qqmlapplicationengine: Handle errors during component creation

Previously QQmlApplicationEngine did not handle any errors that occurred during object creation
(i.e. failures to initialize required properties) which lead to QObject::connect errors and to
the error messages not getting printed among other issues.

Change-Id: I69bc566a6d349c786cae82a963a621388684c8f5
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
(cherry picked from commit 890cb4cb236333fd5b112fffc0e9088ecb43f2df)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/qml/qml/qqmlapplicationengine.cpp b/src/qml/qml/qqmlapplicationengine.cpp
index d866301f84..e0ab25892f 100644
--- a/src/qml/qml/qqmlapplicationengine.cpp
+++ b/src/qml/qml/qqmlapplicationengine.cpp
@@ -152,6 +152,14 @@ void QQmlApplicationEnginePrivate::finishLoad(QQmlComponent *c)
         break;
     case QQmlComponent::Ready: {
         auto newObj = initialProperties.empty() ? c->create() : c->createWithInitialProperties(initialProperties);
+
+        if (c->isError()) {
+           qWarning() << "QQmlApplicationEngine failed to create component";
+           warning(c->errors());
+           q->objectCreated(nullptr, c->url());
+           break;
+        }
+
         objects << newObj;
         QObject::connect(newObj, &QObject::destroyed, q, [&](QObject *obj) { objects.removeAll(obj); });
         q->objectCreated(objects.constLast(), c->url());