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FA-30881 / Keyboard interactions / Open access

Physical press ownership registry: Device disconnect removes the wrong ownership set · case 01

The event trace violates the disconnect scope rule and produces incorrect keyboard state or command output.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Device disconnect removes the wrong ownership set.

VERIFIED REPAIR

Use the contract transition `held={x for x in held if x[0]!=device}` at the disconnect scope fault site; preserve the other state transitions.

Unsuccessful approach: The partial repair changes this transition to held={x for x in held if x[0]==device}, which still violates the model contract on the explicit regression traces.

Case contract

Events are [kind,device,code,location]. Down inserts a unique physical token; up removes exactly that token; disconnect clears that device; blur clears all. Track maximum simultaneous held count, accepted presses, releases, orphan ups and sorted held tokens. 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):
        held=set(); peak=0; presses=0; releases=0; orphan=0
        for kind,device,code,location in c:
            token=(device,code,location)
            if kind=='down':
                fresh=token not in held
                if fresh: presses+=1
                held.add(token)
                peak=max(peak,len(held))
            elif kind=='up':
                if token in held:
                    held.remove(token)
                    releases+=1
                else: orphan+=1
            elif kind=='disconnect':
                held.clear()
            elif kind=='blur':
                held.clear()
        return [sorted([list(x) for x in held]),peak,presses,releases,orphan]
    return [run(c) for c in cases]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('physical-registry scenario 0', solve([[]] * N), [[[], 0, 0, 0, 0]] * N)
check('physical-registry scenario 1', solve([[['up', 'a', 'A', 0], ['up', 'a', 'B', 0]]] * N), [[[], 0, 0, 0, 2]] * N)
check('physical-registry scenario 2', solve([[['down', 'a', 'A', 0], ['down', 'a', 'A', 0], ['down', 'a', 'A', 0]]] * N), [[[['a', 'A', 0]], 1, 1, 0, 0]] * N)
check('physical-registry scenario 3', solve([[['down', 'a', 'A', 0], ['down', 'b', 'A', 0], ['up', 'a', 'A', 0]]] * N), [[[['b', 'A', 0]], 2, 2, 1, 0]] * N)
check('physical-registry scenario 4', solve([[['down', 'a', 'S', 1], ['down', 'a', 'S', 3], ['up', 'a', 'S', 1]]] * N), [[[['a', 'S', 3]], 2, 2, 1, 0]] * N)
check('physical-registry scenario 5', solve([[['down', 'a', 'A', 0], ['down', 'a', 'B', 0], ['up', 'a', 'A', 0], ['down', 'a', 'C', 0], ['up', 'a', 'B', 0], ['up', 'a', 'C', 0], ['down', 'a', 'D', 0]]] * N), [[[['a', 'D', 0]], 2, 4, 3, 0]] * N)
check('physical-registry scenario 6', solve([[['down', 'a', 'A', 0], ['down', 'b', 'B', 0], ['disconnect', 'a', '', 0]]] * N), [[[['b', 'B', 0]], 2, 2, 0, 0]] * N)
check('physical-registry scenario 7', solve([[['down', 'a', 'A', 0], ['down', 'a', 'B', 1], ['blur', '', '', 0]]] * N), [[[], 2, 2, 0, 0]] * 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
physical-registry scenario 0[[[], 0, 0, 0, 0]][[[], 0, 0, 0, 0]]Passed
physical-registry scenario 1[[[], 0, 0, 0, 2]][[[], 0, 0, 0, 2]]Passed
physical-registry scenario 2[[[['a', 'A', 0]], 1, 1, 0, 0]][[[['a', 'A', 0]], 1, 1, 0, 0]]Passed
physical-registry scenario 3[[[['b', 'A', 0]], 2, 2, 1, 0]][[[['b', 'A', 0]], 2, 2, 1, 0]]Passed
physical-registry scenario 4[[[['a', 'S', 3]], 2, 2, 1, 0]][[[['a', 'S', 3]], 2, 2, 1, 0]]Passed
physical-registry scenario 5[[[['a', 'D', 0]], 2, 4, 3, 0]][[[['a', 'D', 0]], 2, 4, 3, 0]]Passed
physical-registry scenario 6[[[], 2, 2, 0, 0]][[[['b', 'B', 0]], 2, 2, 0, 0]]Failed
physical-registry scenario 7[[[], 2, 2, 0, 0]][[[], 2, 2, 0, 0]]Passed

SHA-256 / 2f41fc67c15616e1998caca2e18f55a5b0e3d7f27821d7bda45c03ca7e406929

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):
        held=set(); peak=0; presses=0; releases=0; orphan=0
        for kind,device,code,location in c:
            token=(device,code,location)
            if kind=='down':
                fresh=token not in held
                if fresh: presses+=1
                held.add(token)
                peak=max(peak,len(held))
            elif kind=='up':
                if token in held:
                    held.remove(token)
                    releases+=1
                else: orphan+=1
            elif kind=='disconnect':
                held={x for x in held if x[0]==device}
            elif kind=='blur':
                held.clear()
        return [sorted([list(x) for x in held]),peak,presses,releases,orphan]
    return [run(c) for c in cases]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('physical-registry scenario 0', solve([[]] * N), [[[], 0, 0, 0, 0]] * N)
check('physical-registry scenario 1', solve([[['up', 'a', 'A', 0], ['up', 'a', 'B', 0]]] * N), [[[], 0, 0, 0, 2]] * N)
check('physical-registry scenario 2', solve([[['down', 'a', 'A', 0], ['down', 'a', 'A', 0], ['down', 'a', 'A', 0]]] * N), [[[['a', 'A', 0]], 1, 1, 0, 0]] * N)
check('physical-registry scenario 3', solve([[['down', 'a', 'A', 0], ['down', 'b', 'A', 0], ['up', 'a', 'A', 0]]] * N), [[[['b', 'A', 0]], 2, 2, 1, 0]] * N)
check('physical-registry scenario 4', solve([[['down', 'a', 'S', 1], ['down', 'a', 'S', 3], ['up', 'a', 'S', 1]]] * N), [[[['a', 'S', 3]], 2, 2, 1, 0]] * N)
check('physical-registry scenario 5', solve([[['down', 'a', 'A', 0], ['down', 'a', 'B', 0], ['up', 'a', 'A', 0], ['down', 'a', 'C', 0], ['up', 'a', 'B', 0], ['up', 'a', 'C', 0], ['down', 'a', 'D', 0]]] * N), [[[['a', 'D', 0]], 2, 4, 3, 0]] * N)
check('physical-registry scenario 6', solve([[['down', 'a', 'A', 0], ['down', 'b', 'B', 0], ['disconnect', 'a', '', 0]]] * N), [[[['b', 'B', 0]], 2, 2, 0, 0]] * N)
check('physical-registry scenario 7', solve([[['down', 'a', 'A', 0], ['down', 'a', 'B', 1], ['blur', '', '', 0]]] * N), [[[], 2, 2, 0, 0]] * 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
physical-registry scenario 0[[[], 0, 0, 0, 0]][[[], 0, 0, 0, 0]]Passed
physical-registry scenario 1[[[], 0, 0, 0, 2]][[[], 0, 0, 0, 2]]Passed
physical-registry scenario 2[[[['a', 'A', 0]], 1, 1, 0, 0]][[[['a', 'A', 0]], 1, 1, 0, 0]]Passed
physical-registry scenario 3[[[['b', 'A', 0]], 2, 2, 1, 0]][[[['b', 'A', 0]], 2, 2, 1, 0]]Passed
physical-registry scenario 4[[[['a', 'S', 3]], 2, 2, 1, 0]][[[['a', 'S', 3]], 2, 2, 1, 0]]Passed
physical-registry scenario 5[[[['a', 'D', 0]], 2, 4, 3, 0]][[[['a', 'D', 0]], 2, 4, 3, 0]]Passed
physical-registry scenario 6[[[['a', 'A', 0]], 2, 2, 0, 0]][[[['b', 'B', 0]], 2, 2, 0, 0]]Failed
physical-registry scenario 7[[[], 2, 2, 0, 0]][[[], 2, 2, 0, 0]]Passed

SHA-256 / 95de605ddc21434f83717f493a17d5bb1036dae236e86c3a526021b5b3bdd028

3 / The verified repair

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

N = 1
observations = []
def solve(cases):
    def run(c):
        held=set(); peak=0; presses=0; releases=0; orphan=0
        for kind,device,code,location in c:
            token=(device,code,location)
            if kind=='down':
                fresh=token not in held
                if fresh: presses+=1
                held.add(token)
                peak=max(peak,len(held))
            elif kind=='up':
                if token in held:
                    held.remove(token)
                    releases+=1
                else: orphan+=1
            elif kind=='disconnect':
                held={x for x in held if x[0]!=device}
            elif kind=='blur':
                held.clear()
        return [sorted([list(x) for x in held]),peak,presses,releases,orphan]
    return [run(c) for c in cases]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('physical-registry scenario 0', solve([[]] * N), [[[], 0, 0, 0, 0]] * N)
check('physical-registry scenario 1', solve([[['up', 'a', 'A', 0], ['up', 'a', 'B', 0]]] * N), [[[], 0, 0, 0, 2]] * N)
check('physical-registry scenario 2', solve([[['down', 'a', 'A', 0], ['down', 'a', 'A', 0], ['down', 'a', 'A', 0]]] * N), [[[['a', 'A', 0]], 1, 1, 0, 0]] * N)
check('physical-registry scenario 3', solve([[['down', 'a', 'A', 0], ['down', 'b', 'A', 0], ['up', 'a', 'A', 0]]] * N), [[[['b', 'A', 0]], 2, 2, 1, 0]] * N)
check('physical-registry scenario 4', solve([[['down', 'a', 'S', 1], ['down', 'a', 'S', 3], ['up', 'a', 'S', 1]]] * N), [[[['a', 'S', 3]], 2, 2, 1, 0]] * N)
check('physical-registry scenario 5', solve([[['down', 'a', 'A', 0], ['down', 'a', 'B', 0], ['up', 'a', 'A', 0], ['down', 'a', 'C', 0], ['up', 'a', 'B', 0], ['up', 'a', 'C', 0], ['down', 'a', 'D', 0]]] * N), [[[['a', 'D', 0]], 2, 4, 3, 0]] * N)
check('physical-registry scenario 6', solve([[['down', 'a', 'A', 0], ['down', 'b', 'B', 0], ['disconnect', 'a', '', 0]]] * N), [[[['b', 'B', 0]], 2, 2, 0, 0]] * N)
check('physical-registry scenario 7', solve([[['down', 'a', 'A', 0], ['down', 'a', 'B', 1], ['blur', '', '', 0]]] * N), [[[], 2, 2, 0, 0]] * 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
physical-registry scenario 0[[[], 0, 0, 0, 0]][[[], 0, 0, 0, 0]]Passed
physical-registry scenario 1[[[], 0, 0, 0, 2]][[[], 0, 0, 0, 2]]Passed
physical-registry scenario 2[[[['a', 'A', 0]], 1, 1, 0, 0]][[[['a', 'A', 0]], 1, 1, 0, 0]]Passed
physical-registry scenario 3[[[['b', 'A', 0]], 2, 2, 1, 0]][[[['b', 'A', 0]], 2, 2, 1, 0]]Passed
physical-registry scenario 4[[[['a', 'S', 3]], 2, 2, 1, 0]][[[['a', 'S', 3]], 2, 2, 1, 0]]Passed
physical-registry scenario 5[[[['a', 'D', 0]], 2, 4, 3, 0]][[[['a', 'D', 0]], 2, 4, 3, 0]]Passed
physical-registry scenario 6[[[['b', 'B', 0]], 2, 2, 0, 0]][[[['b', 'B', 0]], 2, 2, 0, 0]]Passed
physical-registry scenario 7[[[], 2, 2, 0, 0]][[[], 2, 2, 0, 0]]Passed

SHA-256 / 592cef79bd0ae8b0ac9411ebd78f708c26e1f71da8d8cc5fcd554bea01d1b1cd

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 2026-09-29T14:41:57.017325+00:00.

Case digest / 771c2e5f0bca94ac99e161312b9c7e366dd39db1c96cd97d5cb3130c686af214