Unexpected debug print when publishing a message

edit

Hello,

when running a ROS node, I see this message printed (which I never had, as far as I can remember):

[DEBUG] [1676642682.790247167]: Trying to publish message of type [nocs_msgs/PowerManagementStatus/d06180ee877801d514cfd505d0b509be] on a publisher with type [nocs_msgs/PowerManagementStatus/d06180ee877801d514cfd505d0b509be]

It looks curious to me since the md5sum is the same for both messages, so I am wondering whether it indicates some error or not. I found that this get printed in the implementation of the publish method when the following condition is met:

(impl_->md5sum_ == "*" || 
 std::string(mt::md5sum<M>(*message)) == "*" || 
 impl_->md5sum_ == mt::md5sum<M>(*message))

but I don't understand what that means. Could someone help me understanding?

Thanks

EDIT: in the following a sample code

#include <ros/ros.h>
#include <std_msgs/String.h>

int main(int argc, char **argv) {
  ros::init(argc, argv, "example");

  if (ros::console::set_logger_level("ros.example_pkg", ros::console::levels::Debug))
    ros::console::notifyLoggerLevelsChanged();

  ros::NodeHandle nh;
  ros::Publisher my_pub = nh.advertise<std_msgs::String>("my_topic", 30, true);

  // Wait to ensure everything is initialised
  sleep(5);

  std_msgs::String msg;
  msg.data = "Initial pub";
  my_pub.publish(msg);

  ros::spin();
  return 0;
}

Using this launch file:

<launch>
  <node pkg="example_pkg" type="example_pkg_pub" name="example" output="screen">
  </node>
</launch>

This is the output I get on the screen:

... logging to /home/davfen/.ros/log/3ee1ef44-b750-11ed-8e0b-2816ad516265/roslaunch-davfen-Precision-7510-1671.log
Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://davfen-Precision-7510:42401/

SUMMARY
========

PARAMETERS
 * /rosdistro: melodic
 * /rosversion: 1.14.13

NODES
  /
    example (example_pkg/example_pkg_pub)

auto-starting new master
process[master]: started with pid [1700]
ROS_MASTER_URI=http://localhost:11311

setting /run_id to 3ee1ef44-b750-11ed-8e0b-2816ad516265
process[rosout-1]: started with pid [1737]
started core service [/rosout]
process[example-2]: started with pid [1741]
[DEBUG] [1677579088.413755111]: Trying to publish message of type [std_msgs/String/992ce8a1687cec8c8bd883ec73ca41d1] on a publisher with type [std_msgs/String/992ce8a1687cec8c8bd883ec73ca41d1]