Prompt to restart when project data (.godot) is missing

editor/editor_node.h

@@ -411,6 +411,7 @@ private:
 
 	Tree *disk_changed_list = nullptr;
 	ConfirmationDialog *disk_changed = nullptr;
+	ConfirmationDialog *project_data_missing = nullptr;
 
 	bool scene_distraction_free = false;
 	bool script_distraction_free = false;
@@ -670,6 +671,8 @@ private:
 
 	void _execute_upgrades();
 
+	bool _is_project_data_missing();
+
 protected:
 	friend class FileSystemDock;