File 0001-Avoid-crash-in-QScroller.patch of Package libqt5-qtbase.17591

From 8d8425d7e28ef0b93bf967f9bd6c604ac83c7475 Mon Sep 17 00:00:00 2001
From: Fabian Vogt <fabian@ritter-vogt.de>
Date: Wed, 25 Nov 2020 20:04:34 +0100
Subject: [PATCH] widgets: Avoid crash in QScroller

Quoting c6a32751 in okular[1]:

QScrollerPrivate::setDpiFromWidget() before Qt 5.14 crashes
when the target widget does not intersect a physical screen,
because QDesktopWidget returns screen index `-1` in this case,
which leads to an out-of-range read from QApplication::screens(),
which leads to a segfault when reading from an invalid QScreen* pointer.

[1] https://invent.kde.org/graphics/okular/-/commit/c6a32751

Fixes: QTBUG-88288
Change-Id: Ia572bf0207aa6d8ca2a209d22daa36b962e6de7d
---
 src/widgets/util/qscroller.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/widgets/util/qscroller.cpp b/src/widgets/util/qscroller.cpp
index 1e84237253..8fd3437eaf 100644
--- a/src/widgets/util/qscroller.cpp
+++ b/src/widgets/util/qscroller.cpp
@@ -1031,7 +1031,8 @@ void QScrollerPrivate::setDpi(const QPointF &dpi)
 */
 void QScrollerPrivate::setDpiFromWidget(QWidget *widget)
 {
-    const QScreen *screen = QGuiApplication::screens().at(QApplication::desktop()->screenNumber(widget));
+    const int screenNumber = QApplication::desktop()->screenNumber(widget);
+    const QScreen *screen = screenNumber < 0 ? QGuiApplication::primaryScreen() : QGuiApplication::screens().at(screenNumber);
     setDpi(QPointF(screen->physicalDotsPerInchX(), screen->physicalDotsPerInchY()));
 }
 
-- 
2.25.1