tzdata-update.yml

name: tzdata update
on:
  schedule:
    - cron: "0 23 * * *"
  workflow_dispatch:

permissions:
  contents: write

jobs:
  update:
    runs-on: ubuntu-latest
    steps:
      - name: Check out repository code
        uses: actions/checkout@v4
      - name: Set up Go
        uses: actions/setup-go@v5
        with:
          go-version-file: go.mod
      - name: Fetch latest tzcode version
        run: |
          set -euo pipefail
          workdir=$(mktemp -d)
          wget -O "$workdir/tzcode-latest.tar.gz" https://www.iana.org/time-zones/repository/tzcode-latest.tar.gz
          tar -xzf "$workdir/tzcode-latest.tar.gz" -C "$workdir"

          version_file=$(find "$workdir" -maxdepth 2 -type f -name version | head -n 1)
          if [ -z "$version_file" ]; then
            echo "version file not found in tzcode-latest.tar.gz" >&2
            exit 1
          fi

          latest_version=$(tr -d ' \n' < "$version_file")
          current_version=$(grep -E 'tzVersion' scripts/tzgen/main.go | sed -E 's/.*"([^"]+)".*/\1/' | head -n 1)

          echo "current=$current_version latest=$latest_version"
          if [ "$latest_version" = "$current_version" ]; then
            echo "tzdata is already up to date"
            exit 0
          fi

          sed -i.bak -E 's/tzVersion = ".*"/tzVersion = "'"$latest_version"'"/' scripts/tzgen/main.go
          rm -f scripts/tzgen/main.go.bak
          gofmt -w scripts/tzgen/main.go
          go run scripts/tzgen/main.go

          git config user.name "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"
          git add scripts/tzgen/main.go tz
          git commit -m "Update tzdata to ${latest_version}"
          git push