Fix use of Component.onCompleted scripts in QQmlPropertyMap sub-types

After commit 9333ea8649838d7e0400b0e94c8cbd4fa5d216b0 when looking up
properties such as "console" in Component.onComplete handlers of
QQmlProperty sub-types, we end up implicitly creating "console"
properties, which is not correct.

At the same time, there are use-cases (and tests such as
tst_QQmlPropertyMap::QTBUG_35233) where a binding expression accesses a
property of a property map sub-type and it doesn't exist. Then later
that property is added and we must re-evaluate that binding. That works
because the implicit property creation when reading it also results in a
property capture.

Therefore we introduce the HFH (hack from hell): Detect the use of a
QQmlPropertyMap sub-type and go back to the old lookup behavior. The
path forward should be a deprecation of QQmlPropertyMap and perhaps the
ability to define abstract interfaces in QML.

Change-Id: Ib87bc1ebae44d7b332be47f1dcb614a19334b559
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

2 files changed, 30 insertions, 1 deletions

diff --git a/tests/auto/qml/qqmlpropertymap/data/PropertyMapSubType.qml b/tests/auto/qml/qqmlpropertymap/data/PropertyMapSubType.qml
new file mode 100644
index 0000000000..90ff179408
--- /dev/null
+++ b/tests/auto/qml/qqmlpropertymap/data/PropertyMapSubType.qml
@@ -0,0 +1,9 @@
+import QtQml 2.0
+import Test 1.0
+
+SimplePropertyMap {
+    Component.onCompleted: {
+        console.log("expected output")
+        newProperty = 42
+    }
+}
diff --git a/tests/auto/qml/qqmlpropertymap/tst_qqmlpropertymap.cpp b/tests/auto/qml/qqmlpropertymap/tst_qqmlpropertymap.cpp
index 86229b95f3..237b65679e 100644
--- a/tests/auto/qml/qqmlpropertymap/tst_qqmlpropertymap.cpp
+++ b/tests/auto/qml/qqmlpropertymap/tst_qqmlpropertymap.cpp
@@ -35,7 +35,7 @@
 #include <QSignalSpy>
 #include <QDebug>
 
-class tst_QQmlPropertyMap : public QObject
+class tst_QQmlPropertyMap : public QQmlDataTest
 {
     Q_OBJECT
 public:
@@ -61,6 +61,7 @@ private slots:
     void disallowExtending();
     void QTBUG_35906();
     void QTBUG_48136();
+    void lookupsInSubTypes();
 };
 
 class LazyPropertyMap : public QQmlPropertyMap, public QQmlParserStatus
@@ -89,9 +90,18 @@ private:
     int value = 0;
 };
 
+class SimplePropertyMap: public QQmlPropertyMap
+{
+    Q_OBJECT
+public:
+    SimplePropertyMap() : QQmlPropertyMap(this, nullptr) {}
+};
+
 void tst_QQmlPropertyMap::initTestCase()
 {
+    QQmlDataTest::initTestCase();
     qmlRegisterType<LazyPropertyMap>("QTBUG_35233", 1, 0, "LazyPropertyMap");
+    qmlRegisterType<SimplePropertyMap>("Test", 1, 0, "SimplePropertyMap");
 }
 
 void tst_QQmlPropertyMap::insert()
@@ -496,6 +506,16 @@ void tst_QQmlPropertyMap::QTBUG_48136()
     QCOMPARE(valueChangedSpy.count(), 1);
 }
 
+void tst_QQmlPropertyMap::lookupsInSubTypes()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine, testFileUrl("PropertyMapSubType.qml"));
+    QTest::ignoreMessage(QtDebugMsg, "expected output");
+    QScopedPointer<QObject> object(component.create());
+    QVERIFY(!object.isNull());
+    QCOMPARE(object->property("newProperty").toInt(), 42);
+}
+
 QTEST_MAIN(tst_QQmlPropertyMap)
 
 #include "tst_qqmlpropertymap.moc"