Improve resource load cache

-Added a new method in Resource: reset_state , used for reloading the same resource from disk
-Added a new cache mode "replace" in ResourceLoader, which reuses existing loaded sub-resources but resets their data from disk (or replaces them if they chaged type)
-Because the correct sub-resource paths are always loaded now, this fixes bugs with subresource folding or subresource ordering when saving.

modules/visual_script/visual_script_expression.cpp

@@ -1506,6 +1506,19 @@ VisualScriptNodeInstance *VisualScriptExpression::instance(VisualScriptInstance
 	return instance;
 }
 
+void VisualScriptExpression::reset_state() {
+	if (nodes) {
+		memdelete(nodes);
+		nodes = nullptr;
+		root = nullptr;
+	}
+
+	error_str = String();
+	error_set = false;
+	str_ofs = 0;
+	inputs.clear();
+}
+
 VisualScriptExpression::VisualScriptExpression() {
 }
 

modules/visual_script/visual_script_expression.h

@@ -256,6 +256,8 @@ protected:
 	void _get_property_list(List<PropertyInfo> *p_list) const;
 
 public:
+	virtual void reset_state() override;
+
 	virtual int get_output_sequence_port_count() const override;
 	virtual bool has_input_sequence_port() const override;
 

modules/visual_script/visual_script_flow_control.cpp

@@ -677,6 +677,10 @@ void VisualScriptSwitch::_get_property_list(List<PropertyInfo> *p_list) const {
 	}
 }
 
+void VisualScriptSwitch::reset_state() {
+	case_values.clear();
+}
+
 void VisualScriptSwitch::_bind_methods() {
 }
 

modules/visual_script/visual_script_flow_control.h

@@ -202,6 +202,8 @@ protected:
 	static void _bind_methods();
 
 public:
+	virtual void reset_state() override;
+
 	virtual int get_output_sequence_port_count() const override;
 	virtual bool has_input_sequence_port() const override;
 

modules/visual_script/visual_script_nodes.cpp

@@ -303,6 +303,14 @@ VisualScriptNodeInstance *VisualScriptFunction::instance(VisualScriptInstance *p
 	return instance;
 }
 
+void VisualScriptFunction::reset_state() {
+	arguments.clear();
+	stack_size = 256;
+	stack_less = false;
+	sequenced = true;
+	rpc_mode = MultiplayerAPI::RPC_MODE_DISABLED;
+}
+
 VisualScriptFunction::VisualScriptFunction() {
 	stack_size = 256;
 	stack_less = false;
@@ -687,6 +695,13 @@ bool VisualScriptLists::is_sequenced() const {
 	return sequenced;
 }
 
+void VisualScriptLists::reset_state() {
+	inputports.clear();
+	outputports.clear();
+	sequenced = false;
+	flags = 0;
+}
+
 VisualScriptLists::VisualScriptLists() {
 	// initialize
 	sequenced = false;

modules/visual_script/visual_script_nodes.h

@@ -99,6 +99,8 @@ public:
 
 	virtual VisualScriptNodeInstance *instance(VisualScriptInstance *p_instance) override;
 
+	virtual void reset_state() override;
+
 	VisualScriptFunction();
 };
 
@@ -134,6 +136,8 @@ protected:
 	static void _bind_methods();
 
 public:
+	virtual void reset_state() override;
+
 	virtual bool is_output_port_editable() const;
 	virtual bool is_output_port_name_editable() const;
 	virtual bool is_output_port_type_editable() const;