Any system is detected as `Unicos` if `cray` is somewhere in the `PATH` environment variable

[climbfuji]

This is a real bug in the ESMF OS/compiler detection logic.

My laptop is auto-detected as ESMF_OS=Unicos because

• I am using spack, which has a ftn in the default search path in the build environment
• I have cray in the path to spack on my local disk, because this is how the working branch is called (testing something locally first before testing on a Cray)

This is because the ESMF_OS detection logic in ESMF is flawed (scripts/esmf_os):

...
if [ $esmf_os = Linux ]; then
# determine if this is Linux on Cray, i.e. Unicos
which ftn > esmf_os.tmp 2>&1
ftn_test=`grep -e cray -e bin/ftn esmf_os.tmp`
rm -f esmf_os.tmp
if [ -n "$ftn_test" ]; then
esmf_os=Unicos
fi

With spack and a local path like mine:

bash-5.1$ which ftn
~/work/spack-stack/spst-dev-20250613-modulepurgecray/spack/lib/spack/env/ftn
$ which ftn > esmf_os.tmp 2>&1
$ cat esmf_os.tmp
/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/spack/lib/spack/env/ftn
$ export ftn_test=`grep -e cray -e bin/ftn esmf_os.tmp`
$ export | grep ftn
declare -x ftn_test="/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/spack/lib/spack/env/ftn"

Yet another reason to implement a clean, standard CMake build for ESMF?

[climbfuji]

It gets even better! It's sufficient to just have cray somewhere in any search path. I removed ftn from the spack code, and then this happens:

+ '[' -n '/usr/bin/which: no ftn in (/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/envs/ne-gcc-13.3.0/install/gcc/13.3.0/gmake-4.2.1-2auqkxz/bin:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/envs/ne-gcc-13.3.0/install/gcc/13.3.0/py-numpy-1.26.4-lustnxb/bin:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/envs/ne-gcc-13.3.0/install/gcc/13.3.0/py-pip-24.3.1-rawopib/bin:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/envs/ne-gcc-13.3.0/install/gcc/13.3.0/py-wheel-0.45.1-a2rdj5a/bin:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/envs/ne-gcc-13.3.0/install/gcc/13.3.0/netcdf-fortran-4.6.1-kxqgrhl/bin:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/envs/ne-gcc-13.3.0/install/gcc/13.3.0/py-numpy-1.26.4-lustnxb/bin:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/envs/ne-gcc-13.3.0/install/gcc/13.3.0/py-wheel-0.45.1-a2rdj5a/bin:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/envs/ne-gcc-13.3.0/install/gcc/13.3.0/py-pip-24.3.1-rawopib/bin:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/envs/ne-gcc-13.3.0/install/gcc/13.3.0/python-venv-1.0-oiotmdx/bin:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/envs/ne-gcc-13.3.0/install/gcc/13.3.0/netcdf-c-4.9.2-a5ul6th/bin:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/envs/ne-gcc-13.3.0/install/gcc/13.3.0/netcdf-c-4.9.2-a5ul6th/.spack/spack-nc-config:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/envs/ne-gcc-13.3.0/install/gcc/13.3.0/python-3.11.11-goqkyom/bin:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/envs/ne-gcc-13.3.0/install/gcc/13.3.0/openmpi-5.0.6-7hk3muz/bin:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/envs/ne-gcc-13.3.0/install/gcc/13.3.0/pkg-config-0.29.2-nfovk24/bin:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/envs/ne-gcc-13.3.0/install/gcc/13.3.0/openssh-9.9p1-dyiggx5/bin:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/spack/lib/spack/env/gcc:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/spack/lib/spack/env/case-insensitive:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/spack/lib/spack/env:/home/dom/work/spack-stack/spst-dev-20250613-modulepurgecray/spack/bin:/home/dom/.local/bin:/home/dom/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/usr/lib/wsl/lib:/mnt/c/WINDOWS/system32:/mnt/c/WINDOWS:/mnt/c/WINDOWS/System32/Wbem:/mnt/c/WINDOWS/System32/WindowsPowerShell/v1.0/:/mnt/c/WINDOWS/System32/OpenSSH/:/mnt/c/Program Files/dotnet/:/mnt/c/Program Files/Meld/:/mnt/c/Users/climb/AppData/Local/Microsoft/WindowsApps:/mnt/c/Users/climb/AppData/Local/Programs/Microsoft VS Code/bin)' ']'

Because cray is a substring in one or more of these search path, the esmf_os script says "this is unicos"!

[danrosen25]

Hi @climbfuji
We'll look into this but in the meantime you can override the automated setting by configuring this in your environment variables.
ESMF_OS=Linux

See section 9.5 ESMF Environment Variables in the ESMF User Guide

ESMF_OS
Possible value: output of uname -s except when cross-compiling or for UNICOS/mp where ESMF_OS is Unicos.
Not normally set by user unless cross-compiling. This variable indicates the target system for which the ESMF library is being built. Under normal circumstances, i.e. ESMF is being build on the target system, ESMF_OS is set automatically. However, when cross-compiling for a different target system ESMF_OS must be set to the respective target OS. For example, when compiling for the Cray X1 on an interactive X1 node ESMF_OS will be set automatically. However, when ESMF is being cross-compiled for the X1 on a Linux host the user must set ESMF_OS to Unicos manually in order to indicate the intended target platform.

[climbfuji]

Yes, thanks. Unfortunately, this doesn't really work when using spack unless I edit the spack package and set ESMF_OS in package.py explicitly.

[theurich]

@climbfuji PR #443 is addressing at least the bug flagged by your "it gets even better" comment. This way, as long as you do not have ftn in your search path on your laptop, you should not get the false positive ESMF_OS=Unicos setting - even when you have cray in the path.

[climbfuji]

@climbfuji PR #443 is addressing at least the bug flagged by your "it gets even better" comment. This way, as long as you do not have ftn in your search path on your laptop, you should not get the false positive ESMF_OS=Unicos setting - even when you have cray in the path.

That's great, thanks for fixing this part!

[theurich]

After 8.9.0 is out, consider discussion #443 (review) to fully resolve the issues with esmf_os script.

[theurich]

@climbfuji back to your original issue description, when you had ftn in the path on your laptop. What was the ftn executable in that case? If you executed it as a command on your laptop, what would it do?