check-diff.yaml

name: Check for changes in subdirectory

on:
  workflow_call:
    inputs:
      directory:
        description: The directory of the image files
        required: true
        type: string
      parent-image-is-diff:
        description: Parent image has been changed?
        required: true
        type: string
      branch-name:
        description: The name of the current branch 
        required: true
        type: string
    outputs:
      is-diff:
        description: Is there a difference between the master branch and the current branch
        value: ${{ jobs.check-diff.outputs.is-diff }}

jobs:
  check-diff:
    runs-on: ubuntu-latest
    outputs:
      is-diff: ${{ steps.check-changes.outputs.is-diff }}

    steps:
      - uses: actions/checkout@v4

      - name: Fetch master branch
        run: |
          git fetch origin master

      - name: Check for changes
        id: check-changes
        run: | # Check for changes excluding README.md
          if [ "${{ inputs.branch-name }}" == "master" ]; then
            echo "Always build master"
            echo "is-diff=true" >> $GITHUB_OUTPUT
          elif [ "${{ inputs.parent-image-is-diff }}" == "true" ]; then
            echo "Parent is diff"
            echo "is-diff=true" >> $GITHUB_OUTPUT
          # Check if the subdirectory exists in the base branch
          elif ! git ls-tree -d origin/master -- "images/${{ inputs.directory }}" >/dev/null 2>&1; then
            echo "Subdirectory does not exist in the base branch"
            echo "is-diff='true'" >> $GITHUB_OUTPUT
          else
            CHANGES=$(git diff --name-only origin/master HEAD -- "images/${{ inputs.directory }}" | grep -v "README.md" || true)
            NEW_FILES=$(git diff --name-only --diff-filter=A origin/master HEAD -- "images/${{ inputs.directory }}" | grep -v "README.md" || true)
            
            CHANGES="${CHANGES}${NEW_FILES}"

            if [ -n "$CHANGES" ]; then
              echo "Changes detected (excluding README.md)"
              echo "is-diff=true" >> $GITHUB_OUTPUT
            else
              echo "No changes detected"
              echo "is-diff=false" >> $GITHUB_OUTPUT
            fi
          fi