.github/workflows/validate-pr.yml

name: validate-pr

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

permissions:
  contents: read

on:
  pull_request:
    types: [opened, edited, labeled, unlabeled, synchronize]

jobs:
  check-labels:
    runs-on: ubuntu-24.04
    timeout-minutes: 120 # guardrails timeout for the whole job
    steps:
      - name: Missing `area/` label
        if: always() && contains(join(github.event.pull_request.labels.*.name, ','), 'impact/') && !contains(join(github.event.pull_request.labels.*.name, ','), 'area/')
        run: |
          echo "::error::Every PR with an 'impact/*' label should also have an 'area/*' label"
          exit 1
      - name: Missing `kind/` label
        if: always() && contains(join(github.event.pull_request.labels.*.name, ','), 'impact/') && !contains(join(github.event.pull_request.labels.*.name, ','), 'kind/')
        run: |
          echo "::error::Every PR with an 'impact/*' label should also have a 'kind/*' label"
          exit 1
      - name: OK
        run: exit 0

  check-changelog:
    runs-on: ubuntu-24.04
    timeout-minutes: 120 # guardrails timeout for the whole job
    env:
      HAS_IMPACT_LABEL: ${{ contains(join(github.event.pull_request.labels.*.name, ','), 'impact/') }}
      PR_BODY: |
        ${{ github.event.pull_request.body }}
    steps:
      - name: Check changelog description
        run: |
          # Extract the `markdown changelog` note code block
          block=$(echo -n "$PR_BODY" | tr -d '\r' | awk '/^```markdown changelog$/{flag=1;next}/^```$/{flag=0}flag')

          # Strip empty lines
          desc=$(echo "$block" |  awk NF)

          if [ "$HAS_IMPACT_LABEL" = "true" ]; then
            if [ -z "$desc" ]; then
              echo "::error::Changelog section is empty. Please provide a description for the changelog."
              exit 1
            fi

            len=$(echo -n "$desc" | wc -c)
            if [[ $len -le 6 ]]; then
              echo "::error::Description looks too short: $desc"
              exit 1
            fi
          else
            if [ -n "$desc" ]; then
              echo "::error::PR has a changelog description, but no changelog label"
              echo "::error::Please add the relevant 'impact/' label to the PR or remove the changelog description"
              exit 1
            fi
          fi

          echo "This PR will be included in the release notes with the following note:"
          echo "$desc"

  check-pr-branch:
    runs-on: ubuntu-24.04
    timeout-minutes: 120 # guardrails timeout for the whole job
    env:
      PR_TITLE: ${{ github.event.pull_request.title }}
    steps:
      # Backports or PR that target a release branch directly should mention the target branch in the title, for example:
      # [X.Y backport] Some change that needs backporting to X.Y
      # [X.Y] Change directly targeting the X.Y branch
      - name: Check release branch
        id: title_branch
        run: |
          # If PR targets a different branch than master, the PR title should mention the target branch in square brackets, for example:
          # [27.1 backport] Some change that needs backporting to 27.1
          # [27.1] Change directly targeting the 27.1 branch
          # [docker-29.x] Change directly targeting the docker-29.x branch
          # [docker-29.x backport] Some change that needs backporting to docker-29.x

          # get the intended major version prefix ("[27.1 backport]" -> "27.") from the PR title.
          target_branch=$(echo "$PR_TITLE" | sed -nE 's/^\[([^]]+)\].*/\1/p' | sed 's/ backport$//')

          echo "target_branch: $target_branch"
          echo "GITHUB_BASE_REF: $GITHUB_BASE_REF"

          # If the PR is opened against the master branch and the target branch is not specified, exit early.
          if [[ "$GITHUB_BASE_REF" == "master" && "$target_branch" == "" ]]; then
            exit 0
          fi

          if [[ "$target_branch" != "$GITHUB_BASE_REF" ]]; then
              echo "::error::PR is opened against the $GITHUB_BASE_REF branch, but its title suggests otherwise."
              exit 1
          fi