message: Allow empty values in conditionals
diff: @@ -52,7 +52,7 @@ runs:
  run: |
  echo "--- Prepare Configuration ---"
  MPI="NO"
  - if [[ ${{ inputs.mpi }} == 'parallel' ]]; then
  + if [[ "${{ inputs.mpi }}" == 'parallel' ]]; then
  MPI="YES"
  echo "Hypre symlink:"
  ln -s ${{ inputs.hypre-dir }} hypre;
  @@ -61,21 +61,21 @@ runs:
  fi
  CPPFLAGS="";
  DEBUG="NO";
  - if [[ ${{ inputs.hypre }} == 'bigint' ]]; then
  + if [[ "${{ inputs.hypre }}" == 'bigint' ]]; then
  CPPFLAGS+=" -DHYPRE_BIGINT"
  fi
  - if [[ ${{ inputs.target }} == 'debug' ]]; then
  + if [[ "${{ inputs.target }}" == 'debug' ]]; then
  DEBUG="YES";
  - if [[ ${{ inputs.os }} == 'ubuntu-18.04' ]]; then
  + if [[ "${{ inputs.os }}" == 'ubuntu-18.04' ]]; then
  CPPFLAGS+=" -pedantic -Wall -Werror";
  fi
  fi
  - if [[ ${{ inputs.codecov }} == 'YES' ]]; then
  + if [[ "${{ inputs.codecov }}" == 'YES' ]]; then
  CPPFLAGS+=" -fprofile-arcs -ftest-coverage -fPIC -O0";
  fi
  echo "--- Configure mfem ---"
  cd ${{ inputs.mfem-dir }};
  - if [[ ${{ inputs.build-system }} == 'cmake' ]]; then
  + if [[ "${{ inputs.build-system }}" == 'cmake' ]]; then
  mkdir build && cd build;
  cmake .. -DMFEM_USE_MPI=${MPI} -DMFEM_MPI_NP=2 -DHYPRE_DIR=../../hypre/src/hypre
  else
  @@ -87,7 +87,7 @@ runs:
  run: |
  echo "--- Build mfem ---"
  cd ${{ inputs.mfem-dir }}
  - if [[ ${{ inputs.build-system }} == "cmake" ]]; then
  + if [[ "${{ inputs.build-system }}" == "cmake" ]]; then
  cd build
  make -j3 mfem examples
  cd tests/unit
  