action.yml

name: 'Find Impacted Tests'
description: 'Find test files impacted by code changes using static dependency analysis'
author: 'sozua'

branding:
  icon: 'filter'
  color: 'blue'

inputs:
  base:
    description: 'Base ref to compare against (commit SHA, branch, or tag)'
    required: false
    default: ${{ github.event.pull_request.base.sha || 'HEAD~1' }}
  head:
    description: 'Head ref (commit SHA, branch, or tag)'
    required: false
    default: 'HEAD'
  pattern:
    description: 'Glob pattern for test files'
    required: false
    default: '**/*.{test,spec}.{js,mjs,cjs,jsx,ts,mts,cts,tsx}'
  working-directory:
    description: 'Working directory'
    required: false
    default: '.'

outputs:
  files:
    description: 'Space-separated list of impacted test files (for xargs/node --test)'
    value: ${{ steps.impacted.outputs.files }}
  files-json:
    description: 'JSON array of impacted test files'
    value: ${{ steps.impacted.outputs.files_json }}
  count:
    description: 'Number of impacted test files'
    value: ${{ steps.impacted.outputs.count }}
  has-impacted:
    description: 'Whether there are any impacted tests (true/false)'
    value: ${{ steps.impacted.outputs.has_impacted }}

runs:
  using: 'composite'
  steps:
    - name: Setup Node.js
      uses: actions/setup-node@v4
      with:
        node-version: '20'

    - name: Get changed files
      id: changed
      shell: bash
      working-directory: ${{ inputs.working-directory }}
      run: |
        # Get changed files between base and head
        CHANGED=$(git diff --name-only ${{ inputs.base }} ${{ inputs.head }} -- '*.js' '*.mjs' '*.cjs' '*.jsx' '*.ts' '*.mts' '*.cts' '*.tsx' || true)

        if [ -z "$CHANGED" ]; then
          echo "No source files changed"
          echo "changed=" >> $GITHUB_OUTPUT
        else
          # Escape newlines for GitHub Actions
          CHANGED_ESCAPED="${CHANGED//$'\n'/'%0A'}"
          echo "changed<<EOF" >> $GITHUB_OUTPUT
          echo "$CHANGED" >> $GITHUB_OUTPUT
          echo "EOF" >> $GITHUB_OUTPUT
        fi

    - name: Find impacted tests
      id: impacted
      shell: bash
      working-directory: ${{ inputs.working-directory }}
      run: |
        if [ -z "${{ steps.changed.outputs.changed }}" ]; then
          echo "files=" >> $GITHUB_OUTPUT
          echo "files_json=[]" >> $GITHUB_OUTPUT
          echo "count=0" >> $GITHUB_OUTPUT
          echo "has_impacted=false" >> $GITHUB_OUTPUT
          exit 0
        fi

        # Install impacted
        npm install --no-save impacted 2>/dev/null || npx impacted --help >/dev/null 2>&1 || {
          echo "Installing impacted..."
          npm install -g impacted
        }

        # Run impacted with changed files
        IMPACTED=$(echo "${{ steps.changed.outputs.changed }}" | npx impacted -p "${{ inputs.pattern }}" 2>/dev/null || true)

        if [ -z "$IMPACTED" ]; then
          echo "files=" >> $GITHUB_OUTPUT
          echo "files_json=[]" >> $GITHUB_OUTPUT
          echo "count=0" >> $GITHUB_OUTPUT
          echo "has_impacted=false" >> $GITHUB_OUTPUT
        else
          # Space-separated for node --test
          FILES_SPACE=$(echo "$IMPACTED" | tr '\n' ' ' | sed 's/ $//')
          echo "files=$FILES_SPACE" >> $GITHUB_OUTPUT

          # JSON array
          FILES_JSON=$(echo "$IMPACTED" | jq -R -s -c 'split("\n") | map(select(length > 0))')
          echo "files_json=$FILES_JSON" >> $GITHUB_OUTPUT

          # Count
          COUNT=$(echo "$IMPACTED" | wc -l | tr -d ' ')
          echo "count=$COUNT" >> $GITHUB_OUTPUT
          echo "has_impacted=true" >> $GITHUB_OUTPUT

          echo "Found $COUNT impacted test files"
        fi