Immediately complete component upon creation failure

We do not want to wait until reaching the Component destructor (at which
point e.g. the engine might be gone).

Change-Id: Ic0e4383ec4e3759d9f02847413a25191a01286cb
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Maximilian Goldstein <max.goldstein@qt.io>
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
(cherry picked from commit 759090f59140d0b38c7bd57480ea6cd93d4cf0d3)

2 files changed, 9 insertions, 4 deletions

diff --git a/src/qml/qml/qqmlcomponent.cpp b/src/qml/qml/qqmlcomponent.cpp
index addee70b6b..f54eee3e72 100644
--- a/src/qml/qml/qqmlcomponent.cpp
+++ b/src/qml/qml/qqmlcomponent.cpp
@@ -862,8 +862,16 @@ QObject *QQmlComponent::create(QQmlContext *context)
     Q_D(QQmlComponent);
 
     QObject *rv = d->doBeginCreate(this, context);
-    if (rv)
+    if (rv) {
         completeCreate();
+    } else if (d->state.completePending) {
+        // overridden completCreate might assume that
+        // the object has actually been created
+        ++creationDepth.localData();
+        QQmlEnginePrivate *ep = QQmlEnginePrivate::get(d->engine);
+        d->complete(ep, &d->state);
+        --creationDepth.localData();
+    }
     if (rv && !d->requiredProperties().empty()) {
         delete  rv;
         return nullptr;
diff --git a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
index b25dec67f1..ab23f71f3e 100644
--- a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
+++ b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
@@ -4418,9 +4418,6 @@ void tst_qqmllanguage::deepProperty()
 void tst_qqmllanguage::groupAssignmentFailure()
 {
     auto ep = std::make_unique<QQmlEngine>();
-    QTest::ignoreMessage(QtMsgType::QtWarningMsg, "QQmlComponent: Component destroyed while completion pending");
-    QTest::ignoreMessage(QtMsgType::QtWarningMsg, "This may have been caused by one of the following errors:");
-    QTest::ignoreMessage(QtMsgType::QtWarningMsg, QRegularExpression(".*Cannot set properties on b as it is null.*"));
     QTest::ignoreMessage(QtMsgType::QtWarningMsg, QRegularExpression(".*Invalid property assignment: url expected - Assigning null to incompatible properties in QML is deprecated. This will become a compile error in future versions of Qt..*"));
     QQmlComponent component(ep.get(), testFileUrl("groupFailure.qml"));
     QScopedPointer<QObject> o(component.create());