Try working around current CI issues with clang14 on MacOS

.github/workflows/macos.yml

@@ -40,7 +40,8 @@ jobs:
           -DopenPMD_USE_MPI=ON    \
           -DopenPMD_USE_HDF5=ON   \
           -DopenPMD_USE_ADIOS2=ON \
-          -DopenPMD_USE_INVASIVE_TESTS=ON
+          -DopenPMD_USE_INVASIVE_TESTS=ON \
+          -DMPIEXEC_EXECUTABLE=../.github/workflows/mpirun_workaround.sh
         cmake --build build --parallel 3
         ctest --test-dir build --verbose
 

.github/workflows/mpirun_workaround.sh

@@ -0,0 +1,46 @@
+#!/usr/bin/env bash
+
+# mpiexec currently seems to have a bug where it tries to parse parameters
+# of the launched application when they start with a dash, e.g.
+# `mpiexec python ./openpmd-pipe --infile in.bp --outfile out.bp`
+# leads to:
+# >  An unrecognized option was included on the mpiexec command line:
+# >
+# >    Option: --infile
+# >
+# >  Please use the "mpiexec --help" command to obtain a list of all
+# >  supported options.
+#
+# This script provides a workaround by putting the called sub-command into
+# a script in a temporary file.
+
+mpirun_args=()
+
+script_file="$(mktemp -p .)"
+
+cleanup() {
+    rm "$script_file"
+}
+trap cleanup EXIT
+
+while true; do
+    case "$1" in
+        -c | -np | --np | -n | --n )
+            mpirun_args+=("$1" "$2")
+            shift
+            shift
+            ;;
+        *)
+            break
+            ;;
+    esac
+done
+
+echo -e '#!/usr/bin/env bash\n' > "$script_file"
+for item in "$@"; do
+    echo -n "'$item' " >> "$script_file"
+done
+
+chmod +x "$script_file"
+
+mpirun "${mpirun_args[@]}" "$script_file"