3], [1, 2]], \"passed\": true}, {\"check\": \"null child\", \"actual\": [[null, 2]], \"expected\": [[null, 2]], \"passed\": true}, {\"check\": \"hidden null list\", \"actual\": [null], \"expected\": [null], \"passed\": true}, {\"check\": \"empty valid list\", \"actual\": [[], [1]], \"expected\": [[], [1]], \"passed\": true}, {\"check\": \"repeated list\", \"actual\": [[2], [2]], \"expected\": [[2], [2]], \"passed\": true}, {\"check\": \"no rows\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"nonzero physical origin\", \"actual\": [[1, 2]], \"expected\": [[1, 2]], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}