pr-is-up-to-date.yml

name: PR is up-to-date
on:
  pull_request_target:
    branches: [ trunk ]
  push:
    branches: [ trunk ]
    tags:
      - pr-update-to
      - pr-update-to-projects/**

jobs:
  check:
    name: Check
    runs-on: ubuntu-latest
    timeout-minutes: 5  # 2021-03-23: The run on push to the tag might take a minute or two.
    steps:

      # We basically have two workflows in one here, one for pushes to trunk and one for PRs and pushes to tags.
      # The reason we don't separate them into two is because GitHub's UI would then always be showing a skipped job
      # in the PR check list, which is kind of annoying.

      # First, the "PR or tag" job.

      - name: Checkout trunk for tag push or PR
        uses: actions/checkout@v4
        if: github.event_name != 'push' || github.ref != 'refs/heads/trunk'
        with:
          ref: trunk
          token: ${{ secrets.API_TOKEN_GITHUB }}

      # On a PR, we need to fetch (but not check out) the actual PR too.
      - name: Deepen to merge base
        if: github.event_name != 'push'
        uses: ./.github/actions/deepen-to-merge-base
        with:
          checkout: false

      - name: Determine tags for PR or tag and paths for tag push
        id: determine
        if: github.event_name != 'push' || github.ref != 'refs/heads/trunk'
        env:
          REF: ${{ github.event.pull_request.head.sha }}
        run: |
          TAGS=()
          TAG=
          PATHS=
          if [[ "$GITHUB_EVENT_NAME" == "push" ]]; then
            TAG="${GITHUB_REF#refs/tags/}"
            if [[ "$TAG" == pr-update-to-* ]]; then
              PATHS="${TAG#pr-update-to-}"
            fi
          else
            TMP="$(git -c core.quotepath=off diff --name-only "origin/trunk...${REF}" projects/*/*/ | sed -nE 's!^(projects/[^/]+/[^/]+)/.*!pr-update-to-\1!p' | sort -u)"
            mapfile -t TAGS <<<"$TMP"
            TAGS+=( pr-update-to )
          fi
          echo "pr-tags=${TAGS[*]}" >> "$GITHUB_OUTPUT"
          echo "push-tag=$TAG" >> "$GITHUB_OUTPUT"
          echo "push-paths=$PATHS" >> "$GITHUB_OUTPUT"

      - name: Check PR or tag push
        if: github.event_name != 'push' || github.ref != 'refs/heads/trunk'
        uses: ./projects/github-actions/pr-is-up-to-date
        with:
          tags: ${{ steps.determine.outputs.pr-tags }}
          tag: ${{ steps.determine.outputs.push-tag }}
          paths: ${{ steps.determine.outputs.push-paths }}
          token: ${{ secrets.API_TOKEN_GITHUB }}
          status: PR is up to date

      # Second, the "push to trunk" job.

      - name: Checkout push to trunk
        uses: actions/checkout@v4
        if: github.event_name == 'push' && github.ref == 'refs/heads/trunk'
        with:
          # The "Check whether the tag needs updating for trunk commit" needs the previous commit for diffing.
          fetch-depth: 2
          token: ${{ secrets.API_TOKEN_GITHUB }}

      - name: Wait for prior instances of the workflow to finish
        if: github.event_name == 'push' && github.ref == 'refs/heads/trunk'
        uses: ./.github/actions/turnstile

      - name: Check whether the tag needs updating for trunk commit
        if: github.event_name == 'push' && github.ref == 'refs/heads/trunk'
        run: .github/files/pr-update-to.sh