core: fix shutdown sequence crashing

src/core/generation.cpp

@@ -84,6 +84,14 @@ void EngineGeneration::destroy() {
 	}
 }
 
+void EngineGeneration::shutdown() {
+	delete this->root;
+	this->root = nullptr;
+	delete this->engine;
+	this->engine = nullptr;
+	delete this;
+}
+
 void EngineGeneration::onReload(EngineGeneration* old) {
 	if (old != nullptr) {
 		// if the old generation holds the window incubation controller as the

src/core/generation.hpp

@@ -51,6 +51,7 @@ public:
 	QuickshellGlobal* qsgInstance = nullptr;
 
 	void destroy();
+	void shutdown();
 
 signals:
 	void filesChanged();

src/core/rootwrapper.cpp

@@ -35,11 +35,8 @@ RootWrapper::RootWrapper(QString rootPath)
 RootWrapper::~RootWrapper() {
 	// event loop may no longer be running so deleteLater is not an option
 	if (this->generation != nullptr) {
-		delete this->generation->root;
-		this->generation->root = nullptr;
+		this->generation->shutdown();
 	}
-
-	delete this->generation;
 }
 
 void RootWrapper::reloadGraph(bool hard) {