backport-pr.yml

name: Link-Backport-PR-Issue

on:
  pull_request:
    types: [ opened ]
    branches:
    - master
    - "v*"

jobs:
  check-backport:
    runs-on: ubuntu-latest
    steps:
    - name: Checkout repository
      uses: actions/checkout@v4

    - name: Check if PR is a backport
      run: |
        if [[ "$(echo "${{ github.event.pull_request.title }}" | sed 's/"/\\"/g')" =~ "backport #" ]]; then
          echo "BACKPORT=true" >> $GITHUB_ENV
        else
          echo "BACKPORT=false" >> $GITHUB_ENV
        fi

    - name: Extract backport branch and issue number
      if: env.BACKPORT == 'true'
      run: |
        # Extract branch from the target branch of the PR
        BRANCH=$(echo "${{ github.event.pull_request.base.ref }}")
        BRANCH=${BRANCH%.x}   # Remove the '.x' suffix
        BRANCH=$(echo "${BRANCH}" | sed 's/\./\\./g')   # Escape periods
        echo "BRANCH=$BRANCH" >> $GITHUB_ENV
        
        # Extract issue number from the PR description
        ORIGINAL_ISSUE_NUMBER=$(echo '${{ github.event.pull_request.body }}'' | grep -oE 'longhorn/longhorn#[0-9]+' | cut -d'#' -f2)
        echo "ORIGINAL_ISSUE_NUMBER=$ORIGINAL_ISSUE_NUMBER" >> $GITHUB_ENV

    - name: Link the PR with the backport issue
      if: ${{ env.BACKPORT == 'true' && env.ORIGINAL_ISSUE_NUMBER != '' }}
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
      run: |
        for issue_number in "${{ env.ORIGINAL_ISSUE_NUMBER }}"; do
          echo "Found source issue longhorn/longhorn#${issue_number}"
          issue_title=$(gh issue view "$issue_number" --repo longhorn/longhorn --json 'title' -q '.title')
        
          if [[ $? -eq 0 && -n "$issue_number" ]]; then
            backport_issue_number=$(
              curl -s "https://api.github.com/search/issues?q=repo:longhorn/longhorn+is:open+is:issue+in:title+${{ env.BRANCH }}+\"${issue_title}\"" \
              | jq .items[0].number
            )

            if [[ -n "$backport_issue_number" ]]; then
              echo "Found backport issue longhorn/longhorn#${backport_issue_number}"
              echo "Linking backport issue longhorn/longhorn#${backport_issue_number}"
              gh issue comment --repo longhorn/longhorn "${backport_issue_number}" --body "Backport PR: ${{ github.event.pull_request.html_url }}"
              continue
            fi
          fi
        
          echo "No issue title found"
        done