Pass URDF to controllers on init

[bmagyar]

This should help avoiding extra legwork in controllers to get access to the /robot_description.

[aprotyas]

Should this be a std::optional<std::string> urdf_ = std::nullopt instead?

[bmagyar]

I don't want to communicate the option of not being set as anything close to valid. The empty string initial value is only there so we can test if it was properly set...

I also thought about how we could do this better, a const string would be nice but that can only be set once which doesn't work well with the longer term idea of getting URDF updates from topics.

[saikishor]

The provision of the URDF directly to the controllers is a brilliant idea. This reduces the hassles one should go through to set up their controllers.

ros2_control/controller_manager/src/controller_manager.cpp

Line 1143 in 757ccd4

controller.c->init(controller.info.name, get_namespace()) ==

However, I think there is a missing part in assigning this URDF from the controller_manager's end, and at least one test that verifies the robot_description string from the topic or param is the same as that inside the controller.
Another test that checks when a URDF is updated in the topic, the newly initialized controllers get the new URDF rather than the old one.

Brilliant work 👏

[destogl]

This looks good!

[mergify]

This pull request is in conflict. Could you fix it @bmagyar?

[codecov]

Codecov Report

Merging #1088 (caef34d) into master (bd6911d) will decrease coverage by 0.08%.
The diff coverage is 11.86%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1088      +/-   ##
==========================================
- Coverage   31.62%   31.55%   -0.08%     
==========================================
  Files          94       94              
  Lines       10838    10878      +40     
  Branches     7419     7454      +35     
==========================================
+ Hits         3428     3433       +5     
+ Misses        804      802       -2     
- Partials     6606     6643      +37     

Flag	Coverage Δ
unittests	31.55% <11.86%> (-0.08%)	⬇️

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Files	Coverage Δ
...controller_interface/controller_interface_base.hpp	33.33% <ø> (-16.67%)	⬇️
...roller_interface/src/controller_interface_base.cpp	48.14% <100.00%> (+1.99%)	⬆️
...er_interface/test/test_controller_with_options.hpp	45.00% <100.00%> (ø)
.../include/controller_manager/controller_manager.hpp	18.18% <ø> (ø)
...r_manager/test/test_controller/test_controller.hpp	100.00% <ø> (ø)
...roller_failed_init/test_controller_failed_init.cpp	55.55% <ø> (ø)
...roller_failed_init/test_controller_failed_init.hpp	20.00% <ø> (ø)
...er_interface/test/test_controller_with_options.cpp	29.62% <0.00%> (ø)
...oller_interface/test/test_controller_interface.cpp	21.79% <0.00%> (ø)
...rface/test/test_chainable_controller_interface.cpp	14.44% <0.00%> (ø)
... and 3 more