Fix deadlock with QQuickView embedded via QWidget::createWindowContainer

A QQuickView embedded in a widget application will be deleted in the
QApplication destructor. At that point, events are not being posted,
so the QQmlThread cannot properly shut down, and will deadlock waiting
for an event.

Task-number: QTBUG-36115
Change-Id: I4595f03e0afcf9463cfbc2ba95146d4777d19c56
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/src/qml/qml/ftw/qqmlthread.cpp b/src/qml/qml/ftw/qqmlthread.cpp
index 18b257dc0e..b3d7bddff7 100644
--- a/src/qml/qml/ftw/qqmlthread.cpp
+++ b/src/qml/qml/ftw/qqmlthread.cpp
@@ -139,6 +139,7 @@ void QQmlThreadPrivate::run()
 
     q->startupThread();
     exec();
+    q->shutdownThread();
 }
 
 void QQmlThreadPrivate::mainEvent()
@@ -177,7 +178,6 @@ void QQmlThreadPrivate::threadEvent()
             quit();
             wakeOne();
             unlock();
-            q->shutdownThread();
 
             return;
         } else if (!threadList.isEmpty()) {
@@ -229,7 +229,14 @@ void QQmlThread::shutdown()
     Q_ASSERT(!d->m_shutdown);
     d->m_shutdown = true;
     if (d->threadList.isEmpty() && d->m_threadProcessing == false) {
-        d->triggerThreadEvent();
+        if (QCoreApplication::closingDown()) {
+            d->quit();
+            d->unlock();
+            d->QThread::wait();
+            return;
+        } else {
+            d->triggerThreadEvent();
+        }
     } else if (d->mainSync) {
         d->wakeOne();
     }