Bug 511028

This is fixed in Plasma 6.5.

(In reply to Nate Graham from comment #1)
> This is fixed in Plasma 6.5.

well,it still work in Plasma 6.5.I try it today.

Can you attach a screen recording that shows it happening?

Created attachment 186631 [details]
the video

look at this video

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Thanks, I can reproduce the issue now.

I don't have an amazing backtrace, but it's hung somewhere in the style:

Using host libthread_db library "/usr/lib/libthread_db.so.1".
0x00007ff496a80cf1 in QObjectPrivate::connectImpl(QObject const*, int, QObject const*, void**, QtPrivate::QSlotObjectBase*, int, int const*, QMetaObject const*) () from /usr/lib/libQt6Core.so.6
(gdb) bt
#0  0x00007ff496a80cf1 in QObjectPrivate::connectImpl(QObject const*, int, QObject const*, void**, QtPrivate::QSlotObjectBase*, int, int const*, QMetaObject const*) () at /usr/lib/libQt6Core.so.6
#1  0x00007ff496a81011 in QObject::connectImpl(QObject const*, void**, QObject const*, void**, QtPrivate::QSlotObjectBase*, Qt::ConnectionType, int const*, QMetaObject const*) ()
    at /usr/lib/libQt6Core.so.6
#2  0x00007ff467048f86 in ??? ()
    at /usr/lib/qt6/plugins/kf6/kirigami/platform/KirigamiPlasmaStyle.so
#3  0x00007ff46704a1b9 in ??? ()
    at /usr/lib/qt6/plugins/kf6/kirigami/platform/KirigamiPlasmaStyle.so
#4  0x00007ff46704a3eb in ??? ()
    at /usr/lib/qt6/plugins/kf6/kirigami/platform/KirigamiPlasmaStyle.so
#5  0x00007ff48c2b44a7 in Kirigami::Platform::PlatformTheme::qmlAttachedProperties(QObject*) ()
    at /usr/lib/libKirigamiPlatform.so.6
#6  0x00007ff497d57eca in qmlAttachedPropertiesObject(QObject*, QObject* (*)(QObject*), bool) ()
    at /usr/lib/libQt6Qml.so.6
#7  0x00007ff497eba9cd in QV4::QQmlTypeWrapper::virtualGet(QV4::Managed const*, QV4::PropertyKey, QV4::Value const*, bool*) () at /usr/lib/libQt6Qml.so.6
#8  0x00007ff497c9f234 in QV4::Lookup::getterFallback(QV4::Lookup*, QV4::ExecutionEngine*, QV4::Value const&) () at /usr/lib/libQt6Qml.so.6
#9  0x00007ff447d5628f in ??? ()
#10 0x00007ffce6b7b240 in ??? ()
#11 0x0000555d2f3e9450 in ??? ()
#12 0x0000000000000000 in ??? ()

Will update once I get a better one.

Created attachment 188056 [details]
backtrace full

Attaching full backtrace.

From the attached backtrace:

> #0  0x00007fff6f09c14c in QObjectPrivate::connectImpl
>     (sender=sender@entry=0x5556001d0f00, signal_index=24, receiver=receiver@entry=0x5556103b70c0, slot=slot@entry=0x7ffffd12e870, slotObjRaw=slotObjRaw@entry=0x5556103b8690, type=type@entry=128, types=types@entry=0x0, senderMetaObject=senderMetaObject@entry=0x7fff710890a8 <QQuickWindow::staticMetaObject>)
>     at /home/kde/kde/src/qtbase/src/corelib/kernel/qobject.cpp:5322

```
QMetaObject::Connection QObjectPrivate::connectImpl(...)
{
    if (c2->receiver.loadRelaxed() == receiver && c2->isSlotObject && c2->slotObj->compare(slot))
}
```

> #3  PlasmaTheme::syncWindow (this=0x5556103b70c0) at /home/kde/kde/src/libplasma/src/declarativeimports/kirigamiplasmastyle/plasmatheme.cpp:98

```
void PlasmaTheme::syncWindow()
{
    connect(qw, &QQuickWindow::sceneGraphInitialized, this, &PlasmaTheme::syncWindow, Qt::UniqueConnection);
}
```

> #4  0x00007fff456e771c in PlasmaTheme::PlasmaTheme (this=this@entry=0x5556103b70c0, parent=0x5556103b6840)
>     at /home/kde/kde/src/libplasma/src/declarativeimports/kirigamiplasmastyle/plasmatheme.cpp:56

```
PlasmaTheme::PlasmaTheme(QObject *parent)
{
    syncWindow();
}
```

Getting context:

```
git blame plasmatheme.cpp | grep sceneGraphInitialized
f40f745993 (Marco Martin             2025-03-24 14:09:54 +0000  98)             connect(qw, &QQuickWindow::sceneGraphInitialized, this, &PlasmaTheme::syncWindow, Qt::UniqueConnection);

git log f40f745993^..f40f745993
commit f40f7459938667e8c66bb0585d8df5957a59a979
Author: Marco Martin <notmart@gmail.com>
Date:   Mon Mar 24 14:09:54 2025 +0000

    Use Disabled Text color when needed
    
    With the same logic taken 1:1 from the plugin in qqc2-desktop-style,
    notice when the parent item or window is disabled, and change the text
    color accordingly
    
    BUG:501633
```

Comparing with qqc2-desktop-style I came up with:

```
diff --git a/src/declarativeimports/kirigamiplasmastyle/plasmatheme.cpp b/src/declarativeimports/kirigamiplasmastyle/plasmatheme.cpp
index 1897a9344..dc230e2b6 100644
--- a/src/declarativeimports/kirigamiplasmastyle/plasmatheme.cpp
+++ b/src/declarativeimports/kirigamiplasmastyle/plasmatheme.cpp
@@ -94,8 +94,12 @@ void PlasmaTheme::syncWindow()
         if (!window) {
             window = qw;
         }
-        if (qw) {
-            connect(qw, &QQuickWindow::sceneGraphInitialized, this, &PlasmaTheme::syncWindow, Qt::UniqueConnection);
+
+        disconnect(m_sgConnection);
+        if (qw && !qw->isSceneGraphInitialized() && qw != m_window) {
+            m_sgConnection = connect(qw, &QQuickWindow::sceneGraphInitialized, this, &PlasmaTheme::syncWindow);
+        } else if (!qw) {
+            m_sgConnection = QMetaObject::Connection();
         }
     }
     m_window = window;
diff --git a/src/declarativeimports/kirigamiplasmastyle/plasmatheme.h b/src/declarativeimports/kirigamiplasmastyle/plasmatheme.h
index 462c8713d..ca645f326 100644
--- a/src/declarativeimports/kirigamiplasmastyle/plasmatheme.h
+++ b/src/declarativeimports/kirigamiplasmastyle/plasmatheme.h
@@ -38,6 +38,7 @@ protected:
 private:
     Plasma::Theme m_theme;
     QPointer<QWindow> m_window;
+    QMetaObject::Connection m_sgConnection;
 };
 
 #endif // PLASMATHEME_H
```

Unfortunately even with that patch applied the freeze still happens but now the backtrace looks very strange :-/