Qt6 changed the mouse scroll wheel handling for QtQuick to a type that mimics how touch pads/screens work, which most people find feels very poor. KDE fixes this by creating a custom type which re-implements the QtWidgets handling (see https://invent.kde.org/frameworks/kirigami/-/merge_requests/415).
On Matrix Nico has expressed a desire not to have to deal with compiling Kirigami for Windows and Mac, which is understandable. Linux users on the other hand almost always have kirigami available in their package repos which sidesteps that particular issue. We can search for Kirigami at build time and if present define a QML context property to allow it to be used, which should fix this issue for Linux users at least.
Helps with nheko-reborn/nheko#1819 (which won't be completely resolved until this is working for Windows and Mac as well).
Signed-off-by: Reilly Brogan <reilly@reillybrogan.com>
Backtrace:
Thread 1 "nheko" received signal SIGSEGV, Segmentation fault.
containerWidget (w=w@entry=0x0) at /usr/src/debug/dev-qt/qtwidgets-5.15.7/qtbase-everywhere-src-5.15.7/src/widgets/styles/qstylesheetstyle.cpp:2467
2467 if (const QAbstractScrollArea *sa = qobject_cast<const QAbstractScrollArea *>(w->parentWidget())) {
(gdb) bt
#0 containerWidget(QWidget const*) (w=w@entry=0x0) at /usr/src/debug/dev-qt/qtwidgets-5.15.7/qtbase-everywhere-src-5.15.7/src/widgets/styles/qstylesheetstyle.cpp:2467
#1 0x00007ffff4aa0ad6 in QStyleSheetStyle::drawPrimitive(QStyle::PrimitiveElement, QStyleOption const*, QPainter*, QWidget const*) const (this=0x555559917900, pe=<optimized out>, opt=0x55555ea4b5c0, p=0x7fffffffcfd0, w=0x0) at /usr/src/debug/dev-qt/qtwidgets-5.15.7/qtbase-everywhere-src-5.15.7/src/widgets/styles/qstylesheetstyle.cpp:4452
#2 0x00007fff61d4a86b in KQuickStyleItem::paint(QPainter*) (this=this@entry=0x55555ea4a1e0, painter=painter@entry=0x7fffffffcfd0) at /usr/src/debug/kde-frameworks/qqc2-desktop-style-5.101.0/qqc2-desktop-style-5.101.0/plugin/kquickstyleitem.cpp:1667
#3 0x00007fff61d4b22a in KQuickStyleItem::updatePolish() (this=0x55555ea4a1e0) at /usr/src/debug/kde-frameworks/qqc2-desktop-style-5.101.0/qqc2-desktop-style-5.101.0/plugin/kquickstyleitem.cpp:1928
#4 0x00007ffff57717c2 in QQuickWindowPrivate::polishItems() (this=0x55555ea2e760) at /usr/src/debug/dev-qt/qtdeclarative-5.15.7-r1/qtdeclarative-everywhere-src-5.15.7/src/quick/items/qquickwindow.cpp:393
#5 0x00007ffff570f4ef in QSGThreadedRenderLoop::polishAndSync(QSGThreadedRenderLoop::Window*, bool) (this=this@entry=0x5555598eb770, w=w@entry=0x7fffe000aef0, inExpose=inExpose@entry=true) at /usr/src/debug/dev-qt/qtdeclarative-5.15.7-r1/qtdeclarative-everywhere-src-5.15.7/src/quick/scenegraph/qsgthreadedrenderloop.cpp:1576
#6 0x00007ffff5710a8e in QSGThreadedRenderLoop::handleExposure(QQuickWindow*) (this=0x5555598eb770, window=<optimized out>) at /usr/src/debug/dev-qt/qtdeclarative-5.15.7-r1/qtdeclarative-everywhere-src-5.15.7/src/quick/scenegraph/qsgthreadedrenderloop.cpp:1374
#7 0x00007ffff43d2b45 in QWindow::event(QEvent*) (this=0x7fffe0006eb0, ev=<optimized out>) at /usr/src/debug/dev-qt/qtgui-5.15.7-r1/qtbase-everywhere-src-5.15.7/src/gui/kernel/qwindow.cpp:2450
#8 0x00007ffff49ee481 in QApplicationPrivate::notify_helper(QObject*, QEvent*) (this=<optimized out>, receiver=0x7fffe0006eb0, e=0x7fffffffd460) at /usr/src/debug/dev-qt/qtwidgets-5.15.7/qtbase-everywhere-src-5.15.7/src/widgets/kernel/qapplication.cpp:3637
#9 0x00007ffff3e2d618 in QCoreApplication::notifyInternal2(QObject*, QEvent*) (receiver=0x7fffe0006eb0, event=0x7fffffffd460) at /usr/src/debug/dev-qt/qtcore-5.15.7/qtbase-everywhere-src-5.15.7/src/corelib/kernel/qcoreapplication.cpp:1064
#10 0x00007ffff43c8368 in QGuiApplicationPrivate::processExposeEvent(QWindowSystemInterfacePrivate::ExposeEvent*) (e=0x55555f648b30) at /usr/src/debug/dev-qt/qtgui-5.15.7-r1/qtbase-everywhere-src-5.15.7/src/gui/kernel/qguiapplication.cpp:3261
#11 0x00007ffff43a55ab in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) (flags=flags@entry=...) at /usr/src/debug/dev-qt/qtgui-5.15.7-r1/qtbase-everywhere-src-5.15.7/src/gui/kernel/qwindowsysteminterface.cpp:1169
#12 0x00007fffef102622 in xcbSourceDispatch(GSource*, GSourceFunc, gpointer) (source=<optimized out>) at /usr/src/debug/dev-qt/qtgui-5.15.7-r1/qtbase-everywhere-src-5.15.7/src/plugins/platforms/xcb/qxcbeventdispatcher.cpp:105
#13 0x00007ffff386d030 in g_main_context_dispatch () at /usr/lib64/libglib-2.0.so.0
#14 0x00007ffff386d2d8 in () at /usr/lib64/libglib-2.0.so.0
#15 0x00007ffff386d36f in g_main_context_iteration () at /usr/lib64/libglib-2.0.so.0
#16 0x00007ffff3e80e55 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x5555596a4770, flags=...) at /usr/src/debug/dev-qt/qtcore-5.15.7/qtbase-everywhere-src-5.15.7/src/corelib/kernel/qeventdispatcher_glib.cpp:423
#17 0x00007ffff3e2c00b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7fffffffd700, flags=..., flags@entry=...) at /usr/src/debug/dev-qt/qtcore-5.15.7/qtbase-everywhere-src-5.15.7/include/QtCore/../../src/corelib/global/qflags.h:69
#18 0x00007ffff3e344ea in QCoreApplication::exec() () at /usr/src/debug/dev-qt/qtcore-5.15.7/qtbase-everywhere-src-5.15.7/include/QtCore/../../src/corelib/global/qflags.h:121
#19 0x00005555594a5c43 in main(int, char**) (argc=2, argv=0x7fffffffdab8) at /home/nicolas/Dokumente/devel/open-source/nheko/src/main.cpp:401
(gdb) p w
$1 = (const QWidget *) 0x0
