FA-7551 / Multiplexed protocols / Open access
Quic stream count limit converts index to one based count · case 01
Quic stream count limit converts index to one based count.
ROOT CAUSE
The faulty implementation uses `stream//4` for the quic-stream-count-limit-converts-index-to-one-based-count decision.
VERIFIED REPAIR
Apply the explicit quic-stream-count-limit-converts-index-to-one-based-count contract, including the tested boundary and negative cases.
Unsuccessful approach: The attempted repair uses `stream+1` and still violates a separate fixture.
Case contract
Bounded offline decision model: quic stream count limit converts index to one based count. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.
Why this case matters
This deterministic multiplexed protocols model isolates the quic-stream-count-limit-converts-index-to-one-based-count 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(stream):
return stream//4
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(0), 1)", "check('fixture 2', solve(4), 2)", "check('fixture 3', solve(3), 1)", "check('fixture 4', solve(8), 3)"]
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 | 1 | 2 | Failed |
| fixture 3 | 0 | 1 | Failed |
| fixture 4 | 2 | 3 | Failed |
| fixture 1 | 0 | 1 | Failed |
SHA-256 / 9e4fc39da3ea1106550345834c8ff4843e85a9132bf2d766069fefffa5246706
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(stream):
return stream+1
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(0), 1)", "check('fixture 2', solve(4), 2)", "check('fixture 3', solve(3), 1)", "check('fixture 4', solve(8), 3)"]
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 | 5 | 2 | Failed |
| fixture 3 | 4 | 1 | Failed |
| fixture 4 | 9 | 3 | Failed |
| fixture 1 | 1 | 1 | Passed |
SHA-256 / f3979e5633187071c980432cc8c99077f0de15254ea4c5e93082498f34955eb9
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(stream):
return stream//4+1
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(0), 1)", "check('fixture 2', solve(4), 2)", "check('fixture 3', solve(3), 1)", "check('fixture 4', solve(8), 3)"]
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 | 2 | 2 | Passed |
| fixture 3 | 1 | 1 | Passed |
| fixture 4 | 3 | 3 | Passed |
| fixture 1 | 1 | 1 | Passed |
SHA-256 / e3a4a301656abf262dff5dc56ca9ec5142d1c66fec5d45a71c922cbbd875586c
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 2026-09-29T14:38:13.035150+00:00.
Case digest / 49538d06d37239829cf7eb8cf3d1f2fa619c1fcab3926d3d1cebd2582e607d78