Fix use after free in tst_WaylandClient::dontCrashOnMultipleCommitsv5.11.0-beta1

QBackingStore had a pointer to TestWindow window, but it was destroyed only
after the TestWindow was already deleted.

Change-Id: Id8fe38277cf843d532f2d8c2fdbe1f69d0309a7f
Reviewed-by: Johan Helsing <johan.helsing@qt.io>

1 files changed, 14 insertions, 12 deletions

diff --git a/tests/auto/client/client/tst_client.cpp b/tests/auto/client/client/tst_client.cpp
index e244de7f2..eb99b2e2f 100644
--- a/tests/auto/client/client/tst_client.cpp
+++ b/tests/auto/client/client/tst_client.cpp
@@ -487,19 +487,21 @@ void tst_WaylandClient::dontCrashOnMultipleCommits()
 
     QRect rect(QPoint(), window->size());
 
-    QBackingStore backingStore(window);
-    backingStore.resize(rect.size());
-    backingStore.beginPaint(rect);
-    QPainter p(backingStore.paintDevice());
-    p.fillRect(rect, Qt::magenta);
-    p.end();
-    backingStore.endPaint();
-
-    backingStore.flush(rect);
-    backingStore.flush(rect);
-    backingStore.flush(rect);
+    {
+        QBackingStore backingStore(window);
+        backingStore.resize(rect.size());
+        backingStore.beginPaint(rect);
+        QPainter p(backingStore.paintDevice());
+        p.fillRect(rect, Qt::magenta);
+        p.end();
+        backingStore.endPaint();
+
+        backingStore.flush(rect);
+        backingStore.flush(rect);
+        backingStore.flush(rect);
 
-    compositor->processWaylandEvents();
+        compositor->processWaylandEvents();
+    }
 
     delete window;