{"abstract":"The operation returns a result or retained state that violates this contract: Return true only when both lists have the same values at the same positions.","category":"Collection algebra","checks":5,"contract":"Return true only when both lists have the same values at the same positions. Inputs are the finite Python values shown by the executable fixtures; no concurrent execution is assumed.","evaluation_group":"model-6cb4b40a2c08c560","failed_approach":"Sorting preserves counts but still discards positional order.","family":"xr-sequence-equality-retains-order","id":"FA-4316","implementations":{"attempt":{"sha256":"7c9c1820cef13e52971833108a2a9e3f35088de44df1e0782a7e2d54df91eec3","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x, y=None):\n    return sorted(x)==sorted(y)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('both empty', solve([], []), True)\ncheck('empty right operand', solve(['a'], []), False)\ncheck('empty left operand', solve([], ['b']), False)\ncheck('overlap and multiplicity', solve(['b', 'a', 'b'], ['b', 'c', 'c']), False)\ncheck('permutation is unequal', solve(['a','b'], ['b','a']), False)\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":"00ba74d6704352aaf43ebed09a278df0aab0740ec8885e350ec8b084afe92758","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x, y=None):\n    return set(x)==set(y)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('both empty', solve([], []), True)\ncheck('empty right operand', solve(['a'], []), False)\ncheck('empty left operand', solve([], ['b']), False)\ncheck('overlap and multiplicity', solve(['b', 'a', 'b'], ['b', 'c', 'c']), False)\ncheck('permutation is unequal', solve(['a','b'], ['b','a']), False)\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":"c263485dbb5595efe1c3e454cbc8ea3ac20923bb4e8a4a38570759eee0fa49ee","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x, y=None):\n    return x==y\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('both empty', solve([], []), True)\ncheck('empty right operand', solve(['a'], []), False)\ncheck('empty left operand', solve([], ['b']), False)\ncheck('overlap and multiplicity', solve(['b', 'a', 'b'], ['b', 'c', 'c']), False)\ncheck('permutation is unequal', solve(['a','b'], ['b','a']), False)\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-sequence-equality-retains-order","generated_at":"2026-09-29T14:37:37.864270+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 true only when both lists have the same values at the same positions.","root_cause":"Set equality discards both order and multiplicity.","sha256":"65e07d2b680c54c2bdfcf8c2161e7ac32b3253b4658f68eea50fcbee6e6d6050","title":"Sequence equality retains order · 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":127.272,"exit_code":1,"observations":[{"actual":true,"check":"both empty","expected":true,"passed":true},{"actual":false,"check":"empty right operand","expected":false,"passed":true},{"actual":false,"check":"empty left operand","expected":false,"passed":true},{"actual":false,"check":"overlap and multiplicity","expected":false,"passed":true},{"actual":true,"check":"permutation is unequal","expected":false,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"both empty\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"empty right operand\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"empty left operand\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"overlap and multiplicity\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"permutation is unequal\", \"actual\": true, \"expected\": false, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.137,"exit_code":1,"observations":[{"actual":true,"check":"both empty","expected":true,"passed":true},{"actual":false,"check":"empty right operand","expected":false,"passed":true},{"actual":false,"check":"empty left operand","expected":false,"passed":true},{"actual":false,"check":"overlap and multiplicity","expected":false,"passed":true},{"actual":true,"check":"permutation is unequal","expected":false,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"both empty\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"empty right operand\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"empty left operand\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"overlap and multiplicity\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"permutation is unequal\", \"actual\": true, \"expected\": false, \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":38.985,"exit_code":0,"observations":[{"actual":true,"check":"both empty","expected":true,"passed":true},{"actual":false,"check":"empty right operand","expected":false,"passed":true},{"actual":false,"check":"empty left operand","expected":false,"passed":true},{"actual":false,"check":"overlap and multiplicity","expected":false,"passed":true},{"actual":false,"check":"permutation is unequal","expected":false,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"both empty\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"empty right operand\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"empty left operand\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"overlap and multiplicity\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"permutation is unequal\", \"actual\": false, \"expected\": false, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}