name: Setup Rust Toolchain for GitHub CI
description: |
  Setup specific Rust versions and integrate nicely into the ecosystem.
  The action enabled caching of Rust tools and build artifacts and sets environment variables for faster and more efficient caching.
  It also sets up problem matchers showing compilation and formatting 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 "RUSTFLAGS=-D warnings" >> $GITHUB_ENV
      shell: bash