input: Only forward modifiers in KeyboardInnerHandle::set_focus

[luveti]

This should fix #1107.

[Drakulix]

Looks good! Thanks

[cmeissl]

LGTM

[ids1024]

How does this compare to behavior in other compositors? wl_keyboard::enter takes an array of pressed keys, so the previously implementation of this looks like how the Wayland protocol is intended to implement.

[Drakulix]

How does this compare to behavior in other compositors? wl_keyboard::enter takes an array of pressed keys, so the previously implementation of this looks like how the Wayland protocol is intended to implement.

Hmm sway does seem to indeed send the pressed keys: https://github.com/swaywm/sway/blob/89f85312687b7fd1777c936e169e6400cee0a4b4/sway/input/seat.c#L164-L166

[Drakulix]

So I was wondering why I don't observe this behaviour in cosmic-comp and it seems to come do to, at which point you trigger the shortcut. cosmic-comp triggers them on key-release, which means the key is removed from pressed_keys before the focus changes. There is obviously value in allowing this to work on key-pressed as well, so if we don't want to always send an empty set of keys, we need to at least honour the compositors which to intercept a key and consequentially remove the key from pressed_keys again.

[luveti]

@ids1024 @Drakulix I observed that XFCE (X11) will maintain pressed keys when switching windows. So I've implemented the second option and it appears to work well.

[codecov-commenter]

Codecov Report

Patch coverage: 40.00% and project coverage change: -1.11% ⚠️

Comparison is base (c569c87) 24.01% compared to head (6e63f32) 22.90%.
Report is 35 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1110      +/-   ##
==========================================
- Coverage   24.01%   22.90%   -1.11%     
==========================================
  Files         140      143       +3     
  Lines       21591    22859    +1268     
==========================================
+ Hits         5184     5235      +51     
- Misses      16407    17624    +1217     

Flag	Coverage Δ
wlcs-buffer	20.00% <40.00%> (-1.03%)	⬇️
wlcs-core	19.65% <40.00%> (-1.01%)	⬇️
wlcs-output	8.17% <20.00%> (-0.30%)	⬇️
wlcs-pointer-input	21.67% <40.00%> (-1.04%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
src/wayland/tablet_manager/tablet_seat.rs	4.72% <0.00%> (ø)
src/input/keyboard/mod.rs	12.69% <33.33%> (+0.19%)	⬆️
src/wayland/shell/xdg/mod.rs	30.97% <100.00%> (-0.63%)	⬇️

... and 27 files with indirect coverage changes

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[Drakulix]

Now this is only a bugfix, not forwarding any intercepted key presses. I don't think this is in any way controversial.

Should anyone want to discuss over semantics of key presses on focus swaps, they can open a new issue. This doesn't change behaviour, so lets move on with this PR.

Thanks @luveti for working on this! :)