CMake Error in CMakeLists.txt:
The custom command generating
/Users/runner/work/robotology-superbuild/robotology-superbuild/build/robotology/YCM/CMakeFiles/YCMStamp/$(CONFIGURATION)$(EFFECTIVE_PLATFORM_NAME)/YCM-mkdir
is attached to multiple targets:
YCM-update
YCM
but none of these is a common dependency of the other(s). This is not
allowed by the Xcode "new build system".
It turns out that there have been several changes in CMake 3.19 to ExternalProject , that also involved the creation of a policy:
This changes means that, as YCM ships a vendored ExternalProject, basically any project that uses both YCM and ExternalProject can't support Xcode 12 and CMake 3.19 without more complex changes (dropping the vendored ExternalProject, as suggested in https://github.com/robotology/ycm/issues/50#issuecomment-659540091 ?). In any case, for sure for 2020.11 distro we will simply not support Xcode 12.
Even by fixing the clear copy&paste problems https://github.com/robotology/ycm/pull/367 and https://github.com/robotology/ycm/pull/364, the combination of XCode 12 and CMake 3.19 is not working with the following error:
It turns out that there have been several changes in CMake 3.19 to ExternalProject , that also involved the creation of a policy:
This changes means that, as YCM ships a vendored ExternalProject, basically any project that uses both YCM and ExternalProject can't support Xcode 12 and CMake 3.19 without more complex changes (dropping the vendored ExternalProject, as suggested in https://github.com/robotology/ycm/issues/50#issuecomment-659540091 ?). In any case, for sure for 2020.11 distro we will simply not support Xcode 12.