FA-24746 / Client state / Open access

A pointer leaves a link but its speculative prefetch still starts · case 01

A pointer leaves a link but its speculative prefetch still starts.

Verified by executionVariant 1 · 6 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The faulty implementation violates Pointer dwell schedules per-link prefetch intent; leave cancels it, reentry restarts its clock, and each uninterrupted dwell starts at most once.

THE FAILURE

The faulty implementation violates Pointer dwell schedules per-link prefetch intent; leave cancels it, reentry restarts its clock, and each uninterrupted dwell starts at most once.

Unsuccessful approach: The partial repair still violates at least one explicit regression oracle.

Case contract

Pointer dwell schedules per-link prefetch intent; leave cancels it, reentry restarts its clock, and each uninterrupted dwell starts at most once.

Why this case matters

A bounded offline client-state transition with explicit lifecycle inputs.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(events, dwell):
    return list(dict.fromkeys(key for time,kind,key in events if kind=='enter'))
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('leave cancels', solve([(0,'enter','a'),(1,'leave','a'),(5,'tick','')],3), [])
check('dwell threshold', solve([(0,'enter','a'),(N,'tick','')],N), ['a'])
check('not yet due', solve([(0,'enter','a'),(1,'tick','')],2), [])
check('one launch', solve([(0,'enter','a'),(3,'tick',''),(5,'tick','')],2), ['a'])
check('reentry resets dwell', solve([(0,'enter','a'),(1,'leave','a'),(3,'enter','a'),(4,'tick','')],2), [])
check('independent links', solve([(0,'enter','a'),(1,'enter','b'),(2,'leave','a'),(3,'tick','')],2), ['b'])
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
leave cancels	`['a']`	`[]`	Failed
dwell threshold	`['a']`	`['a']`	Passed
not yet due	`['a']`	`[]`	Failed
one launch	`['a']`	`['a']`	Passed
reentry resets dwell	`['a']`	`[]`	Failed
independent links	`['a', 'b']`	`['b']`	Failed

SHA-256 / 9fc15b104e093845a2f4fc12455f0bccd9b386b99e4c3c2118997c52287d9bd0

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(events, dwell):
    active={}
    started=[]
    for time,kind,key in events:
        if kind=='enter': active[key]=time
        elif kind=='tick':
            for candidate,start in list(active.items()):
                if time-start>=dwell:
                    started.append(candidate); del active[candidate]
    return started
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('leave cancels', solve([(0,'enter','a'),(1,'leave','a'),(5,'tick','')],3), [])
check('dwell threshold', solve([(0,'enter','a'),(N,'tick','')],N), ['a'])
check('not yet due', solve([(0,'enter','a'),(1,'tick','')],2), [])
check('one launch', solve([(0,'enter','a'),(3,'tick',''),(5,'tick','')],2), ['a'])
check('reentry resets dwell', solve([(0,'enter','a'),(1,'leave','a'),(3,'enter','a'),(4,'tick','')],2), [])
check('independent links', solve([(0,'enter','a'),(1,'enter','b'),(2,'leave','a'),(3,'tick','')],2), ['b'])
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
leave cancels	`['a']`	`[]`	Failed
dwell threshold	`['a']`	`['a']`	Passed
not yet due	`[]`	`[]`	Passed
one launch	`['a']`	`['a']`	Passed
reentry resets dwell	`[]`	`[]`	Passed
independent links	`['a', 'b']`	`['b']`	Failed

SHA-256 / 6781537b8cb41fdead59702b7f766208c14469d2da18af2d089920f8344a46cc

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 6 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

Verification & scope

This models the stated application policy only; no browser or framework conformance is claimed. 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 2026-09-29T14:41:00.344618+00:00.

Case digest / 917e3aa19152a7e04251c5a61ab60d752bcd6027b4bb99461c78f7d1d32799cc