pre_commit_autoupdate.yml

name: Autoupdate pre-commit config

on:
  schedule:
    - cron: "0 0 * * 0"

jobs:
  pre_commit_autoupdate:
    env:
      config_path: .pre-commit-config.yaml
      update_message_path: /tmp/message.txt
      update_branch: chore/pre-commit-autoupdate
    runs-on: ubuntu-latest
    steps:
      - name: Generate a token
        id: generate-token
        uses: actions/create-github-app-token@v1
        with:
          app-id: ${{ vars.WRITE_CONTENTS_PR_APP }}
          private-key: ${{ secrets.WRITE_CONTENTS_PR_KEY }}
      - uses: actions/checkout@v4
        with:
          ref: main
      - name: Create or checkout update branch
        id: create_branch
        env:
          GH_TOKEN: ${{ steps.generate-token.outputs.token }}
        run: |
          export pr_number=$( gh pr view ${{ env.update_branch }} --json number --jq '.number' )
          export pr_state=$( gh pr view ${{ env.update_branch }} --json state --jq '.state' )
          echo "pr_number=$pr_number" >> "$GITHUB_OUTPUT"
          echo "pr_state=$pr_state" >> "$GITHUB_OUTPUT"

          if git fetch origin ${{ env.update_branch }}; then
            # If branch wasn't deleted after merge, do so here
            if [ "$pr_state" = "MERGED" ]; then
              git push -d origin ${{ env.update_branch }}
              git checkout -b ${{ env.update_branch }}
              git push origin ${{ env.update_branch }}
            fi
            git checkout ${{ env.update_branch }}
          else
            git checkout -b ${{ env.update_branch }}
            git push origin ${{ env.update_branch }}
          fi

      # Pre-commit setup and autoupdate steps
      - name: Set up Python 3.13
        uses: actions/setup-python@v5
        with:
          python-version: 3.13
          # Re-enable when going public
          # cache: pip
      - name: Upgrade Pip
        run: python -m pip install --upgrade pip
      - name: Install pre-commit
        run: pip install pre-commit
      - name: Store hash of baseline pre-commit config for comparison
        id: old_file
        run: echo "hash=$( sha256sum $config_path )" >> $GITHUB_OUTPUT
      - name: Overwrite config on branch with version from main
        run: git checkout main ${{ env.config_path }}
      - name: Store hash of main pre-commit config for comparison
        id: main_file
        run: echo "hash=$( sha256sum $config_path )" >> $GITHUB_OUTPUT
      - name: Run pre-commit autoupdate on main pre-commit config
        id: autoupdate
        run: |
          pre-commit autoupdate > ${{ env.update_message_path }}
          sed -i "/updating/!d" ${{ env.update_message_path }}
      - name: Store hash of new pre-commit config for comparison
        id: new_file
        run: echo "hash=$( sha256sum $config_path )" >> $GITHUB_OUTPUT
      # Commit authoring and pull-request creation/updating
      - name: Commit (with signature) pre-commit config
        id: commit
        if: steps.old_file.outputs.hash != steps.new_file.outputs.hash
        env:
          GH_TOKEN: ${{ steps.generate-token.outputs.token }}
        run: |
          export message="chore(deps): autoupdate pre-commit hooks"
          export sha=$( git rev-parse ${{ env.update_branch }}:${{ env.config_path }} )
          export content=$( base64 -i ${{ env.config_path }} )
          gh api --method PUT /repos/:owner/:repo/contents/${{ env.config_path }} \
            --field message="$message" \
            --field content="$content" \
            --field branch=${{ env.update_branch }} \
            --field sha="$sha"
      - name: Create or update pre-commit-autoupdate pull-request
        if: steps.commit.conclusion == 'success' || ( steps.main_file.outputs.hash != steps.new_file.outputs.hash )
        env:
          GH_TOKEN: ${{ steps.generate-token.outputs.token }}
        run : |
          export title="chore(deps): autoupdate pre-commit hooks"
          export body=$( cat ${{ env.update_message_path }} )
          export pr_number=${{ steps.create_branch.outputs.pr_number }}
          export pr_state=${{ steps.create_branch.outputs.pr_state }}

          # If the PR is closed, can it be reopened, or is the PR already open?
          if ( [ "$pr_state" = "CLOSED" ] && gh pr reopen $pr_number ) || [ "$pr_state" = "OPEN" ]; then
            gh api --method PATCH /repos/:owner/:repo/pulls/$pr_number \
              --field title="$title" \
              --field body="$body"
          else
            # If a PR doesn't already exist, and no previous PR can be reopened, create a new PR.
            gh pr create -t "$title" -b "$body" -l dependencies -B main -H ${{ env.update_branch }}
          fi