FAILURE MAP
← Case archive

FA-9006 / Keyboard interactions / Open access

Scoped keyboard shortcut dispatch: Already-consumed key events dispatch another command · case 01

Already-consumed key events dispatch another command.

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

ROOT CAUSE

The prevented operation uses `if repeat:` where the contract requires `if prevented or repeat:`.

VERIFIED REPAIR

Implement the prevented operation as `if prevented or repeat:`.

Unsuccessful approach: Requiring both flags still ignores independently prevented events.

Case contract

Ignore prevented, repeated, and editable-origin events; use platform primary modifier; Alt blocks shortcuts; Shift-Z redoes, Z undoes, unshifted S saves.

Why this case matters

A deterministic model of scoped keyboard shortcut dispatch; 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(key, ctrl, meta, alt, shift, platform, editable, repeat, prevented):
    if repeat: return None
    if editable: return None
    primary = meta if platform == 'mac' else ctrl
    if not primary or alt: return None
    if key.lower() == 'z': return 'redo' if shift else 'undo'
    if key.lower() == 's' and not shift: return 'save'
    return None
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('prevented', solve('z', True, False, False, False, 'win', False, False, True), None)
check('repeat', solve('z', True, False, False, False, 'win', False, True, False), None)
check('editable', solve('z', True, False, False, False, 'win', True, False, False), None)
check('mac', solve('z', False, True, False, False, 'mac', False, False, False), 'undo')
check('win', solve('z', True, False, False, False, 'win', False, False, False), 'undo')
check('redo', solve('z', True, False, False, True, 'win', False, False, False), 'redo')
check('alt', solve('z', True, False, True, False, 'win', False, False, False), None)
check('parameterized target context', solve('z',True,False,False,False,'win',bool(N%2),False,False), None if N%2 else 'undo')
for repetition in range(N):
    check('repeat alt', solve('z', True, False, True, False, 'win', False, False, False), None)
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
preventedundoNoneFailed
repeatNoneNonePassed
editableNoneNonePassed
macundoundoPassed
winundoundoPassed
redoredoredoPassed
altNoneNonePassed
parameterized target contextNoneNonePassed
repeat altNoneNonePassed

SHA-256 / 129faee6051673dec40327b83d04001bc9703a6d39ccea4ca55330c7dca94fe7

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(key, ctrl, meta, alt, shift, platform, editable, repeat, prevented):
    if prevented and repeat: return None
    if editable: return None
    primary = meta if platform == 'mac' else ctrl
    if not primary or alt: return None
    if key.lower() == 'z': return 'redo' if shift else 'undo'
    if key.lower() == 's' and not shift: return 'save'
    return None
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('prevented', solve('z', True, False, False, False, 'win', False, False, True), None)
check('repeat', solve('z', True, False, False, False, 'win', False, True, False), None)
check('editable', solve('z', True, False, False, False, 'win', True, False, False), None)
check('mac', solve('z', False, True, False, False, 'mac', False, False, False), 'undo')
check('win', solve('z', True, False, False, False, 'win', False, False, False), 'undo')
check('redo', solve('z', True, False, False, True, 'win', False, False, False), 'redo')
check('alt', solve('z', True, False, True, False, 'win', False, False, False), None)
check('parameterized target context', solve('z',True,False,False,False,'win',bool(N%2),False,False), None if N%2 else 'undo')
for repetition in range(N):
    check('repeat alt', solve('z', True, False, True, False, 'win', False, False, False), None)
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
preventedundoNoneFailed
repeatundoNoneFailed
editableNoneNonePassed
macundoundoPassed
winundoundoPassed
redoredoredoPassed
altNoneNonePassed
parameterized target contextNoneNonePassed
repeat altNoneNonePassed

SHA-256 / bb257173271b73b2801e1e946c743fa93ddde6808398a4c562ef536c97a2eff6

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(key, ctrl, meta, alt, shift, platform, editable, repeat, prevented):
    if prevented or repeat: return None
    if editable: return None
    primary = meta if platform == 'mac' else ctrl
    if not primary or alt: return None
    if key.lower() == 'z': return 'redo' if shift else 'undo'
    if key.lower() == 's' and not shift: return 'save'
    return None
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('prevented', solve('z', True, False, False, False, 'win', False, False, True), None)
check('repeat', solve('z', True, False, False, False, 'win', False, True, False), None)
check('editable', solve('z', True, False, False, False, 'win', True, False, False), None)
check('mac', solve('z', False, True, False, False, 'mac', False, False, False), 'undo')
check('win', solve('z', True, False, False, False, 'win', False, False, False), 'undo')
check('redo', solve('z', True, False, False, True, 'win', False, False, False), 'redo')
check('alt', solve('z', True, False, True, False, 'win', False, False, False), None)
check('parameterized target context', solve('z',True,False,False,False,'win',bool(N%2),False,False), None if N%2 else 'undo')
for repetition in range(N):
    check('repeat alt', solve('z', True, False, True, False, 'win', False, False, False), None)
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
preventedNoneNonePassed
repeatNoneNonePassed
editableNoneNonePassed
macundoundoPassed
winundoundoPassed
redoredoredoPassed
altNoneNonePassed
parameterized target contextNoneNonePassed
repeat altNoneNonePassed

SHA-256 / 57e8128ff05fe833f1456d79a412d1065dd2e5fcb142e213a048dee71ea1c567

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 2026-09-29T14:38:26.213303+00:00.

Case digest / 92f10c660cb4427ffde0ef8a076accf7e6e7909a0b02b6d9a21dc0680e3656e9