_detect-code-changes.yml

name: Detect code changes

# Reusable workflow that reports whether a pull request touches anything
# other than README.md / docs/**. Callers gate their real jobs on the
# `code` output so docs-only PRs skip CI work while still reporting success.
on:
  workflow_call:
    outputs:
      code:
        description: "true if non-docs files changed (or not a pull request)"
        value: ${{ jobs.detect.outputs.code }}

jobs:
  detect:
    runs-on: ubuntu-latest
    permissions:
      contents: read
    outputs:
      code: ${{ steps.filter.outputs.code }}
    steps:
      - name: Checkout
        uses: actions/checkout@v6.0.2
        with:
          fetch-depth: 0

      - name: Detect non-docs changes
        id: filter
        run: |
          if [ "${{ github.event_name }}" != "pull_request" ]; then
            echo "code=true" >> "$GITHUB_OUTPUT"
            exit 0
          fi
          if git diff --name-only \
              "${{ github.event.pull_request.base.sha }}...${{ github.event.pull_request.head.sha }}" \
              | grep -qvE '^(README\.md$|docs/)'; then
            echo "code=true" >> "$GITHUB_OUTPUT"
          else
            echo "code=false" >> "$GITHUB_OUTPUT"
          fi