add-to-project/.github/workflows/check-dist.yml

# `dist/index.js` is a special file in Actions.
# When you reference an action with `uses:` in a workflow,
# `index.js` is the code that will run.
# For our project, we generate this file through a build process from other source files.
# We need to make sure the checked-in `index.js` actually matches what we expect it to be.
name: Check dist/

on:
  push:
    branches:
      - main
    paths-ignore:
      - '**.md'
  pull_request:
    paths-ignore:
      - '**.md'

env:
  # A pipe-separated array of files to ignore when comparing the expected and actual dist/ directories,
  # which are used as a regular expression filter in the `grep` command.
  FILES_TO_IGNORE: 'index.js.map|sourcemap-register.js'

jobs:
  check-dist:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v4

      - name: Set Node.js 20.x
        uses: actions/setup-node@v4
        with:
          node-version: 20.x
          cache: npm

      - name: Install dependencies
        run: npm ci

      - name: Rebuild the dist/ directory
        run: |
          npm run build:compile
          npm run build:package

      - name: Compare the expected and actual dist/ directories
        run: |
          # Get a list of files that are different between the checked-in dist/ directory and the generated dist/ directory,
          # then trim the list to remove any leading or trailing whitespace.
          CHANGED_FILES=$(git diff --ignore-space-at-eol --name-only dist/ | grep -vE "$FILES_TO_IGNORE" | sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//')
          if [ -n "$CHANGED_FILES" ]; then
            echo "❗️ Detected uncommitted changes after build (see diff output below)." >&2
            echo "This indicates that the dist/ directory is out of sync with the checked-in index.js." >&2
            echo "⭐️ If the changes below are expected, run 'npm run build:compile && npm run build:package' and commit the output files." >&2
            # Run `git diff` for each line/file in $CHANGED_FILES:
            echo "$CHANGED_FILES" | xargs -I {} git diff --ignore-space-at-eol --text -- {}
            exit 1
          else
            echo "✅ No uncommitted changes detected after build."
          fi
        id: diff

      # If index.js was different than expected, upload the expected version as an artifact
      - uses: actions/upload-artifact@v4
        if: ${{ failure() && steps.diff.conclusion == 'failure' }}
        with:
          name: dist
          path: dist/