Fix component registering in subdirectories

[pum1k]

Description

This PR allows using rclcpp_components_register_node and rclcpp_components_register_nodes functions in subdirectories added by add_subdirectory (and other non global scopes). This was done by storing the internal data in a property of the project directory instead of variable.

Fixes: #1698

Is this user-facing behavior change?

Yes, users will be able to use the above mentioned functions inside nested scopes.

Did you use Generative AI?

No

[fujitatomoya]

lgtm with green CI.

i think that the approach of using directory properties on PROJECT_SOURCE_DIR is the right fix to avoid the CMake variable scoping problem cleanly without polluting the cache.

one minor suggestion: would it be worth adding a brief comment in the hook file explaining why properties are used like original problem?

[pum1k]

@fujitatomoya Is this what you meant?

[ahcorde]

Pulls: #3064
Gist: https://gist.githubusercontent.com/ahcorde/41da3d924b8795359675fc94caaaa1a5/raw/8fc503931b6a63733ca4324052ac4297a4f01bc0/ros2.repos
BUILD args: --packages-above-and-dependencies rclcpp_components
TEST args: --packages-above rclcpp_components
ROS Distro: rolling
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/18247

• Linux
• Linux-aarch64
• Linux-rhel
• Windows

[pum1k]

@ahcorde Could this be backported to Jazzy?

[ahcorde]

https://github.com/Mergifyio backport kilted jazzy humble

[mergify]

backport kilted jazzy humble

✅ Backports have been created

Details

• #3074 Fix component registering in subdirectories (backport #3064) has been created for branch kilted
• #3075 Fix component registering in subdirectories (backport #3064) has been created for branch jazzy
• #3076 Fix component registering in subdirectories (backport #3064) has been created for branch humble