Add a functionality to look for the controller type in the params file when not parsed

[saikishor]

This will enable to have the config file as in ROS1 with their type defined in the params file. The advantage of having it like this is that the controller type and the parameters that are parsed are dependent, it is better to define the dependent data in one place.

Thank you

[christophfroehlich]

Does this mean that instead of

controller_manager:
  ros__parameters:
    update_rate: 10  # Hz

    forward_position_controller:
      type: forward_command_controller/ForwardCommandController

forward_position_controller:
  ros__parameters:
    joints:
      - joint1
      - joint2
    interface_name: position

one can use this?

controller_manager:
  ros__parameters:
    update_rate: 10  # Hz

forward_position_controller:
  ros__parameters:
    type: forward_command_controller/ForwardCommandController
    joints:
      - joint1
      - joint2
    interface_name: position

[saikishor]

@christophfroehlich Yes, that should be possible now

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.42%. Comparing base (c935b50) to head (0dcf3e2).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1502      +/-   ##
==========================================
+ Coverage   88.31%   88.42%   +0.10%     
==========================================
  Files         101      101              
  Lines        8313     8327      +14     
  Branches      725      726       +1     
==========================================
+ Hits         7342     7363      +21     
+ Misses        711      703       -8     
- Partials      260      261       +1     

Flag	Coverage Δ
unittests	88.42% <100.00%> (+0.10%)	⬆️

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Files	Coverage Δ
controller_manager/test/test_spawner_unspawner.cpp	98.82% <100.00%> (+0.21%)	⬆️

... and 1 file with indirect coverage changes

[christophfroehlich]

LGTM

[saikishor]

@christophfroehlich I've found a corner case when loading multiple controllers from same file. This is fixed now. If you can take a look it would be great. Thanks

[christophfroehlich]

I played around with the tests, it seems to work fine now.

[saikishor]

Now using the --controller-type argument should print the following deprecation warning

/home/user/rolling_worspace/ros2_control_ws/install/controller_manager/lib/python3.10/site-packages/controller_manager/spawner.py:209: DeprecationWarning: The '--controller-type' argument is deprecated and will be removed in future releases. Declare the controller type parameter in the param file instead.

[saikishor]

In the upcoming days, I will make changes on the ros2_control_demos, so you can check how this change will affect

[saikishor]

@christophfroehlich I've added the deprecation note to the controller_type argument as you have mentioned in the #1503

[bmagyar]

Thank you!