FA-7761 / Connection lifecycle / Open access

Happy eyeballs winner cancels only other attempts · case 01

Happy eyeballs winner cancels only other attempts.

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

ROOT CAUSE

The faulty implementation uses `[a for a,state in attempts if a != winner]` for the happy-eyeballs-winner-cancels-only-other-attempts decision.

VERIFIED REPAIR

Apply the explicit happy-eyeballs-winner-cancels-only-other-attempts contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `[a for a,state in attempts if state == "pending"]` and still violates a separate fixture.

Case contract

Given attempts, winner, happy eyeballs winner cancels only other attempts. Return the protocol decision or transformed value; fields are validated and fixtures state boundary outcomes.

Why this case matters

This deterministic connection lifecycle model isolates the happy-eyeballs-winner-cancels-only-other-attempts 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(attempts, winner):
    return [a for a,state in attempts if a != winner]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve([('v6', 'pending'), ('v4', 'pending'), ('old', 'failed')], 'v4'), ['v6'])", "check('fixture 2', solve([], 'v4'), [])", "check('fixture 3', solve([('v4', 'pending')], 'v4'), [])", "check('fixture 4', solve([('v6', 'failed')], 'v4'), [])"]
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	`[]`	`[]`	Passed
fixture 3	`[]`	`[]`	Passed
fixture 4	`['v6']`	`[]`	Failed
fixture 1	`['v6', 'old']`	`['v6']`	Failed

SHA-256 / 9498e3a3c34b8a0f0a7e40a9edf2fbff2de46568fe82b5f297c0a5fdb7140291

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(attempts, winner):
    return [a for a,state in attempts if state == "pending"]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve([('v6', 'pending'), ('v4', 'pending'), ('old', 'failed')], 'v4'), ['v6'])", "check('fixture 2', solve([], 'v4'), [])", "check('fixture 3', solve([('v4', 'pending')], 'v4'), [])", "check('fixture 4', solve([('v6', 'failed')], 'v4'), [])"]
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	`[]`	`[]`	Passed
fixture 3	`['v4']`	`[]`	Failed
fixture 4	`[]`	`[]`	Passed
fixture 1	`['v6', 'v4']`	`['v6']`	Failed

SHA-256 / 7f30ba75b101d0d2a2269a894bafc47d4fdf662a7dd311ea1a53b1c986a9624c

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(attempts, winner):
    return [a for a,state in attempts if a != winner and state == "pending"]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve([('v6', 'pending'), ('v4', 'pending'), ('old', 'failed')], 'v4'), ['v6'])", "check('fixture 2', solve([], 'v4'), [])", "check('fixture 3', solve([('v4', 'pending')], 'v4'), [])", "check('fixture 4', solve([('v6', 'failed')], 'v4'), [])"]
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	`[]`	`[]`	Passed
fixture 3	`[]`	`[]`	Passed
fixture 4	`[]`	`[]`	Passed
fixture 1	`['v6']`	`['v6']`	Passed

SHA-256 / 9deefecf662595cbe2c1d8af82c05892043d1acfa1613d37bedbe16c7ade3e8b

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 2026-09-29T14:38:14.952534+00:00.

Case digest / 63cb36303293268e3e81f5fb899524a3772c6e7742b4cc9ee7ae16d484273550