Remove broken rviz_ogre_vendor::RenderSystem_GL target

[sloretz]

This fixes an issue that happens on the ROS 2 buildfarm, but has gone unnoticed because nothing uses these targets. It was noticed in bazel_ros2_rules: RobotLocomotion/drake-ros#188

The issue is these find library calls are looking for libraries that don't have the lib prefix. The version of CMake on jammy no longer looks for libraries without the lib prefix on Linux by default. This restores that behavior. Edit: Incorrect.

This should be backported to Humble.

[clalancette]

Your analysis of the problem makes sense to me. But I find two things weird:

1. That change in behavior in CMake seems like a major change (it looks like it went in in CMake 3.22). I'm surprised it didn't cause more widespread breakage, though maybe the distributions dealt with it.
2. I'm not super familiar with how OGRE works, but it kind of seems like these libraries don't have lib prefix deliberately. That is, they seem to be plugins that get loaded at runtime into OGRE, not things that external programs should build and link against. That would explain why nothing used the targets before.

With the latter thing said, should we be trying to find_library them at all?

[sloretz]

That change in behavior in CMake seems like a major change (it looks like it went in in CMake 3.22). I'm surprised it didn't cause more widespread breakage, though maybe the distributions dealt with it.

That's a good point, and it looks like my explanation is wrong. The libraries aren't found on Foxy (Focal) either.

-- rviz_ogre_vendor::RenderSystem_GL for IMPORTED_LOCATION_RELEASE: _render_system_gl_static_library_abs-NOTFOUND
-- rviz_ogre_vendor::RenderSystem_GL for IMPORTED_LOCATION_DEBUG: _render_system_gl_static_library_abs-NOTFOUND

With the latter thing said, should we be trying to find_library them at all?

Probably not - and since the target has never worked I think we could remove it and backport it.

[clalancette]

So this seems completely reasonable to me for Rolling. Though I might suggest that once you merge this, you immediately do a release of rviz into Rolling to ensure that there is no downstream breakage.

I'm more nervous about backporting it to Humble. Like you, I think nobody was actually depending on this, but I'm still worried about the side-effects. I'm not totally sure how to alleviate those worries, but I thought I would bring it up.

[sloretz]

CI (build: --packages-above-and-dependencies rviz_ogre_vendor test: --packages-above rviz_ogre_vendor)

• Linux
• Linux-aarch64
• Windows edit: unrelated networking issue, rerun