From 01aeb5f7e4fd977e9698fffdc7650897664ecb82 Mon Sep 17 00:00:00 2001
From: Volker Hilsheimer <volker.hilsheimer@qt.io>
Date: Fri, 20 Aug 2021 10:41:06 +0200
Subject: [PATCH] QGraphicsProxyWidget: forward Window(De)Activate events

The nested widget might be a QGraphicsView as well (documented to be
supported), and QGraphicsScene maintains it's own activation status by
counting Window(De)Activate events. We need to make sure that the
embedded widget is informed about its activation status so that deeper
nested children can receive focus.

Forward WindowActivate/Deactivate events to the nested widget, which
will pass it on to all its children. Add test case, which without this
fix fails when verifying the inner scene's isActive state, or later
when testing that focusInEvent is delivered to the embedded widget.

Fixes: QTBUG-94091
Pick-to: 5.15 6.1 6.2
Change-Id: I4e0ecef50685ed081d15c7f76b6c1a4a40ed2682
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
---
 .../graphicsview/qgraphicsproxywidget.cpp     |  4 ++
 .../qgraphicsview/tst_qgraphicsview.cpp       | 55 +++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/src/widgets/graphicsview/qgraphicsproxywidget.cpp b/src/widgets/graphicsview/qgraphicsproxywidget.cpp
index 4d997b3443..cb19b32763 100644
--- a/src/widgets/graphicsview/qgraphicsproxywidget.cpp
+++ b/src/widgets/graphicsview/qgraphicsproxywidget.cpp
@@ -832,6 +832,10 @@ bool QGraphicsProxyWidget::event(QEvent *event)
         return QGraphicsWidget::event(event);
 
     switch (event->type()) {
+    case QEvent::WindowActivate:
+    case QEvent::WindowDeactivate:
+        QCoreApplication::sendEvent(d->widget, event);
+        break;
     case QEvent::StyleChange:
         // Propagate style changes to the embedded widget.
         if (!d->styleChangeMode) {
diff --git a/tests/auto/widgets/graphicsview/qgraphicsview/tst_qgraphicsview.cpp b/tests/auto/widgets/graphicsview/qgraphicsview/tst_qgraphicsview.cpp
index bb6af30c22..ebc5464674 100644
--- a/tests/auto/widgets/graphicsview/qgraphicsview/tst_qgraphicsview.cpp
+++ b/tests/auto/widgets/graphicsview/qgraphicsview/tst_qgraphicsview.cpp
@@ -227,6 +227,7 @@ private slots:
     void replayMouseMove();
     void itemsUnderMouse();
     void embeddedViews();
+    void embeddedViewsWithFocus();
     void scrollAfterResize_data();
     void scrollAfterResize();
     void moveItemWhileScrolling_data();
@@ -3668,6 +3669,60 @@ void tst_QGraphicsView::embeddedViews()
     delete v1;
 }
 
+/*!
+    Verify that a nested graphics view and embedded widgets receive window
+    activation and focus correctly.
+
+    See QTBUG-94091.
+*/
+void tst_QGraphicsView::embeddedViewsWithFocus()
+{
+    class FocusWidget : public QWidget
+    {
+    public:
+        FocusWidget() { setFocusPolicy(Qt::StrongFocus); }
+        QSize sizeHint() const override { return QSize(100, 100); }
+
+        int focusCount = 0;
+    protected:
+        void mousePressEvent(QMouseEvent *) override {} // accept event to avoid warning
+        void focusInEvent(QFocusEvent *) override { ++focusCount; }
+        void focusOutEvent(QFocusEvent *) override { --focusCount; }
+    };
+
+    QGraphicsScene *innerScene = new QGraphicsScene;
+    FocusWidget *innerWidget = new FocusWidget;
+    innerScene->addWidget(innerWidget);
+    QGraphicsView *innerView = new QGraphicsView(innerScene);
+
+    QGraphicsScene outerScene;
+    FocusWidget *outerWidget = new FocusWidget;
+    QGraphicsProxyWidget *outerProxy = outerScene.addWidget(outerWidget);
+    QGraphicsProxyWidget *nestedProxy = outerScene.addWidget(innerView);
+    outerProxy->setPos(0, 0);
+    nestedProxy->setPos(0, outerWidget->sizeHint().height());
+    QGraphicsView outerView(&outerScene);
+    outerView.show();
+    outerView.activateWindow();
+    QVERIFY(QTest::qWaitForWindowActive(&outerView));
+    const QPoint outerCenter(QPoint(innerWidget->sizeHint().width() / 2,
+                                    innerWidget->sizeHint().height() / 2));
+    const QPoint innerCenter(outerCenter + QPoint(0, innerWidget->sizeHint().height()));
+    QCOMPARE(outerView.itemAt(outerCenter), outerProxy);
+    QCOMPARE(outerView.itemAt(innerCenter), nestedProxy);
+    QVERIFY(outerScene.isActive());
+    QVERIFY(innerScene->isActive());
+
+    QCOMPARE(outerWidget->focusCount, 0);
+    QCOMPARE(innerWidget->focusCount, 0);
+    QTest::mouseClick(outerView.viewport(), Qt::LeftButton, {}, outerCenter);
+    QCOMPARE(outerWidget->focusCount, 1);
+    QCOMPARE(innerWidget->focusCount, 0);
+    QTest::mouseClick(outerView.viewport(), Qt::LeftButton, {}, innerCenter);
+    QCOMPARE(outerWidget->focusCount, 0);
+    QCOMPARE(innerWidget->focusCount, 1);
+}
+
 void tst_QGraphicsView::scrollAfterResize_data()
 {
     QTest::addColumn<bool>("reverse");