[JTC] Invalidate empty trajectory messages

[christophfroehlich]

I introduced a bug with #567: If an empty trajectory (no points) is received with allow_nonzero_velocity_at_trajectory_end=true then trajectory.points.back() is undefined behavior and may result in a segfault.

I added now a check to skip empty trajectories. Or is there a point for accepting them? Trajectory::sample() will return false with an empty trajectory.

ros2_controllers/joint_trajectory_controller/src/trajectory.cpp

Lines 68 to 73 in 999eae5

	if (trajectory_msg_->points.empty())
	{
	start_segment_itr = end();
	end_segment_itr = end();
	return false;
	}

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (9f7e9e9) 47.71% compared to head (fba33dd) 47.47%.
Report is 5 commits behind head on master.

❗ Current head fba33dd differs from pull request most recent head ac4205d. Consider uploading reports for the commit ac4205d to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #902      +/-   ##
==========================================
- Coverage   47.71%   47.47%   -0.24%     
==========================================
  Files          41       41              
  Lines        3871     3865       -6     
  Branches     1833     1818      -15     
==========================================
- Hits         1847     1835      -12     
- Misses        751      768      +17     
+ Partials     1273     1262      -11     

Flag	Coverage Δ
unittests	47.47% <66.66%> (-0.24%)	⬇️

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Files	Coverage Δ
...ory_controller/src/joint_trajectory_controller.cpp	48.62% <66.66%> (+1.50%)	⬆️

... and 5 files with indirect coverage changes

[saikishor]

LGTM. Thanks for the change

[destogl]

Looking good to me, just a small proposal to rename test for clarity.

Maybe I tend to have tooooooooo long test names lately, but this brings clarity what is tested.

[destogl]

Just a bit more clarity.

Suggested change

	TEST_P(TrajectoryControllerTestParameterized, invalid_message_nonzero_vel)
	TEST_P(
	TrajectoryControllerTestParameterized,
	expect_invalid_when_message_with_nonzero_end_velocity_and_when_param_false)