Captured 2026-10-12 after two complete successful final workflow runs.
Test platform: Docker Desktop on macOS ARM64; image platform linux/arm64.
Other architectures and emulation were not tested.
Base: ros:jazzy-ros-base@sha256:066420e07f60aa18262f2479981def87ebcfcec42eefb0c0c57c4a46098348ca
Local image tag: dustin-nav2-costmap-lesson:jazzy
Pinned map-server package: 1.3.13-1noble.20260921.044109
Pinned costmap package: 1.3.13-1noble.20260921.044133
Other apt dependencies resolve at build time; this is not a complete package snapshot.
Minimal installation estimate: 36.1 MB archives, 176 MB installed, before Docker overhead.
Runtime external network: none (ROS participants communicate inside the container).
RMW_IMPLEMENTATION=rmw_fastrtps_cpp
ROS_DOMAIN_ID=77 for narrow; 78 for wide.
use_sim_time=false on both map_server and costmap; supplied static map->base_link.

Version-scoped teardown workaround:
The runner invokes the costmap through ros2 run --prefix with
LD_PRELOAD=/opt/ros/jazzy/lib/liblayers.so, scoped only to that executable.
Without it, this binary set reproduced a CallbackGroup destructor fault after checks,
including after explicit lifecycle cleanup. A debugger confirmed the failure location;
its general root cause was not established. Keeping the official plugin library loaded
allowed both final runs to finish with exit code 0 for every ROS process. No Nav2 source
or cost calculation was patched. The base ROS client libraries were not changed.

Verification:
- Both final runs checked all 441 authored map cells and 882 raw costmap bytes.
- Both configurations read back correctly and differed only in inflation radius.
- Published 16-vertex footprint, active lifecycle states, and clean exits checked.
- Independent review checked PGM row order, polygon geometry, and all expected costs.
- Radius change added gradient cost to 84 cells; other nonzero classes stayed fixed.
- Existing-output protection refused the directory; all 27 artifact hashes unchanged.
- reference-costmaps.json is copied from final-1/comparison.json.
- Source and raw cell arrays matched across final runs; timestamps differ.
- No path planning, obstacle avoidance, localization, or robot result is claimed.

Captured runtime metadata:
PRETTY_NAME="Ubuntu 24.04.5 LTS"
NAME="Ubuntu"
VERSION_ID="24.04"
VERSION="24.04.5 LTS (Noble Numbat)"
VERSION_CODENAME=noble
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=noble
LOGO=ubuntu-logo
aarch64
Python 3.12.3
ros-jazzy-nav2-costmap-2d	1.3.13-1noble.20260921.044133
ros-jazzy-nav2-map-server	1.3.13-1noble.20260921.044109
ros-jazzy-nav2-msgs	1.3.13-1noble.20260921.042153
ros-jazzy-nav2-util	1.3.13-1noble.20260921.043534
ros-jazzy-rclcpp	28.1.22-1noble.20260902.143108
ros-jazzy-rclcpp-lifecycle	28.1.22-1noble.20260902.151236
ros-jazzy-rclpy	7.1.12-1noble.20260902.143245
ros-jazzy-rmw-fastrtps-cpp	8.4.4-1noble.20260902.140744
ros-jazzy-tf2-ros	0.36.22-1noble.20260902.154805