Closes#26468#16667
This PR fixes the spacebar not working with multiple keyboard layouts on
Linux X11. I have tested this with Czech, Russian, German, German Neo 2,
etc. It seems to work correctly.
`XkbStateNotify` events correctly update XKB state with complete
modifier info (depressed/latched/locked), but `KeyPress/KeyRelease`
events immediately overwrite that state using `update_mask()` with only
raw X11 modifier bits. This breaks xkb state as we reset `latched_mods`
and `locked_mods` to 0, as well as we might not correctly handle cases
where this new xkb state needs to change.
Previous logic is flawed because `KeyPress/KeyRelease` event only gives
you depressed modifiers (`event.state`) and not others, which we try to
fill in from `previous_xkb_state`. This patch was introduced to fix
capitalization issue with Neo 2
(https://github.com/zed-industries/zed/pull/14466) and later to fix
wrong keys with German layout
(https://github.com/zed-industries/zed/pull/31193), both of which I have
tested this PR with.
Now, instead of manually managing XKB state, we use the `update_key`
method, which internally handles modifier states and other cases we
might have missed.
From `update_key` docs:
> Update the keyboard state to reflect a given key being pressed or
released.
>
> This entry point is intended for programs which track the keyboard
state explictly (like an evdev client). If the state is serialized to
you by a master process (like a Wayland compositor) using functions like
`xkb_state_serialize_mods()`, you should use `xkb_state_update_mask()`
instead. **_The two functins should not generally be used together._**
>
> A series of calls to this function should be consistent; that is, a
call with `xkb::KEY_DOWN` for a key should be matched by an
`xkb::KEY_UP`; if a key is pressed twice, it should be released twice;
etc. Otherwise (e.g. due to missed input events), situations like "stuck
modifiers" may occur.
>
> This function is often used in conjunction with the function
`xkb_state_key_get_syms()` (or `xkb_state_key_get_one_sym()`), for
example, when handling a key event. In this case, you should prefer to
get the keysyms *before* updating the key, such that the keysyms
reported for the key event are not affected by the event itself. This is
the conventional behavior.
Release Notes:
- Fix the issue where the spacebar doesn’t work with multiple keyboard
layouts on Linux X11.
d4110fd2ab