submodule-sync.yaml

# Adapted from https://stackoverflow.com/questions/64407333/using-github-actions-to-automatically-update-the-repos-submodules

name: 'Submodules sync'

on:
  # Allows you to run this workflow manually from the Actions tab or through HTTP API
  workflow_dispatch:
  # We need to run this periodically as well, because we don't want to fork every upstream in order to 
  # keep them up to date in my use of them. Once per day should be good enough for release cycle and
  # security patch purposes
  schedule:
  - cron: "0 0 * * *"

jobs:
  sync:
    name: 'Submodules sync'
    runs-on: ubuntu-latest

    # Use the Bash shell regardless whether the GitHub Actions runner is ubuntu-latest, macos-latest, or windows-latest
    defaults:
      run:
        shell: bash

    steps:
    - name: Checkout
      uses: actions/checkout@v2.4.0
      with:
        token: ${{ secrets.PAT_TOKEN }}
        submodules: recursive

    # Update references
    - name: Git submodule update
      run: |
        git submodule foreach 'git fetch --unshallow'
        git submodule foreach 'git pull origin $(git config -f $GITHUB_WORKSPACE/.gitmodules --get submodule.$name.branch)'

    - name: Commit update to submodule-updates for PR
      env:
        PAT_GITHUB_TOKEN: ${{ secrets.PAT_TOKEN }}
      run: |
        git config --global user.name 'Git Bot'
        git config --global user.email 'bot@noreply.github.com'
        git fetch --unshallow
        git remote set-url origin https://$PAT_TOKEN@github.com/$GITHUB_REPOSITORY
        git commit -am "Updated all submodule references" && git push -f origin HEAD:refs/heads/automerge/submodule-updates || echo "No changes to commit"