FA-31374 / Keyboard interactions / Member archive

Sticky modifier latch lifecycle: Emitted chord modifier representation is noncanonical or omits latches · case 04

The event trace violates the modifier order rule and produces incorrect keyboard state or command output.

Member previewVariant 4 · 3 implementations · 9 checks per implementation

Case contract

Events [kind,key]. Tap of modifier cycles absent -> once -> locked -> absent. Modifier down/up sets physical state independently. Character emits [key,sorted effective modifiers] then consumes all once latches but preserves locked and physical modifiers. Cancel clears latches only; blur clears both. Return emitted events, latches and physical state. 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.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
sticky-modifiers scenario 4	`[[[["A", ["Control", "Alt"]]], [], ["Alt", "Control"]], [[["A", ["Control", "Alt"]]], [], ["Alt", "Control"]], [[["A", ["Control", "Alt"]]], [], ["Alt", "Control"]], [[["A", ["Control", "Alt"]]], [], ["Alt", "Control"]]]`	`[[[["A", ["Alt", "Control"]]], [], ["Alt", "Control"]], [[["A", ["Alt", "Control"]]], [], ["Alt", "Control"]], [[["A", ["Alt", "Control"]]], [], ["Alt", "Control"]], [[["A", ["Alt", "Control"]]], [], ["Alt", "Control"]]]`	Failed

MEMBER ARCHIVE

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This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

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