linked-issue.yml

name: Sync Issue Labels to PR
on:
  pull_request_target:
    types: [opened, reopened, synchronize, edited]
permissions:
  contents: read
  pull-requests: write
jobs:
  sync-labels:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repo
        uses: actions/checkout@v4

      - name: Extract linked issues from PR body
        id: issues
        env:
          PR_BODY: ${{ github.event.pull_request.body }}
        run: |
          ISSUES=$(echo "$PR_BODY" | grep -oE '#[0-9]+' | tr -d '#' | tr '\n' ' ' || true)
          echo "issues=$ISSUES" >> $GITHUB_OUTPUT

      - name: Collect labels from linked issues
        if: ${{ steps.issues.outputs.issues != '' }}
        id: labels
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          ISSUE_NUMBERS: ${{ steps.issues.outputs.issues }}
          REPO: ${{ github.repository }}
        run: |
          ALL_LABELS=""
          REAL_ISSUES=""
          for ISSUE_NUM in $ISSUE_NUMBERS; do
            IS_PR=$(gh api "repos/$REPO/issues/$ISSUE_NUM" --jq '.pull_request // empty' || echo "")
            if [ -n "$IS_PR" ]; then
              echo "#$ISSUE_NUM is a PR, skipping"
              continue
            fi
            REAL_ISSUES="$REAL_ISSUES $ISSUE_NUM"
            LABELS=$(gh issue view "$ISSUE_NUM" --json labels -q '.labels[].name' || echo "")
            if [ -n "$LABELS" ]; then
              ALL_LABELS="$ALL_LABELS"$'\n'"$LABELS"
            fi
          done
          ALL_LABELS=$(echo "$ALL_LABELS" | sed '/^$/d' | sort -u | paste -sd, - || true)
          echo "real_issues=$REAL_ISSUES" >> $GITHUB_OUTPUT
          echo "labels=$ALL_LABELS" >> $GITHUB_OUTPUT

      - name: Comment if no valid issues linked
        if: ${{ steps.labels.outputs.real_issues == '' }}
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          PR_NUM: ${{ github.event.pull_request.number }}
        run: |
          gh pr comment "$PR_NUM" --body "⚠️ No issue was linked in the PR description.
          Please make sure to link an issue (e.g., 'Fixes #issue_number')"

      - name: Apply labels to PR
        if: ${{ steps.labels.outputs.labels != '' }}
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          LABELS_TO_APPLY: ${{ steps.labels.outputs.labels }}
          PR_NUMBER: ${{ github.event.pull_request.number }}
        run: |
          echo "Applying labels: $LABELS_TO_APPLY"
          gh pr edit "$PR_NUMBER" --add-label "$LABELS_TO_APPLY"