Duplicate project name directories in installation include directory

[ekilmer]

Hello, is it intentional to duplicate the project name in the installation layout for the headers?

I see the following when installing the shared/static library (initialized with cmake-init -s /tmp/test-shared) example:

$ cmake --install build/dev --prefix prefix
-- Install configuration: "Debug"
-- Installing: /tmp/test-shared/prefix/include/test-shared
-- Installing: /tmp/test-shared/prefix/include/test-shared/test-shared
-- Installing: /tmp/test-shared/prefix/include/test-shared/test-shared/test-shared.hpp
-- Up-to-date: /tmp/test-shared/prefix/include/test-shared
-- Up-to-date: /tmp/test-shared/prefix/include/test-shared/test-shared
-- Installing: /tmp/test-shared/prefix/include/test-shared/test-shared/test-shared_export.hpp
-- Installing: /tmp/test-shared/prefix/lib/libtest-shared.a
-- Installing: /tmp/test-shared/prefix/share/test-shared/test-sharedConfig.cmake
-- Installing: /tmp/test-shared/prefix/share/test-shared/test-sharedConfigVersion.cmake
-- Installing: /tmp/test-shared/prefix/share/test-shared/test-sharedTargets.cmake
-- Installing: /tmp/test-shared/prefix/share/test-shared/test-sharedTargets-debug.cmake

Note the line here with duplicate test-shared/test-shared/ directories

-- Installing: /tmp/test-shared/prefix/include/test-shared/test-shared/test-shared.hpp

I would have expected it to read

-- Installing: /tmp/test-shared/prefix/include/test-shared/test-shared.hpp

which is a more compact directory layout while still maintaining directory isolation of the project headers.

I realize I can manually set -DCMAKE_INSTALL_INCLUDEDIR=include when configuring, but I think the expected behavior should be default for this initializer project.

I also realize that test-sharedTargets.cmake contains the following

set_target_properties(test-shared::test-shared PROPERTIES
  [...]
  INTERFACE_INCLUDE_DIRECTORIES "${_IMPORT_PREFIX}/include/test-shared"
)

which means that an #include <test-shared/test-shared.hpp> still works from a CMake project that finds the library and uses the target with the duplicate project name directories in the include directory, but I still would have expected the include directory layout of the installation to be more compact by default, which would then make this snippet read INTERFACE_INCLUDE_DIRECTORIES "${_IMPORT_PREFIX}/include".

I believe the line(s) responsible for directory duplication are here and removal would produce the expected directory layout by default

cmake-init/cmake-init/templates/common/cmake/install-rules.cmake

Lines 1 to 3 in 44b8e24

	if(PROJECT_IS_TOP_LEVEL)
	set(CMAKE_INSTALL_INCLUDEDIR include/%(name)s CACHE PATH "")
	endif(){type header}

---

Unrelated: I'm not sure whether this kind of post belongs in the Issues or Discussions section, so apologies if this is posted in the wrong spot.

[friendlyanon]

This is a very conscious decision, because it solves an issue described here: Dobiasd/FunctionalPlus#222

As a CMake user, you are unaffected by this extra directory in the path for the includes, because the exported CMake package is very much aware of it. Of course, something like this is entirely avoided when using Conan and vcpkg, because those do things in locations where you know you won't accidentally include something you aren't supposed to.

[ekilmer]

Very informative! Thank you for the reference!