add-backport-label.yaml

name: Add backport label

on:
  pull_request:
    types:
      - opened
      - synchronize
      - reopened
      - edited
      - labeled
      - unlabeled

jobs:
  check-issues:
    if: ${{ github.event.label.name != 'auto-backport' }}
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code to allow hub to communicate with the project
        if: ${{ !contains(github.event.pull_request.labels.*.name, 'force-skip-ci') }}
        uses: actions/checkout@v3

      - name: Install hub extension script
        run: |
          pushd $(mktemp -d) &>/dev/null
          git clone --single-branch --depth 1 "https://github.com/kata-containers/.github" && cd .github/scripts
          sudo install hub-util.sh /usr/local/bin
          popd &>/dev/null

      - name: Determine whether to add label 
        if: ${{ !contains(github.event.pull_request.labels.*.name, 'force-skip-ci') }}
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          CONTAINS_AUTO_BACKPORT: ${{ contains(github.event.pull_request.labels.*.name, 'auto-backport') }}
        id: add_label
        run: |
          pr=${{ github.event.pull_request.number }}
          linked_issue_urls=$(hub-util.sh \
            list-issues-for-pr "$pr" |\
            grep -v "^\#"  |\
            cut -d';' -f3 || true)
          [ -z "$linked_issue_urls" ] && {
            echo "::error::No linked issues for PR $pr"
            exit 1
          }
          has_bug=false
          for issue_url in $(echo "$linked_issue_urls")
          do
            issue=$(echo "$issue_url"| awk -F\/ '{print $NF}' || true)
            [ -z "$issue" ] && {
              echo "::error::Cannot determine issue number from $issue_url for PR $pr"
              exit 1
            }
            labels=$(hub-util.sh list-labels-for-issue "$issue")
            
            label_names=$(echo $labels | jq -r '.[].name' || true)
            if [[ "$label_names" =~ "bug" ]]; then
              has_bug=true
              break
            fi
          done

          has_backport_needed_label=${{ contains(github.event.pull_request.labels.*.name, 'needs-backport') }}
          has_no_backport_needed_label=${{ contains(github.event.pull_request.labels.*.name, 'no-backport-needed') }}

          echo "::set-output name=add_backport_label::false"
          if [ $has_backport_needed_label  = true ] || [ $has_bug  = true ]; then
            if [[ $has_no_backport_needed_label = false ]]; then
              echo "::set-output name=add_backport_label::true"
            fi
          fi

          # Do not spam comment, only if auto-backport label is going to be newly added.
          echo "::set-output name=auto_backport_added::$CONTAINS_AUTO_BACKPORT"

      - name: Add comment
        if: ${{ !contains(github.event.pull_request.labels.*.name, 'force-skip-ci') && steps.add_label.outputs.add_backport_label == 'true' && steps.add_label.outputs.auto_backport_added == 'false' }}
        uses: actions/github-script@v6
        with:
          script: |
            github.rest.issues.createComment({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              body: 'This issue has been marked for auto-backporting. Add label(s) backport-to-BRANCHNAME to backport to them'
            })

      # Allow label to be removed by adding no-backport-needed label
      - name: Remove auto-backport label
        if: ${{ !contains(github.event.pull_request.labels.*.name, 'force-skip-ci') && steps.add_label.outputs.add_backport_label == 'false' }}
        uses: andymckay/labeler@e6c4322d0397f3240f0e7e30a33b5c5df2d39e90
        with:
          remove-labels: "auto-backport"
          repo-token: ${{ secrets.GITHUB_TOKEN }}

      - name: Add auto-backport label
        if: ${{ !contains(github.event.pull_request.labels.*.name, 'force-skip-ci') && steps.add_label.outputs.add_backport_label == 'true' }}
        uses: andymckay/labeler@e6c4322d0397f3240f0e7e30a33b5c5df2d39e90
        with:
          add-labels: "auto-backport"
          repo-token: ${{ secrets.GITHUB_TOKEN }}