action.yml

name: Nix Diff Action
description: Compare Nix derivations between base and PR branches using dix
author: natsukium

branding:
  icon: package
  color: blue

inputs:
  mode:
    description: 'Operation mode: "full" for simple single-job workflow, "diff-only" for parallel execution, "comment-only" for aggregating results'
    required: false
    default: "full"
  attributes:
    description: |
      Nix attributes to compare in YAML array format. Each item requires:
        - displayName: Name shown in PR comment headers (e.g., "myhost" appears as "### myhost")
        - attribute: Nix attribute path (without '#' prefix)
      Example:
        - displayName: myapp
          attribute: packages.x86_64-linux.default
        - displayName: nixos-config
          attribute: nixosConfigurations.myhost.config.system.build.toplevel
      Note: Do not include '#' or '.#' prefix - the reference is constructed automatically.
    required: false
  build:
    description: "Build outputs before comparing. Enables closure size comparison but increases workflow time. Requires running on a platform matching the output (e.g., x86_64-linux outputs need Linux runners)."
    required: false
    default: "false"
  directory:
    description: "Directory containing the Nix expression to evaluate. Defaults to repository root."
    required: false
    default: "."
  github-token:
    description: GitHub token for commenting on PRs. Required for full and comment-only modes.
    required: false
    default: ${{ github.token }}
  skip-no-change:
    description: Skip posting comment when there are no differences.
    required: false
    default: "true"
  comment-strategy:
    description: "'create' to always create new comment, 'update' to update existing comment instead of creating new one."
    required: false
    default: "create"

outputs:
  diff:
    description: JSON array of diff results. Each item has `displayName` and `diff` keys.

runs:
  using: node24
  main: dist/index.js
  post: dist/cleanup.js