I noticed when working on display management downstream that rotations of outputs did corrupt the cursor input for Xwayland clients. Looking into it I discovered the mode seems to be set incorrectly in xwl-output when we have xdg-output support.
The mode update code was also unnecessarily complex (double negation), so it is simplified a bit.
What I'm wondering is that I couldn't find any other reports of this problem which seems rather obvious on rotated outputs (the lower area of an output can't be reached with the cursor when in portrait mode). So while in theory the change makes sense to me some more data points from other compositors could be useful.
As of my session see following xrandr output with a single rotated display:
Master branch
Screen 0: minimum 16 x 16, current 1200 x 1920, maximum 32767 x 32767
XWAYLAND0 connected 1920x1200+0+0 right (normal left inverted right x axis y axis) 290mm x 180mm
1200x1920 59.87*+
1152x864 59.78
1024x768 59.68
800x600 59.86
640x480 59.38
320x240 59.52
720x480 59.71
640x400 59.20
320x200 58.96
1024x576 59.90
864x486 59.45
720x400 59.55
640x350 59.77Patched
Screen 0: minimum 16 x 16, current 1200 x 1920, maximum 32767 x 32767
XWAYLAND0 connected 1200x1920+0+0 right (normal left inverted right x axis y axis) 290mm x 180mm
1920x1200 59.88*+
1600x1200 59.87
1440x1080 59.87
1400x1050 59.86
1280x1024 59.76
1280x960 59.94
1152x864 59.78
1024x768 59.68
800x600 59.86
640x480 59.38
320x240 59.52
1680x1050 59.85
1440x900 59.89
1280x800 59.81
720x480 59.71
640x400 59.20
320x200 58.96
1920x1080 59.88
1600x900 59.82
1368x768 59.88
1280x720 59.86
1024x576 59.90
864x486 59.45
720x400 59.55
640x350 59.77