Reject overrides of final properties (and potentially methods)

If you specify FINAL in Q_PROPERTY you explicitly don't want it to be
overridden. Before, we would still accept overrides of such properties.
Issue a warning and decline overriding them.

For consistency, treat methods the same, even though we cannot declare
them final yet.

[ChangeLog][QtQml][Important Behavior Changes] C++ properties declared
FINAL now refuse to be overridden by other C++ properties. This mirrors
the treatment of QML properties trying to override FINAL properties. As
we cannot reject the C++ types the way we can reject QML types, the
overrides are ignored and a warning is issued. It is also impossible to
override final properties with functions now. This used to be possible
in the past.

Task-number: QTBUG-93662
Change-Id: I244c3e83a33875472bc5bf6786a1e949fe981995
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>

1 files changed, 18 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmlpropertycache/data/finalProp.qml b/tests/auto/qml/qqmlpropertycache/data/finalProp.qml
new file mode 100644
index 0000000000..1133ddc292
--- /dev/null
+++ b/tests/auto/qml/qqmlpropertycache/data/finalProp.qml
@@ -0,0 +1,18 @@
+import QtQml
+import Test.PropertyCache
+
+QtObject {
+    property BaseObject obj: BaseObject {}
+    property int a: obj.finalProp
+
+    property BaseObject obj2: BaseObject {
+        property int callCount: 0
+        function finalProp() { ++callCount }
+        Component.onCompleted: finalProp()
+    }
+
+    property var b: obj2.finalProp
+    Component.onCompleted: obj2.finalProp()
+
+    property int c: obj2.callCount
+}