blank.yml

name: Check Feature Branch Origin

on:
  pull_request:
    types:
      - opened
      - synchronize
    branches:
      - 'vnext/*'

jobs:
  check-branch-origin:
    runs-on: ubuntu-latest
    env:
      MY_COMMAND: 'git show-branch -a | sed "s/].*//" | grep "\*" | grep -v "$(git rev-parse --abbrev-ref HEAD)" | head -n1 | sed "s/^.*\[//"'

    steps:
      - name: Checkout code
        uses: actions/checkout@v2

      - name: git fetch
        run: git fetch

      - name: Set Environment Variable
        run: echo "TEST=$MY_COMMAND" >> $GITHUB_ENV

      - name: Echo Command
        run: echo "$TEST"
        
      - name: Get common ancestor commit
        id: merge-base
        run: echo "COMMIT_HASH=$(git merge-base origin/${{ github.base_ref }} origin/${{ github.head_ref }})" >> $GITHUB_ENV

      - name: Verify branch origin
        run: |
          common_ancestor_commit="$COMMIT_HASH"
          first_commit_in_feature_branch=$(git rev-list --max-parents=0 HEAD)

          if [ "$common_ancestor_commit" != "$first_commit_in_feature_branch" ]; then
            echo "Error: Feature branch was not created from master."
            exit 1
          fi