Got LibraryUnloadException on correct unloading

[roversch]

I'm on 1.13.0-1focal.20210727.062753 with ROS noetic.

I have the following plugin situation, both are part of the same dynamic library:

  <class type="Child1" base_class_type="Parent"/>
  <class type="Child2" base_class_type="Parent"/>

When I call createUnmanagedInstance with the name of Child1, it correctly gets resolved_library_path_ set. When I do the same for Child2, it is not updated from UNRESOLVED.

When I then try to call unloadLibraryForClass, the Child1 is correctly unloaded, but for Child2 I get LibraryUnloadException, since there is a check for the resolved_library_path_:

  if (it != classes_available_.end() && it->second.resolved_library_path_ != "UNRESOLVED") {
    ...
  }

Basically, I'm not able to correctly unload it.

How can I get around this? Is it correct to assume that resolved_library_path_ should always be set, and thus we have a bug here?