QMdi: Don't emit subWindowActivated during StyleChange handling.

The handling of StyleChange de-maximizes the child window temporarily,
which was emitting subWindowActivated.
This would crash lokalize, because deactivating a window means deleting
the widgets associated with it, and style-change handling is done in
QApplication by looping over QApplication::allWidgets, which would then
contain dangling pointers.

Full valgrind log at https://bugs.kde.org/show_bug.cgi?id=271494#c7

Change-Id: I256da214bf00fd7925dcee67b4f0414e57fc453b
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
(cherry picked from qtbase/a6e5ccbe223c5a606e15556e8708e863442d9f72)

1 files changed, 34 insertions, 0 deletions

diff --git a/tests/auto/qmdisubwindow/tst_qmdisubwindow.cpp b/tests/auto/qmdisubwindow/tst_qmdisubwindow.cpp
index 928e2c6..e672ce9 100644
--- a/tests/auto/qmdisubwindow/tst_qmdisubwindow.cpp
+++ b/tests/auto/qmdisubwindow/tst_qmdisubwindow.cpp
@@ -163,6 +163,7 @@ Q_DECLARE_METATYPE(Qt::WindowState);
 Q_DECLARE_METATYPE(Qt::WindowStates);
 Q_DECLARE_METATYPE(Qt::WindowType);
 Q_DECLARE_METATYPE(Qt::WindowFlags);
+Q_DECLARE_METATYPE(QMdiSubWindow*);
 
 //TESTED_CLASS=
 //TESTED_FILES=
@@ -214,6 +215,7 @@ private slots:
     void task_182852();
     void task_233197();
     void task_226929();
+    void styleChange();
 };
 
 void tst_QMdiSubWindow::initTestCase()
@@ -2039,6 +2041,38 @@ void tst_QMdiSubWindow::task_226929()
     QVERIFY(sub1->isMaximized());
 }
 
+void tst_QMdiSubWindow::styleChange()
+{
+    QMdiArea mdiArea;
+    mdiArea.show();
+
+#ifdef Q_WS_X11
+    qt_x11_wait_for_window_manager(&mdiArea);
+#endif
+
+    QMdiSubWindow *sub1 = mdiArea.addSubWindow(new QTextEdit);
+    sub1->showMaximized();
+
+    QMdiSubWindow *sub2 = mdiArea.addSubWindow(new QTextEdit);
+    sub2->showMinimized();
+
+    mdiArea.setActiveSubWindow(sub1);
+
+    QTest::qWait(100);
+
+    qRegisterMetaType<QMdiSubWindow *>();
+    QSignalSpy spy(&mdiArea, SIGNAL(subWindowActivated(QMdiSubWindow*)));
+    QVERIFY(spy.isValid());
+
+    QEvent event(QEvent::StyleChange);
+    QApplication::sendEvent(sub1, &event);
+    QApplication::sendEvent(sub2, &event);
+
+    // subWindowActivated should NOT be activated by a style change,
+    // even if internally QMdiSubWindow un-minimizes subwindows temporarily.
+    QCOMPARE(spy.count(), 0);
+}
+
 QTEST_MAIN(tst_QMdiSubWindow)
 #include "tst_qmdisubwindow.moc"