FA-21931 / Autocomplete interactions / Open access
Suggestion request context: zero-capacity completion still asks for results · case 01
The limit completion transition produces an incorrect observable state.
ROOT CAUSE
At request-context/limit, the implementation evaluates `max(1,d['limit'])` instead of preserving the specified completion transition.
VERIFIED REPAIR
Implement the limit contract using `d['limit']`.
Unsuccessful approach: The attempted repair uses `d['limit'] or 10`, which still violates a normal or boundary completion fixture.
Case contract
A suggestion request is bound to draft, field identity, selection range, locale and dependency scope. Each outgoing descriptor carries those values from the initiating snapshot; accepting a response requires the same query epoch and field instance. No transport behavior is modeled.
Why this case matters
Autocomplete couples draft text, suggestion identity and asynchronous presentation; this bounded lifecycle model isolates one observable interaction defect.
1 / The failure
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(event, d):
if event == 'query': return {'text':d['query']}
if event == 'epoch': return d['epoch']
if event == 'field': return d['field']
if event == 'instance': return d['instance']
if event == 'locale': return d['locale']
if event == 'scope': return d['scope']
if event == 'range': return [d['start'],d['end']]
if event == 'exclusions': return d['selected']
if event == 'limit': return max(1,d['limit'])
if event == 'accept': return d['response_epoch']==d['epoch'] and d['response_field']==d['field']
return {'unchanged': True}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
normal = {'query':'pear','epoch':N,'field':'billing','instance':N+2,'locale':'fr','scope':'fruit','start':1,'end':3,'selected':['p1'],'limit':7,'response_epoch':N-1,'response_field':'shipping'}
boundary = {'query':'','epoch':N,'field':'billing','instance':N,'locale':'en','scope':'all','start':0,'end':0,'selected':[],'limit':0,'response_epoch':N,'response_field':'billing'}
check('normal query', solve('query', normal), {'text':'pear'})
check('boundary query', solve('query', boundary), {'text':''})
check('normal epoch', solve('epoch', normal), N)
check('boundary epoch', solve('epoch', boundary), N)
check('normal field', solve('field', normal), 'billing')
check('boundary field', solve('field', boundary), 'billing')
check('normal instance', solve('instance', normal), N+2)
check('boundary instance', solve('instance', boundary), N)
check('normal locale', solve('locale', normal), 'fr')
check('boundary locale', solve('locale', boundary), 'en')
check('normal scope', solve('scope', normal), 'fruit')
check('boundary scope', solve('scope', boundary), 'all')
check('normal range', solve('range', normal), [1,3])
check('boundary range', solve('range', boundary), [0,0])
check('normal exclusions', solve('exclusions', normal), ['p1'])
check('boundary exclusions', solve('exclusions', boundary), [])
check('normal limit', solve('limit', normal), 7)
check('boundary limit', solve('limit', boundary), 0)
check('normal accept', solve('accept', normal), False)
check('boundary accept', solve('accept', boundary), True)
variant = dict(normal, **{'query':'q'*N})
check('variant query or selection payload', solve('query', variant), {'text':'q'*N})
check('unknown completion event', solve('unrecognized', normal), {'unchanged': True})
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 |
|---|---|---|---|
| normal query | {'text': 'pear'} | {'text': 'pear'} | Passed |
| boundary query | {'text': ''} | {'text': ''} | Passed |
| normal epoch | 1 | 1 | Passed |
| boundary epoch | 1 | 1 | Passed |
| normal field | billing | billing | Passed |
| boundary field | billing | billing | Passed |
| normal instance | 3 | 3 | Passed |
| boundary instance | 1 | 1 | Passed |
| normal locale | fr | fr | Passed |
| boundary locale | en | en | Passed |
| normal scope | fruit | fruit | Passed |
| boundary scope | all | all | Passed |
| normal range | [1, 3] | [1, 3] | Passed |
| boundary range | [0, 0] | [0, 0] | Passed |
| normal exclusions | ['p1'] | ['p1'] | Passed |
| boundary exclusions | [] | [] | Passed |
| normal limit | 7 | 7 | Passed |
| boundary limit | 1 | 0 | Failed |
| normal accept | False | False | Passed |
| boundary accept | True | True | Passed |
| variant query or selection payload | {'text': 'q'} | {'text': 'q'} | Passed |
| unknown completion event | {'unchanged': True} | {'unchanged': True} | Passed |
SHA-256 / 03b9dd735e4db2648f0c907b2490f93edb93d40dec1404f6378c3af6bde06084
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(event, d):
if event == 'query': return {'text':d['query']}
if event == 'epoch': return d['epoch']
if event == 'field': return d['field']
if event == 'instance': return d['instance']
if event == 'locale': return d['locale']
if event == 'scope': return d['scope']
if event == 'range': return [d['start'],d['end']]
if event == 'exclusions': return d['selected']
if event == 'limit': return d['limit'] or 10
if event == 'accept': return d['response_epoch']==d['epoch'] and d['response_field']==d['field']
return {'unchanged': True}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
normal = {'query':'pear','epoch':N,'field':'billing','instance':N+2,'locale':'fr','scope':'fruit','start':1,'end':3,'selected':['p1'],'limit':7,'response_epoch':N-1,'response_field':'shipping'}
boundary = {'query':'','epoch':N,'field':'billing','instance':N,'locale':'en','scope':'all','start':0,'end':0,'selected':[],'limit':0,'response_epoch':N,'response_field':'billing'}
check('normal query', solve('query', normal), {'text':'pear'})
check('boundary query', solve('query', boundary), {'text':''})
check('normal epoch', solve('epoch', normal), N)
check('boundary epoch', solve('epoch', boundary), N)
check('normal field', solve('field', normal), 'billing')
check('boundary field', solve('field', boundary), 'billing')
check('normal instance', solve('instance', normal), N+2)
check('boundary instance', solve('instance', boundary), N)
check('normal locale', solve('locale', normal), 'fr')
check('boundary locale', solve('locale', boundary), 'en')
check('normal scope', solve('scope', normal), 'fruit')
check('boundary scope', solve('scope', boundary), 'all')
check('normal range', solve('range', normal), [1,3])
check('boundary range', solve('range', boundary), [0,0])
check('normal exclusions', solve('exclusions', normal), ['p1'])
check('boundary exclusions', solve('exclusions', boundary), [])
check('normal limit', solve('limit', normal), 7)
check('boundary limit', solve('limit', boundary), 0)
check('normal accept', solve('accept', normal), False)
check('boundary accept', solve('accept', boundary), True)
variant = dict(normal, **{'query':'q'*N})
check('variant query or selection payload', solve('query', variant), {'text':'q'*N})
check('unknown completion event', solve('unrecognized', normal), {'unchanged': True})
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 |
|---|---|---|---|
| normal query | {'text': 'pear'} | {'text': 'pear'} | Passed |
| boundary query | {'text': ''} | {'text': ''} | Passed |
| normal epoch | 1 | 1 | Passed |
| boundary epoch | 1 | 1 | Passed |
| normal field | billing | billing | Passed |
| boundary field | billing | billing | Passed |
| normal instance | 3 | 3 | Passed |
| boundary instance | 1 | 1 | Passed |
| normal locale | fr | fr | Passed |
| boundary locale | en | en | Passed |
| normal scope | fruit | fruit | Passed |
| boundary scope | all | all | Passed |
| normal range | [1, 3] | [1, 3] | Passed |
| boundary range | [0, 0] | [0, 0] | Passed |
| normal exclusions | ['p1'] | ['p1'] | Passed |
| boundary exclusions | [] | [] | Passed |
| normal limit | 7 | 7 | Passed |
| boundary limit | 10 | 0 | Failed |
| normal accept | False | False | Passed |
| boundary accept | True | True | Passed |
| variant query or selection payload | {'text': 'q'} | {'text': 'q'} | Passed |
| unknown completion event | {'unchanged': True} | {'unchanged': True} | Passed |
SHA-256 / f508c0b4c0aecd75032f4685bba8aa8a0731b18ce30e51acb065a7bd45e2161b
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(event, d):
if event == 'query': return {'text':d['query']}
if event == 'epoch': return d['epoch']
if event == 'field': return d['field']
if event == 'instance': return d['instance']
if event == 'locale': return d['locale']
if event == 'scope': return d['scope']
if event == 'range': return [d['start'],d['end']]
if event == 'exclusions': return d['selected']
if event == 'limit': return d['limit']
if event == 'accept': return d['response_epoch']==d['epoch'] and d['response_field']==d['field']
return {'unchanged': True}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
normal = {'query':'pear','epoch':N,'field':'billing','instance':N+2,'locale':'fr','scope':'fruit','start':1,'end':3,'selected':['p1'],'limit':7,'response_epoch':N-1,'response_field':'shipping'}
boundary = {'query':'','epoch':N,'field':'billing','instance':N,'locale':'en','scope':'all','start':0,'end':0,'selected':[],'limit':0,'response_epoch':N,'response_field':'billing'}
check('normal query', solve('query', normal), {'text':'pear'})
check('boundary query', solve('query', boundary), {'text':''})
check('normal epoch', solve('epoch', normal), N)
check('boundary epoch', solve('epoch', boundary), N)
check('normal field', solve('field', normal), 'billing')
check('boundary field', solve('field', boundary), 'billing')
check('normal instance', solve('instance', normal), N+2)
check('boundary instance', solve('instance', boundary), N)
check('normal locale', solve('locale', normal), 'fr')
check('boundary locale', solve('locale', boundary), 'en')
check('normal scope', solve('scope', normal), 'fruit')
check('boundary scope', solve('scope', boundary), 'all')
check('normal range', solve('range', normal), [1,3])
check('boundary range', solve('range', boundary), [0,0])
check('normal exclusions', solve('exclusions', normal), ['p1'])
check('boundary exclusions', solve('exclusions', boundary), [])
check('normal limit', solve('limit', normal), 7)
check('boundary limit', solve('limit', boundary), 0)
check('normal accept', solve('accept', normal), False)
check('boundary accept', solve('accept', boundary), True)
variant = dict(normal, **{'query':'q'*N})
check('variant query or selection payload', solve('query', variant), {'text':'q'*N})
check('unknown completion event', solve('unrecognized', normal), {'unchanged': True})
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 |
|---|---|---|---|
| normal query | {'text': 'pear'} | {'text': 'pear'} | Passed |
| boundary query | {'text': ''} | {'text': ''} | Passed |
| normal epoch | 1 | 1 | Passed |
| boundary epoch | 1 | 1 | Passed |
| normal field | billing | billing | Passed |
| boundary field | billing | billing | Passed |
| normal instance | 3 | 3 | Passed |
| boundary instance | 1 | 1 | Passed |
| normal locale | fr | fr | Passed |
| boundary locale | en | en | Passed |
| normal scope | fruit | fruit | Passed |
| boundary scope | all | all | Passed |
| normal range | [1, 3] | [1, 3] | Passed |
| boundary range | [0, 0] | [0, 0] | Passed |
| normal exclusions | ['p1'] | ['p1'] | Passed |
| boundary exclusions | [] | [] | Passed |
| normal limit | 7 | 7 | Passed |
| boundary limit | 0 | 0 | Passed |
| normal accept | False | False | Passed |
| boundary accept | True | True | Passed |
| variant query or selection payload | {'text': 'q'} | {'text': 'q'} | Passed |
| unknown completion event | {'unchanged': True} | {'unchanged': True} | Passed |
SHA-256 / c3c68e5e6973fbdc7b476dc3add9a355786b193fc26e977adbbe2acaa21a233a
Verification & scope
Stipulated deterministic widget transition model; inputs are validated snapshots. It does not model browser event dispatch, network transport, or linguistic standards. 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 2026-09-29T14:40:33.617791+00:00.
Case digest / 2ce334471b8f1c5bf71c340c39adaaeae7624ba3b6a3fd82860d41dc591f9e0e