on:
  pull_request:
  workflow_dispatch:
  push:
    branches: ["main"]

env:
  # disable incremental compilation.
  #
  # incremental compilation is useful as part of an edit-build-test-edit cycle,
  # as it lets the compiler avoid recompiling code that hasn't changed. however,
  # on CI, we're not making small edits; we're almost always building the entire
  # project from scratch. thus, incremental compilation on CI actually
  # introduces *additional* overhead to support making future builds
  # faster...but no future builds will ever occur in any given CI environment.
  #
  # see https://matklad.github.io/2021/09/04/fast-rust-builds.html#ci-workflow
  # for details.
  CARGO_INCREMENTAL: 0
  # allow more retries for network requests in cargo (downloading crates) and
  # rustup (installing toolchains). this should help to reduce flaky CI failures
  # from transient network timeouts or other issues.
  CARGO_NET_RETRY: 10
  RUSTUP_MAX_RETRIES: 10
  # don't emit giant backtraces in the CI logs.
  RUST_BACKTRACE: short
  RUSTFLAGS: -Dwarnings
  msrv: 1.57.0
  LOOM_LOG: 'thingbuf=trace,debug'

name: CI

jobs:
  changed_paths:
    continue-on-error: true
    runs-on: ubuntu-latest
    outputs:
      should_skip: ${{ steps.skip_check.outputs.should_skip }}
    steps:
      - id: skip_check
        uses: fkirc/skip-duplicate-actions@master
        with:
          do_not_skip: '["workflow_dispatch", "push"]'
          paths: '["**/*.rs", "**/Cargo.toml", ".github/workflows/ci.yml"]'

  build_no_std:
    name: Check no_std
    needs: changed_paths
    if: needs.changed_paths.outputs.should_skip != 'true'
    strategy:
      matrix:
        feature: [alloc, static]
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
    - name: Install toolchain
      uses: actions-rs/toolchain@v1
      with:
        profile: minimal
        toolchain: stable
        override: true
        components: rustfmt
    - uses: actions-rs/cargo@v1
      with:
        command: check
        args: --no-default-features --features ${{ matrix.feature }}

  tests:
    name: Tests
    needs: changed_paths
    if: needs.changed_paths.outputs.should_skip != 'true'
    strategy:
      matrix:
        # test all Rust versions on Ubuntu
        rust: [stable, 1.57.0]
        os: [ubuntu-latest]
        # test stable Rust on Windows and MacOS as well
        include:
          - rust: stable
            os: windows-latest
          - rust: stable
            os: macos-latest
    runs-on: ${{ matrix.os }}
    steps:
      - uses: actions/checkout@v2
      - name: Install toolchain
        uses: actions-rs/toolchain@v1
        with:
          profile: minimal
          toolchain: ${{ matrix.rust }}
          override: true
          components: rustfmt
      - name: Run cargo test (with static APIs)
        if: ${{ matrix.rust != env.msrv }}
        uses: actions-rs/cargo@v1
        with:
          command: test
          args: --all-features
      - name: Run cargo test (no static APIs)
        if: ${{ matrix.rust == env.msrv }}
        uses: actions-rs/cargo@v1
        with:
          command: test
          # skip doctests, which require all features to be enabled
          args: --lib --tests

  benches:
    name: Compile benchmarks
    needs: changed_paths
    if: needs.changed_paths.outputs.should_skip != 'true'
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Install stable toolchain
        uses: actions-rs/toolchain@v1
        with:
          profile: minimal
          toolchain: stable
          override: true
          components: rustfmt
      - name: Run cargo check
        uses: actions-rs/cargo@v1
        with:
          command: check
          args: -p bench --benches

  rustfmt:
    runs-on: ubuntu-latest
    needs: changed_paths
    if: needs.changed_paths.outputs.should_skip != 'true'
    steps:
      - uses: actions/checkout@v2
      - name: Install stable toolchain
        uses: actions-rs/toolchain@v1
        with:
          profile: minimal
          toolchain: stable
          override: true
          components: rustfmt
      - name: Run cargo fmt
        uses: actions-rs/cargo@v1
        with:
          command: fmt
          args: --all -- --check

  clippy_check:
    name: Clippy check
    needs: changed_paths
    if: needs.changed_paths.outputs.should_skip != 'true'
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Install stable toolchain
        uses: actions-rs/toolchain@v1
        with:
            toolchain: stable
            components: clippy
            override: true
      - uses: actions-rs/clippy-check@v1
        with:
          token: ${{ secrets.GITHUB_TOKEN }}

  # Run particularly slow loom models individually
  slow_models:
    needs: changed_paths
    if: needs.changed_paths.outputs.should_skip != 'true'
    strategy:
      matrix:
        model:
          - mpsc_send_recv_wrap
          - mpsc_try_send_recv
          - mpsc_try_recv_ref
          - mpsc_async::rx_close_unconsumed
          - mpsc_blocking::rx_close_unconsumed
    name: model '${{ matrix.model }}''
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Install stable toolchain
        uses: actions-rs/toolchain@v1
        with:
          profile: minimal
          toolchain: stable
          override: true
      - name: Run model
        run: cargo test --profile loom --lib -- ${{ matrix.model }}
        env:
          # it would be nice to run these with more preemptions, but
          # that makes these models super slow...and LOOM_MAX_PREEMPTIONS=1 is
          # good enough for Tokio's CI, so...
          LOOM_MAX_PREEMPTIONS: 1
          RUSTFLAGS: "--cfg loom"

  # Run other loom models by scope
  models:
    needs: changed_paths
    if: needs.changed_paths.outputs.should_skip != 'true'
    strategy:
      matrix:
        scope:
          # NOTE: if adding loom models in a new module, that module needs to be
          # added to this list!
          - mpsc_blocking
          - mpsc_async
          - thingbuf
          - util
    name: models in '${{ matrix.scope }}'
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Install stable toolchain
        uses: actions-rs/toolchain@v1
        with:
          profile: minimal
          toolchain: stable
          override: true
      - name: Run models
        run: cargo test --profile loom --lib -- ${{ matrix.scope }}
        env:
          LOOM_MAX_PREEMPTIONS: 2
          # `--cfg ci_skip_slow_models` will exclude the loom models that are
          # tested in `slow-models`.
          RUSTFLAGS: "--cfg loom --cfg ci_skip_slow_models"

  # Dummy job that requires all loom models to pass
  all_models:
    name: all loom models
    runs-on: ubuntu-latest
    needs:
      - slow_models
      - models
    steps:
      - run: exit 0

  miri:
    name: Miri tests
    needs: changed_paths
    if: needs.changed_paths.outputs.should_skip != 'true'
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Install nightly toolchain
        uses: actions-rs/toolchain@v1
        with:
          profile: minimal
          toolchain: nightly
          override: true
          components: miri
      - name: Run Miri tests
        run: cargo miri test --lib --no-fail-fast
        env:
          MIRIFLAGS: -Zmiri-disable-isolation -Zmiri-tag-raw-pointers