action.yaml

name: Detect Workspace Changes
description: Detects which workspace packages have changed using pnpm
outputs:
  changed_workspaces:
    description: "Space-separated list of changed workspace paths"
    value: ${{ steps.detect.outputs.changed_workspaces }}
  changed_workspaces_json:
    description: "JSON array of changed workspace paths"
    value: ${{ steps.detect.outputs.changed_workspaces_json }}
  all_workspaces:
    description: "JSON array of all workspace paths"
    value: ${{ steps.detect.outputs.all_workspaces }}
  has_changes:
    description: "Whether any workspaces have changes"
    value: ${{ steps.detect.outputs.has_changes }}

runs:
  using: composite
  steps:
  - name: Detect changed workspaces
    id: detect
    shell: bash
    run: |
      set -e

      # Determine base commit for comparison
      if [[ "${{ github.event_name }}" == "pull_request" ]]; then
        base_ref="${{ github.event.pull_request.base.sha }}"
      else
        # For push events, compare with previous commit
        if git rev-parse HEAD~1 >/dev/null 2>&1; then
          base_ref="HEAD~1"
        else
          # First commit in repository
          base_ref=""
        fi
      fi

      echo "Base ref: $base_ref"
      echo ""

      # Use pnpm to detect changed workspaces
      if [[ -n "$base_ref" ]]; then
        # Get list of changed workspaces using pnpm --filter
        # The [...$base_ref] syntax filters to packages that have changes since base_ref
        changed_output=$(pnpm list --recursive --depth -1 --filter "...[${base_ref}]" --json 2>/dev/null || echo "[]")
      else
        # First commit - all workspaces are considered changed
        changed_output=$(pnpm list --recursive --depth -1 --json 2>/dev/null || echo "[]")
      fi

      echo "Changed packages output:"
      echo "$changed_output" | jq .
      echo ""

      # Extract workspace paths from pnpm output
      changed_workspaces=$(echo "$changed_output" | jq -r '.[].path // empty' | sed "s|^$PWD/||" || echo "")

      # Convert to array
      readarray -t changed_array <<< "$changed_workspaces"

      # Filter out empty entries
      filtered_changed=()
      for ws in "${changed_array[@]}"; do
        if [[ -n "$ws" ]]; then
          filtered_changed+=("$ws")
          echo "✓ Changed: $ws"
        fi
      done

      echo ""

      # Get all workspaces for reference
      all_output=$(pnpm list --recursive --depth -1 --json 2>/dev/null || echo "[]")
      all_workspaces=$(echo "$all_output" | jq -r '.[].path // empty' | sed "s|^$PWD/||" || echo "")

      # Output results
      if [[ ${#filtered_changed[@]} -eq 0 ]]; then
        echo "No workspace changes detected"
        echo "changed_workspaces=" >> "$GITHUB_OUTPUT"
        echo "changed_workspaces_json=[]" >> "$GITHUB_OUTPUT"
        echo "has_changes=false" >> "$GITHUB_OUTPUT"
      else
        echo "Changed workspaces: ${filtered_changed[*]}"
        # Output as space-separated string
        echo "changed_workspaces=${filtered_changed[*]}" >> "$GITHUB_OUTPUT"
        # Output as JSON array (compact format, no newlines)
        json_array=$(printf '%s\n' "${filtered_changed[@]}" | jq -R . | jq -s -c .)
        echo "changed_workspaces_json=$json_array" >> "$GITHUB_OUTPUT"
        echo "has_changes=true" >> "$GITHUB_OUTPUT"
      fi

      # Output all workspaces for reference (compact format, no newlines)
      all_workspaces_json=$(echo "$all_workspaces" | grep -v '^$' | jq -R . | jq -s -c . || echo "[]")
      echo "all_workspaces=$all_workspaces_json" >> "$GITHUB_OUTPUT"

  - name: Display detection results
    shell: bash
    run: |
      echo "## Workspace Change Detection Results" >> "$GITHUB_STEP_SUMMARY"
      echo "" >> "$GITHUB_STEP_SUMMARY"

      if [[ "${{ steps.detect.outputs.has_changes }}" == "true" ]]; then
        echo "### Changed Workspaces" >> "$GITHUB_STEP_SUMMARY"
        echo "" >> "$GITHUB_STEP_SUMMARY"
        echo '${{ steps.detect.outputs.changed_workspaces_json }}' | jq -r '.[] | "- `" + . + "`"' >> "$GITHUB_STEP_SUMMARY"
      else
        echo "No workspace changes detected." >> "$GITHUB_STEP_SUMMARY"
      fi

      echo "" >> "$GITHUB_STEP_SUMMARY"
      echo "### All Workspaces" >> "$GITHUB_STEP_SUMMARY"
      echo "" >> "$GITHUB_STEP_SUMMARY"
      echo '${{ steps.detect.outputs.all_workspaces }}' | jq -r '.[] | "- `" + . + "`"' >> "$GITHUB_STEP_SUMMARY"