{"abstract":"The operation returns a result or retained state that violates this contract: Zip corresponding positions and stop at the shorter operand.","category":"Collection algebra","checks":4,"contract":"Zip corresponding positions and stop at the shorter operand. Inputs are the finite Python values shown by the executable fixtures; no concurrent execution is assumed.","evaluation_group":"model-84ea5ed5317a8cf4","failed_approach":"Cartesian expansion invents cross-position pairs.","family":"xr-zip-stops-at-shorter","id":"FA-4271","implementations":{"attempt":{"sha256":"efebb3f828a029ee74c08ab57cac93cab1d361ecf72077b3308f4eaeef016a3c","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x, y=None):\n    return [[a,b] for a in x for b in y]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('both empty', solve([], []), [])\ncheck('empty right operand', solve(['a'], []), [])\ncheck('empty left operand', solve([], ['b']), [])\ncheck('overlap and multiplicity', solve(['b', 'a', 'b'], ['b', 'c', 'c']), [['b', 'b'], ['a', 'c'], ['b', 'c']])\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":"6c4f458efa33b2482dbb9008c8211f59dd45c90b8a35a316d7d714e4a996f15b","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x, y=None):\n    return [[a,y[0]] for a in x] if y else []\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('both empty', solve([], []), [])\ncheck('empty right operand', solve(['a'], []), [])\ncheck('empty left operand', solve([], ['b']), [])\ncheck('overlap and multiplicity', solve(['b', 'a', 'b'], ['b', 'c', 'c']), [['b', 'b'], ['a', 'c'], ['b', 'c']])\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":"c8c570a595badfd31a30e0df666536c8234666256d17ca7baf110a94162b2599","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x, y=None):\n    return [[a,b] for a,b in zip(x,y)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('both empty', solve([], []), [])\ncheck('empty right operand', solve(['a'], []), [])\ncheck('empty left operand', solve([], ['b']), [])\ncheck('overlap and multiplicity', solve(['b', 'a', 'b'], ['b', 'c', 'c']), [['b', 'b'], ['a', 'c'], ['b', 'c']])\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-zip-stops-at-shorter","generated_at":"2026-09-29T14:37:37.455458+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":"Zip corresponding positions and stop at the shorter operand.","root_cause":"Each left value is paired with the first right value rather than its positional counterpart.","sha256":"7f7b8080e7b8d0320b16820aa0b9dbdfc3d683e251bfac7f1cdd147dee9b77a9","title":"Zip stops at shorter · 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":40.544,"exit_code":1,"observations":[{"actual":[],"check":"both empty","expected":[],"passed":true},{"actual":[],"check":"empty right operand","expected":[],"passed":true},{"actual":[],"check":"empty left operand","expected":[],"passed":true},{"actual":[["b","b"],["b","c"],["b","c"],["a","b"],["a","c"],["a","c"],["b","b"],["b","c"],["b","c"]],"check":"overlap and multiplicity","expected":[["b","b"],["a","c"],["b","c"]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"both empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty right operand\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty left operand\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"overlap and multiplicity\", \"actual\": [[\"b\", \"b\"], [\"b\", \"c\"], [\"b\", \"c\"], [\"a\", \"b\"], [\"a\", \"c\"], [\"a\", \"c\"], [\"b\", \"b\"], [\"b\", \"c\"], [\"b\", \"c\"]], \"expected\": [[\"b\", \"b\"], [\"a\", \"c\"], [\"b\", \"c\"]], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":37.552,"exit_code":1,"observations":[{"actual":[],"check":"both empty","expected":[],"passed":true},{"actual":[],"check":"empty right operand","expected":[],"passed":true},{"actual":[],"check":"empty left operand","expected":[],"passed":true},{"actual":[["b","b"],["a","b"],["b","b"]],"check":"overlap and multiplicity","expected":[["b","b"],["a","c"],["b","c"]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"both empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty right operand\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty left operand\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"overlap and multiplicity\", \"actual\": [[\"b\", \"b\"], [\"a\", \"b\"], [\"b\", \"b\"]], \"expected\": [[\"b\", \"b\"], [\"a\", \"c\"], [\"b\", \"c\"]], \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":41.914,"exit_code":0,"observations":[{"actual":[],"check":"both empty","expected":[],"passed":true},{"actual":[],"check":"empty right operand","expected":[],"passed":true},{"actual":[],"check":"empty left operand","expected":[],"passed":true},{"actual":[["b","b"],["a","c"],["b","c"]],"check":"overlap and multiplicity","expected":[["b","b"],["a","c"],["b","c"]],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"both empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty right operand\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty left operand\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"overlap and multiplicity\", \"actual\": [[\"b\", \"b\"], [\"a\", \"c\"], [\"b\", \"c\"]], \"expected\": [[\"b\", \"b\"], [\"a\", \"c\"], [\"b\", \"c\"]], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}