Tell QQmlImportInstance::resolveType what kind of type we want

In QQmlTypeData::resolveTypes() we know if we're looking at a reference
to a composite singleton type, or some other type reference. When we
call resolveType() we expect the correct type to be returned, not only
based on URL, but also based on its singleton property.

QQmlTypeData::resolveType() eventually invokes
QQmlImportInstance::resolveType() which will call
fetchOrCreateTypeForUrl(), passing a parameter on whether the result
should be a composite singleton. When operating on a qmldir component
the component itself encodes this. When fetching a type from a local
file without qmldir, we currently assume that it isn't a singleton, no
matter QQmlTypeData::resolveTypes() has determined. This means that
actual singletons loaded this way later get refused by the sanity check.

In order to fix this, pass the information about the expected singleton
property on to QQmlImportInstance. This is done using
QQmlType::RegistrationType, which gets another entry for "any type". If
the expected type is CompositeSingletonType QQmlTypeData::resolveType()
will not create a non-singleton type. If it is any specific other type,
it will not create a composite singleton. And if it is
AnyRegistrationType, it will behave as it previously did.

Change-Id: I6b7e082b63582e0aed946bb3d19077b94c7a45f7
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

2 files changed, 32 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmltypeloader/data/ValueSource.qml b/tests/auto/qml/qqmltypeloader/data/ValueSource.qml
new file mode 100644
index 0000000000..19e6e730c8
--- /dev/null
+++ b/tests/auto/qml/qqmltypeloader/data/ValueSource.qml
@@ -0,0 +1,7 @@
+pragma Singleton
+import QtQuick 2.6
+
+Item {
+    id: valueSource
+    property int something: 10
+}
diff --git a/tests/auto/qml/qqmltypeloader/tst_qqmltypeloader.cpp b/tests/auto/qml/qqmltypeloader/tst_qqmltypeloader.cpp
index 3d3a7ff725..24f3cbc20d 100644
--- a/tests/auto/qml/qqmltypeloader/tst_qqmltypeloader.cpp
+++ b/tests/auto/qml/qqmltypeloader/tst_qqmltypeloader.cpp
@@ -43,6 +43,7 @@ private slots:
     void loadComponentSynchronously();
     void trimCache();
     void trimCache2();
+    void keepSingleton();
 };
 
 void tst_QQMLTypeLoader::testLoadComplete()
@@ -120,6 +121,30 @@ void tst_QQMLTypeLoader::trimCache2()
     QCOMPARE(loader.isTypeLoaded(testFileUrl("MyComponent2.qml")), false);
 }
 
+static void checkSingleton(const QString &dataDirectory)
+{
+    QQmlEngine engine;
+    engine.addImportPath(dataDirectory);
+    QQmlComponent component(&engine);
+    component.setData("import ClusterDemo 1.0\n"
+                      "import QtQuick 2.6\n"
+                      "import \"..\"\n"
+                      "Item { property int t: ValueSource.something }",
+                      QUrl::fromLocalFile(dataDirectory + "/abc/Xyz.qml"));
+    QCOMPARE(component.status(), QQmlComponent::Ready);
+    QScopedPointer<QObject> o(component.create());
+    QVERIFY(o.data());
+    QCOMPARE(o->property("t").toInt(), 10);
+}
+
+void tst_QQMLTypeLoader::keepSingleton()
+{
+    qmlRegisterSingletonType(testFileUrl("ValueSource.qml"), "ClusterDemo", 1, 0, "ValueSource");
+    checkSingleton(dataDirectory());
+    QQmlMetaType::freeUnusedTypesAndCaches();
+    checkSingleton(dataDirectory());
+}
+
 QTEST_MAIN(tst_QQMLTypeLoader)
 
 #include "tst_qqmltypeloader.moc"