{"abstract":"The operation returns a result or retained state that violates this contract: Exhausting islice(start,stop,step) consumes through stop regardless of the last yielded position; return [yielded,remaining].","category":"Iterator consumption","checks":4,"contract":"Exhausting islice(start,stop,step) consumes through stop regardless of the last yielded position; return [yielded,remaining]. Inputs are the finite Python values shown by the executable fixtures; no concurrent execution is assumed.","contract_signature":"x, y=None","evaluation_group":"model-9d1337549501ca52","failed_approach":"Returning the suffix from start ignores every position consumed by slicing.","family":"xr-islice-step-consumes-stop-prefix","id":"FA-4656","implementations":{"attempt":{"sha256":"795892bfdc7cebfa5bf17617fe55dc94fffdf0e6e5a715693a8953dd8c12dd2a","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 [x[y[0]:y[1]:y[2]],x[y[0]:]]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('stop beyond last yield', solve(['a', 'b', 'c', 'd', 'e'], [0, 4, 3]), [['a', 'd'], ['e']])\ncheck('skipped final position consumed', solve(['a', 'b', 'c', 'd', 'e'], [0, 4, 2]), [['a', 'c'], ['e']])\ncheck('empty slice consumes start', solve(['a', 'b', 'c'], [2, 2, 1]), [[], ['c']])\ncheck('empty input', solve([], [0, 3, 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":"beb784bff714fee722ec85c590de768f2b699232ac7eef2960999e92c9141858","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 [x[y[0]:y[1]:y[2]],x[(y[0]+((max(0,y[1]-y[0])-1)//y[2])*y[2]+1) if y[1]>y[0] else y[0]:]]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('stop beyond last yield', solve(['a', 'b', 'c', 'd', 'e'], [0, 4, 3]), [['a', 'd'], ['e']])\ncheck('skipped final position consumed', solve(['a', 'b', 'c', 'd', 'e'], [0, 4, 2]), [['a', 'c'], ['e']])\ncheck('empty slice consumes start', solve(['a', 'b', 'c'], [2, 2, 1]), [[], ['c']])\ncheck('empty input', solve([], [0, 3, 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-islice-step-consumes-stop-prefix","generated_at":"2026-09-29T14:37:41.473162+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":"Consumption stops after the last emitted position rather than the requested stop boundary.","sha256":"169fa116af7d23dfd9258f2c9cc928fbabb042ea2fff3ce8bf0e6b09698f7a1e","title":"Islice step consumes stop prefix · 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":39.88,"exit_code":1,"observations":[{"actual":[["a","d"],["a","b","c","d","e"]],"check":"stop beyond last yield","expected":[["a","d"],["e"]],"passed":false},{"actual":[["a","c"],["a","b","c","d","e"]],"check":"skipped final position consumed","expected":[["a","c"],["e"]],"passed":false},{"actual":[[],["c"]],"check":"empty slice consumes start","expected":[[],["c"]],"passed":true},{"actual":[[],[]],"check":"empty input","expected":[[],[]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"stop beyond last yield\", \"actual\": [[\"a\", \"d\"], [\"a\", \"b\", \"c\", \"d\", \"e\"]], \"expected\": [[\"a\", \"d\"], [\"e\"]], \"passed\": false}, {\"check\": \"skipped final position consumed\", \"actual\": [[\"a\", \"c\"], [\"a\", \"b\", \"c\", \"d\", \"e\"]], \"expected\": [[\"a\", \"c\"], [\"e\"]], \"passed\": false}, {\"check\": \"empty slice consumes start\", \"actual\": [[], [\"c\"]], \"expected\": [[], [\"c\"]], \"passed\": true}, {\"check\": \"empty input\", \"actual\": [[], []], \"expected\": [[], []], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.891,"exit_code":1,"observations":[{"actual":[["a","d"],["e"]],"check":"stop beyond last yield","expected":[["a","d"],["e"]],"passed":true},{"actual":[["a","c"],["d","e"]],"check":"skipped final position consumed","expected":[["a","c"],["e"]],"passed":false},{"actual":[[],["c"]],"check":"empty slice consumes start","expected":[[],["c"]],"passed":true},{"actual":[[],[]],"check":"empty input","expected":[[],[]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"stop beyond last yield\", \"actual\": [[\"a\", \"d\"], [\"e\"]], \"expected\": [[\"a\", \"d\"], [\"e\"]], \"passed\": true}, {\"check\": \"skipped final position consumed\", \"actual\": [[\"a\", \"c\"], [\"d\", \"e\"]], \"expected\": [[\"a\", \"c\"], [\"e\"]], \"passed\": false}, {\"check\": \"empty slice consumes start\", \"actual\": [[], [\"c\"]], \"expected\": [[], [\"c\"]], \"passed\": true}, {\"check\": \"empty input\", \"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."}}