action.yml

name: 'CI Diff Changed Files'
description: 'Outputs a JSON array of changed files between a base ref and HEAD, optionally filtered by a regex. No container, no runtime — just bash + git + jq.'
author: 'Michael Gill'

branding:
  icon: 'check-circle'
  color: 'green'

inputs:
  base-ref:
    description: 'Base commit, branch, or tag to compare against.'
    required: false
    default: 'origin/main'
  pattern:
    description: 'Optional ERE regex (grep -E). Only matching file paths are included. Empty matches everything.'
    required: false
    default: ''
  exclude:
    description: 'Optional ERE regex (grep -E). File paths matching this pattern are EXCLUDED from results. Applied after pattern filter.'
    required: false
    default: ''

outputs:
  changed_files:
    description: 'JSON-encoded string array of matching changed file paths.'
    value: ${{ steps.diff.outputs.changed_files }}
  has_changes:
    description: '"true" if at least one file matched, otherwise "false".'
    value: ${{ steps.diff.outputs.has_changes }}

runs:
  using: 'composite'
  steps:
    - name: Compute changed files
      id: diff
      shell: bash
      env:
        BASE_REF: ${{ inputs.base-ref }}
        PATTERN: ${{ inputs.pattern }}
        EXCLUDE: ${{ inputs.exclude }}
      run: 'bash "$GITHUB_ACTION_PATH"/scripts/diff.sh'