FA-97906 / Dataset split isolation / Open access

Dataset split: training data includes observations from validation period · case 01

training data includes observations from validation period.

Verified by executionVariant 1 · 6 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The boundary condition admits a record at validation start.

THE FAILURE

The boundary condition admits a record at validation start.

Unsuccessful approach: A strict check is applied to only the first matching record.

Case contract

Given training and validation [id,time] rows, return whether max(train time) < min(validation time); empty side is true.

Why this case matters

This toy split allocator makes membership rules explicit for reproducible evaluation fixtures.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(train, validation):
    return not train or not validation or max(t for i,t in train)<=min(t for i,t in validation)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('strict chronology',solve([['a',N]], [['b',N+1]]),True)
check('equal boundary',solve([['a',N]], [['b',N]]),False)
check('overlap order',solve([['a',N+1]], [['b',N]]),False)
check('empty train',solve([], [['b',N]]),True)
check('empty validation',solve([['a',N]], []),True)
check('late train row',solve([['a',N],['c',N+2]], [['b',N+1]]),False)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
strict chronology	`True`	`True`	Passed
equal boundary	`True`	`False`	Failed
overlap order	`False`	`False`	Passed
empty train	`True`	`True`	Passed
empty validation	`True`	`True`	Passed
late train row	`False`	`False`	Passed

SHA-256 / e55540518c03a1d09d93b5c5229e6c3f721d07488337b976e68d127cde58c0ec

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(train, validation):
    return not train or not validation or all(t<min(v for i,v in validation) for i,t in train[:1])
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('strict chronology',solve([['a',N]], [['b',N+1]]),True)
check('equal boundary',solve([['a',N]], [['b',N]]),False)
check('overlap order',solve([['a',N+1]], [['b',N]]),False)
check('empty train',solve([], [['b',N]]),True)
check('empty validation',solve([['a',N]], []),True)
check('late train row',solve([['a',N],['c',N+2]], [['b',N+1]]),False)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
strict chronology	`True`	`True`	Passed
equal boundary	`False`	`False`	Passed
overlap order	`False`	`False`	Passed
empty train	`True`	`True`	Passed
empty validation	`True`	`True`	Passed
late train row	`True`	`False`	Failed

SHA-256 / b76327f504eef5e07e75981720515d8f856ef27fee648bb9dbd0ab5612a6abb7

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 6 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

Verification & scope

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.

Observations recorded using Python 3.12.14 at 2026-09-30T16:48:07.116733+00:00.

Case digest / 1ebf1cda675c762801605f8c3a2c1d9579bdb2684146b42d979c454b79143e27