Undefined symbol when importing UTTG Python interface: missing linkage to imc / irmv_core libraries

[ChloeZ427]

Hi, I’m trying to build and use the UTTG library on Ubuntu 20.04 (GCC 9.4, Python 3.10).
I was able to compile UTTG successfully after installing irmv_core and imc from the .deb packages provided in the release page.

However, when I try to run the Python example:

python example/fr3_test.py ( exactly the same with python usage example in readme.md )

I get the following error:

ImportError: /path/to/libUTTG.so: undefined symbol: _ZTVN16bot_traj_planner25TrajectoryIterativeSplineE

This symbol belongs to bot_traj_planner::TrajectoryIterativeSpline, which I believe is implemented inside imc or irmv_core.
It looks like libUTTG.so is not linked against the correct version of these libraries.

What I found so far
✔ 1. UTTG detects system-installed irmv_core & imc

During configuration:

Using system-installed irmv_core, skipping add_subdirectory()
Using system-installed imc, skipping add_subdirectory()

So CMake does not build the bundled source, and instead uses the system .deb version.

✘ 2. But the final library (libUTTG.so) seems not linked with all required dependencies

Because of the missing symbol, it looks like CMake does not add:

imc

irmv_core

bot_traj_planner

other dependent libraries

to the target_link_libraries() list.

Since these libraries are only available as .deb, I cannot easily inspect the exported symbols or rebuild them manually.

My questions

How should UTTG link against the system-installed imc and irmv_core?
The current CMake logic calls find_package(), but the resulting ${PKG_NAME}_LIBRARIES variables do not seem to be propagated to the Python binding target.

Is the .deb version of imc / irmv_core known to contain the required symbols?
Or do I need a source version of these packages?

Could you provide build instructions or CMake patches showing how to correctly link UTTG_interface_py with these dependencies?

Environment

Ubuntu 20.04

GCC 9.4

Python 3.10

UTTG latest commit

Installed:

irmv_core-0.3.4.deb

imc-1.2.0.deb

Thanks a lot! Any guidance on correct linking or dependency setup would be greatly appreciated.