FA-7411 / DNS resolution / Open access

Dns ndots threshold selects absolute query first · case 01

Dns ndots threshold selects absolute query first.

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

ROOT CAUSE

The faulty implementation uses `name.count(".") > ndots` for the dns-ndots-threshold-selects-absolute-query-first decision.

VERIFIED REPAIR

Apply the explicit dns-ndots-threshold-selects-absolute-query-first contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `"." in name` and still violates a separate fixture.

Case contract

Bounded offline decision model: dns ndots threshold selects absolute query first. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.

Why this case matters

This deterministic dns resolution model isolates the dns-ndots-threshold-selects-absolute-query-first 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(name, ndots):
    return name.count(".") > ndots
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve('a.b', 1), True)", "check('fixture 2', solve('a.b', 2), False)", "check('fixture 3', solve('a', 0), True)", "check('fixture 4', solve('a', 1), False)"]
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`	`True`	Failed
fixture 4	`False`	`False`	Passed
fixture 1	`False`	`True`	Failed

SHA-256 / 98c2be2767e62cc1dc069f3bbe5d462787734f292c4ff48e6b7ccfc8c718579c

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(name, ndots):
    return "." in name
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve('a.b', 1), True)", "check('fixture 2', solve('a.b', 2), False)", "check('fixture 3', solve('a', 0), True)", "check('fixture 4', solve('a', 1), False)"]
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`	`True`	Failed
fixture 4	`False`	`False`	Passed
fixture 1	`True`	`True`	Passed

SHA-256 / 1f0be0715aa5379ae220b9a158374fd0c94c84b0a5bc7c93db9efb759b706012

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(name, ndots):
    return name.count(".") >= ndots
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve('a.b', 1), True)", "check('fixture 2', solve('a.b', 2), False)", "check('fixture 3', solve('a', 0), True)", "check('fixture 4', solve('a', 1), False)"]
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	`True`	`True`	Passed
fixture 4	`False`	`False`	Passed
fixture 1	`True`	`True`	Passed

SHA-256 / 956b632cf8532b5a70a36374d6abef0c118bdf476f160f6905dd8c3c33e90982

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 2026-09-29T14:38:11.606824+00:00.

Case digest / add4072f12af70a719af6fbd63b4315b53b526f6ccafd4388e97b11717fba2f9