FA-8141 / Autocomplete interactions / Open access

Combobox keyboard commit: Tab unexpectedly commits an unconfirmed suggestion · case 01

Tab unexpectedly commits an unconfirmed suggestion.

Verified by executionVariant 1 · 9 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The tab operation uses `if key == 'Tab': return (active, query, False)` where the contract requires `if key == 'Tab': return (value, query, False)`.

VERIFIED REPAIR

Implement the tab operation as `if key == 'Tab': return (value, query, False)`.

Unsuccessful approach: Keeping the popup open leaves an orphaned overlay after focus moves.

Case contract

Escape discards query but preserves committed value; Enter commits only an existing active option in an open popup; Tab closes without commit; Clear resets both; typing opens suggestions.

Why this case matters

A deterministic model of combobox keyboard commit; this isolates one interface invariant without requiring a browser.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(options, active, value, query, opened, key):
    if key == 'Escape': return (value, '', False)
    if key == 'Enter' and opened and active in options: return (active, query, False)
    if key == 'Tab': return (active, query, False)
    if key == 'Clear': return (None, '', opened)
    if key == 'Input': return (value, query, True)
    return (value, query, opened)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('escape', solve(['a','b'], 'b', 'a', 'b', True, 'Escape'), ('a', '', False))
check('closed enter', solve(['a','b'], 'b', 'a', 'b', False, 'Enter'), ('a', 'b', False))
check('removed active', solve(['a'], 'b', 'a', 'b', True, 'Enter'), ('a', 'b', True))
check('commit', solve(['a','b'], 'b', 'a', 'b', True, 'Enter'), ('b', 'b', False))
check('tab', solve(['a','b'], 'b', 'a', 'b', True, 'Tab'), ('a', 'b', False))
check('clear', solve(['a'], 'a', 'a', 'a', True, 'Clear'), (None, '', True))
check('typing', solve(['a'], 'a', 'a', 'b', False, 'Input'), ('a', 'b', True))
check('parameterized suggestion', solve(list(range(N+1)), N, 0, str(N), True, 'Enter'), (N,str(N),False))
for repetition in range(N):
    check('repeat typing', solve(['a'], 'a', 'a', 'b', False, 'Input'), ('a', 'b', 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
escape	`['a', '', False]`	`['a', '', False]`	Passed
closed enter	`['a', 'b', False]`	`['a', 'b', False]`	Passed
removed active	`['a', 'b', True]`	`['a', 'b', True]`	Passed
commit	`['b', 'b', False]`	`['b', 'b', False]`	Passed
tab	`['b', 'b', False]`	`['a', 'b', False]`	Failed
clear	`[None, '', True]`	`[None, '', True]`	Passed
typing	`['a', 'b', True]`	`['a', 'b', True]`	Passed
parameterized suggestion	`[1, '1', False]`	`[1, '1', False]`	Passed
repeat typing	`['a', 'b', True]`	`['a', 'b', True]`	Passed

SHA-256 / 06689f2a350ae4b68d7a36b9ecb72894e1cb969292624cf8ffa19d0b046d54fa

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(options, active, value, query, opened, key):
    if key == 'Escape': return (value, '', False)
    if key == 'Enter' and opened and active in options: return (active, query, False)
    if key == 'Tab': return (value, query, True)
    if key == 'Clear': return (None, '', opened)
    if key == 'Input': return (value, query, True)
    return (value, query, opened)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('escape', solve(['a','b'], 'b', 'a', 'b', True, 'Escape'), ('a', '', False))
check('closed enter', solve(['a','b'], 'b', 'a', 'b', False, 'Enter'), ('a', 'b', False))
check('removed active', solve(['a'], 'b', 'a', 'b', True, 'Enter'), ('a', 'b', True))
check('commit', solve(['a','b'], 'b', 'a', 'b', True, 'Enter'), ('b', 'b', False))
check('tab', solve(['a','b'], 'b', 'a', 'b', True, 'Tab'), ('a', 'b', False))
check('clear', solve(['a'], 'a', 'a', 'a', True, 'Clear'), (None, '', True))
check('typing', solve(['a'], 'a', 'a', 'b', False, 'Input'), ('a', 'b', True))
check('parameterized suggestion', solve(list(range(N+1)), N, 0, str(N), True, 'Enter'), (N,str(N),False))
for repetition in range(N):
    check('repeat typing', solve(['a'], 'a', 'a', 'b', False, 'Input'), ('a', 'b', 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
escape	`['a', '', False]`	`['a', '', False]`	Passed
closed enter	`['a', 'b', False]`	`['a', 'b', False]`	Passed
removed active	`['a', 'b', True]`	`['a', 'b', True]`	Passed
commit	`['b', 'b', False]`	`['b', 'b', False]`	Passed
tab	`['a', 'b', True]`	`['a', 'b', False]`	Failed
clear	`[None, '', True]`	`[None, '', True]`	Passed
typing	`['a', 'b', True]`	`['a', 'b', True]`	Passed
parameterized suggestion	`[1, '1', False]`	`[1, '1', False]`	Passed
repeat typing	`['a', 'b', True]`	`['a', 'b', True]`	Passed

SHA-256 / cc9711c337166de82d16ba215034b5b40ef31ac8abc4264bdd6f8b863bb7552d

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(options, active, value, query, opened, key):
    if key == 'Escape': return (value, '', False)
    if key == 'Enter' and opened and active in options: return (active, query, False)
    if key == 'Tab': return (value, query, False)
    if key == 'Clear': return (None, '', opened)
    if key == 'Input': return (value, query, True)
    return (value, query, opened)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('escape', solve(['a','b'], 'b', 'a', 'b', True, 'Escape'), ('a', '', False))
check('closed enter', solve(['a','b'], 'b', 'a', 'b', False, 'Enter'), ('a', 'b', False))
check('removed active', solve(['a'], 'b', 'a', 'b', True, 'Enter'), ('a', 'b', True))
check('commit', solve(['a','b'], 'b', 'a', 'b', True, 'Enter'), ('b', 'b', False))
check('tab', solve(['a','b'], 'b', 'a', 'b', True, 'Tab'), ('a', 'b', False))
check('clear', solve(['a'], 'a', 'a', 'a', True, 'Clear'), (None, '', True))
check('typing', solve(['a'], 'a', 'a', 'b', False, 'Input'), ('a', 'b', True))
check('parameterized suggestion', solve(list(range(N+1)), N, 0, str(N), True, 'Enter'), (N,str(N),False))
for repetition in range(N):
    check('repeat typing', solve(['a'], 'a', 'a', 'b', False, 'Input'), ('a', 'b', 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
escape	`['a', '', False]`	`['a', '', False]`	Passed
closed enter	`['a', 'b', False]`	`['a', 'b', False]`	Passed
removed active	`['a', 'b', True]`	`['a', 'b', True]`	Passed
commit	`['b', 'b', False]`	`['b', 'b', False]`	Passed
tab	`['a', 'b', False]`	`['a', 'b', False]`	Passed
clear	`[None, '', True]`	`[None, '', True]`	Passed
typing	`['a', 'b', True]`	`['a', 'b', True]`	Passed
parameterized suggestion	`[1, '1', False]`	`[1, '1', False]`	Passed
repeat typing	`['a', 'b', True]`	`['a', 'b', True]`	Passed

SHA-256 / 27fd573a100cd9f334d842986b2fda43037577f50f135b310d544acb9f6e7cab

Verification & scope

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 2026-09-29T14:38:18.754956+00:00.

Case digest / 6bd5c5ed13c70a0474ea1c828b41ed151c316ed40fbf77656ba7b3e6b59ffe30