Import Python bindings while building a downstream package fails to find libGL.so.1

[diegoferigo]

• I read the conda-forge documentation and could not find the solution for my problem there.

I'm trying to build a downstream conda package (conda-forge/staged-recipes#16582) that needs to import in CI the idyntree Python package. It fails with the following error:

  File "/home/conda/staged-recipes/build_artifacts/gym-ignition-split_1634739628523/_h_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_pl/lib/python3.8/site-packages/idyntree/__init__.py", line 1, in <module>
    from . import swig
  File "/home/conda/staged-recipes/build_artifacts/gym-ignition-split_1634739628523/_h_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_pl/lib/python3.8/site-packages/idyntree/swig.py", line 13, in <module>
    from . import _iDynTree
ImportError: libGL.so.1: cannot open shared object file: No such file or directory

As far as I understood, while building the recipe of this repo, the libGL.so.1 is provided by either the cdt requirements or the system packages defined in yum_requirements.txt (not really sure which one of the two).

It is not clear what kind of action we can take in the idyntree recipe so that downstream libraries don't have to mind about these upstream workarounds.

cc @traversaro

[traversaro]

This is due to the the irrlicht dependency. From what I know, any downstream user of the idyntree python package needs to install a libGL.so.1 via its system package manager, but I may be wrong on this.

[diegoferigo]

Yep, it seems that what suggested in https://conda-forge.org/docs/maintainer/knowledge_base.html#libgl is necessary to get a valid CI environment (i.e. both the cdt packages and the yum dependencies).

I'm closing this issue since now it is documented and can be hopefully found if this error occurs again.

[traversaro]

This was fixed in #99 .