FA-9021 / Keyboard interactions / Open access
Scoped keyboard shortcut dispatch: Mac command shortcuts require Control instead of Command · case 01
Mac command shortcuts require Control instead of Command.
ROOT CAUSE
The platform modifier operation uses `ctrl` where the contract requires `meta if platform == 'mac' else ctrl`.
VERIFIED REPAIR
Implement the platform modifier operation as `meta if platform == 'mac' else ctrl`.
Unsuccessful approach: Always requiring Command breaks other platforms.
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 prevented or repeat: return None
if editable: return None
primary = 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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| prevented | None | None | Passed |
| repeat | None | None | Passed |
| editable | None | None | Passed |
| mac | None | undo | Failed |
| win | undo | undo | Passed |
| redo | redo | redo | Passed |
| alt | None | None | Passed |
| parameterized target context | None | None | Passed |
| repeat alt | None | None | Passed |
SHA-256 / 7bb11ca114c9e10fc766ad3cf96fc7011ac916bec84fd5b4be38e4d366f07c18
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 or repeat: return None
if editable: return None
primary = meta
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| prevented | None | None | Passed |
| repeat | None | None | Passed |
| editable | None | None | Passed |
| mac | undo | undo | Passed |
| win | None | undo | Failed |
| redo | None | redo | Failed |
| alt | None | None | Passed |
| parameterized target context | None | None | Passed |
| repeat alt | None | None | Passed |
SHA-256 / 632aeb371bf79557818df5b0d21fbcb64f1ea4e1facf59b3bd0138c43bcc8422
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 fixture | Actual | Expected | Outcome |
|---|---|---|---|
| prevented | None | None | Passed |
| repeat | None | None | Passed |
| editable | None | None | Passed |
| mac | undo | undo | Passed |
| win | undo | undo | Passed |
| redo | redo | redo | Passed |
| alt | None | None | Passed |
| parameterized target context | None | None | Passed |
| repeat alt | None | None | Passed |
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 2026-09-29T14:38:26.331554+00:00.
Case digest / 2eed4aa26fe362027b615ba81006221d7328623e300d21c29760529bcd0450e1