We should validate ament_cmake packages after installation about ament_tools

[wjwwood]

I might also be useful to suggest the reason behind the issue you ran into, something like:

Package 'foo' did not install some required files for an 'ament_cmake' package type:
  - '<prefix>/share/foo/package.xml' was found
  - '<prefix>/share/ament_index/resource_index/packages/foo' is missing
[ ... ]

Did you forget to call `ament_package()` in your `CMakeLists.txt`?

[dirk-thomas]

I can see certain packages could be skipping the ament_package() call if e.g. a required dependency is not available (as a graceful fallback for example). In that case the warning would be annoying since it is intended.

[wjwwood]

Well, lots of our code assumes that there is a package file in the ament resource, and potentially other things, so if we don't enforce this we'll have undo those assumptions. For example, @rohbotics' problem was that he had a workspace with only a pair of ament_cmake build type packages, neither of which actually called ament_package() and so the setup file crashed trying to ls the share/ament_index/.../packages folder.

[wjwwood]

That would probably also be a problem if the workspace was empty.

[rohbotics]

In an empty workspace ament build does nothing, no setup.bash is created

rohan@machina:~/test_ws$ ls src
rohan@machina:~/test_ws$ ament build
# Topological order
All selected packages are being skipped. Nothing to do.
rohan@machina:~/test_ws$ ls
src
rohan@machina:~/test_ws$

[dirk-thomas]

Closing since the repo is archived.