install-nix-action/.github/workflows/update-nix.yml

name: "Update nix"
on:
  repository_dispatch:
  workflow_dispatch:
  schedule:
    - cron: "31 2 * * *"
jobs:
  update-nix-releases:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v6
      - name: Update nix releases
        env:
         GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          latest_nix=$(
            gh api repos/NixOS/nix/tags --paginate --jq '.[].name' |
            grep -E '^[0-9]+\.[0-9]+\.[0-9]+$' |
            sort -V |
            tail -n 1
          )
          if [ -z "$latest_nix" ]; then
            echo "Failed to determine latest Nix version." >&2
            exit 1
          fi
          current_nix=$(grep -oE 'nix_version=[0-9.]+' ./install-nix.sh | cut -d= -f2)
          echo "Current Nix version: ${current_nix}"
          echo "Latest Nix version: ${latest_nix}"
          echo "CURRENT_NIX=${current_nix}" >> $GITHUB_ENV
          echo "LATEST_NIX=${latest_nix}" >> $GITHUB_ENV
          sed -i -E "s/nix_version=[0-9.]+/nix_version=${latest_nix}/" ./install-nix.sh
      - name: Create Pull Request
        uses: peter-evans/create-pull-request@v8
        with:
          title: "nix: ${{ env.CURRENT_NIX }} -> ${{ env.LATEST_NIX }}"
          commit-message: "nix: ${{ env.CURRENT_NIX }} -> ${{ env.LATEST_NIX }}"
          body: |
            This PR updates the Nix version from ${{ env.CURRENT_NIX }} to ${{ env.LATEST_NIX }}.

            **To trigger the CI:**

            1. Checkout the PR branch:
               ```bash
               gh pr checkout <pr-number>
               ```

            2. Amend and force push:
               ```bash
               git commit --amend --no-edit
               git push --force-with-lease
               ```
          labels: dependencies