From b08e8ba2e62d4f5cdf69ac207320d49141c096ed Mon Sep 17 00:00:00 2001
From: c4pp4
Date: Fri, 1 May 2026 11:48:59 +0200
Subject: [PATCH 1/1] Fix Krita global menu

Defer QGnomePortalInterface DBus init until event dispatcher exists.

Signed-off-by: c4pp4
---
 .../platform/unix/qgnomeportalinterface.cpp   | 33 ++++++++++++++++++-
 .../platform/unix/qgnomeportalinterface_p.h   |  2 ++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/src/gui/platform/unix/qgnomeportalinterface.cpp b/src/gui/platform/unix/qgnomeportalinterface.cpp
index 8c089388..f42063ca 100644
--- a/src/gui/platform/unix/qgnomeportalinterface.cpp
+++ b/src/gui/platform/unix/qgnomeportalinterface.cpp
@@ -5,6 +5,8 @@
 #include "qgnomeportalinterface_p.h"
 #include "qdbussettings_p.h"
 #include <private/qdbusplatformmenu_p.h>
+#include <QtCore/QCoreApplication>
+#include <QtCore/QMetaObject>
 #include <QtDBus/QDBusMessage>
 #include <QtDBus/QDBusPendingCall>
 #include <QtDBus/QDBusReply>
@@ -19,8 +21,33 @@ Q_STATIC_LOGGING_CATEGORY(lcQpaThemeGnome, "qt.qpa.theme.gnome")
 using namespace Qt::StringLiterals;
 
 QGnomePortalInterface::QGnomePortalInterface(QObject *parent)
-    : QObject(parent), m_dbus{ new QDBusListener }
+    : QObject(parent)
 {
+    ensureDbusInitialized();
+}
+
+void QGnomePortalInterface::ensureDbusInitialized()
+{
+    if (m_dbus)
+        return;
+
+    // Do not touch session bus before the event dispatcher exists.
+    // On some setups (e.g. gtk3 platform theme), doing so can create a DBus
+    // connection that never processes incoming messages, breaking DBusMenu.
+    if (!QCoreApplication::eventDispatcher()) {
+        if (!m_dbusInitScheduled) {
+            m_dbusInitScheduled = true;
+            QMetaObject::invokeMethod(this,
+                                      [this] {
+                                          m_dbusInitScheduled = false;
+                                          ensureDbusInitialized();
+                                      },
+                                      Qt::QueuedConnection);
+        }
+        return;
+    }
+
+    m_dbus.reset(new QDBusListener);
     QObject::connect(m_dbus.get(), &QDBusListener::settingChanged, this,
                      &QGnomePortalInterface::dbusSettingChanged);
 
@@ -60,6 +87,10 @@ QGnomePortalInterface::contrastPreference(Qt::ContrastPreference fallback) const
 
 void QGnomePortalInterface::querySettings()
 {
+    // Safety net: if called too early for any reason, just bail out.
+    if (!QCoreApplication::eventDispatcher())
+        return;
+
     QDBusConnection dbus = QDBusConnection::sessionBus();
     if (!dbus.isConnected()) {
         qCWarning(lcQpaThemeGnome) << "dbus connection failed. Last error: " << dbus.lastError();
diff --git a/src/gui/platform/unix/qgnomeportalinterface_p.h b/src/gui/platform/unix/qgnomeportalinterface_p.h
index a1ff267f..b92e3feb 100644
--- a/src/gui/platform/unix/qgnomeportalinterface_p.h
+++ b/src/gui/platform/unix/qgnomeportalinterface_p.h
@@ -37,6 +37,7 @@ public:
             Qt::ContrastPreference fallback = Qt::ContrastPreference::NoPreference) const;
 
 private:
+    void ensureDbusInitialized();
     void querySettings();
     void updateColorScheme(Qt::ColorScheme colorScheme);
     void updateContrast(Qt::ContrastPreference contrast);
@@ -54,6 +55,7 @@ private:
     std::optional<Qt::ColorScheme> m_colorScheme;
     std::optional<Qt::ContrastPreference> m_contrast;
     std::unique_ptr<QDBusListener> m_dbus;
+    bool m_dbusInitScheduled = false;
     static constexpr QLatin1StringView s_service{ "org.freedesktop.portal.Desktop" };
     static constexpr QLatin1StringView s_path{ "/org/freedesktop/portal/desktop" };
     static constexpr QLatin1StringView s_interface{ "org.freedesktop.portal.Settings" };
-- 
2.53.0