Updating Publishers from CTurtle to Diamondback

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Hi, I'm in the process of migrating some other people's CTurtle code to Diamondback (while learning ROS at the same time), and I'd like to confirm some behaviour that I haven't seen documented.

In the CTurtle code, there are a lot of simple publishers that use std_msgs, such as:

stringPublisher_ = nodeHandle_.advertise<std_msgs::String>("/string", 1);

or

floatPublisher_ = nodeHandle_.advertise<std_msgs::Float32>("/float", 1);

When these are called however, it's not with a std_msgs:: data type, but instead the base data type, e.g.:

 std::string state = "IDLE"
 stringPublisher_.publish(state);

or

 floatPublisher_.publish((float)3.14);

This code worked fine under CTurtle, but now that I'm trying to port it to Diamondback it treats the std::string/float32 as a ROS message and as a result throws an error. Specifically:

 /ros-diamondback/ros_comm/clients/cpp/roscpp_traits/include/ros/message_traits.h:121: error: request for member ‘__getMD5Sum’ in ‘m’, which is of non-class type ‘const float’

This is easily fixed by pushing the data into the message variable, for e.g.:

 std_msgs::String msgStr;
 msgStr.data = state;
 stringPublisher_.publish(msgStr);

But I'm just curious if this is an intended change or if I'm missing something?

Thanks!