Modifiers (e.g. Alt) are sometimes ignored when using programmable keyboard

[quadruple-output]

Describe the bug
I am using a programmable keyboard on a Mac. Sometimes when I enter, for example, the "{" character, neovide outputs "8" (Alt-8 is how you enter "{" on a mac). This only seems to occur when I have neovide maximized on my external 4K monitor. It happens at seemingly random times, but often enough to really drive me crazy.

Spoiler: I think I found a fix for the issue and plan to submit a PR.

To Reproduce
Steps to reproduce the behavior:

1. Setup a programmable keyboard, such that a single key press corresponds to pressing "Alt-8". In almost all apps, pressing this key should produce "{" in any kind of text input control.
2. Startup neovide and maximize it on a high resolution monitor (it may be possible to achieve the same effect by putting the CPU under load, but I did not test this at all).
3. Enter Insert Mode and keep hitting your programmed key. Use different time intervals, for example hit the key fast a few times, then wait 2 seconds, continue, wait longer or shorter, continue …
4. When I follow these steps, I see something like this: 8{{88{{8{{8{{{{8{{{ (in a random order). This is an extreme but real example. Sometimes it just works as expected, especially when I keep hitting the key in short intervals.

Expected behavior
I would expect to see a series of "{" characters without any "8" in-between.

Screenshots

Desktop (please complete the following information):

• macOS 12.4
• Neovide Version 0.9.0
• Neovim Version 0.7.0

Please run neovide --log and paste the contents of the .log file created in the current directory here:

I had to add a few log statements in KeyboardManager::handle_event() in order to see something. This is the condensed result. The first block reflects the "Ok" situation where hitting the key results in "{", while the second block reflects the error. Watch out for the ModifiersChanged event which is processed out-of-order with respect to the queued input events. (The time stamps show how quickly the events follow each other.

[2022-06-17 20:01:15.096005 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:59: handle_event(WindowEvent { window_id: WindowId(Id(5198875936)), event: KeyboardInput { device_id: DeviceId(DeviceId), event: KeyEvent { physical_key: AltLeft, logical_key: Alt, text: None, location: Left, state: Pressed, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: None, key_without_modifiers: Super } }, is_synthetic: false } })
[2022-06-17 20:01:15.112254 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:79: handle_event(WindowEvent { window_id: WindowId(Id(5198875936)), event: ModifiersChanged(ALT) })
[2022-06-17 20:01:15.112324 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:59: handle_event(WindowEvent { window_id: WindowId(Id(5198875936)), event: KeyboardInput { device_id: DeviceId(DeviceId), event: KeyEvent { physical_key: Digit8, logical_key: Character("8"), text: Some("8"), location: Standard, state: Pressed, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: Some("{"), key_without_modifiers: Character("8") } }, is_synthetic: false } })
[2022-06-17 20:01:15.112387 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:95: handle_event: handling queued input event KeyEvent(KeyEvent { physical_key: AltLeft, logical_key: Alt, text: None, location: Left, state: Pressed, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: None, key_without_modifiers: Super } })
[2022-06-17 20:01:15.112418 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:95: handle_event: handling queued input event KeyEvent(KeyEvent { physical_key: Digit8, logical_key: Character("8"), text: Some("8"), location: Standard, state: Pressed, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: Some("{"), key_without_modifiers: Character("8") } })
[2022-06-17 20:01:15.112647 +02:00] TRACE [neovide::bridge::ui_commands] src/bridge/ui_commands.rs:50: Keyboard Input Sent: {
[2022-06-17 20:01:15.112979 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:59: handle_event(WindowEvent { window_id: WindowId(Id(5198875936)), event: KeyboardInput { device_id: DeviceId(DeviceId), event: KeyEvent { physical_key: Digit8, logical_key: Character("8"), text: None, location: Standard, state: Released, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: Some("{"), key_without_modifiers: Character("8") } }, is_synthetic: false } })
[2022-06-17 20:01:15.124893 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:59: handle_event(WindowEvent { window_id: WindowId(Id(5198875936)), event: KeyboardInput { device_id: DeviceId(DeviceId), event: KeyEvent { physical_key: AltLeft, logical_key: Alt, text: None, location: Left, state: Released, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: None, key_without_modifiers: Super } }, is_synthetic: false } })
[2022-06-17 20:01:15.125012 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:79: handle_event(WindowEvent { window_id: WindowId(Id(5198875936)), event: ModifiersChanged((empty)) })
[2022-06-17 20:01:15.125071 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:95: handle_event: handling queued input event KeyEvent(KeyEvent { physical_key: Digit8, logical_key: Character("8"), text: None, location: Standard, state: Released, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: Some("{"), key_without_modifiers: Character("8") } })
[2022-06-17 20:01:15.125102 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:95: handle_event: handling queued input event KeyEvent(KeyEvent { physical_key: AltLeft, logical_key: Alt, text: None, location: Left, state: Released, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: None, key_without_modifiers: Super } })

[2022-06-17 20:01:15.612608 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:59: handle_event(WindowEvent { window_id: WindowId(Id(5198875936)), event: KeyboardInput { device_id: DeviceId(DeviceId), event: KeyEvent { physical_key: AltLeft, logical_key: Alt, text: None, location: Left, state: Pressed, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: None, key_without_modifiers: Super } }, is_synthetic: false } })
[2022-06-17 20:01:15.613117 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:79: handle_event(WindowEvent { window_id: WindowId(Id(5198875936)), event: ModifiersChanged(ALT) })
[2022-06-17 20:01:15.613247 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:95: handle_event: handling queued input event KeyEvent(KeyEvent { physical_key: AltLeft, logical_key: Alt, text: None, location: Left, state: Pressed, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: None, key_without_modifiers: Super } })
[2022-06-17 20:01:15.641187 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:59: handle_event(WindowEvent { window_id: WindowId(Id(5198875936)), event: KeyboardInput { device_id: DeviceId(DeviceId), event: KeyEvent { physical_key: Digit8, logical_key: Character("8"), text: Some("8"), location: Standard, state: Pressed, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: Some("{"), key_without_modifiers: Character("8") } }, is_synthetic: false } })
[2022-06-17 20:01:15.653703 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:59: handle_event(WindowEvent { window_id: WindowId(Id(5198875936)), event: KeyboardInput { device_id: DeviceId(DeviceId), event: KeyEvent { physical_key: Digit8, logical_key: Character("8"), text: None, location: Standard, state: Released, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: Some("{"), key_without_modifiers: Character("8") } }, is_synthetic: false } })
[2022-06-17 20:01:15.653817 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:59: handle_event(WindowEvent { window_id: WindowId(Id(5198875936)), event: KeyboardInput { device_id: DeviceId(DeviceId), event: KeyEvent { physical_key: AltLeft, logical_key: Alt, text: None, location: Left, state: Released, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: None, key_without_modifiers: Super } }, is_synthetic: false } })
[2022-06-17 20:01:15.653860 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:79: handle_event(WindowEvent { window_id: WindowId(Id(5198875936)), event: ModifiersChanged((empty)) })
[2022-06-17 20:01:15.653905 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:95: handle_event: handling queued input event KeyEvent(KeyEvent { physical_key: Digit8, logical_key: Character("8"), text: Some("8"), location: Standard, state: Pressed, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: Some("{"), key_without_modifiers: Character("8") } })
[2022-06-17 20:01:15.654029 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:95: handle_event: handling queued input event KeyEvent(KeyEvent { physical_key: Digit8, logical_key: Character("8"), text: None, location: Standard, state: Released, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: Some("{"), key_without_modifiers: Character("8") } })
[2022-06-17 20:01:15.654087 +02:00] DEBUG [neovide::window::keyboard_manager] src/window/keyboard_manager.rs:95: handle_event: handling queued input event KeyEvent(KeyEvent { physical_key: AltLeft, logical_key: Alt, text: None, location: Left, state: Released, repeat: false, platform_specific: KeyEventExtra { text_with_all_modifiers: None, key_without_modifiers: Super } })
[2022-06-17 20:01:15.654135 +02:00] TRACE [neovide::bridge::ui_commands] src/bridge/ui_commands.rs:50: Keyboard Input Sent: 8

Additional context

[fredizzimo]

I think that the new winit keyboard API merged in #1789, might fix the issue. Could you try again with the latest Neovide master?

[quadruple-output]

I think that the new winit keyboard API merged in #1789, might fix the issue. Could you try again with the latest Neovide master?

@fredizzimo I just compiled and tested the current master. I can confirm that the issue I reported does not exist, any more, while it did exist with the previous commit.
Good job by everyone involved in the fix. Thank you very much. ❤️