mettle 0.5.0

Retry for Rust, async and blocking: backoff, jitter, per-attempt timeouts, and a clock you can mock.
Documentation
name: CI

on:
  push:
    branches: [main]
  pull_request:

env:
  CARGO_TERM_COLOR: always
  RUSTFLAGS: "-D warnings"

jobs:
  test:
    name: test (${{ matrix.features }})
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        features:
          - --all-features
          - --no-default-features --features async
          - --no-default-features --features blocking
    steps:
      - uses: actions/checkout@v4
      - uses: dtolnay/rust-toolchain@stable
      - run: cargo test ${{ matrix.features }}

  lint:
    name: lint (${{ matrix.features }})
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        features:
          - --all-features
          - --no-default-features --features async
          - --no-default-features --features blocking
    steps:
      - uses: actions/checkout@v4
      - uses: dtolnay/rust-toolchain@stable
        with:
          components: clippy
      # Every feature combination, not just the union. A lint that only ever sees `--all-features`
      # never looks at the code a minimal build actually compiles.
      - run: cargo clippy --all-targets ${{ matrix.features }} -- -D warnings

  fmt:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: dtolnay/rust-toolchain@stable
        with:
          components: rustfmt
      # Formatting does not vary by feature, so this is one job rather than a matrix.
      - run: cargo fmt --all --check

  docs:
    name: docs (${{ matrix.features }})
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        features:
          - --all-features
          - --no-default-features --features async
          - --no-default-features --features blocking
    steps:
      - uses: actions/checkout@v4
      - uses: dtolnay/rust-toolchain@stable
      # Matrixed because an intra-doc link can point at a feature-gated item and resolve fine
      # under `--all-features` while breaking every smaller build.
      - run: cargo doc ${{ matrix.features }} --no-deps
        env:
          RUSTDOCFLAGS: "-D warnings"

  msrv:
    name: msrv 1.85 (${{ matrix.features }})
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        features:
          - --all-features
          - --no-default-features --features async
          - --no-default-features --features blocking
    steps:
      - uses: actions/checkout@v4
      - uses: dtolnay/rust-toolchain@1.85.0
      # --all-targets so examples and tests are held to the MSRV too; a plain `cargo check`
      # compiles neither.
      - run: cargo check --all-targets ${{ matrix.features }}

  semver:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: obi1kenobi/cargo-semver-checks-action@v2