{"abstract":"Cache rows are assigned by transient request list position.","category":"KV cache position mapping","checks":6,"contract":"Given request_id to row mapping and an ordered ID list, return corresponding rows; unknown IDs map to None.","contract_signature":"owners, request_ids","evaluation_group":"w3-kv-map-stable-row-ownership","failed_approach":"Returning rows by owner-table iteration ignores the requested batch order.","family":"w3-kv-cache-position-mapping-stable-row-ownership","id":"FA-98616","implementations":{"attempt":{"sha256":"7363668da90197456d46b94ac4525a0e1834d21cb39f123296843b5bef16acb8","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(owners, request_ids):\n    return [owners[k] for k in owners if k in request_ids]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nowners={'a':['A'],'b':['B'],'c':['C']}\ncheck('reordered batch',solve(owners,['c','a']),[['C'],['A']])\ncheck('unknown owner',solve(owners,['x']),[None])\ncheck('repeat request',solve(owners,['b','b']),[['B'],['B']])\ncheck('empty request',solve(owners,[]),[])\ncheck('empty owners',solve({},['a']),[None])\ncheck('original order',solve(owners,['a','b','c']),[['A'],['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":"d43c43ab3583b4a0c8f6c577e46ab45f4dd0744470088c6b1f12617dee06363e","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(owners, request_ids):\n    return [list(owners.values())[i] if i<len(owners) else None for i,_ in enumerate(request_ids)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nowners={'a':['A'],'b':['B'],'c':['C']}\ncheck('reordered batch',solve(owners,['c','a']),[['C'],['A']])\ncheck('unknown owner',solve(owners,['x']),[None])\ncheck('repeat request',solve(owners,['b','b']),[['B'],['B']])\ncheck('empty request',solve(owners,[]),[])\ncheck('empty owners',solve({},['a']),[None])\ncheck('original order',solve(owners,['a','b','c']),[['A'],['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":"These toy integer maps omit tensor layout, concurrency, device memory, and model-specific cache formats. 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":"w3-kv-cache-position-mapping-stable-row-ownership","generated_at":"2026-09-30T16:48:14.973330+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A small in-memory model makes the cache address contract explicit for a serving component.","root_cause":"The batch reorder step assumes the input order is the stable cache owner order.","sha256":"2d850f419f3dcfbdae7d3bef7cabbaa85fcbd282f5e04840d558480d08355e52","title":"Batch row ownership follows request IDs · case 01","variant":1,"variant_policy":"The same explicitly authored fixtures repeat across all five numbered records; runtime N is unused. These records share one mechanism and must remain together in evaluation splits.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":26.58,"exit_code":1,"observations":[{"actual":[["A"],["C"]],"check":"reordered batch","expected":[["C"],["A"]],"passed":false},{"actual":[],"check":"unknown owner","expected":[null],"passed":false},{"actual":[["B"]],"check":"repeat request","expected":[["B"],["B"]],"passed":false},{"actual":[],"check":"empty request","expected":[],"passed":true},{"actual":[],"check":"empty owners","expected":[null],"passed":false},{"actual":[["A"],["B"],["C"]],"check":"original order","expected":[["A"],["B"],["C"]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"reordered batch\", \"actual\": [[\"A\"], [\"C\"]], \"expected\": [[\"C\"], [\"A\"]], \"passed\": false}, {\"check\": \"unknown owner\", \"actual\": [], \"expected\": [null], \"passed\": false}, {\"check\": \"repeat request\", \"actual\": [[\"B\"]], \"expected\": [[\"B\"], [\"B\"]], \"passed\": false}, {\"check\": \"empty request\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty owners\", \"actual\": [], \"expected\": [null], \"passed\": false}, {\"check\": \"original order\", \"actual\": [[\"A\"], [\"B\"], [\"C\"]], \"expected\": [[\"A\"], [\"B\"], [\"C\"]], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":27.771,"exit_code":1,"observations":[{"actual":[["A"],["B"]],"check":"reordered batch","expected":[["C"],["A"]],"passed":false},{"actual":[["A"]],"check":"unknown owner","expected":[null],"passed":false},{"actual":[["A"],["B"]],"check":"repeat request","expected":[["B"],["B"]],"passed":false},{"actual":[],"check":"empty request","expected":[],"passed":true},{"actual":[null],"check":"empty owners","expected":[null],"passed":true},{"actual":[["A"],["B"],["C"]],"check":"original order","expected":[["A"],["B"],["C"]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"reordered batch\", \"actual\": [[\"A\"], [\"B\"]], \"expected\": [[\"C\"], [\"A\"]], \"passed\": false}, {\"check\": \"unknown owner\", \"actual\": [[\"A\"]], \"expected\": [null], \"passed\": false}, {\"check\": \"repeat request\", \"actual\": [[\"A\"], [\"B\"]], \"expected\": [[\"B\"], [\"B\"]], \"passed\": false}, {\"check\": \"empty request\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty owners\", \"actual\": [null], \"expected\": [null], \"passed\": true}, {\"check\": \"original order\", \"actual\": [[\"A\"], [\"B\"], [\"C\"]], \"expected\": [[\"A\"], [\"B\"], [\"C\"]], \"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."}}