With keyboard enhancement protocol Alt+Shift bindings no longer work

[mkon]

Summary

Recently my terminal alacritty started supporting the kitty keyboard protocol. I can verify that helix is now using it since there is this message when booting helix with -vv: The keyboard enhancement protocol is supported in this terminal.

I also have some keybinds like:

[keys.normal]
"A-n" = "extend_search_next"
"A-N" = "extend_search_prev"

So far this always worked, but now it only runs the lower case binding even when holding shift. Is there a different way to bind keys with the kitty protocol?

In terminal I can run ctrl-v and then alt-shift-n and it will print ^[N (without shift it is ^[n) which looks correct to me. But running hx from the same terminal will not recognise the shift.

Reproduction Steps

I tried this:

Configure helix with alt-shift combinations like the example above.

1. hx

I expected this to happen:

alt-shift-n to search backwards.

Instead, this happened:

alt-shift-n searched forwards.

Helix log

Is there a way to get keypress events in logs? -vv Was not enough.

Platform

macOS

Terminal Emulator

alacritty

Installation Method

brew

Helix Version

helix 23.10 (f6021dd)

[the-mikedavis]

I can't reproduce this with Kitty. AFAIK the kitty keyboard protocol support in alacritty is fairly new so this might be an alacritty bug.

The way I typically debug key events is to run our terminal manipulation library's event-read example: https://github.com/crossterm-rs/crossterm/blob/master/examples/event-read.rs (i.e. clone that repository and run cargo run --example event-read).

In order to make the kitty keyboard protocol settings the same, you can modify this block: https://github.com/crossterm-rs/crossterm/blob/08762b3ef4519e7f834453bf91e3fe36f4c63fe7/examples/event-read.rs#L78-L86

to be:

PushKeyboardEnhancementFlags(
    KeyboardEnhancementFlags::DISAMBIGUATE_ESCAPE_CODES
        | KeyboardEnhancementFlags::REPORT_ALTERNATE_KEYS
)

Those are the settings we enable in Helix.

[mkon]

Hey @the-mikedavis, thanks for the swift response. It seems to be alacritty indeed. It sends these events both both N and n:

Event: Key(KeyEvent { code: Char('n'), modifiers: KeyModifiers(ALT), kind: Press, state: KeyEventState(0x0) })
Event: Key(KeyEvent { code: Char('n'), modifiers: KeyModifiers(ALT), kind: Press, state: KeyEventState(0x0) })

While in kitty it is this:

Event: Key(KeyEvent { code: Char('n'), modifiers: KeyModifiers(ALT), kind: Press, state: KeyEventState(0x0) })
Event: Key(KeyEvent { code: Char('N'), modifiers: KeyModifiers(ALT), kind: Press, state: KeyEventState(0x0) })

I assumed the ctrl-v output pointing to helix, but I guess this does not use the advanced keyboard protocol.