{"abstract":"Overlapping windows advance by the overlap instead of stride.","category":"Sequence batch packing","checks":6,"contract":"Emit windows of width, advancing by width-overlap; stop after the window reaches the sequence end. A final shorter window is retained.","contract_signature":"tokens, width, overlap","evaluation_group":"w3-seqpack-window-stride-v1","failed_approach":"Adding one to the stride repairs some windows but skips a valid start for larger widths.","family":"w3-sequence-batch-packing-overlap-window-start","id":"FA-98076","implementations":{"attempt":{"sha256":"a0473dc77a211624ce56fe9d711d9136d68569f490593b74e301d73ab627915f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(tokens, width, overlap):\n    return [tokens[i:i+width] for i in range(0,len(tokens),width-overlap+1)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ndata=list(range(2*N+1)); w=N+1; o=1\ncheck('overlap and tail', solve(data,w,o), [data[:w],data[N:2*N+1]])\ntokens=list(range(N+2))\ncheck('no overlap', solve(tokens,N,0), [tokens[i:i+N] for i in range(0,len(tokens),N)])\ncheck('full single window', solve([N],N+2,1), [[N]])\ncheck('empty', solve([],N,min(1,N-1)), [])\ncheck('overlap repeats', solve(list(range(5)),3,2), [[0,1,2],[1,2,3],[2,3,4]])\ndata=list(range(2*N))\nexpected=[list(range(N)),list(range(1,2))] if N==1 else [list(range(N)),list(range(N-1,2*N-1)),list(range(2*N-2,2*N))]\ncheck('exact end', solve(data,N,min(1,N-1)), expected)\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":"bc1e5648b24efa070d7da8226fa3b9ae95079db0b8e0c4963a50657b2c3c8891","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(tokens, width, overlap):\n    return [tokens[i:i+width] for i in range(0,len(tokens),max(1,overlap))]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ndata=list(range(2*N+1)); w=N+1; o=1\ncheck('overlap and tail', solve(data,w,o), [data[:w],data[N:2*N+1]])\ntokens=list(range(N+2))\ncheck('no overlap', solve(tokens,N,0), [tokens[i:i+N] for i in range(0,len(tokens),N)])\ncheck('full single window', solve([N],N+2,1), [[N]])\ncheck('empty', solve([],N,min(1,N-1)), [])\ncheck('overlap repeats', solve(list(range(5)),3,2), [[0,1,2],[1,2,3],[2,3,4]])\ndata=list(range(2*N))\nexpected=[list(range(N)),list(range(1,2))] if N==1 else [list(range(N)),list(range(N-1,2*N-1)),list(range(2*N-2,2*N))]\ncheck('exact end', solve(data,N,min(1,N-1)), expected)\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-overlap-window-start","generated_at":"2026-09-30T16:48:08.896898+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":"The start increment is set to overlap length, causing excessive repetition.","sha256":"4c46a75088fda22f8e0fbbddb9aa9b6221ed6b52ac68fd9602c124c1310a5e7f","title":"Overlapping windows advance by the overlap instead of stride · 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":30.092,"exit_code":1,"observations":[{"actual":[[0,1],[2]],"check":"overlap and tail","expected":[[0,1],[1,2]],"passed":false},{"actual":[[0],[2]],"check":"no overlap","expected":[[0],[1],[2]],"passed":false},{"actual":[[1]],"check":"full single window","expected":[[1]],"passed":true},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[[0,1,2],[2,3,4],[4]],"check":"overlap repeats","expected":[[0,1,2],[1,2,3],[2,3,4]],"passed":false},{"actual":[[0]],"check":"exact end","expected":[[0],[1]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"overlap and tail\", \"actual\": [[0, 1], [2]], \"expected\": [[0, 1], [1, 2]], \"passed\": false}, {\"check\": \"no overlap\", \"actual\": [[0], [2]], \"expected\": [[0], [1], [2]], \"passed\": false}, {\"check\": \"full single window\", \"actual\": [[1]], \"expected\": [[1]], \"passed\": true}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"overlap repeats\", \"actual\": [[0, 1, 2], [2, 3, 4], [4]], \"expected\": [[0, 1, 2], [1, 2, 3], [2, 3, 4]], \"passed\": false}, {\"check\": \"exact end\", \"actual\": [[0]], \"expected\": [[0], [1]], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":27.523,"exit_code":1,"observations":[{"actual":[[0,1],[1,2],[2]],"check":"overlap and tail","expected":[[0,1],[1,2]],"passed":false},{"actual":[[0],[1],[2]],"check":"no overlap","expected":[[0],[1],[2]],"passed":true},{"actual":[[1]],"check":"full single window","expected":[[1]],"passed":true},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":[[0,1,2],[2,3,4],[4]],"check":"overlap repeats","expected":[[0,1,2],[1,2,3],[2,3,4]],"passed":false},{"actual":[[0],[1]],"check":"exact end","expected":[[0],[1]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"overlap and tail\", \"actual\": [[0, 1], [1, 2], [2]], \"expected\": [[0, 1], [1, 2]], \"passed\": false}, {\"check\": \"no overlap\", \"actual\": [[0], [1], [2]], \"expected\": [[0], [1], [2]], \"passed\": true}, {\"check\": \"full single window\", \"actual\": [[1]], \"expected\": [[1]], \"passed\": true}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"overlap repeats\", \"actual\": [[0, 1, 2], [2, 3, 4], [4]], \"expected\": [[0, 1, 2], [1, 2, 3], [2, 3, 4]], \"passed\": false}, {\"check\": \"exact end\", \"actual\": [[0], [1]], \"expected\": [[0], [1]], \"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."}}