From 75e5ffe0f71bfccd6ae31d1b437dfea58bfb28a7 Mon Sep 17 00:00:00 2001
From: Dyami Caliri <dyami@dragonframe.com>
Date: Tue, 16 Sep 2014 09:35:11 -0700
Subject: Update widget winId when screen changes

When a window's screen changes it may recreate the platform window.
In that case, update the winId in the widget to keep it in sync.

Task-number: QTBUG-40681
Change-Id: Iec815320214832bb63952de3a5bd1340a04dacd4
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
---
 src/widgets/kernel/qwidget.cpp                     |  6 +++++
 .../kernel/qwidget_window/qwidget_window.pro       |  2 +-
 .../kernel/qwidget_window/tst_qwidget_window.cpp   | 31 ++++++++++++++++++++++
 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp
index 65978ef562..8d1a24a4ec 100644
--- a/src/widgets/kernel/qwidget.cpp
+++ b/src/widgets/kernel/qwidget.cpp
@@ -9042,6 +9042,12 @@ bool QWidget::event(QEvent *event)
         event->ignore();
         break;
 #endif
+    case QEvent::ScreenChangeInternal:
+        if (const QTLWExtra *te = d->maybeTopData()) {
+            const QWindow *win = te->window;
+            d->setWinId((win && win->handle()) ? win->handle()->winId() : 0);
+        }
+        break;
 #ifndef QT_NO_PROPERTIES
     case QEvent::DynamicPropertyChange: {
         const QByteArray &propName = static_cast<QDynamicPropertyChangeEvent *>(event)->propertyName();
diff --git a/tests/auto/widgets/kernel/qwidget_window/qwidget_window.pro b/tests/auto/widgets/kernel/qwidget_window/qwidget_window.pro
index baa2823f9a..d61681d5cb 100644
--- a/tests/auto/widgets/kernel/qwidget_window/qwidget_window.pro
+++ b/tests/auto/widgets/kernel/qwidget_window/qwidget_window.pro
@@ -1,7 +1,7 @@
 CONFIG += testcase
 CONFIG += parallel_test
 TARGET = tst_qwidget_window
-QT += widgets testlib
+QT += widgets testlib core-private gui-private
 SOURCES  += tst_qwidget_window.cpp
 
 x11 {
diff --git a/tests/auto/widgets/kernel/qwidget_window/tst_qwidget_window.cpp b/tests/auto/widgets/kernel/qwidget_window/tst_qwidget_window.cpp
index 8084d50fbe..f9d705de26 100644
--- a/tests/auto/widgets/kernel/qwidget_window/tst_qwidget_window.cpp
+++ b/tests/auto/widgets/kernel/qwidget_window/tst_qwidget_window.cpp
@@ -52,6 +52,8 @@
 #include <qlistwidget.h>
 #include <qpushbutton.h>
 #include <qboxlayout.h>
+#include <qlabel.h>
+#include <private/qwindow_p.h>
 
 static inline void setFrameless(QWidget *w)
 {
@@ -97,6 +99,7 @@ private slots:
 #endif
 
     void tst_qtbug35600();
+    void tst_updateWinId_QTBUG40681();
 };
 
 void tst_QWidget_window::initTestCase()
@@ -603,5 +606,33 @@ void tst_QWidget_window::tst_qtbug35600()
     // QTBUG-35600: program may crash here or on exit
 }
 
+void tst_QWidget_window::tst_updateWinId_QTBUG40681()
+{
+    QWidget w;
+    QVBoxLayout *vl = new QVBoxLayout(&w);
+    QLabel *lbl = new QLabel("HELLO1");
+    lbl->setAttribute(Qt::WA_NativeWindow);
+    lbl->setObjectName("label1");
+    vl->addWidget(lbl);
+    w.setMinimumWidth(200);
+
+    w.show();
+
+    QVERIFY(QTest::qWaitForWindowExposed(&w));
+
+    QCOMPARE(lbl->winId(), lbl->windowHandle()->winId());
+
+     // simulate screen change and notification
+    QWindow *win = w.windowHandle();
+    w.windowHandle()->destroy();
+    lbl->windowHandle()->destroy();
+    w.windowHandle()->create();
+    lbl->windowHandle()->create();
+    QWindowPrivate *p = qt_window_private(win);
+    p->emitScreenChangedRecursion(win->screen());
+
+    QCOMPARE(lbl->winId(), lbl->windowHandle()->winId());
+}
+
 QTEST_MAIN(tst_QWidget_window)
 #include "tst_qwidget_window.moc"
-- 
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