name: Setup Rust Toolchain for GitHub CI
description: |
  Setup specific Rust versions with caching pre-configured.
  It provides problem matchers for cargo and rustfmt issues.

branding:
  icon: "play"
  color: "gray-dark"

# Add option to install directly from rust-toolchain file
# Blocked on rustup support: https://github.com/rust-lang/rustup/issues/2686
#
# The action is heavily inspired by https://github.com/dtolnay/rust-toolchain
inputs:
  toolchain:
    description: "Rust toolchain specification -- see https://rust-lang.github.io/rustup/concepts/toolchains.html#toolchain-specification"
    required: false
    default: "stable"
  target:
    description: "Target triple to install for this toolchain"
    required: false
  components:
    description: "Comma-separated list of components to be additionally installed"
    required: false

outputs:
  rustc-version:
    description: "Version as reported by `rustc --version`"
    value: ${{steps.versions.outputs.rustc-version}}
  cargo-version:
    description: "Version as reported by `cargo --version`"
    value: ${{steps.versions.outputs.cargo-version}}
  rustup-version:
    description: "Version as reported by `rustup --version`"
    value: ${{steps.versions.outputs.rustup-version}}

runs:
  using: composite
  steps:
    - id: flags
      run: |
        : construct rustup command line
        echo "::set-output name=targets::$(for t in ${targets//,/ }; do echo -n ' --target' $t; done)"
        echo "::set-output name=components::$(for c in ${components//,/ }; do echo -n ' --component' $c; done)"
        echo "::set-output name=downgrade::${{inputs.toolchain == 'nightly' && inputs.components && ' --allow-downgrade' || ''}}"
      env:
        targets: ${{inputs.target}}
        components: ${{inputs.components}}
      shell: bash
    - name: rustup toolchain install ${{inputs.toolchain}}
      run: |
        rustup toolchain install ${{inputs.toolchain}}${{steps.flags.outputs.targets}}${{steps.flags.outputs.components}} --profile minimal${{steps.flags.outputs.downgrade}} --no-self-update
        rustup default ${{inputs.toolchain}}
      shell: bash
    - name: Print installed versions
      id: versions
      run: |
        echo "::set-output name=rustc-version::$(rustc --version)"
        rustc --version
        echo "::set-output name=cargo-version::$(cargo --version)"
        cargo --version
        echo "::set-output name=rustup-version::$(rustup --version)"
        rustup --version
      shell: bash

    - name: "Setup Rust Caching"
      uses: Swatinem/rust-cache@v1
    - name: "Install Rust Problem Matcher"
      run: echo "::add-matcher::${{ github.action_path }}/rust.json"
      shell: bash
    - name: "Setting Environment Variables"
      run: |
        echo "CARGO_INCREMENTAL=0" >> $GITHUB_ENV
        echo "CARGO_PROFILE_DEV_DEBUG=0" >> $GITHUB_ENV
        echo "CARGO_TERM_COLOR=always" >> $GITHUB_ENV
        echo "RUST_BACKTRACE=short" >> $GITHUB_ENV
        echo "RUSTFLAGS=-D warnings" >> $GITHUB_ENV
      shell: bash