FA-7516 / Multiplexed protocols / Open access

Http2 pseudoheaders must precede regular fields · case 01

Http2 pseudoheaders must precede regular fields.

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

ROOT CAUSE

The faulty implementation uses `True` for the http2-pseudoheaders-must-precede-regular-fields decision.

VERIFIED REPAIR

Apply the explicit http2-pseudoheaders-must-precede-regular-fields contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `all(n.startswith(":") for n in names)` and still violates a separate fixture.

Case contract

Bounded offline decision model: http2 pseudoheaders must precede regular fields. 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-pseudoheaders-must-precede-regular-fields 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(names):
    return True
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(['x', ':path']), False)", "check('fixture 2', solve([':path', 'x']), True)", "check('fixture 3', solve([]), True)", "check('fixture 4', solve(['x']), 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	`True`	`True`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`True`	`False`	Failed

SHA-256 / f3b9f3c011f50eefa60759d274c950a4155db3e0ef6bf7e7b0408330f1525f0c

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(names):
    return all(n.startswith(":") for n in names)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(['x', ':path']), False)", "check('fixture 2', solve([':path', 'x']), True)", "check('fixture 3', solve([]), True)", "check('fixture 4', solve(['x']), 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	`True`	`True`	Passed
fixture 4	`False`	`True`	Failed
fixture 1	`False`	`False`	Passed

SHA-256 / 4a6ffc9bc06c94e8473a6ca1cf9f2aea10b80700a582cec7bc45a4430813ce60

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(names):
    return not any(name.startswith(":") and any(not prior.startswith(":") for prior in names[:i]) for i,name in enumerate(names))
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(['x', ':path']), False)", "check('fixture 2', solve([':path', 'x']), True)", "check('fixture 3', solve([]), True)", "check('fixture 4', solve(['x']), 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	`True`	`True`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`False`	`False`	Passed

SHA-256 / 5f89537b3666d9e4838da2080fdbf8d9f23f958a03ea702fa3c6fb7db86ec8ec

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 2026-09-29T14:38:12.886816+00:00.

Case digest / 6af3bba29d16b686abf8c4cdd429db67624b40719195fe4d12827a4a7b48261a