return default error if input is nullptr

Author: MarioIvancik

include/common/example_module.hpp

@@ -1,4 +1,5 @@
 #pragma once
 
 static constexpr unsigned int BUTTON_DEVICE_TYPE{0};
-static constexpr unsigned int MODULE_NUMBER{1000};
+static constexpr unsigned int MODULE_NUMBER{1000};
+static constexpr char DEFAULT_ERROR_MESSAGE[]{"Default error"};

source/module_gateway/module_manager.cpp

@@ -54,9 +54,16 @@ int aggregate_status(struct buffer *aggregated_status, const struct buffer curre
 
 int aggregate_error(struct buffer *error_message, const struct buffer current_error_message, const struct buffer status,
 					unsigned int device_type) {
-	allocate(error_message, current_error_message.size_in_bytes);
-	std::memcpy(error_message->data, current_error_message.data,
-				current_error_message.size_in_bytes );
+	if (current_error_message.data != nullptr) {
+		allocate(error_message, current_error_message.size_in_bytes);
+		std::memcpy(error_message->data, current_error_message.data,
+					current_error_message.size_in_bytes);
+	} else {
+		const std::string current_error_message_str = DEFAULT_ERROR_MESSAGE;
+		allocate(error_message, current_error_message_str.size());
+		std::memcpy(error_message->data, current_error_message_str.c_str(),
+					current_error_message_str.size());
+	}
 	return OK;
 }