caching does not seem to work

[maddanio]

when i define the caching dir I get errors like:
-- Cloning git repo (https://github.com/iauns/cpm-glm @ origin/master)
CMake Error at build/libs/DOpenGL/cpm_packages/util/CPMGit.cmake:44 (message):
Failed to checkout tag: 'origin/master'
Call Stack (most recent call first):
build/libs/DOpenGL/cpm_packages/util/CPMCommonSCM.cmake:18 (_cpm_clone_git_repo)
build/libs/DOpenGL/cpm_packages/util/CPMCommonSCM.cmake:92 (_cpm_scm_clone)
build/libs/DOpenGL/cpm_packages/util/CPMGit.cmake:159 (_cpm_ensure_scm_repo_is_current)
build/libs/DOpenGL/cpm_packages/CPM.cmake:906 (_cpm_ensure_git_repo_is_current)
build/libs/DOpenGL/cpm_packages/CPM.cmake:1107 (CPM_EnsureRepoIsCurrent)
libs/DOpenGL/CMakeLists.txt:23 (CPM_AddModule)

[iauns]

Just tried out caching for cpm-glm and it's working for me using CMake 3.5.0. Could you post the cache directory you are using and possibly other relevant info related to your build? I usually set my cache directory by exporting the CPM_CACHE_DIR environment variable to something like $HOME/.cpm_cache . Usually if CPM has a problem creating the cache directory it says so -- but one thing to try would be to use something like

message(STATUS "CPM cache dir ${__CPM_ENSURE_CACHE_DIR}")

in CPMCommonSCM.cmake line 92 to quickly figure out what directory CPM is trying to check out this specific code to.