xkb_file should accept an empty value

[thblt]

I want to use the same default layout for all keyboards, but devices like yubikeys (or barcode scanners, or any devices that pretend to be keyboards) use the US-QWERTY layout. Because my keyboard layout (for real keyboards) is hugely customized, I use a xkb file. My config thus looks like this:

input 4176:1031:Yubico_YubiKey_OTP+FIDO+CCID { 
  xkb_layout us 
} 
input type:keyboard { 
  xkb_file ~/.config/sway/my_weird_layout.xkb 
} 

with this config, the yubikey uses the layout described in my_weird_layout.xkb instead of US-QWERTY. I guess this happens because xkb_file gets merged from input type:keyboard into input 4176:1031:Yubico_YubiKey_OTP+FIDO+CCID.

A nice solution for that issue would be for xkb_file to accept an empty value:

input 4176:1031:Yubico_YubiKey_OTP+FIDO+CCID { 
  xkb_layout us
  xkb_file 
} 
input type:keyboard { 
  xkb_file ~/.config/sway/my_weird_layout.xkb 
} 

I'm aware there are other solutions with the actual config syntax (use a xkb file for us qwerty as well, or configure each keyboard individually), but they're not as nice :)

[emersion]

Should we reset xkb_file when merged into with a config which specifies xkb_layout since these two are conflicting? (And the other way around)

[sahinf]

The last sentence of the blame-commit suggests that new type configs are intended to overwrite existing configs.

$ git show --summary bd3720585          
commit bd3720585e91ae0dfcc4be30149ae4f8f5218174
Author: Benjamin Cheng <ben@bcheng.me>
Date:   Mon Mar 25 22:05:49 2019 -0400

    Implement input type configs (#3784)
    
    Add support for configurations that apply to a type of inputs
    (i.e. natural scrolling on all touchpads). A type config is
    differentiated by a `type:` prefix followed by the type it
    corresponds to.
    
    When new devices appear, the device config is merged on top of its
    type config (if it exists). New type configs are applied on top of
    existing configs.

This would be a hacky "solution" but does it work as you expect if you flip the order as such:

input type:keyboard { 
  xkb_file ~/.config/sway/my_weird_layout.xkb 
} 
input 4176:1031:Yubico_YubiKey_OTP+FIDO+CCID { 
  xkb_layout us 
}