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FA-21536 / Assistive announcements / Open access

Removing active device leaves route pointing to disconnected output · case 01

The announcement trace violates the stated device-handoff contract.

Verified by executionVariant 1 · 7 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Fault site: if current==e[1]: current='local' is implemented as if current==e[1]: pass

THE FAILURE

Fault site: if current==e[1]: current='local' is implemented as if current==e[1]: pass

Unsuccessful approach: The attempted repair substitutes current='local' and still violates a regression oracle.

Case contract

Output routes start at local device. Queue snapshots requested route and utterance text. Begin-handoff sets a target while retaining current route. Commit switches current route and migrates only pending items on old route; cancel-handoff leaves queue unchanged. Device removal drops queued output to that device and chooses local if current removed. Send requires route available and sends one queued item; unavailable items remain. Add makes device available. Return [device,text] output and pending routes.

Why this case matters

Deterministic controlled model of assistive announcement delivery.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(events):
    current='local'; target=None; devices={'local'}; q=[]; out=[]
    for e in events:
        if e[0]=='add': devices.add(e[1])
        elif e[0]=='queue': q.append([current,e[1]])
        elif e[0]=='begin': target=e[1]
        elif e[0]=='cancel': target=None
        elif e[0]=='commit' and target in devices:
            old=current; current=target
            q=[[current if route==old else route,text] for route,text in q]
            target=None
        elif e[0]=='remove':
            devices.discard(e[1])
            q=[x for x in q if x[0]!=e[1]]
            if current==e[1]: pass
        elif e[0]=='send' and q:
            index=next((i for i,x in enumerate(q) if x[0] in devices),None)
            if index is not None: out.append(q.pop(index))
    return [out,q,current,target,sorted(devices)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = ["[['add','Headset'],['queue','hello'*N],['begin','Headset'],['queue','before'],['commit'],['queue','after'],['send']]", "[['queue','keep'*N],['begin','missing'],['commit']]", "[['queue','keep'*N],['begin','remote'],['queue','during'*N],['cancel'],['send']]", "[['add','head'],['begin','head'],['commit'],['queue','remote'*N],['remove','head']]", "[['add','head'],['begin','head'],['commit'],['queue','keep'*N],['remove','unused']]", "[['add','remote'],['queue','local'*N],['remove','remote'],['send']]", '[]']
expected = {1: [[[['Headset', 'hello']], [['Headset', 'before'], ['Headset', 'after']], 'Headset', None, ['Headset', 'local']], [[], [['local', 'keep']], 'local', 'missing', ['local']], [[['local', 'keep']], [['local', 'during']], 'local', None, ['local']], [[], [], 'local', None, ['local']], [[], [['head', 'keep']], 'head', None, ['head', 'local']], [[['local', 'local']], [], 'local', None, ['local']], [[], [], 'local', None, ['local']]], 2: [[[['Headset', 'hellohello']], [['Headset', 'before'], ['Headset', 'after']], 'Headset', None, ['Headset', 'local']], [[], [['local', 'keepkeep']], 'local', 'missing', ['local']], [[['local', 'keepkeep']], [['local', 'duringduring']], 'local', None, ['local']], [[], [], 'local', None, ['local']], [[], [['head', 'keepkeep']], 'head', None, ['head', 'local']], [[['local', 'locallocal']], [], 'local', None, ['local']], [[], [], 'local', None, ['local']]], 3: [[[['Headset', 'hellohellohello']], [['Headset', 'before'], ['Headset', 'after']], 'Headset', None, ['Headset', 'local']], [[], [['local', 'keepkeepkeep']], 'local', 'missing', ['local']], [[['local', 'keepkeepkeep']], [['local', 'duringduringduring']], 'local', None, ['local']], [[], [], 'local', None, ['local']], [[], [['head', 'keepkeepkeep']], 'head', None, ['head', 'local']], [[['local', 'locallocallocal']], [], 'local', None, ['local']], [[], [], 'local', None, ['local']]], 4: [[[['Headset', 'hellohellohellohello']], [['Headset', 'before'], ['Headset', 'after']], 'Headset', None, ['Headset', 'local']], [[], [['local', 'keepkeepkeepkeep']], 'local', 'missing', ['local']], [[['local', 'keepkeepkeepkeep']], [['local', 'duringduringduringduring']], 'local', None, ['local']], [[], [], 'local', None, ['local']], [[], [['head', 'keepkeepkeepkeep']], 'head', None, ['head', 'local']], [[['local', 'locallocallocallocal']], [], 'local', None, ['local']], [[], [], 'local', None, ['local']]], 5: [[[['Headset', 'hellohellohellohellohello']], [['Headset', 'before'], ['Headset', 'after']], 'Headset', None, ['Headset', 'local']], [[], [['local', 'keepkeepkeepkeepkeep']], 'local', 'missing', ['local']], [[['local', 'keepkeepkeepkeepkeep']], [['local', 'duringduringduringduringduring']], 'local', None, ['local']], [[], [], 'local', None, ['local']], [[], [['head', 'keepkeepkeepkeepkeep']], 'head', None, ['head', 'local']], [[['local', 'locallocallocallocallocal']], [], 'local', None, ['local']], [[], [], 'local', None, ['local']]]}[N]
for i, expression in enumerate(fixtures):
    check("trace-"+str(i+1), solve(eval(expression)), expected[i])
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 fixtureActualExpectedOutcome
trace-1[[['Headset', 'hello']], [['Headset', 'before'], ['Headset', 'after']], 'Headset', None, ['Headset', 'local']][[['Headset', 'hello']], [['Headset', 'before'], ['Headset', 'after']], 'Headset', None, ['Headset', 'local']]Passed
trace-2[[], [['local', 'keep']], 'local', 'missing', ['local']][[], [['local', 'keep']], 'local', 'missing', ['local']]Passed
trace-3[[['local', 'keep']], [['local', 'during']], 'local', None, ['local']][[['local', 'keep']], [['local', 'during']], 'local', None, ['local']]Passed
trace-4[[], [], 'head', None, ['local']][[], [], 'local', None, ['local']]Failed
trace-5[[], [['head', 'keep']], 'head', None, ['head', 'local']][[], [['head', 'keep']], 'head', None, ['head', 'local']]Passed
trace-6[[['local', 'local']], [], 'local', None, ['local']][[['local', 'local']], [], 'local', None, ['local']]Passed
trace-7[[], [], 'local', None, ['local']][[], [], 'local', None, ['local']]Passed

SHA-256 / d43d66e13dc4658f9e486defc146ea528cd36677e076846d3b3b6985ed980da9

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(events):
    current='local'; target=None; devices={'local'}; q=[]; out=[]
    for e in events:
        if e[0]=='add': devices.add(e[1])
        elif e[0]=='queue': q.append([current,e[1]])
        elif e[0]=='begin': target=e[1]
        elif e[0]=='cancel': target=None
        elif e[0]=='commit' and target in devices:
            old=current; current=target
            q=[[current if route==old else route,text] for route,text in q]
            target=None
        elif e[0]=='remove':
            devices.discard(e[1])
            q=[x for x in q if x[0]!=e[1]]
            current='local'
        elif e[0]=='send' and q:
            index=next((i for i,x in enumerate(q) if x[0] in devices),None)
            if index is not None: out.append(q.pop(index))
    return [out,q,current,target,sorted(devices)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = ["[['add','Headset'],['queue','hello'*N],['begin','Headset'],['queue','before'],['commit'],['queue','after'],['send']]", "[['queue','keep'*N],['begin','missing'],['commit']]", "[['queue','keep'*N],['begin','remote'],['queue','during'*N],['cancel'],['send']]", "[['add','head'],['begin','head'],['commit'],['queue','remote'*N],['remove','head']]", "[['add','head'],['begin','head'],['commit'],['queue','keep'*N],['remove','unused']]", "[['add','remote'],['queue','local'*N],['remove','remote'],['send']]", '[]']
expected = {1: [[[['Headset', 'hello']], [['Headset', 'before'], ['Headset', 'after']], 'Headset', None, ['Headset', 'local']], [[], [['local', 'keep']], 'local', 'missing', ['local']], [[['local', 'keep']], [['local', 'during']], 'local', None, ['local']], [[], [], 'local', None, ['local']], [[], [['head', 'keep']], 'head', None, ['head', 'local']], [[['local', 'local']], [], 'local', None, ['local']], [[], [], 'local', None, ['local']]], 2: [[[['Headset', 'hellohello']], [['Headset', 'before'], ['Headset', 'after']], 'Headset', None, ['Headset', 'local']], [[], [['local', 'keepkeep']], 'local', 'missing', ['local']], [[['local', 'keepkeep']], [['local', 'duringduring']], 'local', None, ['local']], [[], [], 'local', None, ['local']], [[], [['head', 'keepkeep']], 'head', None, ['head', 'local']], [[['local', 'locallocal']], [], 'local', None, ['local']], [[], [], 'local', None, ['local']]], 3: [[[['Headset', 'hellohellohello']], [['Headset', 'before'], ['Headset', 'after']], 'Headset', None, ['Headset', 'local']], [[], [['local', 'keepkeepkeep']], 'local', 'missing', ['local']], [[['local', 'keepkeepkeep']], [['local', 'duringduringduring']], 'local', None, ['local']], [[], [], 'local', None, ['local']], [[], [['head', 'keepkeepkeep']], 'head', None, ['head', 'local']], [[['local', 'locallocallocal']], [], 'local', None, ['local']], [[], [], 'local', None, ['local']]], 4: [[[['Headset', 'hellohellohellohello']], [['Headset', 'before'], ['Headset', 'after']], 'Headset', None, ['Headset', 'local']], [[], [['local', 'keepkeepkeepkeep']], 'local', 'missing', ['local']], [[['local', 'keepkeepkeepkeep']], [['local', 'duringduringduringduring']], 'local', None, ['local']], [[], [], 'local', None, ['local']], [[], [['head', 'keepkeepkeepkeep']], 'head', None, ['head', 'local']], [[['local', 'locallocallocallocal']], [], 'local', None, ['local']], [[], [], 'local', None, ['local']]], 5: [[[['Headset', 'hellohellohellohellohello']], [['Headset', 'before'], ['Headset', 'after']], 'Headset', None, ['Headset', 'local']], [[], [['local', 'keepkeepkeepkeepkeep']], 'local', 'missing', ['local']], [[['local', 'keepkeepkeepkeepkeep']], [['local', 'duringduringduringduringduring']], 'local', None, ['local']], [[], [], 'local', None, ['local']], [[], [['head', 'keepkeepkeepkeepkeep']], 'head', None, ['head', 'local']], [[['local', 'locallocallocallocallocal']], [], 'local', None, ['local']], [[], [], 'local', None, ['local']]]}[N]
for i, expression in enumerate(fixtures):
    check("trace-"+str(i+1), solve(eval(expression)), expected[i])
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 fixtureActualExpectedOutcome
trace-1[[['Headset', 'hello']], [['Headset', 'before'], ['Headset', 'after']], 'Headset', None, ['Headset', 'local']][[['Headset', 'hello']], [['Headset', 'before'], ['Headset', 'after']], 'Headset', None, ['Headset', 'local']]Passed
trace-2[[], [['local', 'keep']], 'local', 'missing', ['local']][[], [['local', 'keep']], 'local', 'missing', ['local']]Passed
trace-3[[['local', 'keep']], [['local', 'during']], 'local', None, ['local']][[['local', 'keep']], [['local', 'during']], 'local', None, ['local']]Passed
trace-4[[], [], 'local', None, ['local']][[], [], 'local', None, ['local']]Passed
trace-5[[], [['head', 'keep']], 'local', None, ['head', 'local']][[], [['head', 'keep']], 'head', None, ['head', 'local']]Failed
trace-6[[['local', 'local']], [], 'local', None, ['local']][[['local', 'local']], [], 'local', None, ['local']]Passed
trace-7[[], [], 'local', None, ['local']][[], [], 'local', None, ['local']]Passed

SHA-256 / a139b30c94344b71cf58763d71d7451ada9c9112da5d9ddb6a56bb82faaf2ccd

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 7 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.

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Verification & scope

Stipulated bounded policy, not a browser, speech engine, platform API, or standards conformance claim. 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 2026-09-29T14:40:29.759300+00:00.

Case digest / 6d99e344aa67d2a2893eae42028cc37c4ffa892fde2d2e9f8bd4ed97f0f86475