FA-24726 / Client state / Open access

A committed transition leaves its dependent render lanes pending · case 01

A committed transition leaves its dependent render lanes pending.

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

ROOT CAUSE

The faulty implementation violates Committing any render lane commits the undirected transitive closure of its entangled lanes; unrelated pending lanes retain order.

VERIFIED REPAIR

Committing any render lane commits the undirected transitive closure of its entangled lanes; unrelated pending lanes retain order.

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

Case contract

Committing any render lane commits the undirected transitive closure of its entangled lanes; unrelated pending lanes retain order.

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(pending, links, committed):
    return [x for x in pending if x not in committed]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('chain closure', solve(list(range(N+3)),[(i,i+1) for i in range(N+1)],[0]), [N+2])
check('reverse dependency', solve(['a','b','c'],[('a','b')],['b']), ['c'])
check('cycle', solve(['a','b','c'],[('a','b'),('b','a')],['a']), ['c'])
check('unrelated lane', solve(['a','b'],[],['a']), ['b'])
check('no commit', solve(['a','b'],[('a','b')],[]), ['a','b'])
check('already absent', solve(['c'],[('a','b')],['a']), ['c'])
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
chain closure	`[1, 2, 3]`	`[3]`	Failed
reverse dependency	`['a', 'c']`	`['c']`	Failed
cycle	`['b', 'c']`	`['c']`	Failed
unrelated lane	`['b']`	`['b']`	Passed
no commit	`['a', 'b']`	`['a', 'b']`	Passed
already absent	`['c']`	`['c']`	Passed

SHA-256 / 899eba72caf65afd63ad6c5f625edcee9d3b8b872bae755a24c628b905e74182

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(pending, links, committed):
    done=set(committed)|{b for a,b in links if a in committed}
    return [x for x in pending if x not in done]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('chain closure', solve(list(range(N+3)),[(i,i+1) for i in range(N+1)],[0]), [N+2])
check('reverse dependency', solve(['a','b','c'],[('a','b')],['b']), ['c'])
check('cycle', solve(['a','b','c'],[('a','b'),('b','a')],['a']), ['c'])
check('unrelated lane', solve(['a','b'],[],['a']), ['b'])
check('no commit', solve(['a','b'],[('a','b')],[]), ['a','b'])
check('already absent', solve(['c'],[('a','b')],['a']), ['c'])
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
chain closure	`[2, 3]`	`[3]`	Failed
reverse dependency	`['a', 'c']`	`['c']`	Failed
cycle	`['c']`	`['c']`	Passed
unrelated lane	`['b']`	`['b']`	Passed
no commit	`['a', 'b']`	`['a', 'b']`	Passed
already absent	`['c']`	`['c']`	Passed

SHA-256 / bd80b33e13f4c22aa6b29651356a758ceed29761c0539d5e4d7ecd69ffa82f40

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(pending, links, committed):
    done=set(committed)
    while True:
        expanded=done|{b for a,b in links if a in done}|{a for a,b in links if b in done}
        if expanded==done: break
        done=expanded
    return [x for x in pending if x not in done]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('chain closure', solve(list(range(N+3)),[(i,i+1) for i in range(N+1)],[0]), [N+2])
check('reverse dependency', solve(['a','b','c'],[('a','b')],['b']), ['c'])
check('cycle', solve(['a','b','c'],[('a','b'),('b','a')],['a']), ['c'])
check('unrelated lane', solve(['a','b'],[],['a']), ['b'])
check('no commit', solve(['a','b'],[('a','b')],[]), ['a','b'])
check('already absent', solve(['c'],[('a','b')],['a']), ['c'])
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
chain closure	`[3]`	`[3]`	Passed
reverse dependency	`['c']`	`['c']`	Passed
cycle	`['c']`	`['c']`	Passed
unrelated lane	`['b']`	`['b']`	Passed
no commit	`['a', 'b']`	`['a', 'b']`	Passed
already absent	`['c']`	`['c']`	Passed

SHA-256 / 16fece9420a9f4fdf28bb4c5a634c3145dea6cb586e801579917276ea1c86d45

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 2026-09-29T14:41:00.075243+00:00.

Case digest / 019550b2fd1e2a0a3c2232d58c086d4839cc05375301c7edd8fd17f6bed2ea2b