FA-9541 / Version constraints / Open access

Compatible release admission: Compatibility extends through the next incompatible release · case 01

Compatibility extends through the next incompatible release.

Verified by executionVariant 1 · 25 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The implementation substitutes candidate <= ceiling for candidate < ceiling, so compatibility extends through the next incompatible release.

VERIFIED REPAIR

Require strict less-than at the compatibility ceiling.

Unsuccessful approach: The attempted repair substitutes candidate != ceiling. Fixture 21 still yields True instead of False.

Case contract

Accept candidate tuple if not excluded, at least the lower release, below the compatibility ceiling, and prerelease only when opted in; exact pins additionally require equality.

Why this case matters

An offline model of compatible release admission, suitable for testing build and release tooling without external services.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(candidate, low, ceiling, excluded, prerelease, allow_pre, pin):
    return (candidate not in excluded and candidate >= low and candidate <= ceiling and (not prerelease or allow_pre) and (pin is None or candidate == pin))
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve((1, 1), (1, 2), (2, 0), [], False, False, None), False)
check('fixture 2', solve((1, 1), (1, 2), (2, 0), [(1, 2)], False, False, None), False)
check('fixture 3', solve((1, 1), (1, 2), (2, 0), [], True, False, None), False)
check('fixture 4', solve((1, 1), (1, 2), (2, 0), [], True, True, None), False)
check('fixture 5', solve((1, 1), (1, 2), (2, 0), [], False, False, (1, 2)), False)
check('fixture 6', solve((1, 2), (1, 2), (2, 0), [], False, False, None), True)
check('fixture 7', solve((1, 2), (1, 2), (2, 0), [(1, 2)], False, False, None), False)
check('fixture 8', solve((1, 2), (1, 2), (2, 0), [], True, False, None), False)
check('fixture 9', solve((1, 2), (1, 2), (2, 0), [], True, True, None), True)
check('fixture 10', solve((1, 2), (1, 2), (2, 0), [], False, False, (1, 2)), True)
check('fixture 11', solve((1, 9), (1, 2), (2, 0), [], False, False, None), True)
check('fixture 12', solve((1, 9), (1, 2), (2, 0), [(1, 2)], False, False, None), True)
check('fixture 13', solve((1, 9), (1, 2), (2, 0), [], True, False, None), False)
check('fixture 14', solve((1, 9), (1, 2), (2, 0), [], True, True, None), True)
check('fixture 15', solve((1, 9), (1, 2), (2, 0), [], False, False, (1, 2)), False)
check('fixture 16', solve((2, 0), (1, 2), (2, 0), [], False, False, None), False)
check('fixture 17', solve((2, 0), (1, 2), (2, 0), [(1, 2)], False, False, None), False)
check('fixture 18', solve((2, 0), (1, 2), (2, 0), [], True, False, None), False)
check('fixture 19', solve((2, 0), (1, 2), (2, 0), [], True, True, None), False)
check('fixture 20', solve((2, 0), (1, 2), (2, 0), [], False, False, (1, 2)), False)
check('fixture 21', solve((2, 1), (1, 2), (2, 0), [], False, False, None), False)
check('fixture 22', solve((2, 1), (1, 2), (2, 0), [(1, 2)], False, False, None), False)
check('fixture 23', solve((2, 1), (1, 2), (2, 0), [], True, False, None), False)
check('fixture 24', solve((2, 1), (1, 2), (2, 0), [], True, True, None), False)
check('fixture 25', solve((2, 1), (1, 2), (2, 0), [], False, False, (1, 2)), 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
fixture 1	`False`	`False`	Passed
fixture 2	`False`	`False`	Passed
fixture 3	`False`	`False`	Passed
fixture 4	`False`	`False`	Passed
fixture 5	`False`	`False`	Passed
fixture 6	`True`	`True`	Passed
fixture 7	`False`	`False`	Passed
fixture 8	`False`	`False`	Passed
fixture 9	`True`	`True`	Passed
fixture 10	`True`	`True`	Passed
fixture 11	`True`	`True`	Passed
fixture 12	`True`	`True`	Passed
fixture 13	`False`	`False`	Passed
fixture 14	`True`	`True`	Passed
fixture 15	`False`	`False`	Passed
fixture 16	`True`	`False`	Failed
fixture 17	`True`	`False`	Failed
fixture 18	`False`	`False`	Passed
fixture 19	`True`	`False`	Failed
fixture 20	`False`	`False`	Passed
fixture 21	`False`	`False`	Passed
fixture 22	`False`	`False`	Passed
fixture 23	`False`	`False`	Passed
fixture 24	`False`	`False`	Passed
fixture 25	`False`	`False`	Passed

SHA-256 / abc3068b3928b9eeb0ab7d0e2f65bc97f351f81c47495c8509aa98a2802f1bc2

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(candidate, low, ceiling, excluded, prerelease, allow_pre, pin):
    return (candidate not in excluded and candidate >= low and candidate != ceiling and (not prerelease or allow_pre) and (pin is None or candidate == pin))
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve((1, 1), (1, 2), (2, 0), [], False, False, None), False)
check('fixture 2', solve((1, 1), (1, 2), (2, 0), [(1, 2)], False, False, None), False)
check('fixture 3', solve((1, 1), (1, 2), (2, 0), [], True, False, None), False)
check('fixture 4', solve((1, 1), (1, 2), (2, 0), [], True, True, None), False)
check('fixture 5', solve((1, 1), (1, 2), (2, 0), [], False, False, (1, 2)), False)
check('fixture 6', solve((1, 2), (1, 2), (2, 0), [], False, False, None), True)
check('fixture 7', solve((1, 2), (1, 2), (2, 0), [(1, 2)], False, False, None), False)
check('fixture 8', solve((1, 2), (1, 2), (2, 0), [], True, False, None), False)
check('fixture 9', solve((1, 2), (1, 2), (2, 0), [], True, True, None), True)
check('fixture 10', solve((1, 2), (1, 2), (2, 0), [], False, False, (1, 2)), True)
check('fixture 11', solve((1, 9), (1, 2), (2, 0), [], False, False, None), True)
check('fixture 12', solve((1, 9), (1, 2), (2, 0), [(1, 2)], False, False, None), True)
check('fixture 13', solve((1, 9), (1, 2), (2, 0), [], True, False, None), False)
check('fixture 14', solve((1, 9), (1, 2), (2, 0), [], True, True, None), True)
check('fixture 15', solve((1, 9), (1, 2), (2, 0), [], False, False, (1, 2)), False)
check('fixture 16', solve((2, 0), (1, 2), (2, 0), [], False, False, None), False)
check('fixture 17', solve((2, 0), (1, 2), (2, 0), [(1, 2)], False, False, None), False)
check('fixture 18', solve((2, 0), (1, 2), (2, 0), [], True, False, None), False)
check('fixture 19', solve((2, 0), (1, 2), (2, 0), [], True, True, None), False)
check('fixture 20', solve((2, 0), (1, 2), (2, 0), [], False, False, (1, 2)), False)
check('fixture 21', solve((2, 1), (1, 2), (2, 0), [], False, False, None), False)
check('fixture 22', solve((2, 1), (1, 2), (2, 0), [(1, 2)], False, False, None), False)
check('fixture 23', solve((2, 1), (1, 2), (2, 0), [], True, False, None), False)
check('fixture 24', solve((2, 1), (1, 2), (2, 0), [], True, True, None), False)
check('fixture 25', solve((2, 1), (1, 2), (2, 0), [], False, False, (1, 2)), 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
fixture 1	`False`	`False`	Passed
fixture 2	`False`	`False`	Passed
fixture 3	`False`	`False`	Passed
fixture 4	`False`	`False`	Passed
fixture 5	`False`	`False`	Passed
fixture 6	`True`	`True`	Passed
fixture 7	`False`	`False`	Passed
fixture 8	`False`	`False`	Passed
fixture 9	`True`	`True`	Passed
fixture 10	`True`	`True`	Passed
fixture 11	`True`	`True`	Passed
fixture 12	`True`	`True`	Passed
fixture 13	`False`	`False`	Passed
fixture 14	`True`	`True`	Passed
fixture 15	`False`	`False`	Passed
fixture 16	`False`	`False`	Passed
fixture 17	`False`	`False`	Passed
fixture 18	`False`	`False`	Passed
fixture 19	`False`	`False`	Passed
fixture 20	`False`	`False`	Passed
fixture 21	`True`	`False`	Failed
fixture 22	`True`	`False`	Failed
fixture 23	`False`	`False`	Passed
fixture 24	`True`	`False`	Failed
fixture 25	`False`	`False`	Passed

SHA-256 / c486ac7800114d528c5fd97893e1587409d90d0f9bcb4ca0bbf376a3aa4f519c

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(candidate, low, ceiling, excluded, prerelease, allow_pre, pin):
    return (candidate not in excluded and candidate >= low and candidate < ceiling and (not prerelease or allow_pre) and (pin is None or candidate == pin))
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve((1, 1), (1, 2), (2, 0), [], False, False, None), False)
check('fixture 2', solve((1, 1), (1, 2), (2, 0), [(1, 2)], False, False, None), False)
check('fixture 3', solve((1, 1), (1, 2), (2, 0), [], True, False, None), False)
check('fixture 4', solve((1, 1), (1, 2), (2, 0), [], True, True, None), False)
check('fixture 5', solve((1, 1), (1, 2), (2, 0), [], False, False, (1, 2)), False)
check('fixture 6', solve((1, 2), (1, 2), (2, 0), [], False, False, None), True)
check('fixture 7', solve((1, 2), (1, 2), (2, 0), [(1, 2)], False, False, None), False)
check('fixture 8', solve((1, 2), (1, 2), (2, 0), [], True, False, None), False)
check('fixture 9', solve((1, 2), (1, 2), (2, 0), [], True, True, None), True)
check('fixture 10', solve((1, 2), (1, 2), (2, 0), [], False, False, (1, 2)), True)
check('fixture 11', solve((1, 9), (1, 2), (2, 0), [], False, False, None), True)
check('fixture 12', solve((1, 9), (1, 2), (2, 0), [(1, 2)], False, False, None), True)
check('fixture 13', solve((1, 9), (1, 2), (2, 0), [], True, False, None), False)
check('fixture 14', solve((1, 9), (1, 2), (2, 0), [], True, True, None), True)
check('fixture 15', solve((1, 9), (1, 2), (2, 0), [], False, False, (1, 2)), False)
check('fixture 16', solve((2, 0), (1, 2), (2, 0), [], False, False, None), False)
check('fixture 17', solve((2, 0), (1, 2), (2, 0), [(1, 2)], False, False, None), False)
check('fixture 18', solve((2, 0), (1, 2), (2, 0), [], True, False, None), False)
check('fixture 19', solve((2, 0), (1, 2), (2, 0), [], True, True, None), False)
check('fixture 20', solve((2, 0), (1, 2), (2, 0), [], False, False, (1, 2)), False)
check('fixture 21', solve((2, 1), (1, 2), (2, 0), [], False, False, None), False)
check('fixture 22', solve((2, 1), (1, 2), (2, 0), [(1, 2)], False, False, None), False)
check('fixture 23', solve((2, 1), (1, 2), (2, 0), [], True, False, None), False)
check('fixture 24', solve((2, 1), (1, 2), (2, 0), [], True, True, None), False)
check('fixture 25', solve((2, 1), (1, 2), (2, 0), [], False, False, (1, 2)), 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
fixture 1	`False`	`False`	Passed
fixture 2	`False`	`False`	Passed
fixture 3	`False`	`False`	Passed
fixture 4	`False`	`False`	Passed
fixture 5	`False`	`False`	Passed
fixture 6	`True`	`True`	Passed
fixture 7	`False`	`False`	Passed
fixture 8	`False`	`False`	Passed
fixture 9	`True`	`True`	Passed
fixture 10	`True`	`True`	Passed
fixture 11	`True`	`True`	Passed
fixture 12	`True`	`True`	Passed
fixture 13	`False`	`False`	Passed
fixture 14	`True`	`True`	Passed
fixture 15	`False`	`False`	Passed
fixture 16	`False`	`False`	Passed
fixture 17	`False`	`False`	Passed
fixture 18	`False`	`False`	Passed
fixture 19	`False`	`False`	Passed
fixture 20	`False`	`False`	Passed
fixture 21	`False`	`False`	Passed
fixture 22	`False`	`False`	Passed
fixture 23	`False`	`False`	Passed
fixture 24	`False`	`False`	Passed
fixture 25	`False`	`False`	Passed

SHA-256 / 9436aa7f95f2934f855d763d9aed0d45fbc1ed669972258db8f58ff3ff04d713

Verification & scope

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 2026-09-29T14:38:30.906852+00:00.

Case digest / 088a45d59123594055dfacaadee5f38789c7bb80b7ed1e9827e0f9bcefbced7e