[question] Components hide global definitions in layout method

[marausch]

Environment details

• Conan version: 2.0.17
• Python version: 3.11.6

Description

Hi,

When using components in the layout method for a dependency module, it seems that what gets defined through self.cpp.package.includedirs, self.cpp.package.libdirs, and so on is ignored when CMake related file are generated by a conan install for a consumer of the module.

For example, consider a layout method of the dependency's Conanfile containing:

self.cpp.package.includedirs = ["inc"]

but no component related definitions.

In this case the conan_toolchain.cmake file generated for a consumer contains something like:

list(PREPEND CMAKE_INCLUDE_PATH "C:/c2/b/depenf073120889728/p/inc")

By adding just any single component related definition to the layout method, for example:

self.cpp.package.components["comp"].objects = ["crt0_comp"]

what gets generated in the consumer's conan_toolchain.cmake becomes like this:

list(PREPEND CMAKE_INCLUDE_PATH "C:/c2/b/depen532f33fab3b55/p/include")

i.e. with the default "include" instead of "inc", as if no self.cpp.package.includedirs had been defined.

To get the expected conan_toolchain.cmake we need to add the proper includedirs definition for the component:

self.cpp.package.components["comp"].includedirs = ["inc"]

The same thing is true for libdirs, resdirs and probably others too (I haven't tested them all).

I guess this might be the wanted behaviour, even if I expected the global definitions to be concatenated (in case) with the components related ones.

Thank you in advance for any clarification.

Have you read the CONTRIBUTING guide?

• I've read the CONTRIBUTING guide

[memsharded]

Hi @marausch

Thanks for your question.

Your observations are right, once components are defined, the global self.cpp_info.xxxdirs are completely ignored, and the components defaults are used instead. So if you want to change the components ones need to do self.cpp_info.components["mycomp"].includedirs = ["inc"] too.

I have tried to make it that way, because it would be a bit more intuitive, in conan-io/conan#13994. But I finally dropped it, too risky, almost impossible to do it without breaking.

[marausch]

Hi @memsharded,

I was just asking because I probably didn't read the documentation thoroughly (I haven't found where this is explained in the documentation).

Thank you.

[memsharded]

Thats fair, moving this ticket to docs, lets try to add some clarification.