CI fails on ESP-IDF v5.2/v5.3 due to ament_package requiring Python 3.11+

[Narukara]

Generated by AI and checked by humans

Summary:

Our build script clones ament_package from the rolling branch without pinning a specific version (see libmicroros.mk):

git clone -b rolling https://github.com/ament/ament_package src/ament_package

On 2026-07-14, PR #167 "type annotations" was merged into ament_package's rolling branch, adding this import to ament_package/templates.py:

from importlib.resources.abc import Traversable

importlib.resources.abc is a submodule introduced in Python 3.11. On Python < 3.11 this import fails with:

ModuleNotFoundError: No module named 'importlib.resources.abc'; 'importlib.resources' is not a package

and there is no fallback/try-except for older Python versions.

Impact:

This breaks every build that runs ament_cmake_core (which imports ament_package.templates) on Python < 3.11. In our CI matrix (espressif/idf:release-vX.Y containers), this maps directly to Python version by base OS:

ESP-IDF version	Docker base image	System Python	Result
v5.2, v5.3	ubuntu:22.04	3.10	fails
v5.4, v5.5, v6.0	ubuntu:24.04	3.12	passes

Suggested fix (upstream): Wrap the importlib.resources.abc import in a try/except fallback (e.g. importlib.abc.Traversable for Python < 3.11), similar to other projects that support this Python matrix.

Our workaround: Pin ament_package to a commit/tag before PR #167 (e.g. tag 0.19.0) instead of tracking the unpinned rolling branch.

[Narukara]

Any ideas? @Amronos