check-formatting.yml

# GitHub action workflow that performs a source code formatting check.
#
# The workflow fails if one or more of the .hpp or .cpp files in the repository
# are not properly formatted according to the rules in the .clang-format file
# located in the root of the repository directory, using clang-format version 9.
# In that case, the log file provides a list of improperly formatted files.
# Source files with other extensions (including .h, .c, .hh, .cc) are NOT tested
# to allow for differently formatted third-party code.
#
name: Check formatting

# workflow event triggers
on: pull_request

# jobs that run
jobs:
  # automatic formatting check
  check_formatting_job:
    # job name, displayed in the action log
    name: Check source code formatting
    # run this job on a Github-provided runner with Ubuntu 20.04
    # (and not 22.04 because we cannot install clang-format-9)
    runs-on: ubuntu-20.04
    # steps that make up this job
    steps:
    # install clang-format-9
    - name: Install
      run: sudo apt install clang-format-9
    # checkout using a recent version of the checkout action
    - name: Checkout
      uses: actions/checkout@v3
    # run clang-format-9 on all .hpp and .cpp files
    - name: Autoformat
      run: find . \( -name '*.hpp' -or -name '*.cpp' \) -exec clang-format-9 -style=file -i {} \;
    # fail the workflow if anything changed to the repository
    - name: Verify
      run: git diff --stat --no-ext-diff --exit-code