{"abstract":"purging uses row positions instead of timestamps.","category":"Dataset split isolation","checks":6,"contract":"Given [id,time] rows and validation [lo,hi), retain rows strictly before lo or at/after hi.","contract_signature":"rows, lo, hi","evaluation_group":"ds-purged-neighbor","failed_approach":"Using a strict comparison at the upper bound wrongly purges a record exactly at hi.","family":"w3-dataset-split-isolation-purged-fold-neighbor","id":"FA-97931","implementations":{"attempt":{"sha256":"b3f7e23263008239e68339c3258c148744b4b7823343e6cfe2961db5323e2368","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows, lo, hi):\n    return sorted(i for i,t in rows if t<lo or t>hi)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('unordered left right',solve([['c',N+3],['a',N-1],['b',N+1]],N,N+3),['a','c'])\ncheck('exact left boundary',solve([['a',N]],N,N+2),[])\ncheck('exact right boundary',solve([['a',N+2]],N,N+2),['a'])\ncheck('inside',solve([['a',N+1]],N,N+2),[])\ncheck('empty',solve([],N,N+1),[])\ncheck('wide interval',solve([['a',0],['b',N+5]],N,N+5),['a','b'])\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":"d365d438fee47524da34083e588a68c68218c1da4c1bfbbee351c6ea7f1d0dff","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows, lo, hi):\n    return sorted(i for j,(i,t) in enumerate(rows) if j<lo or j>=hi)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('unordered left right',solve([['c',N+3],['a',N-1],['b',N+1]],N,N+3),['a','c'])\ncheck('exact left boundary',solve([['a',N]],N,N+2),[])\ncheck('exact right boundary',solve([['a',N+2]],N,N+2),['a'])\ncheck('inside',solve([['a',N+1]],N,N+2),[])\ncheck('empty',solve([],N,N+1),[])\ncheck('wide interval',solve([['a',0],['b',N+5]],N,N+5),['a','b'])\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 small in-memory records with self-contained contracts; no claim is made about production sampling 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-dataset-split-isolation-purged-fold-neighbor","generated_at":"2026-09-30T16:48:07.547981+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This toy split allocator makes membership rules explicit for reproducible evaluation fixtures.","root_cause":"The implementation compares each row index to temporal bounds, so its result depends on input order and numeric cutoff values.","sha256":"7e8408a4f61245e1f0d5cc36b364e726148c379aee398c8c36452dd8703ba281","title":"Dataset split: purging uses row positions instead of timestamps · 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":27.732,"exit_code":1,"observations":[{"actual":["a"],"check":"unordered left right","expected":["a","c"],"passed":false},{"actual":[],"check":"exact left boundary","expected":[],"passed":true},{"actual":[],"check":"exact right boundary","expected":["a"],"passed":false},{"actual":[],"check":"inside","expected":[],"passed":true},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":["a"],"check":"wide interval","expected":["a","b"],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"unordered left right\", \"actual\": [\"a\"], \"expected\": [\"a\", \"c\"], \"passed\": false}, {\"check\": \"exact left boundary\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"exact right boundary\", \"actual\": [], \"expected\": [\"a\"], \"passed\": false}, {\"check\": \"inside\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"wide interval\", \"actual\": [\"a\"], \"expected\": [\"a\", \"b\"], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":28.309,"exit_code":1,"observations":[{"actual":["c"],"check":"unordered left right","expected":["a","c"],"passed":false},{"actual":["a"],"check":"exact left boundary","expected":[],"passed":false},{"actual":["a"],"check":"exact right boundary","expected":["a"],"passed":true},{"actual":["a"],"check":"inside","expected":[],"passed":false},{"actual":[],"check":"empty","expected":[],"passed":true},{"actual":["a"],"check":"wide interval","expected":["a","b"],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"unordered left right\", \"actual\": [\"c\"], \"expected\": [\"a\", \"c\"], \"passed\": false}, {\"check\": \"exact left boundary\", \"actual\": [\"a\"], \"expected\": [], \"passed\": false}, {\"check\": \"exact right boundary\", \"actual\": [\"a\"], \"expected\": [\"a\"], \"passed\": true}, {\"check\": \"inside\", \"actual\": [\"a\"], \"expected\": [], \"passed\": false}, {\"check\": \"empty\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"wide interval\", \"actual\": [\"a\"], \"expected\": [\"a\", \"b\"], \"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."}}