Checking for target-less components existence in config files

[craig.scott]

@Artemis

(I cannot explain why using two names for the same value, comps and ${CMAKE_FIND_PACKAGE_NAME}_comps, if comps is “usafe”, why bothering with it?)

It’s in part to do with parts of the example that you’ve left out. If you have a call to find_dependency() nestled in among those lines (which the original example in the book does) and the dependency package you try to find has been implemented with the same pattern, its comps variable would overwrite the one for this package. When you then try to iterate over comps in your package’s foreach() loop instead of ${CMAKE_FIND_PACKAGE_NAME}_comps, you would be iterating over a list of components for the dependency, not for this package.

@Artemis

The script checks if the requested components are installed by checking if the corresponding export file exist.
This works only for components that include an exported target. If I were to apply the aforementioned recommended practice, the “development” component would fail the check, because it exports no targets.

You don’t have to do the check that way if you don’t want to. It just happens to be a convenient way to do it when you know there will be at least one exported target. In the case of a header-only library, there’s no library that needs to be installed for runtimes to use, so you can just skip over checking that particular component.

@ben.boeckel

I’m aware. Craig is probably still one of the best to answer it. I’ll try and take a look later as well.

Craig is also drowning in his backlog of stuff to get done by the end of the year.