Fix crash when connecting a new screen

In QWaylandWindow::virtualSiblings, don't include screens that have not been
added yet. I.e. QWaylandScreens for which QPlatformIntegration::screenAdded has
not yet been called.

There are two reasons why this crash wasn't covered by the
removePrimaryScreen() test. First of all, the mock output didn't send
wl_output.done events when updating the mode/geometry. These wayland events are
what causes QWindowSystemInterface::handleScreenGeometryChange() to be called
(where virtualSiblings are called).

Furthermore, virtualSiblings is only called when the geometry actually changes,
so add a new test that changes the screen geometry of the existing screen while
a new one is being added (i.e. moves it to the right).

Task-number: QTBUG-62044
Change-Id: I623fbf8799d21c6b9293e7120ded301277639cc6
Reviewed-by: David Edmundson <davidedmundson@kde.org>
Reviewed-by: Aleix Pol
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/client/qwaylandscreen.cpp b/src/client/qwaylandscreen.cpp
index fba755577..1c9ce23ba 100644
--- a/src/client/qwaylandscreen.cpp
+++ b/src/client/qwaylandscreen.cpp
@@ -138,8 +138,10 @@ QList<QPlatformScreen *> QWaylandScreen::virtualSiblings() const
     QList<QPlatformScreen *> list;
     const QList<QWaylandScreen*> screens = mWaylandDisplay->screens();
     list.reserve(screens.count());
-    foreach (QWaylandScreen *screen, screens)
-        list << screen;
+    for (QWaylandScreen *screen : qAsConst(screens)) {
+        if (screen->screen())
+            list << screen;
+    }
     return list;
 }