action.yml

name: "Standard Discovery"
description: "Find out what to build & run in a Standard project."
author: "The Standard Authors"

inputs:

  ffBuildInstructions:
    required: false
    default: false
    description: |
      Whether to fast forward build instruction (derivations).

      If set to true, discovery will not populate the GH Action Cache
      with the derviations that have been the result of the evaluation.
      Instead, workers will be expected to connect to the state of the
      discovery action (e.g. via ssh) and fetch precisely those
      derivation closures needed. If the global set of derviaton grows
      due to the number and nature of worker, this can help save on
      upload time, restoration time and derviation packet size.

outputs:
  hits:
    value: ${{ steps.eval.outputs.json }}
    description: "JSON object containing CI actions to run."

runs:
  using: "composite"
  steps:

    - if: contains( runner.os, 'macos')
      name: Install compatible bash 5+
      shell: bash
      run: |
        nix profile install nixpkgs/nixpkgs-22.11-darwin#bash

    - name: Discover
      id: eval
      env:
        EVALSTORE_EXPORT: ${{ runner.temp }}/eval-store
        OWNER_AND_REPO: ${{ github.repository }}
        SHA: ${{ github.sha }}
        SKIP_DRV_EXPORT: ${{ inputs.ffBuildInstructions }}
      run: ${{ github.action_path }}/eval.sh
      shell: bash

    - uses: actions/cache/save@v4
      id: cache
      if: inputs.ffBuildInstructions == 'false'
      with:
        path: ${{ runner.temp }}/eval-store
        key: drv-pack-${{ runner.os }}-${{ runner.arch }}-${{ github.sha }}