on:
  push:
    branches: [ main ]
  pull_request:
  merge_group:

name: CI

jobs:
  ci:
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        rust:
          - 1.63.0  # MSRV
          - stable
          - beta
          - nightly
        features:
          - ""
          - "serde"

    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Cache the registry
        uses: actions/cache@v4
        if: startsWith(matrix.rust, '1')
        with:
          path: ~/.cargo/registry/index
          key: cargo-${{ matrix.rust }}-git-index

      - name: Set up Rust
        uses: dtolnay/rust-toolchain@master
        with:
          toolchain: ${{ matrix.rust }}

      - name: Build (no_std)
        run: cargo build --no-default-features --features "${{ matrix.features }}"

      - name: Build
        run: cargo build --features "${{ matrix.features }}"

      - name: Test
        run: cargo test --features "${{ matrix.features }}"

      - name: Doc
        run: cargo doc --features "${{ matrix.features }}"

  clippy:
    name: Rustfmt and Clippy
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Set up nightly Rust
        uses: dtolnay/rust-toolchain@nightly
        with:
          components: rustfmt, clippy

      - name: Rustfmt
        run: cargo fmt --all -- --check

      - name: Clippy
        run: cargo clippy  # -- -D warnings

  # One job that "summarizes" the success state of this pipeline. This can then be added to branch
  # protection, rather than having to add each job separately.
  success:
    name: Success
    runs-on: ubuntu-latest
    needs: [ci, clippy]
    # Github branch protection is exceedingly silly and treats "jobs skipped because a dependency
    # failed" as success. So we have to do some contortions to ensure the job fails if any of its
    # dependencies fails.
    if: always() # make sure this is never "skipped"
    steps:
      # Manually check the status of all dependencies. `if: failure()` does not work.
      - name: check if any dependency failed
        run: jq --exit-status 'all(.result == "success")' <<< '${{ toJson(needs) }}'