FA-7031 / Proxy forwarding / Open access

Proxy buffer limit counts all pending chunks · case 01

Proxy buffer limit counts all pending chunks.

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

ROOT CAUSE

The faulty implementation uses `all(len(c)<=limit for c in chunks)` for the proxy-buffer-limit-counts-all-pending-chunks decision.

VERIFIED REPAIR

Apply the explicit proxy-buffer-limit-counts-all-pending-chunks contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `sum(map(len,chunks)) < limit` and still violates a separate fixture.

Case contract

Bounded offline decision model: proxy buffer limit counts all pending chunks. 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-buffer-limit-counts-all-pending-chunks 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(chunks, limit):
    return all(len(c)<=limit for c in chunks)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(['abc', 'def'], 5), False)", "check('fixture 2', solve(['abc', 'de'], 5), True)", "check('fixture 3', solve([], 0), True)", "check('fixture 4', solve(['abcd'], 3), 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`	`True`	Passed
fixture 3	`True`	`True`	Passed
fixture 4	`False`	`False`	Passed
fixture 1	`True`	`False`	Failed

SHA-256 / 4035039b4bfa57152f5cf7c8d71e5d8744b9fcbf70cdf29c9da295a6b7335fd9

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(chunks, limit):
    return sum(map(len,chunks)) < limit
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(['abc', 'def'], 5), False)", "check('fixture 2', solve(['abc', 'de'], 5), True)", "check('fixture 3', solve([], 0), True)", "check('fixture 4', solve(['abcd'], 3), 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`	`True`	Failed
fixture 3	`False`	`True`	Failed
fixture 4	`False`	`False`	Passed
fixture 1	`False`	`False`	Passed

SHA-256 / 844a95f3c2fe30f1e2337b0367862da914e98d2ed2b5e3d48d67a2512ea95b4e

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(chunks, limit):
    return sum(map(len,chunks)) <= limit
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(['abc', 'def'], 5), False)", "check('fixture 2', solve(['abc', 'de'], 5), True)", "check('fixture 3', solve([], 0), True)", "check('fixture 4', solve(['abcd'], 3), 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`	`True`	Passed
fixture 3	`True`	`True`	Passed
fixture 4	`False`	`False`	Passed
fixture 1	`False`	`False`	Passed

SHA-256 / 73e0e095280d74d9154fedf5067af3f7e9d0557663dcd63c79ff7eb98de6a44b

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 2026-09-29T14:38:07.795535+00:00.

Case digest / f7780b96629e575cd8c46de9df98aa003779ff48e153e25a71d87119a6865fbb