name: parity
# The vanilla harnesses a pull request's changes can affect, on the Mac mini's runner or playhorizon's, which hold the
# maintainer's own Minecraft files (Horizon never downloads the game). Called by ci.yml for pull requests from this repository
# and by run-parity.yml when a maintainer labels a fork's pull request run-parity. See docs/release-flow.md.
on:
  workflow_call:
    inputs:
      base:
        description: The pull request's base commit (the harnesses its changes since then can affect)
        type: string
        required: true
      head:
        description: The commit to check out and test
        type: string
        required: true
      full:
        description: >-
          The pull request carries the full-parity label (a change every harness reaches, such as a crate split): it
          runs on playhorizon's runner only, so the Mac mini's runners stay free for the others. While that runner is
          busy the job waits for it.
        type: boolean
        default: false
permissions:
  contents: read
env:
  # Test runs never reach the telemetry server: no live-count ping, no uploads (docs/telemetry.md).
  HORIZON_TELEMETRY_URL: "off"

jobs:
  parity:
    runs-on: ${{ inputs.full && fromJSON('["self-hosted", "horizon-game", "playhorizon"]') || fromJSON('["self-hosted", "horizon-game"]') }}
    # A change to core crates reruns ~350 harnesses: ~60-90 min on the Mac mini; on playhorizon (4 of its 8 vCPUs, 4
    # harnesses at a time) up to a few hours, and any pull request's job may land there.
    timeout-minutes: ${{ inputs.full && 360 || 180 }}
    steps:
      - uses: actions/checkout@v4
        with:
          # The commit the event names: a fork's later pushes need another run-parity label. The next step merges
          # main into it.
          ref: ${{ inputs.head }}
          fetch-depth: 0
          persist-credentials: false
          # Keeps .local/ (parity state, probe builds, oracle results) and target/ between runs.
          clean: false
      - name: The head merged into main (what merging it would land)
        id: merge
        env:
          BASE_SHA: ${{ inputs.base }}
          HEAD_SHA: ${{ inputs.head }}
        run: |
          # Harness fixes and game fixes that reached main since the branch was made then apply here too: a head
          # tested alone failed harnesses already fixed on main (server_knockback before #2114, mob_ai's heap before
          # #2270, save_roundtrip before #2212). Selection then compares with this main, so it sees only the pull
          # request's own changes. A head that conflicts with main is tested alone.
          set -euo pipefail
          git merge --abort 2>/dev/null || true
          git fetch -q --no-tags origin +refs/heads/main:refs/remotes/origin/main
          main=$(git rev-parse origin/main)
          if git -c user.name=parity -c user.email=parity@localhost merge -q --no-edit --no-ff "$main" >/dev/null 2>&1; then
            echo "base=$main" >> "$GITHUB_OUTPUT"
            echo "Tested: head ${HEAD_SHA:0:9} merged into main ${main:0:9}" | tee -a "$GITHUB_STEP_SUMMARY"
          else
            git merge --abort
            echo "base=$BASE_SHA" >> "$GITHUB_OUTPUT"
            echo "::warning::head ${HEAD_SHA:0:9} conflicts with main ${main:0:9}: tested alone, without main's fixes"
            echo "Tested: head ${HEAD_SHA:0:9} alone (it conflicts with main ${main:0:9})" | tee -a "$GITHUB_STEP_SUMMARY"
          fi
      - uses: dtolnay/rust-toolchain@stable
      - name: Tools from the runner
        run: bash tools/ci/runner-env.sh
      - name: Vanilla data, and resources prepared by this preparer
        run: bash tools/ci/vanilla-data.sh
      - name: The prepared output is the one the preparer's OUTPUT_VERSION says
        env:
          BASE_SHA: ${{ steps.merge.outputs.base }}
        run: |
          # A head made before OUTPUT_VERSION (#1947) that conflicts with main has neither the tool nor the number.
          if [ ! -f tools/prepare_output.py ] || ! grep -q OUTPUT_VERSION crates/horizon-prepare/src/lib.rs; then
            echo "This head's preparer has no OUTPUT_VERSION: nothing to check"
            exit 0
          fi
          python3 tools/prepare_output.py check --cache --base "$BASE_SHA"
      - name: The version constants are the pinned jar's
        run: python3 tools/gen_version_consts.py --check
      - name: The harnesses this change can affect
        env:
          PARITY_HOSTS: ''
          BASE_SHA: ${{ steps.merge.outputs.base }}
        run: python3 tools/parity.py --changed "$BASE_SHA" --timeout 2400  # world_spawn takes ~1480 s on a busy runner
      - name: Logs of the failed harnesses
        if: failure()
        uses: actions/upload-artifact@v4
        with:
          name: parity-logs
          path: .local/parity-runner/logs/
          if-no-files-found: ignore
          retention-days: 3