[gpio_controllers] Build race condition: test_load_gpio_command_controller missing dependency on generated parameters

[Ishan1923]

When building gpio_controllers from a clean workspace (or after deleting build/ and install/), the build frequently fails with a missing header error (fatal error: gpio_controllers/gpio_command_controller_parameters.hpp: No such file or directory) in the test file test_load_gpio_command_controller.cpp.

This appears to be a build race condition in CMakeLists.txt. The test_load_gpio_command_controller target does not explicitly link against the main library (gpio_controllers) or the generated parameter library. Consequently, the build system attempts to compile the test before the parameter header generation is complete.

To Reproduce Steps to reproduce the behavior:

1. Clean the workspace: rm -rf build/ install/ log/

2. Build the package from scratch (forcing parallel execution makes it more likely to fail):

colcon build --packages-select gpio_controllers --parallel-workers 8

3. Observe the build failure:

/src/ros2_controllers/gpio_controllers/include/gpio_controllers/gpio_command_controller.hpp:30:10: 
    fatal error: gpio_controllers/gpio_command_controller_parameters.hpp: No such file or directory

Expected behavior: The package and its tests should build successfully from a clean state without dependency race conditions.

Environment:

• OS: Linux (Pop!_OS / Ubuntu 24.04 based)
• Version: Rolling
• Build Tool: colcon
  Additional context The issue seems to be missing a dependency link in gpio_controllers/CMakeLists.txt.

Currently, the test target is defined as:

  ament_add_gmock(
    test_load_gpio_command_controller
    test/test_load_gpio_command_controller.cpp
  )

  target_link_libraries(test_load_gpio_command_controller
    controller_manager::controller_manager
    hardware_interface::hardware_interface
    ros2_control_test_assets::ros2_control_test_assets
    # MISSING LINK to ${PROJECT_NAME} or gpio_controllers
  )

Adding gpio_controllers to target_link_libraries for this test target resolves the race condition by enforcing the correct build order.

[Ishan1923]

I have verified that adding gpio_controllers to the target_link_libraries fixes the issue locally. I can open a PR for this shortly.