formalities.yml

name: Codestyle etc.

on: [ pull_request ]

permissions:
  contents: read

jobs:
  check-formatting:
    runs-on: ubuntu-latest
    name: Check style
    steps:
      - name: Checkout source code
        uses: actions/checkout@v4

      - name: Set up Java 11
        uses: actions/setup-java@v4
        with:
          distribution: adopt
          java-package: jdk
          java-version: 17
          cache: maven

      # Checks that the code sticks to a common code style
      - name: Run spotless checks
        run: mvn spotless:check || echo "Check the formatting. Use mvn spotless:apply to format the code."

      # Runs Maven's dependency analysis to identify unused and undeclared dependencies and fails the build if there are any warnings.
      - name: Run dependency analysis
        run: mvn dependency:analyze -DfailOnWarning

      - name: Get Proposed Version
        run: |
          echo "PROPOSED_VERSION=$(mvn help:evaluate -Dexpression=project.version -DforceStdout 2>/dev/null | grep -v '^\[' | tail -1)" >> $GITHUB_ENV

      - name: Check Semantic Versioning Pattern
        run: |
          echo "${{ env.PROPOSED_VERSION }}" | \
          grep -P '^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-((?:0|[1-9A-Za-z-][0-9A-Za-z-]*)(?:\.(?:0|[1-9A-Za-z-][0-9A-Za-z-]*))*))?(?:\+([0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*))?$'

      - name: Enforce -SNAPSHOT version suffix except on release branches
        # i.e. release/prep-* branches are allowed to not have -SNAPSHOT.
        # Also blocks merging any other PR into develop while develop itself still
        # carries the just-released, non-SNAPSHOT version - i.e. before the
        # release-publish workflow's auto-merged chore/next-snapshot-* PR has landed.
        run: |
          if echo "${{ env.PROPOSED_VERSION }}" | grep -q -- "-SNAPSHOT$"; then
            HAS_SNAPSHOT_SUFFIX=true
          else
            HAS_SNAPSHOT_SUFFIX=false
          fi

          if [[ "${{ github.head_ref }}" == release/prep-* ]]; then
            if [ "$HAS_SNAPSHOT_SUFFIX" == "true" ]; then
              echo "Release branches (release/prep-*) must not carry a -SNAPSHOT version."
              exit 1
            fi
          else
            if [ "$HAS_SNAPSHOT_SUFFIX" == "false" ]; then
              echo "Non-release branches must keep a -SNAPSHOT version. If the base branch was just released, wait for the automated 'next SNAPSHOT' PR to merge first."
              exit 1
            fi
          fi

      - name: Ensure (strict) monotony of the version
        run: |
          TMP_POM=$(mktemp)
          HTTP_STATUS=$(curl -s -w "%{http_code}" \
                        -H "Authorization: token ${{ secrets.GITHUB_TOKEN }}" \
                        -H "Accept: application/vnd.github.v3.raw" \
                        -o "$TMP_POM" \
                        "https://api.github.com/repos/${{ github.repository }}/contents/pom.xml?ref=${{ github.base_ref }}")

          if [ "$HTTP_STATUS" -ne 200 ]; then
            echo "Warning: pom.xml not found in ${{ github.base_ref }}. HTTP status: $HTTP_STATUS."
            echo "Information: We assume the base branch is new and does not contain a pom.xml yet."
            rm "$TMP_POM"
            exit 0
          fi

          echo "Base branch pom.xml downloaded successfully."

          # hint: unfortunately mvn (as used above) fails if the downloaded pom is an aggregator pom and needs child poms as well
          LATEST_VERSION=$(grep -m1 '<version>' $TMP_POM | sed -E 's/.*<version>(.+)<\/version>.*/\1/')
          rm "$TMP_POM"

          # did the version not change? if not: release branches fail (they must bump), other branches: ok
          if [ "$LATEST_VERSION" == "${{ env.PROPOSED_VERSION }}" ]; then
            if [[ "${{ github.head_ref }}" != release/prep-* ]]; then
              echo "No version change necessary on ${{ github.head_ref }}.";
              exit 0
            else
              echo "Version change necessary on a release branch (release/prep-*)!";
              exit 1
            fi
          fi

          # is the new version higher? hint: does not handle 0.1.3-alpha versions.. just numbers! (or both with the same suffix like -SNAPHSOT)
          if [ "$(printf "%s\n%s" "${{ env.PROPOSED_VERSION }}" "$LATEST_VERSION" | sort -V | head -n1)" = "${{ env.PROPOSED_VERSION }}" ]; then
              echo "Proposed new version is lower than the latest version!"
              echo "${{ env.PROPOSED_VERSION }} <= $LATEST_VERSION"
              exit 1
          fi