Fix v8 handle management in QSGLoader

Previously, setting the source to a remote url and specified some
initial property values while active was false, and then setting
active to true, would cause undefined behaviour.

This commit ensures that the handles are managed correctly, and that
an appropriate v8 context exists during object creation with initial
property values specified.

Task-number: QTBUG-21868
Change-Id: I101c6546537aa05aaeb420195aca670bc71f31e1
Reviewed-on: http://codereview.qt-project.org/6109
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Aaron Kennedy <aaron.kennedy@nokia.com>

4 files changed, 38 insertions, 1 deletions

diff --git a/src/declarative/items/qsgloader.cpp b/src/declarative/items/qsgloader.cpp
index 91dce3b364..93f32b81a1 100644
--- a/src/declarative/items/qsgloader.cpp
+++ b/src/declarative/items/qsgloader.cpp
@@ -266,7 +266,6 @@ void QSGLoader::setActive(bool newVal)
             } else {
                 loadFromSourceComponent();
             }
-            d->disposeInitialPropertyValues(); // release persistent handles
         } else {
             if (d->item) {
                 QSGItemPrivate *p = QSGItemPrivate::get(d->item);
@@ -487,6 +486,7 @@ void QSGLoader::setSource(QDeclarativeV8Function *args)
     d->clear();
     QUrl sourceUrl = d->resolveSourceUrl(args);
     if (!ipv.IsEmpty()) {
+        d->disposeInitialPropertyValues();
         d->initialPropertyValues = qPersistentNew(ipv);
         d->qmlGlobalForIpv = qPersistentNew(args->qmlGlobal());
     }
@@ -539,6 +539,7 @@ void QSGLoaderPrivate::_q_sourceLoaded()
                 emit q->sourceComponentChanged();
             emit q->statusChanged();
             emit q->progressChanged();
+            disposeInitialPropertyValues(); // cleanup
             return;
         }
 
@@ -557,6 +558,7 @@ void QSGLoaderPrivate::_q_sourceLoaded()
                 completeCreateWithInitialPropertyValues(c, obj, initialPropertyValues, qmlGlobalForIpv);
             delete obj;
             delete ctxt;
+            disposeInitialPropertyValues(); // cleanup
             return;
         }
         if (obj) {
@@ -589,6 +591,7 @@ void QSGLoaderPrivate::_q_sourceLoaded()
         emit q->itemChanged();
         emit q->loaded();
     }
+    disposeInitialPropertyValues(); // cleanup
 }
 
 /*!
diff --git a/src/declarative/qml/qdeclarativecomponent.cpp b/src/declarative/qml/qdeclarativecomponent.cpp
index 0bcfd5a28e..e4c3003047 100644
--- a/src/declarative/qml/qdeclarativecomponent.cpp
+++ b/src/declarative/qml/qdeclarativecomponent.cpp
@@ -1134,6 +1134,9 @@ QObject *QDeclarativeComponentPrivate::completeCreateObjectWithInitialProperties
 {
     QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(engine);
     QV8Engine *v8engine = ep->v8engine();
+
+    v8::HandleScope handle_scope;
+    v8::Context::Scope scope(v8engine->context());
     v8::Handle<v8::Value> ov = v8engine->newQObject(toCreate);
     Q_ASSERT(ov->IsObject());
     v8::Handle<v8::Object> object = v8::Handle<v8::Object>::Cast(ov);
diff --git a/tests/auto/declarative/qsgloader/data/initialPropertyValues.8.qml b/tests/auto/declarative/qsgloader/data/initialPropertyValues.8.qml
new file mode 100644
index 0000000000..79e9264d4a
--- /dev/null
+++ b/tests/auto/declarative/qsgloader/data/initialPropertyValues.8.qml
@@ -0,0 +1,20 @@
+import QtQuick 2.0
+
+Item {
+    id: root
+    property int initialValue: 0
+
+    Loader {
+        id: loader
+        objectName: "loader"
+        active: false
+        onLoaded: {
+            root.initialValue = loader.item.canary;         // should be six
+        }
+    }
+
+    Component.onCompleted: {
+        loader.setSource("http://127.0.0.1:14450/InitialPropertyValuesComponent.qml", {"canary": 6});
+        loader.active = true;
+    }
+}
diff --git a/tests/auto/declarative/qsgloader/tst_qsgloader.cpp b/tests/auto/declarative/qsgloader/tst_qsgloader.cpp
index ba8d5e01d7..a073e1f9fd 100644
--- a/tests/auto/declarative/qsgloader/tst_qsgloader.cpp
+++ b/tests/auto/declarative/qsgloader/tst_qsgloader.cpp
@@ -651,6 +651,11 @@ void tst_QSGLoader::initialPropertyValues_data()
             << QStringList()
             << (QStringList() << "loaderValue" << "createObjectValue")
             << (QVariantList() << 1 << 1);
+
+    QTest::newRow("ensure initial property values aren't disposed prior to component completion") << TEST_FILE("initialPropertyValues.8.qml")
+            << QStringList()
+            << (QStringList() << "initialValue")
+            << (QVariantList() << 6);
 }
 
 void tst_QSGLoader::initialPropertyValues()
@@ -660,12 +665,18 @@ void tst_QSGLoader::initialPropertyValues()
     QFETCH(QStringList, propertyNames);
     QFETCH(QVariantList, propertyValues);
 
+    TestHTTPServer server(SERVER_PORT);
+    QVERIFY(server.isValid());
+    server.serveDirectory(SRCDIR "/data");
+
     foreach (const QString &warning, expectedWarnings)
         QTest::ignoreMessage(QtWarningMsg, warning.toAscii().constData());
 
     QDeclarativeComponent component(&engine, qmlFile);
     QObject *object = component.create();
     QVERIFY(object != 0);
+    qApp->processEvents();
+    QTest::qWait(50);
 
     for (int i = 0; i < propertyNames.size(); ++i)
         QCOMPARE(object->property(propertyNames.at(i).toAscii().constData()), propertyValues.at(i));