Improvement: Introduce github workflow using Clang and OpenMPI

.github/workflows/test_t8code_w_clang_and_ompi.yml

@@ -0,0 +1,159 @@
+name: CMake tests t8code with Clang compiler and OpenMPI
+
+
+#  This file is part of t8code.
+#  t8code is a C library to manage a collection (a forest) of multiple
+#  connected adaptive space-trees of general element types in parallel.
+#
+#  Copyright (C) 2025 the developers
+#
+#  t8code is free software; you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation; either version 2 of the License, or
+#  (at your option) any later version.
+#
+#  t8code is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with t8code; if not, write to the Free Software Foundation, Inc.,
+#  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+#  This workflow checks whether building and testing works with the Clang compiler
+#  and openmpi. It was added because all of t8code's remaining CI workflows rely
+#  on gcc and mpich, hence missing Clang- or openmpi-specific issues.
+#  To reduce runtime, (for now) only Debug mode with MPI is tested; also, no external
+#  libraries like VTK, OpenCASCADE etc. are covered.
+
+env:
+  DEBUG_CONFIG: "-O1"
+
+on:
+  workflow_call:
+    # Note: To simplify adding more configurations of this workflow later, the MPI mode and the BUILD_TYPE
+    #       are passed as input.
+    inputs:
+      MAKEFLAGS:
+        required: true
+        type: string
+        description: 'Make flags to use for compilation (like -j4)'
+      MPI:
+        required: true
+        type: string
+        description: 'Use MPI for compilation (ON/OFF)'
+      BUILD_TYPE:
+        required: true
+        type: string
+        description: 'Build type (Release/Debug)'
+      TEST_LEVEL:
+        required: true
+        type: string
+        description: 'Test level used for configuring (T8_TEST_LEVEL_FULL, T8_TEST_LEVEL_MEDIUM, or T8_TEST_LEVEL_BASIC)'
+        default: 'T8_TEST_LEVEL_FULL'
+
+jobs:
+  t8code_cmake_tests:
+  #
+  # Container setup: To avoid unwanted side effects of gcc or mpich, an own Clang version of the
+  #                  t8-dependencies Docker image is used. Aside from some basic packages, it contains a manually built
+  #                  Clang version of OpenMPI.
+    timeout-minutes: 60
+    runs-on: ubuntu-latest
+    container: dlramr/t8code-ubuntu:t8-clang-dependencies
+    steps:
+  #
+  # Part 1: Preparation and sanity checks
+  # -------------------------------------
+    - uses: actions/checkout@v6
+      with:
+        fetch-depth: 0
+    - name: Update packages
+      run: apt-get update && apt-get upgrade -y
+    - name: Show Clang version
+      run: clang --version
+    - name: Make sure MPI was built with CLANG
+      # Note: If "clang" is not found (or "gcc" is), the workflow is exited due to fail-early mode
+      run: |
+        mpicc --version > mpi_version_output
+        cat mpi_version_output
+        grep -i "clang" mpi_version_output
+        ! grep -i "gcc" mpi_version_output
+        rm mpi_version_output
+        echo "CHECKED: MPI was built with Clang."
+    - name: Assert correct MPI paths
+      run: |
+        mpicc --showme:compile  | grep "${OMPI_INSTALL_PATH}"
+        mpicc --showme:link     | grep "${OMPI_INSTALL_PATH}"
+        mpicxx --showme:compile | grep "${OMPI_INSTALL_PATH}"
+        mpicxx --showme:link    | grep "${OMPI_INSTALL_PATH}"
+        echo "CHECKED: mpicc and mpicxx point to correct path"
+      # This seems to be necessary because of the docker container
+    - name: disable ownership checks
+      run: git config --global --add safe.directory '*'
+    - name: init submodules
+      run: git submodule init
+    - name: update submodules
+      run: git submodule update
+    - name: Get input vars
+      run: export MAKEFLAGS="${{ inputs.MAKEFLAGS }}"
+        && export MPI="${{ inputs.MPI }}"
+        && export BUILD_TYPE="${{ inputs.BUILD_TYPE }}"
+        && echo MAKEFLAGS="$MAKEFLAGS" >> $GITHUB_ENV
+        && echo MPI="$MPI" >> $GITHUB_ENV
+        && echo BUILD_TYPE="$BUILD_TYPE" >> $GITHUB_ENV
+  #
+  # Part 2: Build t8code
+  # --------------------
+    # Define build config
+    - name: Set test level
+      run: export TEST_LEVEL_FLAG="-DT8CODE_TEST_LEVEL=${{ inputs.TEST_LEVEL }}"
+           && echo TEST_LEVEL_FLAG="$TEST_LEVEL_FLAG" >> $GITHUB_ENV
+    - name: build config variables
+      run: export CONFIG_OPTIONS="-DCMAKE_C_COMPILER=mpicc -DCMAKE_CXX_COMPILER=mpicxx ${TEST_LEVEL_FLAG} -GNinja -DCMAKE_C_FLAGS_DEBUG=${DEBUG_CONFIG} -DCMAKE_CXX_FLAGS_DEBUG=${DEBUG_CONFIG} -DT8CODE_BUILD_PEDANTIC=ON -DT8CODE_BUILD_WALL=ON -DT8CODE_BUILD_WERROR=OFF -DT8CODE_BUILD_WEXTRA=ON -DT8CODE_ENABLE_MPI=$MPI -DCMAKE_BUILD_TYPE=$BUILD_TYPE"
+        && echo CONFIG_OPTIONS="$CONFIG_OPTIONS" >> $GITHUB_ENV
+    # Run cmake
+    - name: echo cmake line
+      run: echo cmake ../ $CONFIG_OPTIONS
+    - name: cmake
+      run: mkdir build && cd build && cmake ../ $CONFIG_OPTIONS
+    # On failure, upload logs
+    - name: OnFailUploadLog
+      if: failure()
+      uses: actions/upload-artifact@v5
+      with:
+        name: cmake_w_clang_and_ompi_${{ inputs.BUILD_TYPE }}_MPI_${{ inputs.MPI }}.log
+        path: build/CMakeFiles/CMakeOutput.log
+    # Build with ninja
+    - name: ninja
+      run: cd build && ninja $MAKEFLAGS
+    - name: ninja install
+      run: cd build && ninja install $MAKEFLAGS
+  #
+  # Part 3: Run t8code tests
+  # ------------------------
+    - name: serial tests (if MPI is enabled)
+      run: cd build && ctest $MAKEFLAGS -R _serial
+      if: ${{ inputs.MPI == 'ON' }}
+    - name: parallel tests (if MPI is enabled)
+      run: cd build && ctest -R _parallel
+      env:
+        # Note: These openmpi options are required to ensure stable runs in github workflows and avoid stalling.
+        #       In particular, they activate oversubscription and define the communication channels, here tcp (and self).
+        OMPI_ALLOW_RUN_AS_ROOT: 1
+        OMPI_ALLOW_RUN_AS_ROOT_CONFIRM: 1
+        OMPI_MCA_rmaps_base_oversubscribe: 1
+        OMPI_MCA_btl: self,tcp
+        OMPI_MCA_pml: ob1
+      if: ${{ inputs.MPI == 'ON' }}
+    - name: tests (if MPI is disabled)
+      run: cd build && ctest $MAKEFLAGS
+      if: ${{ inputs.MPI == 'OFF' }}
+    # On failure, upload logs
+    - name: OnFailUploadLog
+      if: failure()
+      uses: actions/upload-artifact@v5
+      with:
+        name: test-suite_w_clang_and_ompi_${{ inputs.BUILD_TYPE }}_MPI_${{ inputs.MPI }}.log
+        path: build/Testing/Temporary/LastTest.log

.github/workflows/testsuite.yml

@@ -224,6 +224,28 @@ jobs:
       BUILD_TYPE: Debug
       TEST_LEVEL: ${{ github.event_name == 'pull_request' && 'T8_TEST_LEVEL_MEDIUM' || 'T8_TEST_LEVEL_FULL' }} # Set TEST_LEVEL to medium if the event is a PR, otherwise full.
 
+  # Check t8code building and testing with the Clang compiler and openmpi.
+  # Note: This workflow is meant to detect Clang- or openmpi-specific issues missed by the remaining (gcc- and mpich-based) workflows.
+  #       To reduce its runtime, it currently only used Debug mode with MPI on and does not link to external libraries like VTK or OpenCASCADE.
+  t8code_w_clang_and_ompi_tests:
+    needs: fine_grained_trigger
+    secrets: inherit
+    if: ${{ needs.fine_grained_trigger.outputs.run_ci == 'true' }}
+    uses: ./.github/workflows/test_t8code_w_clang_and_ompi.yml
+    strategy:
+      fail-fast: false
+      matrix:
+        MPI: [ON]
+        BUILD_TYPE: [Debug]
+        include:
+          - MAKEFLAGS: -j4
+    with:
+      MAKEFLAGS: ${{ matrix.MAKEFLAGS }}
+      MPI: ${{ matrix.MPI }}
+      BUILD_TYPE: ${{ matrix.BUILD_TYPE }}
+      TEST_LEVEL: ${{ github.event_name == 'pull_request' && 'T8_TEST_LEVEL_MEDIUM' || 'T8_TEST_LEVEL_FULL' }} # Set TEST_LEVEL to medium if the event is a PR, otherwise full.
+
+  # Build doxygen documentation and check for errors / warnings.
   t8code_doxygen_check:
     uses: ./.github/workflows/check_doxygen.yml