FA-6736 / HTTP caching / Open access

Freshness deadline is exclusive · case 01

Freshness deadline is exclusive.

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

ROOT CAUSE

The faulty implementation uses `age <= lifetime and (request_maxage is None or age <= request_maxage)` for the freshness-deadline-is-exclusive decision.

VERIFIED REPAIR

Apply the explicit freshness-deadline-is-exclusive contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `age < lifetime` and still violates a separate fixture.

Case contract

Given age, lifetime, request_maxage, freshness deadline is exclusive. Return the protocol decision or transformed value; fields are validated and fixtures state boundary outcomes.

Why this case matters

This deterministic http caching model isolates the freshness-deadline-is-exclusive 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(age, lifetime, request_maxage):
    return age <= lifetime and (request_maxage is None or age <= request_maxage)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(10, 10, None), False)", "check('fixture 2', solve(5, 10, 3), False)", "check('fixture 3', solve(3, 10, 3), True)", "check('fixture 4', solve(0, 0, None), 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	`True`	`False`	Failed
fixture 1	`True`	`False`	Failed

SHA-256 / 6f275e752715bb8426a8bc8fac3ea66e34af0522aefb4538780374d34b496b19

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(age, lifetime, request_maxage):
    return age < lifetime
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(10, 10, None), False)", "check('fixture 2', solve(5, 10, 3), False)", "check('fixture 3', solve(3, 10, 3), True)", "check('fixture 4', solve(0, 0, None), 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	`True`	`True`	Passed
fixture 4	`False`	`False`	Passed
fixture 1	`False`	`False`	Passed

SHA-256 / 51f6632b02c692f7fa3c0c9cbfbbeb8187a0b67bc9faffa1d406ed851448ee51

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(age, lifetime, request_maxage):
    return age < lifetime and (request_maxage is None or age <= request_maxage)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(10, 10, None), False)", "check('fixture 2', solve(5, 10, 3), False)", "check('fixture 3', solve(3, 10, 3), True)", "check('fixture 4', solve(0, 0, None), 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	`False`	`False`	Passed

SHA-256 / 7d6c171cc7533efb5592c1897819ceb3b9ee07764edba636c8b40dad3579f426

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 2026-09-29T14:38:04.786122+00:00.

Case digest / be85515da19196cb7ad8c6d36df23e7eb0a893e0a178bbaf8c1a17e2b2184e66