Conan: How to avoid link warnings with header-only dependencies in cmake based recipes?

[sourcedelica]

When using header-only libs like zmqcpp or catch with the cmake generator like:

[requires]
catch/1.5.0@TyRoXx/stable
zmqcpp/4.2.0@sourcedelica/testing

[generators]
cmake

you get linker warnings like:

ld: warning: directory not found for option '-L/Users/eric/.conan/data/catch/1.5.0/TyRoXx/stable/package/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/lib'
ld: warning: directory not found for option '-L/Users/eric/.conan/data/zmqcpp/4.2.0/sourcedelica/testing/package/1686cbbda545ba2177cad298877b69c2401b9b59/lib'

Is there something I can do in the dependency package (for example libzmq in this example) recipe to avoid this? Or in the client package recipe? Though I would prefer fixing it at the source.

[ruipires]

This issue also bothers me (I'm very picky with warnings).

I don't know of a way to fix this in either the depencency or client package. Others may help here.

The only way I do know that could fix this requires a small change in conan itself: check if the actual library is empty and remove it from the cmake variable (not sure where best to do this, most likely in the cmake generator itself).

I have tried this and the warning is indeed gone (was not able to run the tests, so I have no idea of possible side-effects).

[ruipires]

Not sure if it is up to the quality needed (I also didn't run the regression tests), but this fixes the warnings for me:

https://github.com/ruipires/conan/commit/cdf5a282e1c6b733295ab19e9fa18e1c02b3bbd0

[memsharded]

I think it has an easy solution. The issue is that conan is by default adding the "lib" path to the libdirs. I think that doing:

def package_info(self):
    self.cpp_info.libdirs = []

Should fix it.
It is possible that header-only package creators forget about it, but that would be the preferred way to fix the warnings.

[sourcedelica]

Yep, that did it. I just added it to my clones of conan-catch and conan-zmqcpp and it worked. Thx!