Composable node runtime error (undefined symbol) but normal Node has no issue

Bug report

Required Info:

• Operating System:
  • Ubuntu 22.04
• Installation type:
  • binaries
• Version or commit hash:
  • humble
• DDS implementation:
• Client library (if applicable):
  • rclcpp

I am trying to call the python interpreter from a ComposableNode.
I have no issue doing a simple print(), but if I try to do import torch, the program crashes with an undefined symbol error.

terminate called after throwing an instance of 'pybind11::error_already_set'
  what():  ImportError: /usr/lib/python3.10/lib-dynload/_ctypes.cpython-310-x86_64-linux-gnu.so: undefined symbol: PyTuple_Type

At:
  /usr/lib/python3.10/ctypes/__init__.py(8): <module>
  <frozen importlib._bootstrap>(241): _call_with_frames_removed
  <frozen importlib._bootstrap_external>(883): exec_module
  <frozen importlib._bootstrap>(703): _load_unlocked
  <frozen importlib._bootstrap>(1006): _find_and_load_unlocked
  <frozen importlib._bootstrap>(1027): _find_and_load
  /home/mclement/.local/lib/python3.10/site-packages/torch/__init__.py(17): <module>
  <frozen importlib._bootstrap>(241): _call_with_frames_removed
  <frozen importlib._bootstrap_external>(883): exec_module
  <frozen importlib._bootstrap>(703): _load_unlocked
  <frozen importlib._bootstrap>(1006): _find_and_load_unlocked
  <frozen importlib._bootstrap>(1027): _find_and_load

There is no issue when doing this with a normal Node.

Steps to reproduce issue

I made a minimal example showcasing the issue in the following repository: https://github.com/maxime-clem/ros2_composable_node_bug

# requires python3-dev and pybind11-dev
git clone git@github.com:maxime-clem/ros2_composable_node_bug.git
cd ros2_composable_node_bug
colcon build
source install/setup.sh
ros2 run test_exe test_exe  # No issue
ros2 run test_node test_node  # No issue
ros2 run test_composable_node test_composable_node_exe  # undefined symbol error

Expected behavior

Composable node can use the python library without issue, similarly to a normal Node.

Actual behavior

Composable node crashes with an undefined symbol: PyTuple_Type error.

Additional information

I have confirmed the issue with another user so it does not appear to be en environment issue.
The only workaround found so far is to use dlopen("libpython3.10.so", RTLD_GLOBAL | RTLD_NOW) in the code of the ComposableNode.

Start by cloning the linked minimal repository and running its three colcon/ros2 commands to reproduce the failure. Compare the normal and composable node entry points, then investigate the reported Python symbol-loading behavior and dlopen workaround. Done means the composable node can import torch without crashing, matching the normal node.