[ROS2 Humble] Missing OctoMap linkage in octomap_world causes undefined reference errors when building dsv_planner

[JLCucumber]

Description:

I was installing the Autonomous Exploration Development Environment, where the non-planner validation demo worked well. However, I encounted some problems when I wanted to install this planner.

Environment:

• Ubuntu 22.04
• ROS2 Humble
• GCC/G++ 11.4
• CMake 3.22
• Building dsv_planner (depends on octomap_world)

---

Problem:

When building dsv_planner, linking fails with multiple undefined references to octomap::... and octomath::....
Example error:

/usr/bin/ld: /home/.../liboctomap_world.so: undefined reference to `octomap::Pointcloud::~Pointcloud()'
/usr/bin/ld: /home/.../liboctomap_world.so: undefined reference to `octomap::AbstractOccupancyOcTree::readBinary(...)'
collect2: error: ld returned 1 exit status

---

Root cause:

The octomap_world library does not link against OctoMap core libraries (liboctomap.so, liboctomath.so).
While ament_target_dependencies(${PROJECT_NAME} octomap ...) is present, it does not add system-level OctoMap libraries to the linker command.

---

How to reproduce:

1. Fresh ROS2 Humble setup on Ubuntu 22.04

2. Install dependencies as listed in the official setup notes:

   sudo apt install ros-humble-octomap-ros libgoogle-glog-dev libgflags-dev

3. Build dsv_planner:

   colcon build --symlink-install --packages-select dsvplanner

4. Observe undefined reference errors from liboctomap_world.so.

---

Proposed fix:

In
src/volumetric_mapping/octomap_world/CMakeLists.txt,
add explicit OctoMap linkage after ament_target_dependencies():

find_package(octomap REQUIRED)

target_link_libraries(${PROJECT_NAME}
  ${PCL_LIBRARIES}
  ${OCTOMAP_LIBRARIES}  # Ensures liboctomap.so and liboctomath.so are linked
)

---

Verification:

After patching:

ldd install/octomap_world/lib/liboctomap_world.so | grep octomap

Outputs:

liboctomap.so => /usr/lib/x86_64-linux-gnu/liboctomap.so
liboctomath.so => /usr/lib/x86_64-linux-gnu/liboctomath.so

Then, dsv_planner builds successfully, and the exploration demo runs without errors.

---

Additional notes:

• Also, liboctomap-dev is required in addition to ros-humble-octomap-ros, but not mentioned in the setup notes.
  It provides liboctomap.so and liboctomath.so.
• The fix is backward compatible and safe for both ROS2 Humble and Jazzy.

(the mainbody was generated with GPT, so if something unclear pls leave a message)