No keyup events for letter keys on macOS

[jdm]

If I add println!("{:?}", key_event) to

servo/ports/winit/browser.rs

Line 202 in 2e71561

.otherwise(|| WindowEvent::Keyboard(key_event))

, I see Down followed by Up for most keys like Return, Shift, Tab, etc. However I only ever see Down events for any letters I press.

[jdm]

We're getting appropriate events from winit:

[2020-06-11T21:58:59Z INFO  servo::keyutils] winit keyboard input: KeyboardInput { scancode: 0, state: Pressed, virtual_keycode: Some(A), modifiers: ModifiersState { shift: false, ctrl: false, alt: false, logo: false } }
KeyboardEvent { state: Down, key: Character("a"), code: Unidentified, location: Standard, modifiers: (empty), repeat: false, is_composing: false }
[2020-06-11T21:58:59Z INFO  servo::keyutils] winit keyboard input: KeyboardInput { scancode: 0, state: Released, virtual_keycode: Some(A), modifiers: ModifiersState { shift: false, ctrl: false, alt: false, logo: false } }

[jdm]

get_servo_key_from_winit_key is missing all of the letter characters, of course.

[jdm]

That's intentional, because the letter characters are received from ReceivedCharacter events from winit. However we stash the KeyDown event that was missing the key and update it with the character; there's no special processing for a KeyUp event that is missing the key. That's why script never receives any KeyUp events for letter keys.