CMake package registry breaks workspace isolation

[Levi-Armstrong]

We recently ran into issues with packages that leverage the CMake package registry feature. This feature does not seem to be compatible with build tools like catkin, colcon, etc.. Should catkin automatically be passing the CMake disable flags?

  -DCMAKE_EXPORT_NO_PACKAGE_REGISTRY=ON
  -DCMAKE_FIND_PACKAGE_NO_PACKAGE_REGISTRY=ON

[gavanderhoorn]

This feature does not seem to be compatible with build tools like catkin, colcon

What it seems to 'break' is workspace isolation.

Whether it's completely incompatible with Catkin and Colcon I'm not sure.

[dirk-thomas]

I don't know enough about the CMake package registry to make a suggestion here. It sounds reasonable to me though.

Even with these flags embedded by default the user should be able to pass different values if desired.

Would you like to create a pull request for the proposed change? Probably not only to catkin but also catkin_tools.

Just for reference the parallel ticket on colcon: colcon/colcon-cmake#91

[KazNX]

This is a really subtle, but problematic issue with CMake, especially on Windows. I've experienced unexpected and highly undesirable behaviour from CMake's "magic" use of it's package registry where it's basically used a recently built version of a library in an unrelated workspace.

The way I see it, colcon's philosophy is to create a self-contained workspace which is at odds with the CMake package registry. It would be reasonable to disable the package regsitry by default an option to turn restore the default "magic" behaviour.

To avoid the issue though, you can use --cmake-args, --catkin-cmake-args and --ament-cmake-args to pass through the options you list above. Probably best to use either default.yaml or a mixin.