When is the vcpkg includes directory added to CMake generator output?

[trileyinvicro]

I'm using vcpkg as a submodule of a CMake project, with the vcpkg toolchain file. I'm also generating with Visual Studio but I expect that might not be relevant.

I have been going through my CMakeLists.txt files and haven't found a single place where I'm bringing in any of the include paths of vcpkg vendored libraries, yet the vcpkg_installed/<triplet>/include path is getting added to my generator output. When is this added? And more importantly, is it possible to control where in the list of include paths it's added? I have an issue where I need to keep our common includes path for non-vcpkg vendored dependencies, but that path is getting added first and I end up getting the wrong headers.

I've tried every permutation of target_include_directories, list(REMOVE_ITEM <bad include path>), list(PREPEND <vcpkg include path>) etc. I can think of, but vcpkg's includes always end up towards the end of my include paths list.

[jr0me]

I've found a similar problem, when using manifest mode and including the vcpkg toolchain, subdirectories projects end up including by default all of the top level project dependencies. There's no need to use "target_include_directories" and every project can access every include. Is there a way to avoid this?

[dg0yt]

#40307 is the same question, isn't it?

[jr0me]

Yes, #26518 (comment) and #40307 are essentially the same question, but not 100% what trileyinvicro is asking about, that's why I created another, separated, question.

[dg0yt]

The headers in include aren't generally separated into different subdirs per package. Some packages use unique subdirs, some don't, some are even patched to not do that. (msbuild bias.)
So if you link one imported target that adds the top-level include dir (directly or via transitive usage requirements), that dir will be passed to the compiler.