{"abstract":"Only the first physical right chunk participates in row assembly.","category":"Data systems","checks":7,"contract":"Assemble two equally long logical columns from independent chunk layouts. Empty chunks carry no rows. Zip by global row ordinal, retain null values, and apply the requested half-open row slice after alignment.","evaluation_group":"s3-data-systems-chunked-column-zip","failed_approach":"Reversing chunk order restores length but changes global positions.","family":"s3-data-systems-chunked-column-zip-right-chunks","id":"FA-44526","implementations":{"attempt":{"sha256":"dab514de5598d1606cb7120c1298279cf6a293e8c2983c905f18226c5b1326ea","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(d):\n    try:\n        left,right,start,length=d\n        a=[v for chunk in left for v in chunk]\n        b=[v for chunk in reversed(right) for v in chunk]\n        rows=[[a[i],b[i]] for i in range(len(a))]\n        rows=rows[start:start+length]\n        return rows\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('different boundaries', solve([[[1, 2], [3]], [[4], [5, 6]], 0, 3]), [[1, 4], [2, 5], [3, 6]])\n    check('empty internal chunks', solve([[[1], [], [2]], [[], [3, 4]], 0, 2]), [[1, 3], [2, 4]])\n    check('global slice', solve([[[1], [2, 3]], [[4, 5], [6]], 1, 2]), [[2, 5], [3, 6]])\n    check('null field', solve([[[None, 1]], [[2, None]], 0, 2]), [[None, 2], [1, None]])\n    check('repeated rows', solve([[[1, 1]], [[2, 2]], 0, 2]), [[1, 2], [1, 2]])\n    check('zero length', solve([[[1]], [[2]], 0, 0]), [])\n    check('no physical chunks', solve([[], [], 0, 0]), [])\nelif N == 2:\n    check('different boundaries', solve([[[2, 3], [4]], [[5], [6, 7]], 0, 3]), [[2, 5], [3, 6], [4, 7]])\n    check('empty internal chunks', solve([[[2], [], [3]], [[], [4, 5]], 0, 2]), [[2, 4], [3, 5]])\n    check('global slice', solve([[[2], [3, 4]], [[5, 6], [7]], 1, 2]), [[3, 6], [4, 7]])\n    check('null field', solve([[[None, 2]], [[3, None]], 0, 2]), [[None, 3], [2, None]])\n    check('repeated rows', solve([[[2, 2]], [[3, 3]], 0, 2]), [[2, 3], [2, 3]])\n    check('zero length', solve([[[2]], [[3]], 0, 0]), [])\n    check('no physical chunks', solve([[], [], 0, 0]), [])\nelif N == 3:\n    check('different boundaries', solve([[[3, 4], [5]], [[6], [7, 8]], 0, 3]), [[3, 6], [4, 7], [5, 8]])\n    check('empty internal chunks', solve([[[3], [], [4]], [[], [5, 6]], 0, 2]), [[3, 5], [4, 6]])\n    check('global slice', solve([[[3], [4, 5]], [[6, 7], [8]], 1, 2]), [[4, 7], [5, 8]])\n    check('null field', solve([[[None, 3]], [[4, None]], 0, 2]), [[None, 4], [3, None]])\n    check('repeated rows', solve([[[3, 3]], [[4, 4]], 0, 2]), [[3, 4], [3, 4]])\n    check('zero length', solve([[[3]], [[4]], 0, 0]), [])\n    check('no physical chunks', solve([[], [], 0, 0]), [])\nelif N == 4:\n    check('different boundaries', solve([[[4, 5], [6]], [[7], [8, 9]], 0, 3]), [[4, 7], [5, 8], [6, 9]])\n    check('empty internal chunks', solve([[[4], [], [5]], [[], [6, 7]], 0, 2]), [[4, 6], [5, 7]])\n    check('global slice', solve([[[4], [5, 6]], [[7, 8], [9]], 1, 2]), [[5, 8], [6, 9]])\n    check('null field', solve([[[None, 4]], [[5, None]], 0, 2]), [[None, 5], [4, None]])\n    check('repeated rows', solve([[[4, 4]], [[5, 5]], 0, 2]), [[4, 5], [4, 5]])\n    check('zero length', solve([[[4]], [[5]], 0, 0]), [])\n    check('no physical chunks', solve([[], [], 0, 0]), [])\nelif N == 5:\n    check('different boundaries', solve([[[5, 6], [7]], [[8], [9, 10]], 0, 3]), [[5, 8], [6, 9], [7, 10]])\n    check('empty internal chunks', solve([[[5], [], [6]], [[], [7, 8]], 0, 2]), [[5, 7], [6, 8]])\n    check('global slice', solve([[[5], [6, 7]], [[8, 9], [10]], 1, 2]), [[6, 9], [7, 10]])\n    check('null field', solve([[[None, 5]], [[6, None]], 0, 2]), [[None, 6], [5, None]])\n    check('repeated rows', solve([[[5, 5]], [[6, 6]], 0, 2]), [[5, 6], [5, 6]])\n    check('zero length', solve([[[5]], [[6]], 0, 0]), [])\n    check('no physical chunks', solve([[], [], 0, 0]), [])\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":"649b0c163fac49cf8cc74b58fd92c34ac8ee0a7e9dde1708e04db389c0ad8699","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(d):\n    try:\n        left,right,start,length=d\n        a=[v for chunk in left for v in chunk]\n        b=(right[0] if right else []) + [None]*sum(map(len,right[1:]))\n        rows=[[a[i],b[i]] for i in range(len(a))]\n        rows=rows[start:start+length]\n        return rows\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('different boundaries', solve([[[1, 2], [3]], [[4], [5, 6]], 0, 3]), [[1, 4], [2, 5], [3, 6]])\n    check('empty internal chunks', solve([[[1], [], [2]], [[], [3, 4]], 0, 2]), [[1, 3], [2, 4]])\n    check('global slice', solve([[[1], [2, 3]], [[4, 5], [6]], 1, 2]), [[2, 5], [3, 6]])\n    check('null field', solve([[[None, 1]], [[2, None]], 0, 2]), [[None, 2], [1, None]])\n    check('repeated rows', solve([[[1, 1]], [[2, 2]], 0, 2]), [[1, 2], [1, 2]])\n    check('zero length', solve([[[1]], [[2]], 0, 0]), [])\n    check('no physical chunks', solve([[], [], 0, 0]), [])\nelif N == 2:\n    check('different boundaries', solve([[[2, 3], [4]], [[5], [6, 7]], 0, 3]), [[2, 5], [3, 6], [4, 7]])\n    check('empty internal chunks', solve([[[2], [], [3]], [[], [4, 5]], 0, 2]), [[2, 4], [3, 5]])\n    check('global slice', solve([[[2], [3, 4]], [[5, 6], [7]], 1, 2]), [[3, 6], [4, 7]])\n    check('null field', solve([[[None, 2]], [[3, None]], 0, 2]), [[None, 3], [2, None]])\n    check('repeated rows', solve([[[2, 2]], [[3, 3]], 0, 2]), [[2, 3], [2, 3]])\n    check('zero length', solve([[[2]], [[3]], 0, 0]), [])\n    check('no physical chunks', solve([[], [], 0, 0]), [])\nelif N == 3:\n    check('different boundaries', solve([[[3, 4], [5]], [[6], [7, 8]], 0, 3]), [[3, 6], [4, 7], [5, 8]])\n    check('empty internal chunks', solve([[[3], [], [4]], [[], [5, 6]], 0, 2]), [[3, 5], [4, 6]])\n    check('global slice', solve([[[3], [4, 5]], [[6, 7], [8]], 1, 2]), [[4, 7], [5, 8]])\n    check('null field', solve([[[None, 3]], [[4, None]], 0, 2]), [[None, 4], [3, None]])\n    check('repeated rows', solve([[[3, 3]], [[4, 4]], 0, 2]), [[3, 4], [3, 4]])\n    check('zero length', solve([[[3]], [[4]], 0, 0]), [])\n    check('no physical chunks', solve([[], [], 0, 0]), [])\nelif N == 4:\n    check('different boundaries', solve([[[4, 5], [6]], [[7], [8, 9]], 0, 3]), [[4, 7], [5, 8], [6, 9]])\n    check('empty internal chunks', solve([[[4], [], [5]], [[], [6, 7]], 0, 2]), [[4, 6], [5, 7]])\n    check('global slice', solve([[[4], [5, 6]], [[7, 8], [9]], 1, 2]), [[5, 8], [6, 9]])\n    check('null field', solve([[[None, 4]], [[5, None]], 0, 2]), [[None, 5], [4, None]])\n    check('repeated rows', solve([[[4, 4]], [[5, 5]], 0, 2]), [[4, 5], [4, 5]])\n    check('zero length', solve([[[4]], [[5]], 0, 0]), [])\n    check('no physical chunks', solve([[], [], 0, 0]), [])\nelif N == 5:\n    check('different boundaries', solve([[[5, 6], [7]], [[8], [9, 10]], 0, 3]), [[5, 8], [6, 9], [7, 10]])\n    check('empty internal chunks', solve([[[5], [], [6]], [[], [7, 8]], 0, 2]), [[5, 7], [6, 8]])\n    check('global slice', solve([[[5], [6, 7]], [[8, 9], [10]], 1, 2]), [[6, 9], [7, 10]])\n    check('null field', solve([[[None, 5]], [[6, None]], 0, 2]), [[None, 6], [5, None]])\n    check('repeated rows', solve([[[5, 5]], [[6, 6]], 0, 2]), [[5, 6], [5, 6]])\n    check('zero length', solve([[[5]], [[6]], 0, 0]), [])\n    check('no physical chunks', solve([[], [], 0, 0]), [])\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":"2196cf1fdd33c92a742b1de371168062eccca796cbf93d9f8b37ca0f56569df3","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(d):\n    try:\n        left,right,start,length=d\n        a=[v for chunk in left for v in chunk]\n        b=[v for chunk in right for v in chunk]\n        rows=[[a[i],b[i]] for i in range(len(a))]\n        rows=rows[start:start+length]\n        return rows\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('different boundaries', solve([[[1, 2], [3]], [[4], [5, 6]], 0, 3]), [[1, 4], [2, 5], [3, 6]])\n    check('empty internal chunks', solve([[[1], [], [2]], [[], [3, 4]], 0, 2]), [[1, 3], [2, 4]])\n    check('global slice', solve([[[1], [2, 3]], [[4, 5], [6]], 1, 2]), [[2, 5], [3, 6]])\n    check('null field', solve([[[None, 1]], [[2, None]], 0, 2]), [[None, 2], [1, None]])\n    check('repeated rows', solve([[[1, 1]], [[2, 2]], 0, 2]), [[1, 2], [1, 2]])\n    check('zero length', solve([[[1]], [[2]], 0, 0]), [])\n    check('no physical chunks', solve([[], [], 0, 0]), [])\nelif N == 2:\n    check('different boundaries', solve([[[2, 3], [4]], [[5], [6, 7]], 0, 3]), [[2, 5], [3, 6], [4, 7]])\n    check('empty internal chunks', solve([[[2], [], [3]], [[], [4, 5]], 0, 2]), [[2, 4], [3, 5]])\n    check('global slice', solve([[[2], [3, 4]], [[5, 6], [7]], 1, 2]), [[3, 6], [4, 7]])\n    check('null field', solve([[[None, 2]], [[3, None]], 0, 2]), [[None, 3], [2, None]])\n    check('repeated rows', solve([[[2, 2]], [[3, 3]], 0, 2]), [[2, 3], [2, 3]])\n    check('zero length', solve([[[2]], [[3]], 0, 0]), [])\n    check('no physical chunks', solve([[], [], 0, 0]), [])\nelif N == 3:\n    check('different boundaries', solve([[[3, 4], [5]], [[6], [7, 8]], 0, 3]), [[3, 6], [4, 7], [5, 8]])\n    check('empty internal chunks', solve([[[3], [], [4]], [[], [5, 6]], 0, 2]), [[3, 5], [4, 6]])\n    check('global slice', solve([[[3], [4, 5]], [[6, 7], [8]], 1, 2]), [[4, 7], [5, 8]])\n    check('null field', solve([[[None, 3]], [[4, None]], 0, 2]), [[None, 4], [3, None]])\n    check('repeated rows', solve([[[3, 3]], [[4, 4]], 0, 2]), [[3, 4], [3, 4]])\n    check('zero length', solve([[[3]], [[4]], 0, 0]), [])\n    check('no physical chunks', solve([[], [], 0, 0]), [])\nelif N == 4:\n    check('different boundaries', solve([[[4, 5], [6]], [[7], [8, 9]], 0, 3]), [[4, 7], [5, 8], [6, 9]])\n    check('empty internal chunks', solve([[[4], [], [5]], [[], [6, 7]], 0, 2]), [[4, 6], [5, 7]])\n    check('global slice', solve([[[4], [5, 6]], [[7, 8], [9]], 1, 2]), [[5, 8], [6, 9]])\n    check('null field', solve([[[None, 4]], [[5, None]], 0, 2]), [[None, 5], [4, None]])\n    check('repeated rows', solve([[[4, 4]], [[5, 5]], 0, 2]), [[4, 5], [4, 5]])\n    check('zero length', solve([[[4]], [[5]], 0, 0]), [])\n    check('no physical chunks', solve([[], [], 0, 0]), [])\nelif N == 5:\n    check('different boundaries', solve([[[5, 6], [7]], [[8], [9, 10]], 0, 3]), [[5, 8], [6, 9], [7, 10]])\n    check('empty internal chunks', solve([[[5], [], [6]], [[], [7, 8]], 0, 2]), [[5, 7], [6, 8]])\n    check('global slice', solve([[[5], [6, 7]], [[8, 9], [10]], 1, 2]), [[6, 9], [7, 10]])\n    check('null field', solve([[[None, 5]], [[6, None]], 0, 2]), [[None, 6], [5, None]])\n    check('repeated rows', solve([[[5, 5]], [[6, 6]], 0, 2]), [[5, 6], [5, 6]])\n    check('zero length', solve([[[5]], [[6]], 0, 0]), [])\n    check('no physical chunks', solve([[], [], 0, 0]), [])\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-chunked-column-zip-right-chunks","generated_at":"2026-09-29T14:44:13.097048+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: Assemble two equally long logical columns from independent chunk layouts. Empty chunks carry no rows. Zip by global row ordinal, retain null values, and apply the requested half-open row slice after alignment.","root_cause":"chunked-column-zip: Only the first physical right chunk participates in row assembly.","sha256":"bb1ff66606dfb0d203d173c364bd4ee7d5cacaed5f9f37faf0651f0436dc26b6","title":"Only the first physical right chunk participates in row assembly · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":43.801,"exit_code":1,"observations":[{"actual":[[1,5],[2,6],[3,4]],"check":"different boundaries","expected":[[1,4],[2,5],[3,6]],"passed":false},{"actual":[[1,3],[2,4]],"check":"empty internal chunks","expected":[[1,3],[2,4]],"passed":true},{"actual":[[2,4],[3,5]],"check":"global slice","expected":[[2,5],[3,6]],"passed":false},{"actual":[[null,2],[1,null]],"check":"null field","expected":[[null,2],[1,null]],"passed":true},{"actual":[[1,2],[1,2]],"check":"repeated rows","expected":[[1,2],[1,2]],"passed":true},{"actual":[],"check":"zero length","expected":[],"passed":true},{"actual":[],"check":"no physical chunks","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"different boundaries\", \"actual\": [[1, 5], [2, 6], [3, 4]], \"expected\": [[1, 4], [2, 5], [3, 6]], \"passed\": false}, {\"check\": \"empty internal chunks\", \"actual\": [[1, 3], [2, 4]], \"expected\": [[1, 3], [2, 4]], \"passed\": true}, {\"check\": \"global slice\", \"actual\": [[2, 4], [3, 5]], \"expected\": [[2, 5], [3, 6]], \"passed\": false}, {\"check\": \"null field\", \"actual\": [[null, 2], [1, null]], \"expected\": [[null, 2], [1, null]], \"passed\": true}, {\"check\": \"repeated rows\", \"actual\": [[1, 2], [1, 2]], \"expected\": [[1, 2], [1, 2]], \"passed\": true}, {\"check\": \"zero length\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"no physical chunks\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.806,"exit_code":1,"observations":[{"actual":[[1,4],[2,null],[3,null]],"check":"different boundaries","expected":[[1,4],[2,5],[3,6]],"passed":false},{"actual":[[1,null],[2,null]],"check":"empty internal chunks","expected":[[1,3],[2,4]],"passed":false},{"actual":[[2,5],[3,null]],"check":"global slice","expected":[[2,5],[3,6]],"passed":false},{"actual":[[null,2],[1,null]],"check":"null field","expected":[[null,2],[1,null]],"passed":true},{"actual":[[1,2],[1,2]],"check":"repeated rows","expected":[[1,2],[1,2]],"passed":true},{"actual":[],"check":"zero length","expected":[],"passed":true},{"actual":[],"check":"no physical chunks","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"different boundaries\", \"actual\": [[1, 4], [2, null], [3, null]], \"expected\": [[1, 4], [2, 5], [3, 6]], \"passed\": false}, {\"check\": \"empty internal chunks\", \"actual\": [[1, null], [2, null]], \"expected\": [[1, 3], [2, 4]], \"passed\": false}, {\"check\": \"global slice\", \"actual\": [[2, 5], [3, null]], \"expected\": [[2, 5], [3, 6]], \"passed\": false}, {\"check\": \"null field\", \"actual\": [[null, 2], [1, null]], \"expected\": [[null, 2], [1, null]], \"passed\": true}, {\"check\": \"repeated rows\", \"actual\": [[1, 2], [1, 2]], \"expected\": [[1, 2], [1, 2]], \"passed\": true}, {\"check\": \"zero length\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"no physical chunks\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":48.24,"exit_code":0,"observations":[{"actual":[[1,4],[2,5],[3,6]],"check":"different boundaries","expected":[[1,4],[2,5],[3,6]],"passed":true},{"actual":[[1,3],[2,4]],"check":"empty internal chunks","expected":[[1,3],[2,4]],"passed":true},{"actual":[[2,5],[3,6]],"check":"global slice","expected":[[2,5],[3,6]],"passed":true},{"actual":[[null,2],[1,null]],"check":"null field","expected":[[null,2],[1,null]],"passed":true},{"actual":[[1,2],[1,2]],"check":"repeated rows","expected":[[1,2],[1,2]],"passed":true},{"actual":[],"check":"zero length","expected":[],"passed":true},{"actual":[],"check":"no physical chunks","expected":[],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"different boundaries\", \"actual\": [[1, 4], [2, 5], [3, 6]], \"expected\": [[1, 4], [2, 5], [3, 6]], \"passed\": true}, {\"check\": \"empty internal chunks\", \"actual\": [[1, 3], [2, 4]], \"expected\": [[1, 3], [2, 4]], \"passed\": true}, {\"check\": \"global slice\", \"actual\": [[2, 5], [3, 6]], \"expected\": [[2, 5], [3, 6]], \"passed\": true}, {\"check\": \"null field\", \"actual\": [[null, 2], [1, null]], \"expected\": [[null, 2], [1, null]], \"passed\": true}, {\"check\": \"repeated rows\", \"actual\": [[1, 2], [1, 2]], \"expected\": [[1, 2], [1, 2]], \"passed\": true}, {\"check\": \"zero length\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"no physical chunks\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}