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FA-31266 / Keyboard interactions / Open access

Keyboard layout mapping generations: A lookup on an uninitialized device emits labels from an unrelated layout lifecycle · case 01

The event trace violates the lookup lifecycle rule and produces incorrect keyboard state or command output.

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

ROOT CAUSE

A lookup on an uninitialized device emits labels from an unrelated layout lifecycle.

THE FAILURE

A lookup on an uninitialized device emits labels from an unrelated layout lifecycle.

Unsuccessful approach: The partial repair changes this transition to elif kind=='lookup' and bool(generations):, which still violates the model contract on the explicit regression traces.

Case contract

Events [kind,device,a,b]. layout replaces device generation a and clears cached labels; map caches physical code a to label b in current generation; lookup emits cached label or code a as fallback. Disconnect removes generation and cache. Maps and lookups before layout are ignored. Return emitted labels, generations and cached [device,code,label] rows. Inputs are finite ordered event traces; return the stated deterministic state. Batch entries are independent. N varies the number of independent input transactions.

Why this case matters

Controlled keyboard event processing model for debugging application event logic.

1 / The failure

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

N = 1
observations = []
def solve(cases):
    def run(c):
        generations={}; cache={}; out=[]
        for kind,device,a,b in c:
            if kind=='layout':
                generations[device]=a
                cache={k:v for k,v in cache.items() if k[0]!=device}
            elif kind=='map' and device in generations:
                cache[(device,a)]=b
            elif kind=='lookup':
                out.append(cache.get((device,a),a))
            elif kind=='disconnect':
                generations.pop(device,None)
                cache={k:v for k,v in cache.items() if k[0]!=device}
        return [out,sorted([[k,v] for k,v in generations.items()]),sorted([[d,k,v] for (d,k),v in cache.items()])]
    return [run(c) for c in cases]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('layout-cache scenario 0', solve([[]] * N), [[[], [], []]] * N)
check('layout-cache scenario 1', solve([[['map', 'a', 'KeyA', 'x'], ['lookup', 'a', 'KeyA', '']]] * N), [[[], [], []]] * N)
check('layout-cache scenario 2', solve([[['layout', 'a', 1, ''], ['map', 'a', 'KeyA', 'x'], ['lookup', 'a', 'KeyA', '']]] * N), [[['x'], [['a', 1]], [['a', 'KeyA', 'x']]]] * N)
check('layout-cache scenario 3', solve([[['layout', 'a', 1, ''], ['map', 'a', 'KeyA', 'x'], ['map', 'a', 'KeyA', 'y'], ['lookup', 'a', 'KeyA', '']]] * N), [[['y'], [['a', 1]], [['a', 'KeyA', 'y']]]] * N)
check('layout-cache scenario 4', solve([[['layout', 'a', 1, ''], ['map', 'a', 'KeyA', 'x'], ['layout', 'a', 2, ''], ['lookup', 'a', 'KeyA', '']]] * N), [[['KeyA'], [['a', 2]], []]] * N)
check('layout-cache scenario 5', solve([[['layout', 'a', 1, ''], ['layout', 'b', 2, ''], ['map', 'a', 'KeyA', 'x'], ['map', 'b', 'KeyB', 'y'], ['layout', 'a', 3, '']]] * N), [[[], [['a', 3], ['b', 2]], [['b', 'KeyB', 'y']]]] * N)
check('layout-cache scenario 6', solve([[['layout', 'a', 1, ''], ['lookup', 'b', 'KeyA', '']]] * N), [[[], [['a', 1]], []]] * N)
check('layout-cache scenario 7', solve([[['layout', 'a', 1, ''], ['lookup', 'a', 'Unknown', 'fallback']]] * N), [[['Unknown'], [['a', 1]], []]] * N)
check('layout-cache scenario 8', solve([[['layout', 'a', 1, ''], ['layout', 'b', 2, ''], ['map', 'a', 'KeyA', 'x'], ['map', 'b', 'KeyB', 'y'], ['disconnect', 'a', '', '']]] * N), [[[], [['b', 2]], [['b', 'KeyB', 'y']]]] * N)
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
layout-cache scenario 0[[[], [], []]][[[], [], []]]Passed
layout-cache scenario 1[[['KeyA'], [], []]][[[], [], []]]Failed
layout-cache scenario 2[[['x'], [['a', 1]], [['a', 'KeyA', 'x']]]][[['x'], [['a', 1]], [['a', 'KeyA', 'x']]]]Passed
layout-cache scenario 3[[['y'], [['a', 1]], [['a', 'KeyA', 'y']]]][[['y'], [['a', 1]], [['a', 'KeyA', 'y']]]]Passed
layout-cache scenario 4[[['KeyA'], [['a', 2]], []]][[['KeyA'], [['a', 2]], []]]Passed
layout-cache scenario 5[[[], [['a', 3], ['b', 2]], [['b', 'KeyB', 'y']]]][[[], [['a', 3], ['b', 2]], [['b', 'KeyB', 'y']]]]Passed
layout-cache scenario 6[[['KeyA'], [['a', 1]], []]][[[], [['a', 1]], []]]Failed
layout-cache scenario 7[[['Unknown'], [['a', 1]], []]][[['Unknown'], [['a', 1]], []]]Passed
layout-cache scenario 8[[[], [['b', 2]], [['b', 'KeyB', 'y']]]][[[], [['b', 2]], [['b', 'KeyB', 'y']]]]Passed

SHA-256 / e2cb85a3ffae7ca42c3c8c9a53c012628a6f4c9c760c0cb02175182bd8f8d904

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(cases):
    def run(c):
        generations={}; cache={}; out=[]
        for kind,device,a,b in c:
            if kind=='layout':
                generations[device]=a
                cache={k:v for k,v in cache.items() if k[0]!=device}
            elif kind=='map' and device in generations:
                cache[(device,a)]=b
            elif kind=='lookup' and bool(generations):
                out.append(cache.get((device,a),a))
            elif kind=='disconnect':
                generations.pop(device,None)
                cache={k:v for k,v in cache.items() if k[0]!=device}
        return [out,sorted([[k,v] for k,v in generations.items()]),sorted([[d,k,v] for (d,k),v in cache.items()])]
    return [run(c) for c in cases]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('layout-cache scenario 0', solve([[]] * N), [[[], [], []]] * N)
check('layout-cache scenario 1', solve([[['map', 'a', 'KeyA', 'x'], ['lookup', 'a', 'KeyA', '']]] * N), [[[], [], []]] * N)
check('layout-cache scenario 2', solve([[['layout', 'a', 1, ''], ['map', 'a', 'KeyA', 'x'], ['lookup', 'a', 'KeyA', '']]] * N), [[['x'], [['a', 1]], [['a', 'KeyA', 'x']]]] * N)
check('layout-cache scenario 3', solve([[['layout', 'a', 1, ''], ['map', 'a', 'KeyA', 'x'], ['map', 'a', 'KeyA', 'y'], ['lookup', 'a', 'KeyA', '']]] * N), [[['y'], [['a', 1]], [['a', 'KeyA', 'y']]]] * N)
check('layout-cache scenario 4', solve([[['layout', 'a', 1, ''], ['map', 'a', 'KeyA', 'x'], ['layout', 'a', 2, ''], ['lookup', 'a', 'KeyA', '']]] * N), [[['KeyA'], [['a', 2]], []]] * N)
check('layout-cache scenario 5', solve([[['layout', 'a', 1, ''], ['layout', 'b', 2, ''], ['map', 'a', 'KeyA', 'x'], ['map', 'b', 'KeyB', 'y'], ['layout', 'a', 3, '']]] * N), [[[], [['a', 3], ['b', 2]], [['b', 'KeyB', 'y']]]] * N)
check('layout-cache scenario 6', solve([[['layout', 'a', 1, ''], ['lookup', 'b', 'KeyA', '']]] * N), [[[], [['a', 1]], []]] * N)
check('layout-cache scenario 7', solve([[['layout', 'a', 1, ''], ['lookup', 'a', 'Unknown', 'fallback']]] * N), [[['Unknown'], [['a', 1]], []]] * N)
check('layout-cache scenario 8', solve([[['layout', 'a', 1, ''], ['layout', 'b', 2, ''], ['map', 'a', 'KeyA', 'x'], ['map', 'b', 'KeyB', 'y'], ['disconnect', 'a', '', '']]] * N), [[[], [['b', 2]], [['b', 'KeyB', 'y']]]] * N)
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
layout-cache scenario 0[[[], [], []]][[[], [], []]]Passed
layout-cache scenario 1[[[], [], []]][[[], [], []]]Passed
layout-cache scenario 2[[['x'], [['a', 1]], [['a', 'KeyA', 'x']]]][[['x'], [['a', 1]], [['a', 'KeyA', 'x']]]]Passed
layout-cache scenario 3[[['y'], [['a', 1]], [['a', 'KeyA', 'y']]]][[['y'], [['a', 1]], [['a', 'KeyA', 'y']]]]Passed
layout-cache scenario 4[[['KeyA'], [['a', 2]], []]][[['KeyA'], [['a', 2]], []]]Passed
layout-cache scenario 5[[[], [['a', 3], ['b', 2]], [['b', 'KeyB', 'y']]]][[[], [['a', 3], ['b', 2]], [['b', 'KeyB', 'y']]]]Passed
layout-cache scenario 6[[['KeyA'], [['a', 1]], []]][[[], [['a', 1]], []]]Failed
layout-cache scenario 7[[['Unknown'], [['a', 1]], []]][[['Unknown'], [['a', 1]], []]]Passed
layout-cache scenario 8[[[], [['b', 2]], [['b', 'KeyB', 'y']]]][[[], [['b', 2]], [['b', 'KeyB', 'y']]]]Passed

SHA-256 / 5a8375d061b8778e7d276775529811786463fcad2f978e14c010fdef312c81ea

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 9 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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Verification & scope

Offline stipulated event model, not a browser implementation or web standard 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 2026-09-29T14:42:00.606176+00:00.

Case digest / adf82af5af81afd0f0e9b357b24d57ef7670caf8d088dfc11824e68dd667561e