update-submodules.yml

# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
#
# Copyright (c) 2011-2022 ETH Zurich.

name: Update Submodules

on:
  workflow_dispatch: # allow to manually trigger this workflow
  schedule:
    - cron: '0 6 * * *' # run every day at 06:00 UTC

jobs:
  # Update the submodules and create a PR if there are any changes
  update:
    runs-on: ubuntu-latest
    steps:
      - name: Check out the repo
        uses: actions/checkout@v3
        with:
          submodules: true

      - name: Get current commits
        run: |
          echo "PREV_SILICON_REF=$(git -C silicon rev-parse HEAD)" >> $GITHUB_ENV
          echo "PREV_CARBON_REF=$(git -C carbon rev-parse HEAD)" >> $GITHUB_ENV

      - name: Update Silicon submodule
        run: git checkout master && git pull
        working-directory: silicon

      - name: Update Carbon submodule
        run: git checkout master && git pull
        working-directory: carbon

      - name: Get new commits
        run: |
          echo "CUR_SILICON_REF=$(git -C silicon rev-parse HEAD)" >> $GITHUB_ENV
          echo "CUR_CARBON_REF=$(git -C carbon rev-parse HEAD)" >> $GITHUB_ENV

      - name: Create PR body
        run: |
          if [[ "${{ env.PREV_SILICON_REF }}" != "${{ env.CUR_SILICON_REF }}" ]]; then
            echo 'PR_BODY_LINE1=* Updates Silicon from `${{ env.PREV_SILICON_REF }}` to `${{ env.CUR_SILICON_REF }}`.' >> $GITHUB_ENV
          else
            echo 'PR_BODY_LINE1=' >> $GITHUB_ENV
          fi
          if [[ "${{ env.PREV_CARBON_REF }}" != "${{ env.CUR_CARBON_REF }}" ]]; then
            echo 'PR_BODY_LINE2=* Updates Carbon from `${{ env.PREV_CARBON_REF }}` to `${{ env.CUR_CARBON_REF }}`.' >> $GITHUB_ENV
          else
            echo 'PR_BODY_LINE2=' >> $GITHUB_ENV
          fi

      - name: Open a pull request
        id: pr
        uses: peter-evans/create-pull-request@v4
        if: (env.PREV_SILICON_REF != env.CUR_SILICON_REF) || (env.PREV_CARBON_REF != env.CUR_CARBON_REF)
        with:
          # Use viper-admin's token to workaround a restriction of GitHub.
          # See: https://github.com/peter-evans/create-pull-request/issues/48
          token: ${{ secrets.VIPER_ADMIN_TOKEN }}
          commit-message: Updates submodules
          title: Update Submodules
          branch: auto-update-submodules
          delete-branch: true
          labels: |
            automated pr
          body: |
            ${{ env.PR_BODY_LINE1 }}
            ${{ env.PR_BODY_LINE2 }}

      - name: Enable auto-merge of PR
        uses: peter-evans/create-or-update-comment@v2
        if: (env.PREV_SILICON_REF != env.CUR_SILICON_REF) || (env.PREV_CARBON_REF != env.CUR_CARBON_REF)
        with:
          token: ${{ secrets.VIPER_ADMIN_TOKEN }}
          issue-number: ${{ steps.pr.outputs.pull-request-number }}"
          body: bors merge