.github/workflows/unicode-check.yml

# Watches for a new Unicode release and opens an issue when the tables pinned
# in tools/idna-data fall behind. Deliberately opens an issue rather than a
# pull request: a Unicode update warrants human review of the table diff and
# the regenerated UTS #46 conformance tests.

name: Check for new Unicode version

on:
  schedule:
    - cron: '0 6 1 * *'   # monthly, 06:00 UTC on the 1st
  workflow_dispatch:

permissions:
  contents: read

jobs:
  check:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      issues: write
    steps:
      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0

      - name: Compare latest Unicode release against pinned version
        id: compare
        run: |
          pinned=$(sed -n 's/^PREFERRED_VERSION = "\(.*\)"$/\1/p' tools/idna-data)
          latest=$(curl -fsSL https://www.unicode.org/Public/UCD/latest/ReadMe.txt \
            | sed -n 's/.*Version \([0-9][0-9.]*\) of the Unicode Standard.*/\1/p' | head -1)
          echo "pinned=$pinned latest=$latest"
          if [ -z "$latest" ]; then
            echo "::error::Could not determine the latest Unicode version"
            exit 1
          fi
          echo "pinned=$pinned" >> "$GITHUB_OUTPUT"
          echo "latest=$latest" >> "$GITHUB_OUTPUT"
          if [ "$pinned" = "$latest" ]; then
            echo "Tables are current."
          elif [ "$(curl -sSI -o /dev/null -w '%{http_code}' "https://www.unicode.org/Public/${latest}/idna/IdnaMappingTable.txt")" = "200" ]; then
            # The generator also needs the UTS #46 files, which normally publish
            # alongside the UCD but are checked separately to be safe. Redirects
            # are not followed: unreleased version paths 302 to /Public/draft/.
            echo "update=true" >> "$GITHUB_OUTPUT"
          else
            echo "UTS #46 data for ${latest} is not published yet; will check again next run."
          fi

      - name: Set up Python
        if: steps.compare.outputs.update == 'true'
        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
        with:
          python-version: '3.14'

      - name: Preview table changes for the new version
        if: steps.compare.outputs.update == 'true'
        id: preview
        env:
          LATEST: ${{ steps.compare.outputs.latest }}
        run: |
          if python tools/idna-data make-libdata --version "$LATEST" --dir idna --test-dir tests; then
            summary=$(git diff --stat -- idna/idnadata.py idna/uts46data.py tests/test_idna_uts46.py)
          else
            summary="(tools/idna-data failed against ${LATEST}; the generator may need updating for this release)"
          fi
          {
            echo 'summary<<EOF'
            echo "$summary"
            echo 'EOF'
          } >> "$GITHUB_OUTPUT"

      - name: Open tracking issue
        if: steps.compare.outputs.update == 'true'
        env:
          GH_TOKEN: ${{ github.token }}
          PINNED: ${{ steps.compare.outputs.pinned }}
          LATEST: ${{ steps.compare.outputs.latest }}
          SUMMARY: ${{ steps.preview.outputs.summary }}
          RUN_URL: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
        run: |
          existing=$(gh issue list --state all --search "Unicode ${LATEST} in:title" --json number --jq length)
          if [ "$existing" != "0" ]; then
            echo "An issue for Unicode ${LATEST} already exists; nothing to do."
            exit 0
          fi
          cat > body.md <<EOF
          Unicode ${LATEST} has been released; the tables in this repository are generated from ${PINNED}.

          To update:

          1. Set \`PREFERRED_VERSION = "${LATEST}"\` in \`tools/idna-data\`.
          2. Run \`tools/idna-data make-libdata --dir idna --test-dir tests\` to regenerate \`idna/idnadata.py\`, \`idna/uts46data.py\` and \`tests/test_idna_uts46.py\`.
          3. Review the diff and run the test suite; new IdnaTestV2 vectors sometimes need entries in the generator's skip list.

          Preview of the regenerated files against ${LATEST}:

          \`\`\`
          ${SUMMARY}
          \`\`\`

          Opened automatically by [the Unicode version check workflow](${RUN_URL}).
          EOF
          gh issue create --title "Unicode ${LATEST} data available" --body-file body.md