name: 'cargo-semver-checks'
description: 'Ensure your Rust crate's public API follows semantic versioning'
inputs:
  crate-name:
    description: 'The crate whose API to check for semver'
    required: false
    default: ''
  version-tag-prefix:
    description: 'The prefix to use for the git tag for a version; the default "v" creates tags like "v1.0.0"'
    required: false
    default: 'v'
runs:
  using: "composite"
  runs-on: ubuntu-latest
  steps:
    - name: Install rust
      uses: actions-rs/toolchain@v1
      with:
        toolchain: nightly
        profile: minimal
    - run: |
      # Colorize output, since GitHub Actions terminals support color.
      export CARGO_TERM_COLOR=always

      # Record the current git sha, so we can come back to it after generating the baseline.
      export CURRENT_GIT_SHA="$(git rev-parse HEAD)"

      # Ensure this action's scripts are available to run on the path.
      echo "${{ github.action_path }}" >> $GITHUB_PATH

      export PACKAGE_NAME="${{ inputs.crate-name }}"
      if [[ "$PACKAGE_NAME" == '' ]]; then
        export PACKAGE_NAME="$(find_workspace_crates.sh)"
      fi
      export PACKAGE_NAME_WITH_UNDERSCORES="$(echo $"PACKAGE_NAME" | tr '-' '_')"

      # Switch to the tag for the correct baseline version,
      # then build rustdoc JSON.
      #
      # We *do not* want to record and reuse the target directory path
      # across different git commits, since it may be at a different location
      # in different commits.
      git checkout "${{ inputs.version-tag-prefix }}$(find_comparison_version.sh "$PACKAGE_NAME")"
      cargo +nightly rustdoc -- -Zunstable-options --output-format json
      mv "$(cargo metadata --format-version 1 | jq -r .target_directory)/doc/$PACKAGE_NAME_WITH_UNDERSCORES.json" /tmp/baseline.json

      # Return to the original git sha.
      git checkout "$CURRENT_GIT_SHA"

      # Build rustdoc JSON for the current version, and move it to /tmp/
      # so it doesn't get overwritten by the baseline build.
      cargo +nightly rustdoc -- -Zunstable-options --output-format json
      mv "$(cargo metadata --format-version 1 | jq -r .target_directory)/doc/$PACKAGE_NAME_WITH_UNDERSCORES.json" /tmp/current.json

      # Check for semver violations.
      cargo install cargo-semver-checks
      cargo semver-checks check-release --current /tmp/current.json --baseline /tmp/baseline.json