FA-7756 / Connection lifecycle / Open access

Happy eyeballs second family starts after delay unless first failed · case 01

Happy eyeballs second family starts after delay unless first failed.

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

ROOT CAUSE

The faulty implementation uses `elapsed > delay` for the happy-eyeballs-second-family-starts-after-delay-unless-first-failed decision.

VERIFIED REPAIR

Apply the explicit happy-eyeballs-second-family-starts-after-delay-unless-first-failed contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `failed and elapsed >= delay` and still violates a separate fixture.

Case contract

Bounded offline decision model: happy eyeballs second family starts after delay unless first failed. 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 happy-eyeballs-second-family-starts-after-delay-unless-first-failed 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(elapsed, delay, failed):
    return elapsed > delay
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(10, 10, False), True)", "check('fixture 2', solve(0, 10, True), True)", "check('fixture 3', solve(0, 10, False), False)", "check('fixture 4', solve(20, 10, False), 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	`False`	`False`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`False`	`True`	Failed

SHA-256 / c7b4fc809b92dec7567ec06a43ffd1285a1da17514d01163a9df968fc993daff

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(elapsed, delay, failed):
    return failed and elapsed >= delay
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(10, 10, False), True)", "check('fixture 2', solve(0, 10, True), True)", "check('fixture 3', solve(0, 10, False), False)", "check('fixture 4', solve(20, 10, False), 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	`False`	`False`	Passed
fixture 4	`False`	`True`	Failed
fixture 1	`False`	`True`	Failed

SHA-256 / a8d321e91d6c66a37273c6d13a616ae4f35fd2d6210d5be43d198a82ceb30e4f

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(elapsed, delay, failed):
    return failed or elapsed >= delay
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve(10, 10, False), True)", "check('fixture 2', solve(0, 10, True), True)", "check('fixture 3', solve(0, 10, False), False)", "check('fixture 4', solve(20, 10, False), 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	`False`	`False`	Passed
fixture 4	`True`	`True`	Passed
fixture 1	`True`	`True`	Passed

SHA-256 / fa065683eec5dc840edc3b1c87db320cd1f79c53bc6a09bfc24bcb43a6529e02

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 2026-09-29T14:38:14.933846+00:00.

Case digest / 6bb7d96d27bdaaa722e02f4acc96968a7259cebcea2a1a241318cc094edd29ff