FA-7511 / Multiplexed protocols / Open access

Http2 continuation must stay on the unfinished header stream · case 01

Http2 continuation must stay on the unfinished header stream.

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

ROOT CAUSE

The faulty implementation uses `pending is None or frame == "CONTINUATION"` for the http2-continuation-must-stay-on-the-unfinished-header-stream decision.

VERIFIED REPAIR

Apply the explicit http2-continuation-must-stay-on-the-unfinished-header-stream contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `pending is None or stream == pending` and still violates a separate fixture.

Case contract

Bounded offline decision model: http2 continuation must stay on the unfinished header stream. 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-continuation-must-stay-on-the-unfinished-header-stream 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(pending, stream, frame):
    return pending is None or frame == "CONTINUATION"
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(3, 5, 'CONTINUATION'), False)", "check('fixture 2', solve(3, 3, 'DATA'), False)", "check('fixture 3', solve(3, 3, 'CONTINUATION'), True)", "check('fixture 4', solve(None, 5, 'DATA'), 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`	`False`	Passed
fixture 3	`True`	`True`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`True`	`False`	Failed

SHA-256 / ed6993191f578ce3093e76638ab1ae6315f55dc5e3b2888a76da37ffb0ec48fd

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(pending, stream, frame):
    return pending is None or stream == pending
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(3, 5, 'CONTINUATION'), False)", "check('fixture 2', solve(3, 3, 'DATA'), False)", "check('fixture 3', solve(3, 3, 'CONTINUATION'), True)", "check('fixture 4', solve(None, 5, 'DATA'), 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`	`False`	Failed
fixture 3	`True`	`True`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`False`	`False`	Passed

SHA-256 / fc308ca42f17d3eafbe54c7c838e241490bdbb1b5006e011a98c9791a0f247eb

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(pending, stream, frame):
    return pending is None or (frame == "CONTINUATION" and stream == pending)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(3, 5, 'CONTINUATION'), False)", "check('fixture 2', solve(3, 3, 'DATA'), False)", "check('fixture 3', solve(3, 3, 'CONTINUATION'), True)", "check('fixture 4', solve(None, 5, 'DATA'), 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`	`False`	Passed
fixture 3	`True`	`True`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`False`	`False`	Passed

SHA-256 / cba738bd95d2461f209f782672fd1367c56aca469c557c8b3f6809cc04250840

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 2026-09-29T14:38:12.789615+00:00.

Case digest / aa1e0278d3c8a591247137d89158250f0a4e46655d3bb39cb7dda992fac3e310