[bug] CMake generator does not allow multiple namespaces for the exported library.

This affects at least Qt5, Qt6 and most of the libraries on the KDE Frameworks. I’d assume more libraries use this but those are the ones I have to work on daily.

Qt5 exports Qt:: and Qt5:: namespaces, qt6 exports Qt:: and Qt6:: namespaces on their original find modules, and it’s important that we can rely on this for the generated find modules, so that code made for both Qt5 and Qt6 works.

I’m new to conan but I’m quite interested in improving it.

my proposal is to add a metadata on the recipe of such modules:

lass QtConan(ConanFile):
    generators = "pkg_config", "cmake_find_package", "cmake"
    name = "qt"
    cmake_find_package_namespaces = ["Qt", "Qt6"]

and when we run the cmake_find_package generator, we iterate trougth that list, and generate everything for all the cases.

conan-center related issue: https://github.com/conan-io/conan-center-index/issues/6459

[SpaceIm]

@czoido the new cmake_target_name logic fixes this issue I think.

[tcanabrava]

Yes I would. give me a couple of days to familiarize with the codebase.