Emit Component.onDestruction before context is invalidated

When a component no longer has any live references, emit the
destruction signal immediately so that handlers are run before the
associated V8 resources are invalidated.  Also, when the root
context of the engine is destroyed, emit the destruction signal
before destroying any resources needed to process the resulting
binding invocations.

Change-Id: I722dd6e4b60c499b533fc45e33b61e95bca6187f
Reviewed-by: Michael Brasser <michael.brasser@nokia.com>

3 files changed, 84 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmlcomponent/data/onDestructionCount.qml b/tests/auto/qml/qqmlcomponent/data/onDestructionCount.qml
new file mode 100644
index 0000000000..3938acf6a5
--- /dev/null
+++ b/tests/auto/qml/qqmlcomponent/data/onDestructionCount.qml
@@ -0,0 +1,16 @@
+import QtQuick 2.0
+
+Item {
+    Component {
+        id: internalComponent
+
+        Item {
+            Component.onDestruction: console.warn('Component.onDestruction')
+        }
+    }
+
+    Component.onCompleted: {
+        internalComponent.createObject()
+        gc()
+    }
+}
diff --git a/tests/auto/qml/qqmlcomponent/data/onDestructionLookup.qml b/tests/auto/qml/qqmlcomponent/data/onDestructionLookup.qml
new file mode 100644
index 0000000000..a49a86e1f3
--- /dev/null
+++ b/tests/auto/qml/qqmlcomponent/data/onDestructionLookup.qml
@@ -0,0 +1,25 @@
+import QtQuick 2.0
+
+Item {
+    id: root
+
+    property bool success: false
+
+    Component {
+        id: internalComponent
+
+        Item {
+            id: internalRoot
+
+            property string foo: ''
+
+            Component.onCompleted: { internalRoot.foo = 'bar' }
+            Component.onDestruction: { root.success = (internalRoot.foo == 'bar') }
+        }
+    }
+
+    Component.onCompleted: {
+        internalComponent.createObject()
+        gc()
+    }
+}
diff --git a/tests/auto/qml/qqmlcomponent/tst_qqmlcomponent.cpp b/tests/auto/qml/qqmlcomponent/tst_qqmlcomponent.cpp
index b534d0c788..bf76ed962b 100644
--- a/tests/auto/qml/qqmlcomponent/tst_qqmlcomponent.cpp
+++ b/tests/auto/qml/qqmlcomponent/tst_qqmlcomponent.cpp
@@ -112,6 +112,8 @@ private slots:
     void async();
     void asyncHierarchy();
     void componentUrlCanonicalization();
+    void onDestructionLookup();
+    void onDestructionCount();
 
 private:
     QQmlEngine engine;
@@ -366,6 +368,47 @@ void tst_qqmlcomponent::componentUrlCanonicalization()
     }
 }
 
+void tst_qqmlcomponent::onDestructionLookup()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine, testFileUrl("onDestructionLookup.qml"));
+    QScopedPointer<QObject> object(component.create());
+    QVERIFY(object != 0);
+    QVERIFY(object->property("success").toBool());
+}
+
+void tst_qqmlcomponent::onDestructionCount()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine, testFileUrl("onDestructionCount.qml"));
+
+    QLatin1String warning("Component.onDestruction");
+
+    {
+        // Warning should be emitted during create()
+        QTest::ignoreMessage(QtWarningMsg, warning.data());
+
+        QScopedPointer<QObject> object(component.create());
+        QVERIFY(object != 0);
+    }
+
+    // Warning should not be emitted any further
+    QCOMPARE(engine.outputWarningsToStandardError(), true);
+
+    warnings.clear();
+    QtMsgHandler old = qInstallMsgHandler(msgHandler);
+
+    QCoreApplication::sendPostedEvents(0, QEvent::DeferredDelete);
+    QCoreApplication::processEvents();
+
+    qInstallMsgHandler(old);
+
+    engine.setOutputWarningsToStandardError(false);
+    QCOMPARE(engine.outputWarningsToStandardError(), false);
+
+    QCOMPARE(warnings.count(), 0);
+}
+
 QTEST_MAIN(tst_qqmlcomponent)
 
 #include "tst_qqmlcomponent.moc"