FA-7456 / Multiplexed protocols / Open access

Http2 client initiated stream identifiers are positive odd · case 01

Http2 client initiated stream identifiers are positive odd.

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

ROOT CAUSE

The faulty implementation uses `stream % 2 == 1` for the http2-client-initiated-stream-identifiers-are-positive-odd decision.

VERIFIED REPAIR

Apply the explicit http2-client-initiated-stream-identifiers-are-positive-odd contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `stream > 0` and still violates a separate fixture.

Case contract

Bounded offline decision model: http2 client initiated stream identifiers are positive odd. 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 http2-client-initiated-stream-identifiers-are-positive-odd 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 % 2 == 1
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(1), True)", "check('fixture 2', solve(2), False)", "check('fixture 3', solve(0), False)", "check('fixture 4', solve(-1), 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	`False`	`False`	Passed
fixture 4	`True`	`False`	Failed
fixture 1	`True`	`True`	Passed

SHA-256 / 8ab748487e7549c755b334522f729f91a5620ca8a874fb35cefb00d8079bbb2b

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 > 0
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(1), True)", "check('fixture 2', solve(2), False)", "check('fixture 3', solve(0), False)", "check('fixture 4', solve(-1), 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	`False`	`False`	Passed
fixture 4	`False`	`False`	Passed
fixture 1	`True`	`True`	Passed

SHA-256 / 6f1d5397c93f7762489cbf4428fab6eb3bc17707eb5cda2059e221ca00eb281f

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 > 0 and stream % 2 == 1
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(1), True)", "check('fixture 2', solve(2), False)", "check('fixture 3', solve(0), False)", "check('fixture 4', solve(-1), 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	`False`	`False`	Passed
fixture 4	`False`	`False`	Passed
fixture 1	`True`	`True`	Passed

SHA-256 / 16cbb2de68e937d19d95064ed43aaa1ea1bc4aedeac03b04d95374e3261c6f5f

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 2026-09-29T14:38:12.268986+00:00.

Case digest / ae2b717c2b9a75fce986ba0c7030d633b36120960c771b5fbbf7044dfb8dd743