FetchContent calls in dependencies

[Leon0402]

Hi,

I do include some libraries that use FetchContent themself. I wonder if there is a way to use the cache for these as well?
It's probably rather difficult I could imagine, but maybe there is some way.

[TheLartians]

Hey sorry for the late answer, I hope this is still useful.

I believe a solution would be to call FetchContent_Declare using SOURCE_DIR ${<library name>_SOURCE_DIR} argument after adding the library using CPM with the DOWNLOAD_ONLY option. This should overwrite any later calls for the same library, making FetchContent_MakeAvailable or FetchContent_Populate use the source provided by CPM.cmake.

[ClausKlein]

set(FETCHCONTENT_SOURCE_DIR_<LIBRARY_NAME> ${<library name>_SOURCE_DIR}) should be enough.

[ClausKlein]

CPMAddPackage(
  NAME Boost
  VERSION 1.81.0
  GITHUB_REPOSITORY "boostorg/boost"
  GIT_TAG "boost-1.81.0"
)
if(Boost_ADDED)
  set(FETCHCONTENT_SOURCE_DIR_BOOST ${Boost_SOURCE_DIR})
endif()

but what, if an dependency need an other version?

or expected the source archive contents tree, not the git repo with distributed include directories?