Summary:
This is a regression due to changes in Breeze to support Qt 5.8+ behavior
change. KWin's own QPA operates like < Qt 5.7 and breeze was programmed
against that. Due to that it can happen now that Breeze hits code paths
in which KWin does not have a surface.
To trigger one only needed to open the user actions menu twice.
This change adds a test case which simulates the problem and fixes all
crashes happening in the code path.
Most likely shadows are now broken for KWin's own windows, this change is
only to prevent the crash and thus is for 5.10 branch, while shadow
fixing will go to master branch.
BUG: 382063
FIXED-IN: 5.10.4
Test Plan: New test case
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D6533
This introduces an own QPA plugin for KWin. QtWayland's plugin is not
a good solution for KWin as QtWayland is meant for Wayland clients and
not for a Wayland server. Given that it makes more sense to have a very
minimal QPA plugin which supports the use cases we actually have.
With our own QPA plugin we should be able to improve the following
areas:
* no need to create Wayland server before QApplication
* Qt::BypassWindowManagerHint can be supported
* no workaround for creating OpenGL context in main thread
* sharing OpenGL context with Qt
* OpenGL context for Qt on libhybris backend
The plugin supports so far the following features:
* creating a QPlatformWindow using KWayland::Client (ShellSurface)
* creating a QPlatformBackingStore using a ShmPool
* creating a QPlatformOpenGLContext with Wayland::EGL
* or creating a QPlatformOpenGLContext which shares with KWin's scene
* creating a QPlatformScreen for each KWayland::Client::Output
* QPlatformNativeInterface compatible to QtWayland
