SIGSEGV when subscribing to multiple topics

[elekTom]

I encountered a nullptr deref when subscribing to multiple topics with custom options.
See example below:

std::vector<std::string> topicList;
std::vector<int> qosList;
std::vector<mqtt::subscribe_options> subOptsList;
// -----
// fill lists with data
// -----
const auto resp = client->subscribe(topicList, qosList, subOptsList);  // <-- causes SIGSEGV 

More specifically, the nullptr deref happens in MQTTAsync_subscribeMany() because response->subscribeOptionsList is NULL here.

I think this is caused by response_options copy constructor not copying subOpts_.
This means that when response_options_builder::finalize() is called, a response_options instance with subOpts_.data()==nullptr is returned.

My current fix for this looks like this. Although I don't know if there is more to this than that:

diff --git a/src/response_options.cpp b/src/response_options.cpp
index 62166f5..100a373 100644
--- a/src/response_options.cpp
+++ b/src/response_options.cpp
@@ -36,7 +36,7 @@ response_options::response_options(const token_ptr& tok,
 }
 
 response_options::response_options(const response_options& other)
-	: opts_(other.opts_), tok_(other.tok_), props_(other.props_)
+	: opts_(other.opts_), tok_(other.tok_), props_(other.props_), subOpts_(other.subOpts_)
 {
 	update_c_struct();
 }

System info

OS: win11
Compiler: mingw64 12.2.0