Linking to a built static library linked to another static library - cmake

Question

Sorry if the title seems a little convoluted. The basic idea is as follows:
I have a main CMakeLists.txt file that adds three subdirectories.
The first of these is a CMakeLists.txt file that pulls a boost-cmake release.
FetchContent_Declare(boost-cmake
GIT_REPOSITORY https://github.com/ *****/boost-cmake
GIT_TAG master)
FetchContent_GetProperties(boost-cmake)
if(NOT boost-cmake_POPULATED)
FetchContent_Populate(boost-cmake)
add_subdirectory(${boost-cmake_SOURCE_DIR} ${boost-cmake_BINARY_DIR})
endif()
The second creates a library linked to this.
add_library(program Program.cpp)
target_link_libraries(program ${Boost_LIBRARIES})
This succeeds and a .lib file is generated. In saying that, it seems to contain symbols for all the boost functions included in Program.cpp #includes
Lastly, when I try to link the program.lib library against an executable:
include_directories(${CMAKE_SOURCE_DIR}/src)
add_executable(program_test Program_Test.cpp)
target_link_libraries(program_test PRIVATE program)
Building this results in the following error:
FAILED: test/CMakeFiles/program_test.dir/program_test.cpp.obj
C:\PROGRA~2\MICROS~1\2019\COMMUN~1\VC\Tools\MSVC\1421~1.277\bin\HostX64\x64\cl.exe /nologo /TP -I..\src /DWIN32 /D_WINDOWS /W3 /GR /EHsc /MDd /ZI /Ob0 /Od /RTC1 /JMC -std:c++latest /showIncludes /Fotest\CMakeFiles\program_test.dir\program_test.cpp.obj /Fdtest\CMakeFiles\program_test.dir\ /FS -c ..\test\program_test.cpp
D:\Git\program\src\connection\program.hpp(5): fatal error C1083: Cannot open include file: 'boost/beast.hpp': No such file or directory
Is it standard to require all nested dependencies like this? Is there possibly any workaround that would instead ensure all of the boost definitions are included within the library thus only requiring the library itself?
Worth mentioning, I have tried including the boost/beast.hpp file in the same way it is included within the library, however this does not seem to solve the problem either, although this would not be a preferable solution regardless.

Answer 1

You don't have a link error, you have a compile error.
D:\Git\program\src\connection\program.hpp(5): fatal error C1083: Cannot open include file: 'boost/beast.hpp': No such file or directory
The VisualStudio compiler can't find boost/beast.hpp. At no point in the CMakeLists.txt that you shared, did you tell your target, program_test, where to find its include files. Just like you added a target_link_libraries() so that the VisualStudio linker can find the libraries, you need to add a target_include_directories() so that the VisualStudio compiler can find the include files in your Program_Test.cpp.