preview_clear.yml

name: preview_clear

on: workflow_dispatch

jobs:
  preview_clear:
    concurrency:
      group: cpprefjp.gh-pages.lock
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          ref: gh-pages
          fetch-depth: 0
      - name: filter-branch gh-pages
        env:
          GH_TOKEN: ${{ github.token }}
        run: |
          set -ex

          # Note: 以下の 999 という数は適当な大きな数。もし open PR の数が 999
          # を超えるようならば、この数はもっと大きくする必要がある。
          CPPREFJP_OPEN_PR_LIST=$(gh pr list --limit=999 --json number -q '.[].number' | tr '\n' ' ')
          CPPREFJP_OPEN_PR_LIST=${CPPREFJP_OPEN_PR_LIST% }
          export CPPREFJP_OPEN_PR_LIST

          git config user.name 'github-actions[bot]'
          git config user.email '41898282+github-actions[bot]@users.noreply.github.com'
          git filter-branch --commit-filter '
            commit_message=$(git log -n 1 --pretty=format:%s "$GIT_COMMIT")
            if [ "$commit_message" = preview_clear ]; then
              # drop a dummy commit by previous preview_clear
              skip_commit "$@"
              exit
            fi

            pr=$(echo "$commit_message" | sed -n '\''s/^Preview PR \([0-9]\{1,\}\).*/\1/p'\'')
            if [ -n "$pr" ]; then
              case " $CPPREFJP_OPEN_PR_LIST " in
              (*" $pr "*)
                # preserve a commit for an open PR
                git commit-tree "$@" ;;
              (*)
                # drop a commit for a closed PR
                skip_commit "$@" ;;
              esac
              exit
            fi

            # we preserve all the other commits
            git commit-tree "$@"
          ' HEAD || true

          commit_count=$(git rev-list HEAD --count || true)
          if [ -z "$commit_count" ] || [ "$commit_count" = 0 ]; then
            # When no commits are left, we create a dummy commit
            git reset
            git commit --allow-empty -m 'preview_clear'
          fi

          git push -f origin gh-pages