QmlDesigner: Add new node hint

Add a new node hint called "bindParentToProperty" which enables the
metainfo file to specify an automatic binding of a nodes parent id to an
arbitrary property.

Change-Id: Ib16955df608cdca5732882afc1f5ba0891283ca5
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/plugins/qmldesigner/designercore/include/nodehints.h

@@ -72,6 +72,7 @@ public:
     bool visibleInLibrary() const;
     QString forceNonDefaultProperty() const;
     QPair<QString, QVariant> setParentProperty() const;
+    QString bindParentToProperty() const;
 
     QHash<QString, QString> hints() const;
     static NodeHints fromModelNode(const ModelNode &modelNode);

src/plugins/qmldesigner/designercore/metainfo/nodehints.cpp

@@ -295,6 +295,16 @@ QPair<QString, QVariant> NodeHints::setParentProperty() const
     return qMakePair(list.first().trimmed(), parseValue(list.last().trimmed()));
 }
 
+QString NodeHints::bindParentToProperty() const
+{
+    const QString expression = m_hints.value("bindParentToProperty");
+
+    if (expression.isEmpty())
+        return {};
+
+    return Internal::evaluateExpression(expression, modelNode(), ModelNode()).toString();
+}
+
 QHash<QString, QString> NodeHints::hints() const
 {
     return m_hints;

src/plugins/qmldesigner/designercore/model/qmlvisualnode.cpp

@@ -361,6 +361,15 @@ QmlObjectNode QmlVisualNode::createQmlObjectNode(AbstractView *view,
         parent.variantProperty(property).setValue(value);
     }
 
+    if (!hints.bindParentToProperty().isEmpty() && parentProperty.isValid()) {
+        const PropertyName property = hints.bindParentToProperty().toUtf8();
+        ModelNode parent = parentProperty.parentModelNode();
+
+        const NodeMetaInfo metaInfo = newQmlObjectNode.modelNode().metaInfo();
+        if (metaInfo.hasProperty(property))
+            newQmlObjectNode.setBindingProperty(property, parent.validId());
+    }
+
     return newQmlObjectNode;
 }