Added test to avoid saving cyclic scene instancing, fixes #9686

editor/editor_node.cpp

@@ -999,6 +999,22 @@ void EditorNode::_save_scene_with_preview(String p_file, int p_idx) {
 	EditorResourcePreview::get_singleton()->check_for_invalidation(p_file);
 }
 
+bool EditorNode::_validate_scene_recursive(const String &p_filename, Node *p_node) {
+
+	for (int i = 0; i < p_node->get_child_count(); i++) {
+		Node *child = p_node->get_child(i);
+		if (child->get_filename() == p_filename) {
+			return true;
+		}
+
+		if (_validate_scene_recursive(p_filename, child)) {
+			return true;
+		}
+	}
+
+	return false;
+}
+
 void EditorNode::_save_scene(String p_file, int idx) {
 
 	Node *scene = editor_data.get_edited_scene_root(idx);
@@ -1009,6 +1025,11 @@ void EditorNode::_save_scene(String p_file, int idx) {
 		return;
 	}
 
+	if (scene->get_filename() != String() && _validate_scene_recursive(scene->get_filename(), scene)) {
+		show_accept(TTR("This scene can't be saved because there is a cyclic instancing inclusion.\nPlease resolve it and then attempt to save again."), TTR("OK"));
+		return;
+	}
+
 	editor_data.apply_changes_in_editors();
 	_save_default_environment();
 
@@ -1452,7 +1473,7 @@ void EditorNode::_edit_current() {
 	bool is_node = current_obj->is_class("Node");
 
 	String editable_warning; //none by default
-	
+
 	if (is_resource) {
 
 		Resource *current_res = Object::cast_to<Resource>(current_obj);

editor/editor_node.h

@@ -445,6 +445,7 @@ private:
 	void _show_messages();
 	void _vp_resized();
 
+	bool _validate_scene_recursive(const String &p_filename, Node *p_node);
 	void _save_scene(String p_file, int idx = -1);
 	void _save_all_scenes();
 	int _next_unsaved_scene(bool p_valid_filename, int p_start = 0);