{"abstract":"The operation returns a result or retained state that violates this contract: Positive rotation moves elements right, negative rotation moves left, and offsets reduce modulo length; empty remains empty.","category":"Bounded deques","checks":4,"contract":"Positive rotation moves elements right, negative rotation moves left, and offsets reduce modulo length; empty remains empty. Inputs are the finite Python values shown by the executable fixtures; no concurrent execution is assumed.","contract_signature":"x, y=None","evaluation_group":"model-c107ad500afe1831","failed_approach":"Unnormalized slicing fails when offsets exceed collection length.","family":"xr-deque-rotate-reduces-large-and-negative-offsets","id":"FA-4786","implementations":{"attempt":{"sha256":"623fe522b0fd3c6da3a73280108886a6c6f81d54bf74b08573f4436e3c469afb","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom collections import Counter, ChainMap, deque\nimport heapq\nN = 1\nobservations = []\ndef solve(x, y=None):\n    return x[-y:]+x[:-y] if y else list(x)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('positive right', solve(['a', 'b', 'c'], 1), ['c', 'a', 'b'])\ncheck('large offset', solve(['a', 'b', 'c'], 7), ['c', 'a', 'b'])\ncheck('negative left', solve(['a', 'b', 'c'], -1), ['b', 'c', 'a'])\ncheck('empty', solve([], 3), [])\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":"f07dc748789b8d3cbf738fb3fd76dc63b517d994c07be4dd2df342264e84a43f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom collections import Counter, ChainMap, deque\nimport heapq\nN = 1\nobservations = []\ndef solve(x, y=None):\n    return x[y:]+x[:y]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('positive right', solve(['a', 'b', 'c'], 1), ['c', 'a', 'b'])\ncheck('large offset', solve(['a', 'b', 'c'], 7), ['c', 'a', 'b'])\ncheck('negative left', solve(['a', 'b', 'c'], -1), ['b', 'c', 'a'])\ncheck('empty', solve([], 3), [])\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-deque-rotate-reduces-large-and-negative-offsets","generated_at":"2026-09-29T14:37:42.878524+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.","root_cause":"The slicing direction implements left rotation for positive offsets.","sha256":"e919f3134c74d9b1cd718c07fce255e034e0dcfaf0cff38724d7c45fa8ecec6f","title":"Deque rotate reduces large and negative offsets · case 01","variant":1,"variant_policy":"Five execution reruns of a fixed adversarial fixture suite; variant number does not alter semantic inputs.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":40.582,"exit_code":1,"observations":[{"actual":["c","a","b"],"check":"positive right","expected":["c","a","b"],"passed":true},{"actual":["a","b","c"],"check":"large offset","expected":["c","a","b"],"passed":false},{"actual":["b","c","a"],"check":"negative left","expected":["b","c","a"],"passed":true},{"actual":[],"check":"empty","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"positive right\", \"actual\": [\"c\", \"a\", \"b\"], \"expected\": [\"c\", \"a\", \"b\"], \"passed\": true}, {\"check\": \"large offset\", \"actual\": [\"a\", \"b\", \"c\"], \"expected\": [\"c\", \"a\", \"b\"], \"passed\": false}, {\"check\": \"negative left\", \"actual\": [\"b\", \"c\", \"a\"], \"expected\": [\"b\", \"c\", \"a\"], \"passed\": true}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":37.056,"exit_code":1,"observations":[{"actual":["b","c","a"],"check":"positive right","expected":["c","a","b"],"passed":false},{"actual":["a","b","c"],"check":"large offset","expected":["c","a","b"],"passed":false},{"actual":["c","a","b"],"check":"negative left","expected":["b","c","a"],"passed":false},{"actual":[],"check":"empty","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"positive right\", \"actual\": [\"b\", \"c\", \"a\"], \"expected\": [\"c\", \"a\", \"b\"], \"passed\": false}, {\"check\": \"large offset\", \"actual\": [\"a\", \"b\", \"c\"], \"expected\": [\"c\", \"a\", \"b\"], \"passed\": false}, {\"check\": \"negative left\", \"actual\": [\"c\", \"a\", \"b\"], \"expected\": [\"b\", \"c\", \"a\"], \"passed\": false}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}