{"abstract":"Padding positions inherit the last segment owner.","category":"Sequence batch packing","checks":6,"contract":"Expand segment lengths into owner IDs and pad to width with sentinel -1; total length must not exceed width.","contract_signature":"lengths, width","evaluation_group":"w3-seqpack-padding-owner-v1","failed_approach":"A max guard masks overfull rows instead of enforcing the stated width precondition.","family":"w3-sequence-batch-packing-block-padding-owner-sentinel","id":"FA-98136","implementations":{"attempt":{"sha256":"c582c0bc9635118df56794e69908eba7e6734c8c78f29aab880f6488173ec577","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(lengths, width):\n    owners=[i for i,n in enumerate(lengths) for _ in range(n)]; return owners+[-1]*max(0,width-len(owners)-1)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('nonempty padding', solve([N,1],N+3), [0]*N+[1,-1,-1])\ncheck('exact width', solve([N],N), [0]*N)\ncheck('empty row', solve([],N), [-1]*N)\ncheck('zero segment', solve([0,N],N), [1]*N)\ncheck('one valid slot', solve([1],3), [0,-1,-1])\ncheck('mixed owners', solve([1,2],5), [0,1,1,-1,-1])\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":"039c7f2be08cd742d39079caf8bc60bf2b46cf1116ae238b48da3128260b0c82","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(lengths, width):\n    owners=[i for i,n in enumerate(lengths) for _ in range(n)]; return owners+[owners[-1] if owners else -1]*(width-len(owners))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('nonempty padding', solve([N,1],N+3), [0]*N+[1,-1,-1])\ncheck('exact width', solve([N],N), [0]*N)\ncheck('empty row', solve([],N), [-1]*N)\ncheck('zero segment', solve([0,N],N), [1]*N)\ncheck('one valid slot', solve([1],3), [0,-1,-1])\ncheck('mixed owners', solve([1,2],5), [0,1,1,-1,-1])\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":"Inputs are short integer-token lists under the stated toy contract; results do not claim compatibility with a specific training framework. 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-sequence-batch-packing-block-padding-owner-sentinel","generated_at":"2026-09-30T16:48:09.758170+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic toy packing rule models a common boundary in preparing bounded training sequences.","root_cause":"Padding repeats the last valid owner, making padding indistinguishable from sequence content.","sha256":"705868e8de14211d7fb3aee4e4719da9bc511a40b1663eeda51c1a766e3fe3cc","title":"Padding positions inherit the last segment owner · 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":27.619,"exit_code":1,"observations":[{"actual":[0,1,-1],"check":"nonempty padding","expected":[0,1,-1,-1],"passed":false},{"actual":[0],"check":"exact width","expected":[0],"passed":true},{"actual":[],"check":"empty row","expected":[-1],"passed":false},{"actual":[1],"check":"zero segment","expected":[1],"passed":true},{"actual":[0,-1],"check":"one valid slot","expected":[0,-1,-1],"passed":false},{"actual":[0,1,1,-1],"check":"mixed owners","expected":[0,1,1,-1,-1],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"nonempty padding\", \"actual\": [0, 1, -1], \"expected\": [0, 1, -1, -1], \"passed\": false}, {\"check\": \"exact width\", \"actual\": [0], \"expected\": [0], \"passed\": true}, {\"check\": \"empty row\", \"actual\": [], \"expected\": [-1], \"passed\": false}, {\"check\": \"zero segment\", \"actual\": [1], \"expected\": [1], \"passed\": true}, {\"check\": \"one valid slot\", \"actual\": [0, -1], \"expected\": [0, -1, -1], \"passed\": false}, {\"check\": \"mixed owners\", \"actual\": [0, 1, 1, -1], \"expected\": [0, 1, 1, -1, -1], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":26.323,"exit_code":1,"observations":[{"actual":[0,1,1,1],"check":"nonempty padding","expected":[0,1,-1,-1],"passed":false},{"actual":[0],"check":"exact width","expected":[0],"passed":true},{"actual":[-1],"check":"empty row","expected":[-1],"passed":true},{"actual":[1],"check":"zero segment","expected":[1],"passed":true},{"actual":[0,0,0],"check":"one valid slot","expected":[0,-1,-1],"passed":false},{"actual":[0,1,1,1,1],"check":"mixed owners","expected":[0,1,1,-1,-1],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"nonempty padding\", \"actual\": [0, 1, 1, 1], \"expected\": [0, 1, -1, -1], \"passed\": false}, {\"check\": \"exact width\", \"actual\": [0], \"expected\": [0], \"passed\": true}, {\"check\": \"empty row\", \"actual\": [-1], \"expected\": [-1], \"passed\": true}, {\"check\": \"zero segment\", \"actual\": [1], \"expected\": [1], \"passed\": true}, {\"check\": \"one valid slot\", \"actual\": [0, 0, 0], \"expected\": [0, -1, -1], \"passed\": false}, {\"check\": \"mixed owners\", \"actual\": [0, 1, 1, 1, 1], \"expected\": [0, 1, 1, -1, -1], \"passed\": false}], \"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."}}