FA-7746 / Connection lifecycle / Open access

Half close keeps receive direction open · case 01

Half close keeps receive direction open.

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

ROOT CAUSE

The faulty implementation uses `(not write_closed,not write_closed)` for the half-close-keeps-receive-direction-open decision.

VERIFIED REPAIR

Apply the explicit half-close-keeps-receive-direction-open contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `(not read_closed,not read_closed)` and still violates a separate fixture.

Case contract

Bounded offline decision model: half close keeps receive direction open. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.

Why this case matters

This deterministic connection lifecycle model isolates the half-close-keeps-receive-direction-open 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(write_closed, read_closed):
    return (not write_closed,not write_closed)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(True, False), (True, False))", "check('fixture 2', solve(False, True), (False, True))", "check('fixture 3', solve(False, False), (True, True))", "check('fixture 4', solve(True, True), (False, 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]`	`[False, True]`	Failed
fixture 3	`[True, True]`	`[True, True]`	Passed
fixture 4	`[False, False]`	`[False, False]`	Passed
fixture 1	`[False, False]`	`[True, False]`	Failed

SHA-256 / 0d9604f3aa56684d0245ef2663d07621ec64a4003a6c801edc25b6cb6e71a7e3

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(write_closed, read_closed):
    return (not read_closed,not read_closed)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(True, False), (True, False))", "check('fixture 2', solve(False, True), (False, True))", "check('fixture 3', solve(False, False), (True, True))", "check('fixture 4', solve(True, True), (False, 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]`	`[False, True]`	Failed
fixture 3	`[True, True]`	`[True, True]`	Passed
fixture 4	`[False, False]`	`[False, False]`	Passed
fixture 1	`[True, True]`	`[True, False]`	Failed

SHA-256 / b048da8f2505ceda3d9125132038461bfc55e3a548181611e3eb32606ae40cd2

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(write_closed, read_closed):
    return (not read_closed,not write_closed)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(True, False), (True, False))", "check('fixture 2', solve(False, True), (False, True))", "check('fixture 3', solve(False, False), (True, True))", "check('fixture 4', solve(True, True), (False, 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]`	`[False, True]`	Passed
fixture 3	`[True, True]`	`[True, True]`	Passed
fixture 4	`[False, False]`	`[False, False]`	Passed
fixture 1	`[True, False]`	`[True, False]`	Passed

SHA-256 / 92ad52062aea1b7357cf285c5ae8d3428dd142fc885c092c78a2b53746828ba4

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 2026-09-29T14:38:14.863366+00:00.

Case digest / afbf6ee109e4d8e5606b3aeee1694ca3ac9e9d21ea3746f7585e25313f2a7922