tests/regression/issue_472/test.proto

syntax = "proto3";

import "nanopb.proto";

message FirmwareUpdateCommand {
	string version = 1;
	uint32 size = 2;
}

message CommandWrapperMessage {
	option (nanopb_msgopt).submsg_callback = true;

    oneof payload {
		FirmwareUpdateCommand firmware_update = 1;
    }
}