{"abstract":"The operation returns a result or retained state that violates this contract: Return ordered length-r permutations of distinct input positions; equal values may produce equal output tuples.","category":"Iterator consumption","checks":4,"contract":"Return ordered length-r permutations of distinct input positions; equal values may produce equal output tuples. Inputs are the finite Python values shown by the executable fixtures; no concurrent execution is assumed.","evaluation_group":"model-90957007f08c1181","failed_approach":"Combinations omit alternative positional orderings.","family":"xr-permutations-use-positions-not-distinct-values","id":"FA-4596","implementations":{"attempt":{"sha256":"42629902cde49cd67fc1e49d20dd05ddf81ea8aae903a0a12a9e18bf60b2730d","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport itertools as it\nfrom collections import deque\nN = 1\nobservations = []\ndef solve(x, y=None):\n    return [list(v) for v in it.combinations(x,y)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('duplicate positions', solve(['a', 'a'], 2), [['a', 'a'], ['a', 'a']])\ncheck('orderings', solve(['a', 'b'], 2), [['a', 'b'], ['b', 'a']])\ncheck('zero length', solve(['a'], 0), [[]])\ncheck('insufficient positions', solve(['a'], 2), [])\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":"061c0dccff4b609b067bf21b264e0b5464bb09fc7b2eb56b0afe2378d2bddd14","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport itertools as it\nfrom collections import deque\nN = 1\nobservations = []\ndef solve(x, y=None):\n    return [list(v) for v in it.permutations(dict.fromkeys(x),y)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('duplicate positions', solve(['a', 'a'], 2), [['a', 'a'], ['a', 'a']])\ncheck('orderings', solve(['a', 'b'], 2), [['a', 'b'], ['b', 'a']])\ncheck('zero length', solve(['a'], 0), [[]])\ncheck('insufficient positions', solve(['a'], 2), [])\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":"f2690f2a91b539c127138700f1c1175ccdbca594537f2c030a47a13ba3d4cab4","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport itertools as it\nfrom collections import deque\nN = 1\nobservations = []\ndef solve(x, y=None):\n    return [list(v) for v in it.permutations(x,y)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('duplicate positions', solve(['a', 'a'], 2), [['a', 'a'], ['a', 'a']])\ncheck('orderings', solve(['a', 'b'], 2), [['a', 'b'], ['b', 'a']])\ncheck('zero length', solve(['a'], 0), [[]])\ncheck('insufficient positions', solve(['a'], 2), [])\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":" 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":"xr-permutations-use-positions-not-distinct-values","generated_at":"2026-09-29T14:37:40.835404+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A controlled local-runtime regression for collection APIs, language semantics, or ownership wrappers. Fixtures include boundary and interaction cases.","repair":"Return ordered length-r permutations of distinct input positions; equal values may produce equal output tuples.","root_cause":"Deduplicating the source merges distinct equal-valued positions.","sha256":"a2013e168e9a6fe55db828a800c94f6b1da4aef3d1a3502392cdc06075051fff","title":"Permutations use positions not distinct values · case 01","variant":1,"variant_policy":"Five execution reruns of a fixed adversarial fixture suite; variant number does not alter semantic inputs.","verification":{"attempt":{"elapsed_ms":114.592,"exit_code":1,"observations":[{"actual":[["a","a"]],"check":"duplicate positions","expected":[["a","a"],["a","a"]],"passed":false},{"actual":[["a","b"]],"check":"orderings","expected":[["a","b"],["b","a"]],"passed":false},{"actual":[[]],"check":"zero length","expected":[[]],"passed":true},{"actual":[],"check":"insufficient positions","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"duplicate positions\", \"actual\": [[\"a\", \"a\"]], \"expected\": [[\"a\", \"a\"], [\"a\", \"a\"]], \"passed\": false}, {\"check\": \"orderings\", \"actual\": [[\"a\", \"b\"]], \"expected\": [[\"a\", \"b\"], [\"b\", \"a\"]], \"passed\": false}, {\"check\": \"zero length\", \"actual\": [[]], \"expected\": [[]], \"passed\": true}, {\"check\": \"insufficient positions\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.972,"exit_code":1,"observations":[{"actual":[],"check":"duplicate positions","expected":[["a","a"],["a","a"]],"passed":false},{"actual":[["a","b"],["b","a"]],"check":"orderings","expected":[["a","b"],["b","a"]],"passed":true},{"actual":[[]],"check":"zero length","expected":[[]],"passed":true},{"actual":[],"check":"insufficient positions","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"duplicate positions\", \"actual\": [], \"expected\": [[\"a\", \"a\"], [\"a\", \"a\"]], \"passed\": false}, {\"check\": \"orderings\", \"actual\": [[\"a\", \"b\"], [\"b\", \"a\"]], \"expected\": [[\"a\", \"b\"], [\"b\", \"a\"]], \"passed\": true}, {\"check\": \"zero length\", \"actual\": [[]], \"expected\": [[]], \"passed\": true}, {\"check\": \"insufficient positions\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":33.598,"exit_code":0,"observations":[{"actual":[["a","a"],["a","a"]],"check":"duplicate positions","expected":[["a","a"],["a","a"]],"passed":true},{"actual":[["a","b"],["b","a"]],"check":"orderings","expected":[["a","b"],["b","a"]],"passed":true},{"actual":[[]],"check":"zero length","expected":[[]],"passed":true},{"actual":[],"check":"insufficient positions","expected":[],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"duplicate positions\", \"actual\": [[\"a\", \"a\"], [\"a\", \"a\"]], \"expected\": [[\"a\", \"a\"], [\"a\", \"a\"]], \"passed\": true}, {\"check\": \"orderings\", \"actual\": [[\"a\", \"b\"], [\"b\", \"a\"]], \"expected\": [[\"a\", \"b\"], [\"b\", \"a\"]], \"passed\": true}, {\"check\": \"zero length\", \"actual\": [[]], \"expected\": [[]], \"passed\": true}, {\"check\": \"insufficient positions\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}