{"abstract":"The operation returns a result or retained state that violates this contract: Compute the Cartesian product of the supplied pools, yielding one empty tuple for zero pools.","category":"Iterator consumption","checks":4,"contract":"Compute the Cartesian product of the supplied pools, yielding one empty tuple for zero pools. Inputs are the finite Python values shown by the executable fixtures; no concurrent execution is assumed.","evaluation_group":"model-e54964f23f98946e","failed_approach":"Zipping pools pairs positions instead of enumerating their Cartesian product.","family":"xr-product-zero-inputs-has-empty-tuple","id":"FA-4591","implementations":{"attempt":{"sha256":"7908b33b3f4c9543459baa227d410e41046df8105fb2b1a55312ed022a8d7e0d","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 zip(*x)] if x else [[]]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('zero pools identity', solve([]), [[]])\ncheck('empty pool annihilates', solve([['a'], []]), [])\ncheck('two pools all pairs', solve([['a', 'b'], ['c']]), [['a', 'c'], ['b', 'c']])\ncheck('one pool', solve([['a', 'b']]), [['a'], ['b']])\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":"9a1f603ce4cd122c4cc1d9bd87e36c6b7a6443a4d88121d2e53dea2ee39068e7","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.product(*x)] if x else []\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('zero pools identity', solve([]), [[]])\ncheck('empty pool annihilates', solve([['a'], []]), [])\ncheck('two pools all pairs', solve([['a', 'b'], ['c']]), [['a', 'c'], ['b', 'c']])\ncheck('one pool', solve([['a', 'b']]), [['a'], ['b']])\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":"5fec93750693adb7e1c3de5681912b631b66508fe606e58947612e6ad4dd708d","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.product(*x)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('zero pools identity', solve([]), [[]])\ncheck('empty pool annihilates', solve([['a'], []]), [])\ncheck('two pools all pairs', solve([['a', 'b'], ['c']]), [['a', 'c'], ['b', 'c']])\ncheck('one pool', solve([['a', 'b']]), [['a'], ['b']])\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-product-zero-inputs-has-empty-tuple","generated_at":"2026-09-29T14:37:40.807765+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":"Compute the Cartesian product of the supplied pools, yielding one empty tuple for zero pools.","root_cause":"Zero pools are treated as an empty result instead of the multiplicative empty-tuple identity.","sha256":"a7fa183ce4b9911309381471abcc4431e176c961ee284299d0dcd1624c77c767","title":"Product zero inputs has empty tuple · 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":39.927,"exit_code":1,"observations":[{"actual":[[]],"check":"zero pools identity","expected":[[]],"passed":true},{"actual":[],"check":"empty pool annihilates","expected":[],"passed":true},{"actual":[["a","c"]],"check":"two pools all pairs","expected":[["a","c"],["b","c"]],"passed":false},{"actual":[["a"],["b"]],"check":"one pool","expected":[["a"],["b"]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"zero pools identity\", \"actual\": [[]], \"expected\": [[]], \"passed\": true}, {\"check\": \"empty pool annihilates\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"two pools all pairs\", \"actual\": [[\"a\", \"c\"]], \"expected\": [[\"a\", \"c\"], [\"b\", \"c\"]], \"passed\": false}, {\"check\": \"one pool\", \"actual\": [[\"a\"], [\"b\"]], \"expected\": [[\"a\"], [\"b\"]], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":37.203,"exit_code":1,"observations":[{"actual":[],"check":"zero pools identity","expected":[[]],"passed":false},{"actual":[],"check":"empty pool annihilates","expected":[],"passed":true},{"actual":[["a","c"],["b","c"]],"check":"two pools all pairs","expected":[["a","c"],["b","c"]],"passed":true},{"actual":[["a"],["b"]],"check":"one pool","expected":[["a"],["b"]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"zero pools identity\", \"actual\": [], \"expected\": [[]], \"passed\": false}, {\"check\": \"empty pool annihilates\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"two pools all pairs\", \"actual\": [[\"a\", \"c\"], [\"b\", \"c\"]], \"expected\": [[\"a\", \"c\"], [\"b\", \"c\"]], \"passed\": true}, {\"check\": \"one pool\", \"actual\": [[\"a\"], [\"b\"]], \"expected\": [[\"a\"], [\"b\"]], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":117.585,"exit_code":0,"observations":[{"actual":[[]],"check":"zero pools identity","expected":[[]],"passed":true},{"actual":[],"check":"empty pool annihilates","expected":[],"passed":true},{"actual":[["a","c"],["b","c"]],"check":"two pools all pairs","expected":[["a","c"],["b","c"]],"passed":true},{"actual":[["a"],["b"]],"check":"one pool","expected":[["a"],["b"]],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"zero pools identity\", \"actual\": [[]], \"expected\": [[]], \"passed\": true}, {\"check\": \"empty pool annihilates\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"two pools all pairs\", \"actual\": [[\"a\", \"c\"], [\"b\", \"c\"]], \"expected\": [[\"a\", \"c\"], [\"b\", \"c\"]], \"passed\": true}, {\"check\": \"one pool\", \"actual\": [[\"a\"], [\"b\"]], \"expected\": [[\"a\"], [\"b\"]], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}