Ctrl is reported as not pressed when combining Ctrl+Altgr on Windows

[fredizzimo]

On Windows, when pressing a key in combination with altgr for example alt-gr+e, which produces €, the CTRL state is not reported correctly. Here's the log from WindowEvent::KeyboardEvent, and WindowEvent::ModifiersChanged

Modifiers { state: ModifiersState(CONTROL), pressed_mods: ModifiersKeys(0x0) }
KeyEvent {
    physical_key: ControlLeft,
    logical_key: Control,
    text: None,
    location: Left,
    state: Pressed,
    repeat: false,
    platform_specific: KeyEventExtra {
        text_with_all_modifers: None,
        key_without_modifiers: Control,
    },
}
Modifiers { state: ModifiersState(0x0), pressed_mods: ModifiersKeys(0x0) }
KeyEvent {
    physical_key: AltRight,
    logical_key: AltGraph,
    text: None,
    location: Right,
    state: Pressed,
    repeat: false,
    platform_specific: KeyEventExtra {
        text_with_all_modifers: None,
        key_without_modifiers: AltGraph,
    },
}
KeyEvent {
    physical_key: AltRight,
    logical_key: AltGraph,
    text: None,
    location: Right,
    state: Pressed,
    repeat: true,
    platform_specific: KeyEventExtra {
        text_with_all_modifers: None,
        key_without_modifiers: AltGraph,
    },
}
KeyEvent {
    physical_key: AltRight,
    logical_key: AltGraph,
    text: None,
    location: Right,
    state: Pressed,
    repeat: true,
    platform_specific: KeyEventExtra {
        text_with_all_modifers: None,
        key_without_modifiers: AltGraph,
    },
}
KeyEvent {
    physical_key: AltRight,
    logical_key: AltGraph,
    text: None,
    location: Right,
    state: Pressed,
    repeat: true,
    platform_specific: KeyEventExtra {
        text_with_all_modifers: None,
        key_without_modifiers: AltGraph,
    },
}
KeyEvent {
    physical_key: AltRight,
    logical_key: AltGraph,
    text: None,
    location: Right,
    state: Pressed,
    repeat: true,
    platform_specific: KeyEventExtra {
        text_with_all_modifers: None,
        key_without_modifiers: AltGraph,
    },
}
KeyEvent {
    physical_key: KeyE,
    logical_key: Character(
        "€",
    ),
    text: Some(
        "€",
    ),
    location: Standard,
    state: Pressed,
    repeat: false,
    platform_specific: KeyEventExtra {
        text_with_all_modifers: Some(
            "€",
        ),
        key_without_modifiers: Character(
            "e",
        ),
    },
}
KeyEvent {
    physical_key: KeyE,
    logical_key: Character(
        "€",
    ),
    text: None,
    location: Standard,
    state: Released,
    repeat: false,
    platform_specific: KeyEventExtra {
        text_with_all_modifers: None,
        key_without_modifiers: Character(
            "e",
        ),
    },
}
Modifiers { state: ModifiersState(CONTROL), pressed_mods: ModifiersKeys(0x0) }
KeyEvent {
    physical_key: AltRight,
    logical_key: AltGraph,
    text: None,
    location: Right,
    state: Released,
    repeat: false,
    platform_specific: KeyEventExtra {
        text_with_all_modifers: None,
        key_without_modifiers: AltGraph,
    },
}
Modifiers { state: ModifiersState(0x0), pressed_mods: ModifiersKeys(0x0) }
KeyEvent {
    physical_key: ControlLeft,
    logical_key: Control,
    text: None,
    location: Left,
    state: Released,
    repeat: false,
    platform_specific: KeyEventExtra {
        text_with_all_modifers: None,
        key_without_modifiers: Control,
    },
}

As soon as AltGraph is pressed Modifiers::state stops reporting Control, and only starts reporting it again when AltGr is released. Therefore, it's impossible to determine that control is held down using the modifiers state alone.

Note that there's also another, not as critical bug shown in the logs, AltGraph is repeated, although I don't think there should be a key repeat on that since it's a modifier, I'm not even sure if it makes sense to report it as a key press at all, rather than a modifier state.

This was reproduced using Neovide and Winit 0.29.0-beta.0

I think a similar issue was reported by @dhardy here in this comment #2898 (comment)

[fredizzimo]

This is probably some side effect of trying to deal with the fact that in Windows, alt gr and ctrl+alt are the same.

[fredizzimo]

This is probably also related #2945

[fredizzimo]

I just realized that this is more critical than what it seems. I did not think of it at first, but this breaks the default mapping <C-\><C-N>, which is used to go to the normal mode of the built-in terminal of Neovim on my Swedish keyboard layout. So, without custom remaps, it completely breaks the usability of the built-in terminal.

I'm using a custom mapping myself, so I did not think of it, but I recently had to do some testing with a clean nvim configuration, and had big problems. I almost ran into the meme of not being able to exit vim. But fortunately, you can type exit to exit the terminal. Still, it's not possible to do anything else, while keeping the terminal open.