5 files changed, 60 insertions, 1 deletions

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index 67b1ed15c5..bbcb7d9cc5 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -1882,6 +1882,10 @@ bool QGuiApplication::event(QEvent *e)
 {
     if(e->type() == QEvent::LanguageChange) {
         setLayoutDirection(qt_detectRTLLanguage()?Qt::RightToLeft:Qt::LeftToRight);
+        for (auto *topLevelWindow : QGuiApplication::topLevelWindows()) {
+            if (topLevelWindow->flags() != Qt::Desktop)
+                postEvent(topLevelWindow, new QEvent(QEvent::LanguageChange));
+        }
     } else if (e->type() == QEvent::Quit) {
         // Close open windows. This is done in order to deliver de-expose
         // events while the event loop is still running.
diff --git a/src/widgets/kernel/qapplication.cpp b/src/widgets/kernel/qapplication.cpp
index 2d7919e874..f49461b2d0 100644
--- a/src/widgets/kernel/qapplication.cpp
+++ b/src/widgets/kernel/qapplication.cpp
@@ -1904,9 +1904,12 @@ bool QApplication::event(QEvent *e)
     }
 
     if(e->type() == QEvent::LanguageChange) {
+        // QGuiApplication::event does not account for the cases where
+        // there is a top level widget without a window handle. So they
+        // need to have the event posted here
         const QWidgetList list = topLevelWidgets();
         for (auto *w : list) {
-            if (!(w->windowType() == Qt::Desktop))
+            if (!w->windowHandle() && (w->windowType() != Qt::Desktop))
                 postEvent(w, new QEvent(QEvent::LanguageChange));
         }
     }
diff --git a/tests/auto/widgets/kernel/qwidget/hellotr_la.qm b/tests/auto/widgets/kernel/qwidget/hellotr_la.qm
new file mode 100644
index 0000000000..25c0aad583
--- /dev/null
+++ b/tests/auto/widgets/kernel/qwidget/hellotr_la.qm
diff --git a/tests/auto/widgets/kernel/qwidget/qwidget.qrc b/tests/auto/widgets/kernel/qwidget/qwidget.qrc
index 1399c4c9db..597ea872a5 100644
--- a/tests/auto/widgets/kernel/qwidget/qwidget.qrc
+++ b/tests/auto/widgets/kernel/qwidget/qwidget.qrc
@@ -3,5 +3,6 @@
         <file>geometry.dat</file>
         <file>geometry-maximized.dat</file>
         <file>geometry-fullscreen.dat</file>
+        <file>hellotr_la.qm</file>
     </qresource>
 </RCC>
diff --git a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
index 9c16b1a00a..d8f4881ffa 100644
--- a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
+++ b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
@@ -410,6 +410,7 @@ private slots:
     void closeWithChildWindow();
 
     void winIdAfterClose();
+    void receivesLanguageChangeEvent();
 
 private:
     bool ensureScreenSize(int width, int height);
@@ -11360,5 +11361,55 @@ void tst_QWidget::winIdAfterClose()
     delete spy;
 }
 
+class LanguageChangeEventWidget : public QWidget
+{
+public:
+    LanguageChangeEventWidget(QWidget *parent = nullptr) : QWidget(parent) {}
+    int languageChangeCount = 0;
+protected:
+    bool event(QEvent *e) override
+    {
+        if (e->type() == QEvent::LanguageChange)
+            languageChangeCount++;
+        return QWidget::event(e);
+    }
+};
+
+class LanguageChangeEventWindow : public QWindow
+{
+public:
+    LanguageChangeEventWindow(QWindow *parent = nullptr) : QWindow(parent) {}
+    int languageChangeCount = 0;
+protected:
+    bool event(QEvent *e) override
+    {
+        if (e->type() == QEvent::LanguageChange)
+            languageChangeCount++;
+        return QWindow::event(e);
+    }
+};
+
+void tst_QWidget::receivesLanguageChangeEvent()
+{
+    // Confirm that any QWindow or QWidget only gets a single
+    // LanguageChange event when a translator is installed
+    LanguageChangeEventWidget topLevel;
+    auto childWidget = new LanguageChangeEventWidget(&topLevel);
+    topLevel.show();
+    QVERIFY(QTest::qWaitForWindowExposed(&topLevel));
+    LanguageChangeEventWindow ww;
+    ww.show();
+    QVERIFY(QTest::qWaitForWindowExposed(&ww));
+    LanguageChangeEventWidget topLevelNotShown;
+    QTranslator t;
+    QVERIFY(t.load("hellotr_la.qm", ":/"));
+    QVERIFY(qApp->installTranslator(&t));
+    QCoreApplication::sendPostedEvents(0, QEvent::LanguageChange);
+    QCOMPARE(topLevel.languageChangeCount, 1);
+    QCOMPARE(topLevelNotShown.languageChangeCount, 1);
+    QCOMPARE(childWidget->languageChangeCount, 1);
+    QCOMPARE(ww.languageChangeCount, 1);
+}
+
 QTEST_MAIN(tst_QWidget)
 #include "tst_qwidget.moc"