When clearing an incubator also clear incubators it is waiting for.

If an incubator is cleared while waiting for other incubators
to complete also clear the incubators it is waiting for.

Change-Id: I83470920c0fd8a23d0098849192555f7478bb492
Reviewed-by: Andrew den Exter <andrew.den-exter@nokia.com>

src/qml/qml/qqmlincubator.cpp

@@ -542,6 +542,10 @@ void QQmlIncubator::clear()
 
     d->clear();
 
+    // if we're waiting on any incubators then they should be cleared too.
+    while (d->waitingFor.first())
+        static_cast<QQmlIncubatorPrivate*>(d->waitingFor.first())->q->clear();
+
     d->vme.reset();
     d->vmeGuard.clear();
 

tests/auto/qml/qqmlincubator/tst_qqmlincubator.cpp

@@ -76,6 +76,7 @@ private slots:
     void nestedComponent();
     void chainedAsynchronousIfNested();
     void chainedAsynchronousIfNestedOnCompleted();
+    void chainedAsynchronousClear();
     void selfDelete();
     void contextDelete();
 
@@ -934,6 +935,122 @@ void tst_qqmlincubator::chainedAsynchronousIfNestedOnCompleted()
     QVERIFY(incubator3.isReady());
 }
 
+// Checks that new AsynchronousIfNested incubators can be correctly cleared if started in
+// componentCompleted().
+void tst_qqmlincubator::chainedAsynchronousClear()
+{
+    SelfRegisteringType::clearMe();
+
+    QQmlComponent component(&engine, testFileUrl("chainInCompletion.qml"));
+    QVERIFY(component.isReady());
+
+    QQmlComponent c1(&engine, testFileUrl("chainedAsynchronousIfNested.qml"));
+    QVERIFY(c1.isReady());
+
+    struct MyIncubator : public QQmlIncubator {
+        MyIncubator(MyIncubator *next, QQmlComponent *component, QQmlContext *ctxt)
+        : QQmlIncubator(AsynchronousIfNested), next(next), component(component), ctxt(ctxt) {}
+
+    protected:
+        virtual void statusChanged(Status s) {
+            if (s == Ready && next) {
+                component->create(*next, 0, ctxt);
+            }
+        }
+
+    private:
+        MyIncubator *next;
+        QQmlComponent *component;
+        QQmlContext *ctxt;
+    };
+
+    struct CallbackData {
+        CallbackData(QQmlComponent *c, MyIncubator *i, QQmlContext *ct)
+            : component(c), incubator(i), ctxt(ct) {}
+        QQmlComponent *component;
+        MyIncubator *incubator;
+        QQmlContext *ctxt;
+        static void callback(CompletionCallbackType *, void *data) {
+            CallbackData *d = (CallbackData *)data;
+            d->component->create(*d->incubator, 0, d->ctxt);
+        }
+    };
+
+    QQmlIncubator incubator(QQmlIncubator::Asynchronous);
+    component.create(incubator);
+
+    QVERIFY(incubator.isLoading());
+    QVERIFY(SelfRegisteringType::me() == 0);
+
+    while (SelfRegisteringType::me() == 0 && incubator.isLoading()) {
+        bool b = false;
+        controller.incubateWhile(&b);
+    }
+
+    QVERIFY(SelfRegisteringType::me() != 0);
+    QVERIFY(incubator.isLoading());
+
+    MyIncubator incubator3(0, &c1, qmlContext(SelfRegisteringType::me()));
+    MyIncubator incubator2(&incubator3, &c1, qmlContext(SelfRegisteringType::me()));
+    MyIncubator incubator1(&incubator2, &c1, qmlContext(SelfRegisteringType::me()));
+
+    // start incubator1 in componentComplete
+    CallbackData cd(&c1, &incubator1, qmlContext(SelfRegisteringType::me()));
+    CompletionCallbackType::registerCallback(&CallbackData::callback, &cd);
+
+    while (!incubator1.isLoading()) {
+        QVERIFY(incubator.isLoading());
+        QVERIFY(incubator2.isNull());
+        QVERIFY(incubator3.isNull());
+
+        bool b = false;
+        controller.incubateWhile(&b);
+    }
+
+    QVERIFY(incubator.isLoading());
+    QVERIFY(incubator1.isLoading());
+    QVERIFY(incubator2.isNull());
+    QVERIFY(incubator3.isNull());
+
+    while (incubator1.isLoading()) {
+        QVERIFY(incubator.isLoading());
+        QVERIFY(incubator1.isLoading());
+        QVERIFY(incubator2.isNull());
+        QVERIFY(incubator3.isNull());
+
+        bool b = false;
+        controller.incubateWhile(&b);
+    }
+
+    QVERIFY(incubator.isLoading());
+    QVERIFY(incubator1.isReady());
+    QVERIFY(incubator2.isLoading());
+    QVERIFY(incubator3.isNull());
+
+    while (incubator2.isLoading()) {
+        QVERIFY(incubator.isLoading());
+        QVERIFY(incubator1.isReady());
+        QVERIFY(incubator2.isLoading());
+        QVERIFY(incubator3.isNull());
+
+        bool b = false;
+        controller.incubateWhile(&b);
+    }
+
+    QVERIFY(incubator.isLoading());
+    QVERIFY(incubator1.isReady());
+    QVERIFY(incubator2.isReady());
+    QVERIFY(incubator3.isLoading());
+
+    // Any in loading state will become null when cleared.
+    incubator.clear();
+
+    QVERIFY(incubator.isNull());
+    QVERIFY(incubator1.isReady());
+    QVERIFY(incubator2.isReady());
+    QVERIFY(incubator3.isNull());
+}
+
 void tst_qqmlincubator::selfDelete()
 {
     struct MyIncubator : public QQmlIncubator {