3di | Add area and related_scope metadata for related packages lists

[kacperbojakowski-3di]

Description

Adds <area> and <related_scope> to rclcpp's package.xml so the related packages lists in #7240 can match this package. Those lists read exports from the rosdistro cache. Nothing released declares them yet, so the lists are empty. This is one core package as a worked example.

Metadata added

In the existing <export> of rclcpp/package.xml:

<export>
  <build_type>ament_cmake</build_type>
  <area>client-libraries, framework</area>
  <related_scope>core</related_scope>
</export>

• <area>: which docs pages list the package (most specific first).
• <related_scope>: core or federation (missing is treated as community).

Why these values

client-libraries, framework matches docs pages that already use :area: client-libraries, framework. core puts it under Core ROS packages rather than community.

Why this is safe to add

<export> is the passthrough container for tool-specific metadata, and tools are expected to skip any export tags they don't recognise (REP 140). Nothing in the build reads these two, so there's no effect on how rclcpp compiles or runs, and no ABI impact. This is all just for the docs.

Scope and next steps

Limited to rclcpp on purpose, as an example to look at before this goes wider. I'll be adding the same exports to the other core packages. Each one shows up in the docs after relase and cache refresh.

Dependencies

Visible to users once #7240 and #6981 land, and this rclcpp change is released (docs read the released cache, not source).

Changes

• Update rclcpp/package.xml: add <area>client-libraries, framework</area> and <related_scope>core</related_scope>.

Additional Information

Issue: #6991

[github-actions]

ABI Compliance Check

✅ Verdict: compatible

Library	Verdict	Summary
libcomponent_manager.so	✅ compatible	No ABI changes detected.
librclcpp.so	✅ compatible	No ABI changes detected.
librclcpp_action.so	✅ compatible	No ABI changes detected.
librclcpp_lifecycle.so	✅ compatible	No ABI changes detected.

✅ libcomponent_manager.so — full abidiff report

Compared:

• Base: lib-base/libcomponent_manager.so
• Head: lib-pr/libcomponent_manager.so @ c03113d

(empty report — no differences printed by abidiff)

✅ librclcpp.so — full abidiff report

Compared:

• Base: lib-base/librclcpp.so
• Head: lib-pr/librclcpp.so @ c03113d

(empty report — no differences printed by abidiff)

✅ librclcpp_action.so — full abidiff report

Compared:

• Base: lib-base/librclcpp_action.so
• Head: lib-pr/librclcpp_action.so @ c03113d

(empty report — no differences printed by abidiff)

✅ librclcpp_lifecycle.so — full abidiff report

Compared:

• Base: lib-base/librclcpp_lifecycle.so
• Head: lib-pr/librclcpp_lifecycle.so @ c03113d

(empty report — no differences printed by abidiff)

_{Updated for commit c03113d · suppressions: /home/runner/work/_temp/ros2-abi-suppressions.txt}

[jmachowinski]

I don't like the approach for several reasons.

• There is no validation of the fields. E.g. typos etc can go unoticed.
• It is not clear to me what tags exist etc. Can people just come up with tags, is there a curated list of tags ?
• Any package can declare being core. This is my major criticism here. I would rather have a curated list of core packages that is under our control.