FA-9376 / Version constraints / Open access

Closed-open version range intersection: An empty touching range is reported satisfiable · case 01

An empty touching range is reported satisfiable.

Verified by executionVariant 1 · 9 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The implementation substitutes lo > hi for lo >= hi, so an empty touching range is reported satisfiable.

THE FAILURE

The implementation substitutes lo > hi for lo >= hi, so an empty touching range is reported satisfiable.

Unsuccessful approach: The attempted repair substitutes lo == hi. Fixture 5 still yields (4, 2) instead of 'empty'.

Case contract

Intersect all inclusive lower and exclusive upper bounds. None means unbounded. Return empty if lower >= upper, otherwise a bound pair.

Why this case matters

An offline model of closed-open version range intersection, 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(ranges):
    lows = [lo for lo, hi in ranges if lo is not None]
    highs = [hi for lo, hi in ranges if hi is not None]
    lo = max(lows) if lows else None
    hi = min(highs) if highs else None
    if lo is not None and hi is not None and lo > hi: return 'empty'
    return (lo, hi)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve([]), (None, None))
check('fixture 2', solve([(None, None)]), (None, None))
check('fixture 3', solve([(1, 8), (3, 6)]), (3, 6))
check('fixture 4', solve([(2, 2)]), 'empty')
check('fixture 5', solve([(4, 2)]), 'empty')
check('fixture 6', solve([(None, 3), (0, None)]), (0, 3))
check('fixture 7', solve([(0, 3)]), (0, 3))
check('fixture 8', solve([(0, None)]), (0, None))
check('fixture 9', solve([(None, 0)]), (None, 0))
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	`[None, None]`	`[None, None]`	Passed
fixture 2	`[None, None]`	`[None, None]`	Passed
fixture 3	`[3, 6]`	`[3, 6]`	Passed
fixture 4	`[2, 2]`	`empty`	Failed
fixture 5	`empty`	`empty`	Passed
fixture 6	`[0, 3]`	`[0, 3]`	Passed
fixture 7	`[0, 3]`	`[0, 3]`	Passed
fixture 8	`[0, None]`	`[0, None]`	Passed
fixture 9	`[None, 0]`	`[None, 0]`	Passed

SHA-256 / 0d4fd9ecbce1af8681fcc54ba169dd894eb3bafc5040a1f36bd6acfca1d35ec0

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(ranges):
    lows = [lo for lo, hi in ranges if lo is not None]
    highs = [hi for lo, hi in ranges if hi is not None]
    lo = max(lows) if lows else None
    hi = min(highs) if highs else None
    if lo is not None and hi is not None and lo == hi: return 'empty'
    return (lo, hi)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve([]), (None, None))
check('fixture 2', solve([(None, None)]), (None, None))
check('fixture 3', solve([(1, 8), (3, 6)]), (3, 6))
check('fixture 4', solve([(2, 2)]), 'empty')
check('fixture 5', solve([(4, 2)]), 'empty')
check('fixture 6', solve([(None, 3), (0, None)]), (0, 3))
check('fixture 7', solve([(0, 3)]), (0, 3))
check('fixture 8', solve([(0, None)]), (0, None))
check('fixture 9', solve([(None, 0)]), (None, 0))
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	`[None, None]`	`[None, None]`	Passed
fixture 2	`[None, None]`	`[None, None]`	Passed
fixture 3	`[3, 6]`	`[3, 6]`	Passed
fixture 4	`empty`	`empty`	Passed
fixture 5	`[4, 2]`	`empty`	Failed
fixture 6	`[0, 3]`	`[0, 3]`	Passed
fixture 7	`[0, 3]`	`[0, 3]`	Passed
fixture 8	`[0, None]`	`[0, None]`	Passed
fixture 9	`[None, 0]`	`[None, 0]`	Passed

SHA-256 / 71da768666828754ee941b71384b4fd15cf6c6192ff1020f5b76d1e0612a97b6

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 9 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

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 2026-09-29T14:38:29.449267+00:00.

Case digest / 325b87e017e9ef4202c6803f4dbac9313ef11376f1f1d4392e772f232246aac6