FA-7361 / DNS resolution / Open access
Dns ttl is reduced by resident seconds and clamped · case 01
Dns ttl is reduced by resident seconds and clamped.
ROOT CAUSE
The faulty implementation uses `records` for the dns-ttl-is-reduced-by-resident-seconds-and-clamped decision.
VERIFIED REPAIR
Apply the explicit dns-ttl-is-reduced-by-resident-seconds-and-clamped contract, including the tested boundary and negative cases.
Unsuccessful approach: The attempted repair uses `[(value,max(0,ttl-elapsed)) for value,ttl in records]` and still violates a separate fixture.
Case contract
Given records, elapsed, dns ttl is reduced by resident seconds and clamped. Return the protocol decision or transformed value; fields are validated and fixtures state boundary outcomes.
Why this case matters
This deterministic dns resolution model isolates the dns-ttl-is-reduced-by-resident-seconds-and-clamped 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(records, elapsed):
return records
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve([('a', 10), ('b', 30)], 10), [('b', 20)])", "check('fixture 2', solve([], 3), [])", "check('fixture 3', solve([('a', 0)], 0), [])", "check('fixture 4', solve([('a', 10)], 3), [('a', 7)])"]
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 | [] | [] | Passed |
| fixture 3 | [['a', 0]] | [] | Failed |
| fixture 4 | [['a', 10]] | [['a', 7]] | Failed |
| fixture 1 | [['a', 10], ['b', 30]] | [['b', 20]] | Failed |
SHA-256 / 93f19c45256f9165cf3193a65a40cdcaf0e379b29b70ab967f84e26786f8fbb2
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(records, elapsed):
return [(value,max(0,ttl-elapsed)) for value,ttl in records]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve([('a', 10), ('b', 30)], 10), [('b', 20)])", "check('fixture 2', solve([], 3), [])", "check('fixture 3', solve([('a', 0)], 0), [])", "check('fixture 4', solve([('a', 10)], 3), [('a', 7)])"]
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 | [] | [] | Passed |
| fixture 3 | [['a', 0]] | [] | Failed |
| fixture 4 | [['a', 7]] | [['a', 7]] | Passed |
| fixture 1 | [['a', 0], ['b', 20]] | [['b', 20]] | Failed |
SHA-256 / 43261b2808069a9d5608e5bfbe43580df6444dd2aa0256451a17a30af4aaab11
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(records, elapsed):
return [(value,max(0,ttl-elapsed)) for value,ttl in records if ttl > elapsed]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve([('a', 10), ('b', 30)], 10), [('b', 20)])", "check('fixture 2', solve([], 3), [])", "check('fixture 3', solve([('a', 0)], 0), [])", "check('fixture 4', solve([('a', 10)], 3), [('a', 7)])"]
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 | [] | [] | Passed |
| fixture 3 | [] | [] | Passed |
| fixture 4 | [['a', 7]] | [['a', 7]] | Passed |
| fixture 1 | [['b', 20]] | [['b', 20]] | Passed |
SHA-256 / da4e4684080a37a0d06f454161d9c36d8162c27a931104d001ad1fab12240549
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 2026-09-29T14:38:11.094768+00:00.
Case digest / ba1cbbf19540417564380ef2add25a28773991faf1cba3e07425e5b9767e6f2e