{"abstract":"training data includes observations from validation period.","category":"Dataset split isolation","checks":6,"contract":"Given training and validation [id,time] rows, return whether max(train time) < min(validation time); empty side is true.","contract_signature":"train, validation","evaluation_group":"ds-train-before-validation","failed_approach":"A strict check is applied to only the first matching record.","family":"w3-dataset-split-isolation-train-before-validation","id":"FA-97906","implementations":{"attempt":{"sha256":"b76327f504eef5e07e75981720515d8f856ef27fee648bb9dbd0ab5612a6abb7","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(train, validation):\n    return not train or not validation or all(t<min(v for i,v in validation) for i,t in train[:1])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('strict chronology',solve([['a',N]], [['b',N+1]]),True)\ncheck('equal boundary',solve([['a',N]], [['b',N]]),False)\ncheck('overlap order',solve([['a',N+1]], [['b',N]]),False)\ncheck('empty train',solve([], [['b',N]]),True)\ncheck('empty validation',solve([['a',N]], []),True)\ncheck('late train row',solve([['a',N],['c',N+2]], [['b',N+1]]),False)\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":"e55540518c03a1d09d93b5c5229e6c3f721d07488337b976e68d127cde58c0ec","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(train, validation):\n    return not train or not validation or max(t for i,t in train)<=min(t for i,t in validation)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('strict chronology',solve([['a',N]], [['b',N+1]]),True)\ncheck('equal boundary',solve([['a',N]], [['b',N]]),False)\ncheck('overlap order',solve([['a',N+1]], [['b',N]]),False)\ncheck('empty train',solve([], [['b',N]]),True)\ncheck('empty validation',solve([['a',N]], []),True)\ncheck('late train row',solve([['a',N],['c',N+2]], [['b',N+1]]),False)\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-train-before-validation","generated_at":"2026-09-30T16:48:07.116733+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 boundary condition admits a record at validation start.","sha256":"1ebf1cda675c762801605f8c3a2c1d9579bdb2684146b42d979c454b79143e27","title":"Dataset split: training data includes observations from validation period · 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":26.044,"exit_code":1,"observations":[{"actual":true,"check":"strict chronology","expected":true,"passed":true},{"actual":false,"check":"equal boundary","expected":false,"passed":true},{"actual":false,"check":"overlap order","expected":false,"passed":true},{"actual":true,"check":"empty train","expected":true,"passed":true},{"actual":true,"check":"empty validation","expected":true,"passed":true},{"actual":true,"check":"late train row","expected":false,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"strict chronology\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"equal boundary\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"overlap order\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"empty train\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"empty validation\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"late train row\", \"actual\": true, \"expected\": false, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":26.709,"exit_code":1,"observations":[{"actual":true,"check":"strict chronology","expected":true,"passed":true},{"actual":true,"check":"equal boundary","expected":false,"passed":false},{"actual":false,"check":"overlap order","expected":false,"passed":true},{"actual":true,"check":"empty train","expected":true,"passed":true},{"actual":true,"check":"empty validation","expected":true,"passed":true},{"actual":false,"check":"late train row","expected":false,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"strict chronology\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"equal boundary\", \"actual\": true, \"expected\": false, \"passed\": false}, {\"check\": \"overlap order\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"empty train\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"empty validation\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"late train row\", \"actual\": false, \"expected\": false, \"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."}}