1 files changed, 71 insertions, 7 deletions

diff --git a/modules/gdscript/gd_compiler.cpp b/modules/gdscript/gd_compiler.cpp
index 5a6299bcf8..d51f1a4ddc 100644
--- a/modules/gdscript/gd_compiler.cpp
+++ b/modules/gdscript/gd_compiler.cpp
@@ -1414,8 +1414,13 @@ Error GDCompiler::_parse_function(GDScript *p_script,const GDParser::ClassNode *
 
 
 
-Error GDCompiler::_parse_class(GDScript *p_script,GDScript *p_owner,const GDParser::ClassNode *p_class) {
+Error GDCompiler::_parse_class(GDScript *p_script, GDScript *p_owner, const GDParser::ClassNode *p_class, bool p_keep_state) {
 
+	Map<StringName,Ref<GDScript> > old_subclasses;
+
+	if (p_keep_state) {
+		old_subclasses=p_script->subclasses;
+	}
 
 	p_script->native=Ref<GDNativeClass>();
 	p_script->base=Ref<GDScript>();
@@ -1429,6 +1434,7 @@ Error GDCompiler::_parse_class(GDScript *p_script,GDScript *p_owner,const GDPars
 	p_script->member_indices.clear();
 	p_script->member_info.clear();
 	p_script->initializer=NULL;
+
 	p_script->subclasses.clear();
 	p_script->_owner=p_owner;
 	p_script->tool=p_class->tool;
@@ -1662,9 +1668,15 @@ Error GDCompiler::_parse_class(GDScript *p_script,GDScript *p_owner,const GDPars
 	for(int i=0;i<p_class->subclasses.size();i++) {
 		StringName name = p_class->subclasses[i]->name;
 
-		Ref<GDScript> subclass = memnew( GDScript );
+		Ref<GDScript> subclass;
 
-		Error err = _parse_class(subclass.ptr(),p_script,p_class->subclasses[i]);
+		if (old_subclasses.has(name)) {
+			subclass=old_subclasses[name];
+		} else {
+			subclass.instance();
+		}
+
+		Error err = _parse_class(subclass.ptr(),p_script,p_class->subclasses[i],p_keep_state);
 		if (err)
 			return err;
 
@@ -1755,13 +1767,67 @@ Error GDCompiler::_parse_class(GDScript *p_script,GDScript *p_owner,const GDPars
 
 		}
 	}
+
+	//validate instances if keeping state
+
+	if (p_keep_state) {
+
+		print_line("RELOAD KEEP "+p_script->path);
+		for (Set<Object*>::Element *E=p_script->instances.front();E;) {
+
+			Set<Object*>::Element *N = E->next();
+
+			ScriptInstance *si = E->get()->get_script_instance();
+			if (si->is_placeholder()) {
+#ifdef TOOLS_ENABLED
+				PlaceHolderScriptInstance *psi = static_cast<PlaceHolderScriptInstance*>(si);
+
+				if (p_script->is_tool()) {
+					//re-create as an instance
+					p_script->placeholders.erase(psi); //remove placeholder
+
+					GDInstance* instance = memnew( GDInstance );
+					instance->base_ref=E->get()->cast_to<Reference>();
+					instance->members.resize(p_script->member_indices.size());
+					instance->script=Ref<GDScript>(p_script);
+					instance->owner=E->get();
+
+					//needed for hot reloading
+					for(Map<StringName,GDScript::MemberInfo>::Element *E=p_script->member_indices.front();E;E=E->next()) {
+						instance->member_indices_cache[E->key()]=E->get().index;
+					}
+					instance->owner->set_script_instance(instance);
+
+
+					/* STEP 2, INITIALIZE AND CONSRTUCT */
+
+					Variant::CallError ce;
+					p_script->initializer->call(instance,NULL,0,ce);
+
+					if (ce.error!=Variant::CallError::CALL_OK) {
+						//well, tough luck, not goinna do anything here
+					}
+				}
+#endif
+			} else {
+
+				GDInstance *gi = static_cast<GDInstance*>(si);
+				gi->reload_members();
+			}
+
+			E=N;
+
+		}
+
+
+	}
 #endif
 
 	p_script->valid=true;
 	return OK;
 }
 
-Error GDCompiler::compile(const GDParser *p_parser,GDScript *p_script) {
+Error GDCompiler::compile(const GDParser *p_parser,GDScript *p_script,bool p_keep_state) {
 
 	err_line=-1;
 	err_column=-1;
@@ -1772,9 +1838,7 @@ Error GDCompiler::compile(const GDParser *p_parser,GDScript *p_script) {
 
 	source=p_script->get_path();
 
-
-
-	Error err = _parse_class(p_script,NULL,static_cast<const GDParser::ClassNode*>(root));
+	Error err = _parse_class(p_script,NULL,static_cast<const GDParser::ClassNode*>(root),p_keep_state);
 
 	if (err)
 		return err;