FA-21431 / Assistive announcements / Open access
Reversed replacement endpoints are not normalized · case 01
The announcement trace violates the stated edit-narration contract.
ROOT CAUSE
Fault site: a,b=sorted([max(0,min(len(text),e[1])),max(0,min(len(text),e[2]))]) is implemented as a,b=[max(0,min(len(text),e[1])),max(0,min(len(text),e[2]))]
VERIFIED REPAIR
Restore the stated transition: a,b=sorted([max(0,min(len(text),e[1])),max(0,min(len(text),e[2]))])
Unsuccessful approach: The attempted repair substitutes a,b=0,len(text) and still violates a regression oracle.
Case contract
Document announcement state stores text and a cursor. Insert inserts at clamped cursor and announces inserted span. Backspace removes up to count before cursor and announces removed span in original order. Delete removes after cursor without moving it. Move clamps cursor. Replace range uses sorted clamped endpoints, announces old/new, moves cursor to replacement end. Undo restores text and cursor from last mutating edit and announces restored text. Silent toggles suppress cues but not state or undo. Return cues,text,cursor.
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):
text=''; cursor=0; history=[]; silent=False; out=[]
for e in events:
op=e[0]
if op=='move': cursor=max(0,min(len(text),e[1]))
elif op=='silent': silent=e[1]
elif op=='undo' and history:
text,cursor=history.pop()
if not silent: out.append(['undo',text])
elif op in ('insert','backspace','delete','replace'):
history.append([text,cursor])
if op=='insert':
text=text[:cursor]+e[1]+text[cursor:]; cursor+=len(e[1]); cue=['insert',e[1]]
elif op=='backspace':
start=max(0,cursor-e[1]); cue=['remove',text[start:cursor]]
text=text[:start]+text[cursor:]; cursor=start
elif op=='delete':
end=min(len(text),cursor+e[1]); cue=['remove',text[cursor:end]]
text=text[:cursor]+text[end:]
else:
a,b=[max(0,min(len(text),e[1])),max(0,min(len(text),e[2]))]
cue=['replace',text[a:b],e[3]]; text=text[:a]+e[3]+text[b:]; cursor=a+len(e[3])
if not silent: out.append(cue)
return [out,text,cursor]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = ["[['insert','abcd'*N],['move',2],['insert','XY'],['backspace',2],['undo'],['undo']]", "[['insert','abcdef'*N],['move',4],['backspace',2]]", "[['insert','abcdef'*N],['move',2],['delete',2]]", "[['insert','abcdef'*N],['replace',5,2,'Z']]", "[['insert','abcdef'*N],['replace',5,2,'Z'],['undo']]", "[['silent',True],['insert','secret'*N],['silent',False],['move',99],['insert','!']]", "[['insert','x'*N],['move',-5],['backspace',4],['delete',99],['undo']]", '[]']
expected = {1: [[[['insert', 'abcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcd'], ['undo', 'abcd']], 'abcd', 2], [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2], [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2], [[['insert', 'abcdef'], ['replace', 'cde', 'Z']], 'abZf', 3], [[['insert', 'abcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdef']], 'abcdef', 6], [[['insert', '!']], 'secret!', 7], [[['insert', 'x'], ['remove', ''], ['remove', 'x'], ['undo', 'x']], 'x', 0], [[], '', 0]], 2: [[[['insert', 'abcdabcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcdabcd'], ['undo', 'abcdabcd']], 'abcdabcd', 2], [[['insert', 'abcdefabcdef'], ['remove', 'cd']], 'abefabcdef', 2], [[['insert', 'abcdefabcdef'], ['remove', 'cd']], 'abefabcdef', 2], [[['insert', 'abcdefabcdef'], ['replace', 'cde', 'Z']], 'abZfabcdef', 3], [[['insert', 'abcdefabcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdefabcdef']], 'abcdefabcdef', 12], [[['insert', '!']], 'secretsecret!', 13], [[['insert', 'xx'], ['remove', ''], ['remove', 'xx'], ['undo', 'xx']], 'xx', 0], [[], '', 0]], 3: [[[['insert', 'abcdabcdabcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcdabcdabcd'], ['undo', 'abcdabcdabcd']], 'abcdabcdabcd', 2], [[['insert', 'abcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdef'], ['replace', 'cde', 'Z']], 'abZfabcdefabcdef', 3], [[['insert', 'abcdefabcdefabcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdefabcdefabcdef']], 'abcdefabcdefabcdef', 18], [[['insert', '!']], 'secretsecretsecret!', 19], [[['insert', 'xxx'], ['remove', ''], ['remove', 'xxx'], ['undo', 'xxx']], 'xxx', 0], [[], '', 0]], 4: [[[['insert', 'abcdabcdabcdabcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcdabcdabcdabcd'], ['undo', 'abcdabcdabcdabcd']], 'abcdabcdabcdabcd', 2], [[['insert', 'abcdefabcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdefabcdef'], ['replace', 'cde', 'Z']], 'abZfabcdefabcdefabcdef', 3], [[['insert', 'abcdefabcdefabcdefabcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdefabcdefabcdefabcdef']], 'abcdefabcdefabcdefabcdef', 24], [[['insert', '!']], 'secretsecretsecretsecret!', 25], [[['insert', 'xxxx'], ['remove', ''], ['remove', 'xxxx'], ['undo', 'xxxx']], 'xxxx', 0], [[], '', 0]], 5: [[[['insert', 'abcdabcdabcdabcdabcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcdabcdabcdabcdabcd'], ['undo', 'abcdabcdabcdabcdabcd']], 'abcdabcdabcdabcdabcd', 2], [[['insert', 'abcdefabcdefabcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdefabcdefabcdef'], ['replace', 'cde', 'Z']], 'abZfabcdefabcdefabcdefabcdef', 3], [[['insert', 'abcdefabcdefabcdefabcdefabcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdefabcdefabcdefabcdefabcdef']], 'abcdefabcdefabcdefabcdefabcdef', 30], [[['insert', '!']], 'secretsecretsecretsecretsecret!', 31], [[['insert', 'xxxxx'], ['remove', ''], ['remove', 'xxxxx'], ['undo', 'xxxxx']], 'xxxxx', 0], [[], '', 0]]}[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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| trace-1 | [[['insert', 'abcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcd'], ['undo', 'abcd']], 'abcd', 2] | [[['insert', 'abcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcd'], ['undo', 'abcd']], 'abcd', 2] | Passed |
| trace-2 | [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2] | [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2] | Passed |
| trace-3 | [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2] | [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2] | Passed |
| trace-4 | [[['insert', 'abcdef'], ['replace', '', 'Z']], 'abcdeZcdef', 6] | [[['insert', 'abcdef'], ['replace', 'cde', 'Z']], 'abZf', 3] | Failed |
| trace-5 | [[['insert', 'abcdef'], ['replace', '', 'Z'], ['undo', 'abcdef']], 'abcdef', 6] | [[['insert', 'abcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdef']], 'abcdef', 6] | Failed |
| trace-6 | [[['insert', '!']], 'secret!', 7] | [[['insert', '!']], 'secret!', 7] | Passed |
| trace-7 | [[['insert', 'x'], ['remove', ''], ['remove', 'x'], ['undo', 'x']], 'x', 0] | [[['insert', 'x'], ['remove', ''], ['remove', 'x'], ['undo', 'x']], 'x', 0] | Passed |
| trace-8 | [[], '', 0] | [[], '', 0] | Passed |
SHA-256 / 72dc60537abf31195ad5f0c06d9a2395c86b79615b935e0c46c296f161dab80d
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(events):
text=''; cursor=0; history=[]; silent=False; out=[]
for e in events:
op=e[0]
if op=='move': cursor=max(0,min(len(text),e[1]))
elif op=='silent': silent=e[1]
elif op=='undo' and history:
text,cursor=history.pop()
if not silent: out.append(['undo',text])
elif op in ('insert','backspace','delete','replace'):
history.append([text,cursor])
if op=='insert':
text=text[:cursor]+e[1]+text[cursor:]; cursor+=len(e[1]); cue=['insert',e[1]]
elif op=='backspace':
start=max(0,cursor-e[1]); cue=['remove',text[start:cursor]]
text=text[:start]+text[cursor:]; cursor=start
elif op=='delete':
end=min(len(text),cursor+e[1]); cue=['remove',text[cursor:end]]
text=text[:cursor]+text[end:]
else:
a,b=0,len(text)
cue=['replace',text[a:b],e[3]]; text=text[:a]+e[3]+text[b:]; cursor=a+len(e[3])
if not silent: out.append(cue)
return [out,text,cursor]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = ["[['insert','abcd'*N],['move',2],['insert','XY'],['backspace',2],['undo'],['undo']]", "[['insert','abcdef'*N],['move',4],['backspace',2]]", "[['insert','abcdef'*N],['move',2],['delete',2]]", "[['insert','abcdef'*N],['replace',5,2,'Z']]", "[['insert','abcdef'*N],['replace',5,2,'Z'],['undo']]", "[['silent',True],['insert','secret'*N],['silent',False],['move',99],['insert','!']]", "[['insert','x'*N],['move',-5],['backspace',4],['delete',99],['undo']]", '[]']
expected = {1: [[[['insert', 'abcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcd'], ['undo', 'abcd']], 'abcd', 2], [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2], [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2], [[['insert', 'abcdef'], ['replace', 'cde', 'Z']], 'abZf', 3], [[['insert', 'abcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdef']], 'abcdef', 6], [[['insert', '!']], 'secret!', 7], [[['insert', 'x'], ['remove', ''], ['remove', 'x'], ['undo', 'x']], 'x', 0], [[], '', 0]], 2: [[[['insert', 'abcdabcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcdabcd'], ['undo', 'abcdabcd']], 'abcdabcd', 2], [[['insert', 'abcdefabcdef'], ['remove', 'cd']], 'abefabcdef', 2], [[['insert', 'abcdefabcdef'], ['remove', 'cd']], 'abefabcdef', 2], [[['insert', 'abcdefabcdef'], ['replace', 'cde', 'Z']], 'abZfabcdef', 3], [[['insert', 'abcdefabcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdefabcdef']], 'abcdefabcdef', 12], [[['insert', '!']], 'secretsecret!', 13], [[['insert', 'xx'], ['remove', ''], ['remove', 'xx'], ['undo', 'xx']], 'xx', 0], [[], '', 0]], 3: [[[['insert', 'abcdabcdabcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcdabcdabcd'], ['undo', 'abcdabcdabcd']], 'abcdabcdabcd', 2], [[['insert', 'abcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdef'], ['replace', 'cde', 'Z']], 'abZfabcdefabcdef', 3], [[['insert', 'abcdefabcdefabcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdefabcdefabcdef']], 'abcdefabcdefabcdef', 18], [[['insert', '!']], 'secretsecretsecret!', 19], [[['insert', 'xxx'], ['remove', ''], ['remove', 'xxx'], ['undo', 'xxx']], 'xxx', 0], [[], '', 0]], 4: [[[['insert', 'abcdabcdabcdabcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcdabcdabcdabcd'], ['undo', 'abcdabcdabcdabcd']], 'abcdabcdabcdabcd', 2], [[['insert', 'abcdefabcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdefabcdef'], ['replace', 'cde', 'Z']], 'abZfabcdefabcdefabcdef', 3], [[['insert', 'abcdefabcdefabcdefabcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdefabcdefabcdefabcdef']], 'abcdefabcdefabcdefabcdef', 24], [[['insert', '!']], 'secretsecretsecretsecret!', 25], [[['insert', 'xxxx'], ['remove', ''], ['remove', 'xxxx'], ['undo', 'xxxx']], 'xxxx', 0], [[], '', 0]], 5: [[[['insert', 'abcdabcdabcdabcdabcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcdabcdabcdabcdabcd'], ['undo', 'abcdabcdabcdabcdabcd']], 'abcdabcdabcdabcdabcd', 2], [[['insert', 'abcdefabcdefabcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdefabcdefabcdef'], ['replace', 'cde', 'Z']], 'abZfabcdefabcdefabcdefabcdef', 3], [[['insert', 'abcdefabcdefabcdefabcdefabcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdefabcdefabcdefabcdefabcdef']], 'abcdefabcdefabcdefabcdefabcdef', 30], [[['insert', '!']], 'secretsecretsecretsecretsecret!', 31], [[['insert', 'xxxxx'], ['remove', ''], ['remove', 'xxxxx'], ['undo', 'xxxxx']], 'xxxxx', 0], [[], '', 0]]}[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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| trace-1 | [[['insert', 'abcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcd'], ['undo', 'abcd']], 'abcd', 2] | [[['insert', 'abcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcd'], ['undo', 'abcd']], 'abcd', 2] | Passed |
| trace-2 | [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2] | [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2] | Passed |
| trace-3 | [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2] | [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2] | Passed |
| trace-4 | [[['insert', 'abcdef'], ['replace', 'abcdef', 'Z']], 'Z', 1] | [[['insert', 'abcdef'], ['replace', 'cde', 'Z']], 'abZf', 3] | Failed |
| trace-5 | [[['insert', 'abcdef'], ['replace', 'abcdef', 'Z'], ['undo', 'abcdef']], 'abcdef', 6] | [[['insert', 'abcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdef']], 'abcdef', 6] | Failed |
| trace-6 | [[['insert', '!']], 'secret!', 7] | [[['insert', '!']], 'secret!', 7] | Passed |
| trace-7 | [[['insert', 'x'], ['remove', ''], ['remove', 'x'], ['undo', 'x']], 'x', 0] | [[['insert', 'x'], ['remove', ''], ['remove', 'x'], ['undo', 'x']], 'x', 0] | Passed |
| trace-8 | [[], '', 0] | [[], '', 0] | Passed |
SHA-256 / e6d7e43b62bdc0922c711e7b611b1c908d490eefc3bc1671b527963b7a4a0525
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(events):
text=''; cursor=0; history=[]; silent=False; out=[]
for e in events:
op=e[0]
if op=='move': cursor=max(0,min(len(text),e[1]))
elif op=='silent': silent=e[1]
elif op=='undo' and history:
text,cursor=history.pop()
if not silent: out.append(['undo',text])
elif op in ('insert','backspace','delete','replace'):
history.append([text,cursor])
if op=='insert':
text=text[:cursor]+e[1]+text[cursor:]; cursor+=len(e[1]); cue=['insert',e[1]]
elif op=='backspace':
start=max(0,cursor-e[1]); cue=['remove',text[start:cursor]]
text=text[:start]+text[cursor:]; cursor=start
elif op=='delete':
end=min(len(text),cursor+e[1]); cue=['remove',text[cursor:end]]
text=text[:cursor]+text[end:]
else:
a,b=sorted([max(0,min(len(text),e[1])),max(0,min(len(text),e[2]))])
cue=['replace',text[a:b],e[3]]; text=text[:a]+e[3]+text[b:]; cursor=a+len(e[3])
if not silent: out.append(cue)
return [out,text,cursor]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = ["[['insert','abcd'*N],['move',2],['insert','XY'],['backspace',2],['undo'],['undo']]", "[['insert','abcdef'*N],['move',4],['backspace',2]]", "[['insert','abcdef'*N],['move',2],['delete',2]]", "[['insert','abcdef'*N],['replace',5,2,'Z']]", "[['insert','abcdef'*N],['replace',5,2,'Z'],['undo']]", "[['silent',True],['insert','secret'*N],['silent',False],['move',99],['insert','!']]", "[['insert','x'*N],['move',-5],['backspace',4],['delete',99],['undo']]", '[]']
expected = {1: [[[['insert', 'abcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcd'], ['undo', 'abcd']], 'abcd', 2], [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2], [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2], [[['insert', 'abcdef'], ['replace', 'cde', 'Z']], 'abZf', 3], [[['insert', 'abcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdef']], 'abcdef', 6], [[['insert', '!']], 'secret!', 7], [[['insert', 'x'], ['remove', ''], ['remove', 'x'], ['undo', 'x']], 'x', 0], [[], '', 0]], 2: [[[['insert', 'abcdabcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcdabcd'], ['undo', 'abcdabcd']], 'abcdabcd', 2], [[['insert', 'abcdefabcdef'], ['remove', 'cd']], 'abefabcdef', 2], [[['insert', 'abcdefabcdef'], ['remove', 'cd']], 'abefabcdef', 2], [[['insert', 'abcdefabcdef'], ['replace', 'cde', 'Z']], 'abZfabcdef', 3], [[['insert', 'abcdefabcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdefabcdef']], 'abcdefabcdef', 12], [[['insert', '!']], 'secretsecret!', 13], [[['insert', 'xx'], ['remove', ''], ['remove', 'xx'], ['undo', 'xx']], 'xx', 0], [[], '', 0]], 3: [[[['insert', 'abcdabcdabcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcdabcdabcd'], ['undo', 'abcdabcdabcd']], 'abcdabcdabcd', 2], [[['insert', 'abcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdef'], ['replace', 'cde', 'Z']], 'abZfabcdefabcdef', 3], [[['insert', 'abcdefabcdefabcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdefabcdefabcdef']], 'abcdefabcdefabcdef', 18], [[['insert', '!']], 'secretsecretsecret!', 19], [[['insert', 'xxx'], ['remove', ''], ['remove', 'xxx'], ['undo', 'xxx']], 'xxx', 0], [[], '', 0]], 4: [[[['insert', 'abcdabcdabcdabcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcdabcdabcdabcd'], ['undo', 'abcdabcdabcdabcd']], 'abcdabcdabcdabcd', 2], [[['insert', 'abcdefabcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdefabcdef'], ['replace', 'cde', 'Z']], 'abZfabcdefabcdefabcdef', 3], [[['insert', 'abcdefabcdefabcdefabcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdefabcdefabcdefabcdef']], 'abcdefabcdefabcdefabcdef', 24], [[['insert', '!']], 'secretsecretsecretsecret!', 25], [[['insert', 'xxxx'], ['remove', ''], ['remove', 'xxxx'], ['undo', 'xxxx']], 'xxxx', 0], [[], '', 0]], 5: [[[['insert', 'abcdabcdabcdabcdabcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcdabcdabcdabcdabcd'], ['undo', 'abcdabcdabcdabcdabcd']], 'abcdabcdabcdabcdabcd', 2], [[['insert', 'abcdefabcdefabcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdefabcdefabcdef'], ['remove', 'cd']], 'abefabcdefabcdefabcdefabcdef', 2], [[['insert', 'abcdefabcdefabcdefabcdefabcdef'], ['replace', 'cde', 'Z']], 'abZfabcdefabcdefabcdefabcdef', 3], [[['insert', 'abcdefabcdefabcdefabcdefabcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdefabcdefabcdefabcdefabcdef']], 'abcdefabcdefabcdefabcdefabcdef', 30], [[['insert', '!']], 'secretsecretsecretsecretsecret!', 31], [[['insert', 'xxxxx'], ['remove', ''], ['remove', 'xxxxx'], ['undo', 'xxxxx']], 'xxxxx', 0], [[], '', 0]]}[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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| trace-1 | [[['insert', 'abcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcd'], ['undo', 'abcd']], 'abcd', 2] | [[['insert', 'abcd'], ['insert', 'XY'], ['remove', 'XY'], ['undo', 'abXYcd'], ['undo', 'abcd']], 'abcd', 2] | Passed |
| trace-2 | [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2] | [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2] | Passed |
| trace-3 | [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2] | [[['insert', 'abcdef'], ['remove', 'cd']], 'abef', 2] | Passed |
| trace-4 | [[['insert', 'abcdef'], ['replace', 'cde', 'Z']], 'abZf', 3] | [[['insert', 'abcdef'], ['replace', 'cde', 'Z']], 'abZf', 3] | Passed |
| trace-5 | [[['insert', 'abcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdef']], 'abcdef', 6] | [[['insert', 'abcdef'], ['replace', 'cde', 'Z'], ['undo', 'abcdef']], 'abcdef', 6] | Passed |
| trace-6 | [[['insert', '!']], 'secret!', 7] | [[['insert', '!']], 'secret!', 7] | Passed |
| trace-7 | [[['insert', 'x'], ['remove', ''], ['remove', 'x'], ['undo', 'x']], 'x', 0] | [[['insert', 'x'], ['remove', ''], ['remove', 'x'], ['undo', 'x']], 'x', 0] | Passed |
| trace-8 | [[], '', 0] | [[], '', 0] | Passed |
SHA-256 / 57f754d7870db9131c713c229503e67479461553944d07f3e8188446c5bfd29d
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 2026-09-29T14:40:28.813839+00:00.
Case digest / 5761f116d5372db3fa04a020aa76052f48410c244c34b4bd68010ccfb5780dda