3 files changed, 38 insertions, 6 deletions

diff --git a/core/core_bind.cpp b/core/core_bind.cpp
index 9e96d4b079..d34ed29691 100644
--- a/core/core_bind.cpp
+++ b/core/core_bind.cpp
@@ -1733,7 +1733,36 @@ void _Thread::_start_func(void *ud) {
 	memdelete(tud);
 	Callable::CallError ce;
 	const Variant *arg[1] = { &t->userdata };
-	int argc = (int)(arg[0]->get_type() != Variant::NIL);
+	int argc = 0;
+	if (arg[0]->get_type() != Variant::NIL) {
+		// Just pass to the target function whatever came as user data
+		argc = 1;
+	} else {
+		// There are two cases of null user data:
+		// a) The target function has zero parameters and the caller is just honoring that.
+		// b) The target function has at least one parameter with no default and the caller is
+		//    leveraging the fact that user data defaults to null in Thread.start().
+		//    We care about the case of more than one parameter because, even if a thread
+		//    function can have one at most, out mindset here is to do our best with the
+		//    only/first one and let the call handle any other error conditions, like too
+		//    much arguments.
+		// We must check if we are in case b).
+		int target_param_count = 0;
+		int target_default_arg_count = 0;
+		Ref<Script> script = t->target_instance->get_script();
+		if (script.is_valid()) {
+			MethodInfo mi = script->get_method_info(t->target_method);
+			target_param_count = mi.arguments.size();
+			target_default_arg_count = mi.default_arguments.size();
+		} else {
+			MethodBind *method = ClassDB::get_method(t->target_instance->get_class_name(), t->target_method);
+			target_param_count = method->get_argument_count();
+			target_default_arg_count = method->get_default_argument_count();
+		}
+		if (target_param_count >= 1 && target_default_arg_count == target_param_count) {
+			argc = 1;
+		}
+	}
 
 	Thread::set_name(t->target_method);
 
diff --git a/core/io/resource_format_binary.cpp b/core/io/resource_format_binary.cpp
index a3ebc32cc5..00d4d093da 100644
--- a/core/io/resource_format_binary.cpp
+++ b/core/io/resource_format_binary.cpp
@@ -903,10 +903,11 @@ void ResourceLoaderBinary::open(FileAccess *p_f, bool p_no_resources, bool p_kee
 	if (using_uids) {
 		uid = f->get_64();
 	} else {
+		f->get_64(); // skip over uid field
 		uid = ResourceUID::INVALID_ID;
 	}
 
-	for (int i = 0; i < 5; i++) {
+	for (int i = 0; i < ResourceFormatSaverBinaryInstance::RESERVED_FIELDS; i++) {
 		f->get_32(); //skip a few reserved fields
 	}
 
@@ -1209,8 +1210,8 @@ Error ResourceFormatLoaderBinary::rename_dependencies(const String &p_path, cons
 	fw->store_32(flags);
 	fw->store_64(uid_data);
 
-	for (int i = 0; i < 5; i++) {
-		f->store_32(0); // reserved
+	for (int i = 0; i < ResourceFormatSaverBinaryInstance::RESERVED_FIELDS; i++) {
+		fw->store_32(0); // reserved
 		f->get_32();
 	}
 
@@ -1264,7 +1265,7 @@ Error ResourceFormatLoaderBinary::rename_dependencies(const String &p_path, cons
 
 		if (using_uids) {
 			ResourceUID::ID uid = ResourceSaver::get_resource_id_for_path(full_path);
-			f->store_64(uid);
+			fw->store_64(uid);
 		}
 	}
 
@@ -1902,7 +1903,7 @@ Error ResourceFormatSaverBinaryInstance::save(const String &p_path, const RES &p
 	f->store_32(FORMAT_FLAG_NAMED_SCENE_IDS | FORMAT_FLAG_UIDS);
 	ResourceUID::ID uid = ResourceSaver::get_resource_id_for_path(p_path, true);
 	f->store_64(uid);
-	for (int i = 0; i < 5; i++) {
+	for (int i = 0; i < ResourceFormatSaverBinaryInstance::RESERVED_FIELDS; i++) {
 		f->store_32(0); // reserved
 	}
 
diff --git a/core/io/resource_format_binary.h b/core/io/resource_format_binary.h
index ac964d2053..a6e6d1848e 100644
--- a/core/io/resource_format_binary.h
+++ b/core/io/resource_format_binary.h
@@ -164,6 +164,8 @@ public:
 	enum {
 		FORMAT_FLAG_NAMED_SCENE_IDS = 1,
 		FORMAT_FLAG_UIDS = 2,
+		// Amount of reserved 32-bit fields in resource header
+		RESERVED_FIELDS = 11
 	};
 	Error save(const String &p_path, const RES &p_resource, uint32_t p_flags = 0);
 	static void write_variant(FileAccess *f, const Variant &p_property, Map<RES, int> &resource_map, Map<RES, int> &external_resources, Map<StringName, int> &string_map, const PropertyInfo &p_hint = PropertyInfo());