{"abstract":"Committed prefix is reversed before output.","category":"Speculative decoding bookkeeping","checks":7,"contract":"Return the first k draft tokens in their original order.","contract_signature":"draft, accepted","evaluation_group":"s3-http_ranges-resume-client","failed_approach":"Sorting the accepted tokens changes valid sequence order.","family":"w3-speculative-decoding-bookkeeping-accepted-token-order","id":"FA-100701","implementations":{"attempt":{"sha256":"cd530e7df0484cab5f21939bfa62c5f173424ca6ad9764043b60914e14258fb8","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(draft, accepted):\n    return sorted(draft[:accepted])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('ordered prefix', solve([3,1,2],2),[3,1])\ncheck('full sequence', solve([2,0,1],3),[2,0,1])\ncheck('empty acceptance', solve([N],0),[])\ncheck('singleton', solve([N],1),[N])\ncheck('duplicate tokens', solve([4,4,2],2),[4,4])\ncheck('long prefix', solve([5,1,4,2],3),[5,1,4])\ncheck('empty draft', solve([],0),[])\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":"a172e9a79f15d7eada56840f609623da0722a2b3f523528c8951418d141641f6","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(draft, accepted):\n    return list(reversed(draft[:accepted]))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('ordered prefix', solve([3,1,2],2),[3,1])\ncheck('full sequence', solve([2,0,1],3),[2,0,1])\ncheck('empty acceptance', solve([N],0),[])\ncheck('singleton', solve([N],1),[N])\ncheck('duplicate tokens', solve([4,4,2],2),[4,4])\ncheck('long prefix', solve([5,1,4,2],3),[5,1,4])\ncheck('empty draft', solve([],0),[])\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 are finite toy sequences with explicit contracts; they make no claim about production decoder behavior or model quality. 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-speculative-decoding-bookkeeping-accepted-token-order","generated_at":"2026-09-30T16:48:38.598303+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A self-contained bookkeeping model makes prefix and token-count semantics observable without a model runtime.","root_cause":"The accepted prefix is reversed during output assembly.","sha256":"b1f2187cb3a6f28d4ac4f3e6d2946d455d6c998e3be3a520771b61d02cc1d820","title":"Decoding: Committed prefix is reversed before output · case 01","variant":1,"variant_policy":"The fixture code references N, supplied as 1 through 5. Fixed boundary checks may repeat. These records share one mechanism and must remain together in evaluation splits.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":31.416,"exit_code":1,"observations":[{"actual":[1,3],"check":"ordered prefix","expected":[3,1],"passed":false},{"actual":[0,1,2],"check":"full sequence","expected":[2,0,1],"passed":false},{"actual":[],"check":"empty acceptance","expected":[],"passed":true},{"actual":[1],"check":"singleton","expected":[1],"passed":true},{"actual":[4,4],"check":"duplicate tokens","expected":[4,4],"passed":true},{"actual":[1,4,5],"check":"long prefix","expected":[5,1,4],"passed":false},{"actual":[],"check":"empty draft","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"ordered prefix\", \"actual\": [1, 3], \"expected\": [3, 1], \"passed\": false}, {\"check\": \"full sequence\", \"actual\": [0, 1, 2], \"expected\": [2, 0, 1], \"passed\": false}, {\"check\": \"empty acceptance\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"singleton\", \"actual\": [1], \"expected\": [1], \"passed\": true}, {\"check\": \"duplicate tokens\", \"actual\": [4, 4], \"expected\": [4, 4], \"passed\": true}, {\"check\": \"long prefix\", \"actual\": [1, 4, 5], \"expected\": [5, 1, 4], \"passed\": false}, {\"check\": \"empty draft\", \"actual\": [], \"expected\": [], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":31.91,"exit_code":1,"observations":[{"actual":[1,3],"check":"ordered prefix","expected":[3,1],"passed":false},{"actual":[1,0,2],"check":"full sequence","expected":[2,0,1],"passed":false},{"actual":[],"check":"empty acceptance","expected":[],"passed":true},{"actual":[1],"check":"singleton","expected":[1],"passed":true},{"actual":[4,4],"check":"duplicate tokens","expected":[4,4],"passed":true},{"actual":[4,1,5],"check":"long prefix","expected":[5,1,4],"passed":false},{"actual":[],"check":"empty draft","expected":[],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"ordered prefix\", \"actual\": [1, 3], \"expected\": [3, 1], \"passed\": false}, {\"check\": \"full sequence\", \"actual\": [1, 0, 2], \"expected\": [2, 0, 1], \"passed\": false}, {\"check\": \"empty acceptance\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"singleton\", \"actual\": [1], \"expected\": [1], \"passed\": true}, {\"check\": \"duplicate tokens\", \"actual\": [4, 4], \"expected\": [4, 4], \"passed\": true}, {\"check\": \"long prefix\", \"actual\": [4, 1, 5], \"expected\": [5, 1, 4], \"passed\": false}, {\"check\": \"empty draft\", \"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."}}