Why does action-ros-ci fail with missing rmw when running on RHEL?

edit

So I'm trying to add an RHEL CI pipeline to ros-controls/ros2_controllers. I made an ros alma linux container where I installed ros and a few rosdep dependencies. I then created a working ci pipeine(job titled: rhel) that runs rosdep and colcon to build and test. That can be seen here:

rhel:
name: RHEL
runs-on: ubuntu-latest
container: jaronl/ros:galactic-alma
steps:
  - uses: actions/checkout@v2
    with:
      path: src/ros2_controllers
  - run: |
      rosdep init
      rosdep update
      rosdep install -iy --from-path src/ros2_controllers
      source /opt/ros/$ROS_DISTRO/setup.bash
      colcon build
      colcon test

I wanted to take it a little step further to see if I could get it to run with action-ros-ci in case the ros-controls group wants to customize it. To do that, I forked action-ros-ci and modified the action to also be able to use dnf as an alternative to apt-get; however, I get an error about not having a ros middleware installed when it gets to colcon build. The ci file for that run can be seen here:

rhel:
name: RHEL
runs-on: ubuntu-latest
container: jaronl/ros:galactic-alma
steps:
  - uses: jaron-l/action-ros-ci@test_RHEL
    with:
      target-ros2-distro: ${{ env.ROS_DISTRO }}

The failed run job can be seen publicly but I copy it below.

What I don't get is why the difference between the working CI job (just manually calling colcon build) and the failed one is (action-ros-ci). They both checkout ros2_controllers, update the package manager cache, use rosdep to install dependencies, and then run colcon build and test. If someone could just point to the different between the two CI pipelines, that would be great.

Variations I've tried:

• I verified that the same packages are installed with rosdep and they obviously are using the same container.
• Using the exact same colcon build command arguments does not produce the same error.
• Using the exact same rosdep install args does not produce the same error.

As additional context, ros-controls/ros2_controllers has a build error on RHEL, but the one I'm looking for is in joint_state_trajectory_controller. An example of that is here.

Failed action-ros-ci output:

    /usr/bin/bash -c source /opt/ros/galactic/setup.sh && colcon build --event-handlers console_cohesion+ --symlink-install
  Starting >>> forward_command_controller
  Starting >>> diff_drive_controller
  --- output: forward_command_controller
  -- The C compiler identification is GNU 8.5.0
  -- The CXX compiler identification is GNU 8.5.0
  -- Detecting C compiler ABI info
  -- Detecting C compiler ABI info - done
  -- Check for working C compiler: /usr/bin/cc - skipped
  -- Detecting C compile features
  -- Detecting C compile features - done
  -- Detecting CXX compiler ABI info
  -- Detecting CXX compiler ABI info - done
  -- Check for working CXX compiler: /usr/bin/c++ - skipped
  -- Detecting CXX compile features
  -- Detecting CXX compile features - done
  -- Found ament_cmake: 1.1.4 (/opt/ros/galactic/share/ament_cmake/cmake)
  -- Found PythonInterp: /usr/bin/python3 (found suitable version "3.6.8", minimum required is "3")
  -- Using PYTHON_EXECUTABLE: /usr/bin/python3
  -- Override CMake install command with custom implementation using symlinks instead of copying resources
  -- Found controller_interface: 1.1.0 (/opt/ros/galactic/share/controller_interface/cmake)
  -- Found ...