MPI test do not select the correct (system) MPI implementation

[luraess]

Testing MPI v0.20-dev (master) branch on Linux (Ubuntu 20.04) with system MPI

julia> MPIPreferences.use_system_binary()
┌ Info: MPI implementation
│   libmpi = "libmpi"
│   version_string = "Open MPI v4.1.2, package: Open MPI luraess@superzack Distribution, ident: 4.1.2, repo rev: v4.1.2, Nov 24, 2021\0"
│   impl = "OpenMPI"
│   version = v"4.1.2"
└   abi = "OpenMPI"

does not pick up the correct MPI implementation although LocalPreferences.toml contains the above info. Tests would always pick up MPICH_jll

┌ Info: Running MPI tests
│   ArrayType = Array
│   nprocs = 1
│   MPIPreferences.abi = "MPICH"
└   MPIPreferences.binary = "MPICH_jll"

Copying manually LocalPreferences.toml does not solve the issue.

Note that MPI selects the correct implementation outside of test

julia> MPI.MPI_LIBRARY_VERSION_STRING
"Open MPI v4.1.2, package: Open MPI luraess@superzack Distribution, ident: 4.1.2, repo rev: v4.1.2, Nov 24, 2021\0"

[vchuravy]

What version of Julia are you using?

[luraess]

julia> versioninfo()
Julia Version 1.7.2
Commit bf53498635 (2022-02-06 15:21 UTC)
Platform Info:
  OS: Linux (x86_64-pc-linux-gnu)
  CPU: AMD EPYC 7282 16-Core Processor
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-12.0.1 (ORCJIT, znver2)

Same issue with Spack-built v1.7.1

[simonbyrne]

Is this worth fixing, or should we just add a section to the docs on how to run the tests (copy the LocalPreferences.jl into your test directory)

[luraess]

Is this now fixed by #564? Seems that JuliaPackaging/Preferences.jl#37 (comment) and JuliaLang/Pkg.jl#3061, as flagged some months ago to me by @vchuravy got merged (don't know the up to date status though @simonbyrne).