FA-7151 / Network routing / Open access

Healthy endpoint filter retains draining endpoints only for existing flows · case 01

Healthy endpoint filter retains draining endpoints only for existing flows.

Verified by executionVariant 1 · 4 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The faulty implementation uses `healthy and not draining` for the healthy-endpoint-filter-retains-draining-endpoints-only-for-existing-flows decision.

VERIFIED REPAIR

Apply the explicit healthy-endpoint-filter-retains-draining-endpoints-only-for-existing-flows contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `healthy` and still violates a separate fixture.

Case contract

Bounded offline decision model: healthy endpoint filter retains draining endpoints only for existing flows. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.

Why this case matters

This deterministic network routing model isolates the healthy-endpoint-filter-retains-draining-endpoints-only-for-existing-flows policy at a network component boundary.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import ipaddress
import re
from urllib.parse import urlsplit, urljoin
N = 1
observations = []
def solve(healthy, draining, existing):
    return healthy and not draining
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(True, True, True), True)", "check('fixture 2', solve(True, True, False), False)", "check('fixture 3', solve(False, False, True), False)", "check('fixture 4', solve(True, False, False), True)"]
for _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:
    exec(_line)
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 2	`False`	`False`	Passed
fixture 3	`False`	`False`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`False`	`True`	Failed

SHA-256 / 94c8c4e456449a2a0f1c8fae69d8abbb951a281d2b46ab44454b37138b8257fc

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import ipaddress
import re
from urllib.parse import urlsplit, urljoin
N = 1
observations = []
def solve(healthy, draining, existing):
    return healthy
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(True, True, True), True)", "check('fixture 2', solve(True, True, False), False)", "check('fixture 3', solve(False, False, True), False)", "check('fixture 4', solve(True, False, False), True)"]
for _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:
    exec(_line)
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 2	`True`	`False`	Failed
fixture 3	`False`	`False`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`True`	`True`	Passed

SHA-256 / 644909526c523c14b0b57c7a69cd6ba1ee9a7a61779b3908b76ca2f1f153ce1e

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import ipaddress
import re
from urllib.parse import urlsplit, urljoin
N = 1
observations = []
def solve(healthy, draining, existing):
    return healthy and (not draining or existing)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(True, True, True), True)", "check('fixture 2', solve(True, True, False), False)", "check('fixture 3', solve(False, False, True), False)", "check('fixture 4', solve(True, False, False), True)"]
for _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:
    exec(_line)
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 2	`False`	`False`	Passed
fixture 3	`False`	`False`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`True`	`True`	Passed

SHA-256 / bb16d8025b14dedabec38dde7db4efe50f6fb7054029c850e6b4a72fade3035f

Verification & scope

Bounded deterministic policy model over validated inputs; not a complete protocol stack or an interoperability claim. The five variants rotate the same explicit fixture set. 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 2026-09-29T14:38:08.808648+00:00.

Case digest / 4395aad5677925af64012ad54f7b117908d81676ce77f1a5d6007d4cfa0970e1