geometry2/tf2 warning TF_REPEATED_DATA

[stribor14]

Git commit hash: 2712067e0563229248ac60c3e7be9b55c462bdce (and all previous)

This issue is linked with the following issue: ros/geometry2#467

A change in geometry2 package was introduced where there is a warning when multiple transforms between the same frames are published with the same timestamp.

This happens in simulation, but I did not test it on the robot yet, but from looking at the source code, I think the problem is specifically with the simulation at the following lines:

cartographer_ros/cartographer_ros/cartographer_ros/node.cc

Lines 258 to 263 in 2712067

	const ::cartographer::common::Time now = std::max(
	FromRos(ros::Time::now()), extrapolator.GetLastExtrapolatedTime());
	stamped_transform.header.stamp =
	node_options_.use_pose_extrapolator
	? ToRos(now)
	: ToRos(trajectory_data.local_slam_data->time);

My guess: if using the pose_extrapolator, simulated time can(?) trigger the timer event multiple times if trajectory_publish_period_sec is sufficiently small which results in repeated TF publishing (because in the first iteration extrapolator advances which results in stamped_transform.header.stamp being the same in the next iteration)

The resulting repeated transform is ignored by the tf2 buffers (new standard behavior in ROS noetic), so the only consequence is a lot of generated warnings (which makes the roslog unreadable)