update-submodule.yml

name: Update Submodules

on:
  push:
    branches:
      - '**'   # This runs on any branch

jobs:
  update-submodules:
    runs-on: ubuntu-latest

    steps:
    # Step 1: Checkout the repository with submodules
    - name: Checkout repository
      uses: actions/checkout@v3
      with:
        submodules: 'recursive'  # Ensure submodules are checked out
        fetch-depth: 0  # Fetch full history to ensure we can compare commits

    # Step 2: Update submodules only if not at the latest commit
    - name: Selectively Update Submodules
      id: submodule-update
      run: |
        # Initialize submodules
        git submodule update --init --recursive
        
        # Track if any submodules were updated
        updated_submodules=0
        
        # Iterate through each submodule
        git submodule foreach '
          # Get the current commit hash of the submodule
          current_commit=$(git rev-parse HEAD)
          
          # Fetch the latest commits from origin
          git fetch origin main
          
          # Get the latest commit hash from origin/main
          latest_commit=$(git rev-parse origin/main)
          
          # Compare current and latest commits
          if [ "$current_commit" != "$latest_commit" ]; then
            echo "Updating submodule: $path"
            git checkout main
            git pull origin main
            updated_submodules=$((updated_submodules + 1))
          else
            echo "Submodule $path is already up to date"
          fi
        '
        
        # Set output and environment variable for subsequent steps
        if [ $updated_submodules -gt 0 ]; then
          echo "submodules_updated=true" >> $GITHUB_ENV
          echo "Updated $updated_submodules submodules"
        else
          echo "submodules_updated=false" >> $GITHUB_ENV
          echo "No submodules needed updating"
        fi

    # Step 3: Commit changes only if submodules were updated
    - name: Commit changes
      if: env.submodules_updated == 'true'
      run: |
        git config --global user.name "github-actions[bot]"
        git config --global user.email "github-actions[bot]@users.noreply.github.com"
        git add .
        git commit -m "CI: Update specific submodules to latest main branch commits" || echo "No changes to commit"

    # Step 4: Pull the latest changes from the remote branch before pushing
    - name: Pull the latest changes
      if: env.submodules_updated == 'true'
      run: git pull origin ${{ github.ref_name }} --rebase --allow-unrelated-histories

    # Step 5: Push the changes back to the repository
    - name: Push changes
      if: env.submodules_updated == 'true'
      env:
        TOKEN: ${{ secrets.PAT_TOKEN }}
      run: |
        git remote set-url origin https://x-access-token:${TOKEN}@github.com/${{ github.repository }}.git
        git push origin HEAD