FAILURE MAP
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FA-20391 / Assistive announcements / Open access

Replacement speech resumes at the prior cursor · case 01

The announcement trace violates the stated speech-cursor contract.

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

ROOT CAUSE

Fault site: words=list(e[1]); cursor=0; done=False is implemented as words=list(e[1]); cursor=min(cursor,len(words)); done=False

THE FAILURE

Fault site: words=list(e[1]); cursor=0; done=False is implemented as words=list(e[1]); cursor=min(cursor,len(words)); done=False

Unsuccessful approach: The attempted repair substitutes words=list(e[1]); cursor=1 if words else 0; done=False and still violates a regression oracle.

Case contract

Finite word arrays model announcements. Load copies words and resets cursor and completion. Speak advances one word only while unpaused. Seek clamps to [0,length]. Rewind moves one word. Cancel discards current words. Completion is logged exactly once when a speak reaches end, never for an empty load. Speed changes do not move word cursor. Return spoken words, completion count, cursor and paused flag.

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):
    words=[]; cursor=0; paused=False; done=False; spoken=[]; completions=0
    for e in events:
        if e[0]=='load':
            words=list(e[1]); cursor=min(cursor,len(words)); done=False
        elif e[0]=='pause': paused=True
        elif e[0]=='resume': paused=False
        elif e[0]=='seek': cursor=max(0,min(e[1],len(words)))
        elif e[0]=='rewind': cursor=max(0,cursor-1)
        elif e[0]=='cancel': words=[]; cursor=0; done=True
        elif e[0]=='speed': pass
        elif e[0]=='speak':
            if paused: continue
            if cursor<len(words):
                spoken.append(words[cursor]); cursor+=1
            if words and cursor==len(words) and not done:
                completions+=1; done=True
    return [spoken,completions,cursor,paused]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = ["[['load',['word']*(N+3)],['speak'],['speak'],['rewind'],['speed',2],['speak'],['pause'],['speak'],['resume'],['speak']]", "[['load',['x']*(N+1)],['pause'],['speak'],['resume'],['speak'],['load',['a','b']],['speak']]", "[['load',['x']*N]]+[['speak']]*(N+2)+[['load',['y']],['speak'],['speak']]", "[['load',['x']*(N+2)],['speak'],['speak'],['cancel'],['speak']]", "[['load',['x']*N],['seek',N+5],['speak'],['seek',-2]]", "[['load',[]],['speak'],['cancel']]", "[['load',['x']*(N+4)],['seek',3],['rewind']]"]
expected = {1: [[['word', 'word', 'word', 'word'], 0, 3, False], [['x', 'a'], 0, 1, False], [['x', 'y'], 2, 1, False], [['x', 'x'], 0, 0, False], [[], 1, 0, False], [[], 0, 0, False], [[], 0, 2, False]], 2: [[['word', 'word', 'word', 'word'], 0, 3, False], [['x', 'a'], 0, 1, False], [['x', 'x', 'y'], 2, 1, False], [['x', 'x'], 0, 0, False], [[], 1, 0, False], [[], 0, 0, False], [[], 0, 2, False]], 3: [[['word', 'word', 'word', 'word'], 0, 3, False], [['x', 'a'], 0, 1, False], [['x', 'x', 'x', 'y'], 2, 1, False], [['x', 'x'], 0, 0, False], [[], 1, 0, False], [[], 0, 0, False], [[], 0, 2, False]], 4: [[['word', 'word', 'word', 'word'], 0, 3, False], [['x', 'a'], 0, 1, False], [['x', 'x', 'x', 'x', 'y'], 2, 1, False], [['x', 'x'], 0, 0, False], [[], 1, 0, False], [[], 0, 0, False], [[], 0, 2, False]], 5: [[['word', 'word', 'word', 'word'], 0, 3, False], [['x', 'a'], 0, 1, False], [['x', 'x', 'x', 'x', 'x', 'y'], 2, 1, False], [['x', 'x'], 0, 0, False], [[], 1, 0, False], [[], 0, 0, False], [[], 0, 2, False]]}[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[['word', 'word', 'word', 'word'], 0, 3, False][['word', 'word', 'word', 'word'], 0, 3, False]Passed
trace-2[['x', 'b'], 1, 2, False][['x', 'a'], 0, 1, False]Failed
trace-3[['x'], 2, 1, False][['x', 'y'], 2, 1, False]Failed
trace-4[['x', 'x'], 0, 0, False][['x', 'x'], 0, 0, False]Passed
trace-5[[], 1, 0, False][[], 1, 0, False]Passed
trace-6[[], 0, 0, False][[], 0, 0, False]Passed
trace-7[[], 0, 2, False][[], 0, 2, False]Passed

SHA-256 / e7fec2996402f84b4f73f6f16258fc70a18ef88c9d0f459a3edcd1feba9857f2

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(events):
    words=[]; cursor=0; paused=False; done=False; spoken=[]; completions=0
    for e in events:
        if e[0]=='load':
            words=list(e[1]); cursor=1 if words else 0; done=False
        elif e[0]=='pause': paused=True
        elif e[0]=='resume': paused=False
        elif e[0]=='seek': cursor=max(0,min(e[1],len(words)))
        elif e[0]=='rewind': cursor=max(0,cursor-1)
        elif e[0]=='cancel': words=[]; cursor=0; done=True
        elif e[0]=='speed': pass
        elif e[0]=='speak':
            if paused: continue
            if cursor<len(words):
                spoken.append(words[cursor]); cursor+=1
            if words and cursor==len(words) and not done:
                completions+=1; done=True
    return [spoken,completions,cursor,paused]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = ["[['load',['word']*(N+3)],['speak'],['speak'],['rewind'],['speed',2],['speak'],['pause'],['speak'],['resume'],['speak']]", "[['load',['x']*(N+1)],['pause'],['speak'],['resume'],['speak'],['load',['a','b']],['speak']]", "[['load',['x']*N]]+[['speak']]*(N+2)+[['load',['y']],['speak'],['speak']]", "[['load',['x']*(N+2)],['speak'],['speak'],['cancel'],['speak']]", "[['load',['x']*N],['seek',N+5],['speak'],['seek',-2]]", "[['load',[]],['speak'],['cancel']]", "[['load',['x']*(N+4)],['seek',3],['rewind']]"]
expected = {1: [[['word', 'word', 'word', 'word'], 0, 3, False], [['x', 'a'], 0, 1, False], [['x', 'y'], 2, 1, False], [['x', 'x'], 0, 0, False], [[], 1, 0, False], [[], 0, 0, False], [[], 0, 2, False]], 2: [[['word', 'word', 'word', 'word'], 0, 3, False], [['x', 'a'], 0, 1, False], [['x', 'x', 'y'], 2, 1, False], [['x', 'x'], 0, 0, False], [[], 1, 0, False], [[], 0, 0, False], [[], 0, 2, False]], 3: [[['word', 'word', 'word', 'word'], 0, 3, False], [['x', 'a'], 0, 1, False], [['x', 'x', 'x', 'y'], 2, 1, False], [['x', 'x'], 0, 0, False], [[], 1, 0, False], [[], 0, 0, False], [[], 0, 2, False]], 4: [[['word', 'word', 'word', 'word'], 0, 3, False], [['x', 'a'], 0, 1, False], [['x', 'x', 'x', 'x', 'y'], 2, 1, False], [['x', 'x'], 0, 0, False], [[], 1, 0, False], [[], 0, 0, False], [[], 0, 2, False]], 5: [[['word', 'word', 'word', 'word'], 0, 3, False], [['x', 'a'], 0, 1, False], [['x', 'x', 'x', 'x', 'x', 'y'], 2, 1, False], [['x', 'x'], 0, 0, False], [[], 1, 0, False], [[], 0, 0, False], [[], 0, 2, False]]}[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[['word', 'word', 'word', 'word'], 1, 4, False][['word', 'word', 'word', 'word'], 0, 3, False]Failed
trace-2[['x', 'b'], 2, 2, False][['x', 'a'], 0, 1, False]Failed
trace-3[[], 2, 1, False][['x', 'y'], 2, 1, False]Failed
trace-4[['x', 'x'], 1, 0, False][['x', 'x'], 0, 0, False]Failed
trace-5[[], 1, 0, False][[], 1, 0, False]Passed
trace-6[[], 0, 0, False][[], 0, 0, False]Passed
trace-7[[], 0, 2, False][[], 0, 2, False]Passed

SHA-256 / 843631dd810f4610d188884006ebbeb033e56052b6a723a45bd0e9c8ac595d19

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 2026-09-29T14:40:18.894621+00:00.

Case digest / ca75f6ad62a74a42879e7a1fa0776e1dd53de35b3843978066805ab1efa6c572