Takes a parent repo's go.mod changes and applies them to a subdirectory

dependabot_sync_subdirectory_github_action.yml

name: Sync Dependabot to SUB_____________DIRECTORY

on:
  pull_request:
    paths:
      - "go.mod"
      - "go.sum"

permissions:
  contents: write
  pull-requests: write

jobs:
  sync-interchaintest:
    if: github.actor == 'dependabot[bot]'
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          ref: ${{ github.head_ref }}
          fetch-depth: 0
          token: ${{ secrets.GITHUB_TOKEN }}

      - uses: actions/setup-go@v5
        with:
          go-version-file: go.mod

      - name: Extract updated deps from root go.mod
        id: deps
        run: |
          # get the diff of go.mod against base branch
          git fetch origin ${{ github.base_ref }}
          CHANGED=$(git diff origin/${{ github.base_ref }}...HEAD -- go.mod \
            | grep "^+" | grep -v "^+++" \
            | sed 's/^+//' | sed 's/^require //' | sed 's/^\s*//' \
            | grep -oP '^\S+\s+v\S+' || true)
          echo "changed<<EOF" >> "$GITHUB_OUTPUT"
          echo "$CHANGED" >> "$GITHUB_OUTPUT"
          echo "EOF" >> "$GITHUB_OUTPUT"

      - name: Update SUB_____________DIRECTORY/go.mod
        if: steps.deps.outputs.changed != ''
        working-directory: SUB_____________DIRECTORY
        run: |
          while IFS= read -r line; do
            [ -z "$line" ] && continue
            PKG=$(echo "$line" | awk '{print $1}')
            VER=$(echo "$line" | awk '{print $2}')
            # only update if the dep exists in SUB_____________DIRECTORY/go.mod
            if grep -q "$PKG" go.mod; then
              echo "Updating $PKG to $VER in SUB_____________DIRECTORY"
              go get "$PKG@$VER"
            fi
          done <<< "${{ steps.deps.outputs.changed }}"
          go mod tidy

      - name: Commit and push
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"
          if git diff --quiet; then
            echo "No changes to commit"
            exit 0
          fi
          git add SUB_____________DIRECTORY/go.mod SUB_____________DIRECTORY/go.sum
          git commit -m "chore(deps): sync dependabot update to SUB_____________DIRECTORY"
          git push