FA-6796 / HTTP caching / Open access

If match star tests existence not tag presence · case 01

If match star tests existence not tag presence.

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

ROOT CAUSE

The faulty implementation uses `matches` for the if-match-star-tests-existence-not-tag-presence decision.

VERIFIED REPAIR

Apply the explicit if-match-star-tests-existence-not-tag-presence contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `star or matches` and still violates a separate fixture.

Case contract

Bounded offline decision model: if match star tests existence not tag presence. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.

Why this case matters

This deterministic http caching model isolates the if-match-star-tests-existence-not-tag-presence 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(star, exists, matches):
    return matches
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(True, True, False), True)", "check('fixture 2', solve(True, False, True), False)", "check('fixture 3', solve(False, True, True), True)", "check('fixture 4', solve(False, True, False), 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`	`True`	Failed

SHA-256 / 38d66dc595b324192eb050e631a01300d9ed94c2afcc85ad09a7fbaa500463b4

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(star, exists, matches):
    return star or matches
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(True, True, False), True)", "check('fixture 2', solve(True, False, True), False)", "check('fixture 3', solve(False, True, True), True)", "check('fixture 4', solve(False, True, False), 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	`True`	`True`	Passed

SHA-256 / 00055d35dccf4cb7321a5b00da76667319e7674994c76b9a5dbd6c72777a115a

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(star, exists, matches):
    return exists if star else exists and matches
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(True, True, False), True)", "check('fixture 2', solve(True, False, True), False)", "check('fixture 3', solve(False, True, True), True)", "check('fixture 4', solve(False, True, False), 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 / 459c6949c6cdcbd8075760c4fb040a27a9ff00d16e7c22ce9937d70cb5b3420b

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 2026-09-29T14:38:05.216723+00:00.

Case digest / 8a4b4d01f7cab629fa8bae0536c8843d45b9e89956320242e4fe00cd82ac95ba