FA-7056 / Proxy forwarding / Open access

Proxy bypass port constraint must match request port · case 01

Proxy bypass port constraint must match request port.

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

ROOT CAUSE

The faulty implementation uses `hostmatch` for the proxy-bypass-port-constraint-must-match-request-port decision.

VERIFIED REPAIR

Apply the explicit proxy-bypass-port-constraint-must-match-request-port contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `hostmatch and expected == actual` and still violates a separate fixture.

Case contract

Bounded offline decision model: proxy bypass port constraint must match request port. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.

Why this case matters

This deterministic proxy forwarding model isolates the proxy-bypass-port-constraint-must-match-request-port 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(hostmatch, expected, actual):
    return hostmatch
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(True, 80, 443), False)", "check('fixture 2', solve(True, None, 443), True)", "check('fixture 3', solve(False, None, 80), False)", "check('fixture 4', solve(True, 80, 80), 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`	`True`	Passed
fixture 3	`False`	`False`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`True`	`False`	Failed

SHA-256 / 73140bce64d8363074305fe5169ae2963e706262ec12fd82c04cc9500283dcba

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(hostmatch, expected, actual):
    return hostmatch and expected == actual
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(True, 80, 443), False)", "check('fixture 2', solve(True, None, 443), True)", "check('fixture 3', solve(False, None, 80), False)", "check('fixture 4', solve(True, 80, 80), 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`	`True`	Failed
fixture 3	`False`	`False`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`False`	`False`	Passed

SHA-256 / e68053c1e87cf04dbc7ce3e040f8ef0a219cab64ebb14d56a05754cbb2f337a1

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(hostmatch, expected, actual):
    return hostmatch and (expected is None or expected == actual)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(True, 80, 443), False)", "check('fixture 2', solve(True, None, 443), True)", "check('fixture 3', solve(False, None, 80), False)", "check('fixture 4', solve(True, 80, 80), 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`	`True`	Passed
fixture 3	`False`	`False`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`False`	`False`	Passed

SHA-256 / 862386b2fd4d9ff521fa8a35f6a0c0980b98dd4462acb478ae74c0f3e2497142

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 2026-09-29T14:38:07.882718+00:00.

Case digest / 33c9ee0e1921c7b646323416b04f36da220f3e8c29bdbabf9fd4eaaf73962715