fastnetmon-rewritten/.github/workflows/update-nlohmann-json.yml

name: Update bundled nlohmann/json

on:
  schedule:
    # Run daily at 06:10 UTC
    - cron: '10 6 * * *'
  workflow_dispatch:

permissions:
  contents: write
  pull-requests: write

jobs:
  update-json:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Read bundled nlohmann/json version
        id: bundled
        run: |
          file="src/nlohmann/json.hpp"
          if [ ! -f "$file" ]; then
            echo "::error::$file not found"
            exit 1
          fi
          major=$(grep -E '^#define NLOHMANN_JSON_VERSION_MAJOR' "$file" | awk '{print $3}')
          minor=$(grep -E '^#define NLOHMANN_JSON_VERSION_MINOR' "$file" | awk '{print $3}')
          patch=$(grep -E '^#define NLOHMANN_JSON_VERSION_PATCH' "$file" | awk '{print $3}')
          if [ -z "$major" ] || [ -z "$minor" ] || [ -z "$patch" ]; then
            echo "::error::Failed to parse NLOHMANN_JSON_VERSION_* from $file"
            exit 1
          fi
          bundled="${major}.${minor}.${patch}"
          echo "bundled=$bundled" >> "$GITHUB_OUTPUT"
          echo "Bundled nlohmann/json version: $bundled"

      - name: Get latest nlohmann/json release
        id: latest
        env:
          GH_TOKEN: ${{ github.token }}
        run: |
          tag=$(curl -fsSL \
            -H "Authorization: Bearer ${GH_TOKEN}" \
            -H "Accept: application/vnd.github+json" \
            https://api.github.com/repos/nlohmann/json/releases/latest | jq -r .tag_name)
          if [ -z "$tag" ] || [ "$tag" = "null" ]; then
            echo "::error::Failed to fetch latest nlohmann/json release tag"
            exit 1
          fi
          # Release tags look like "v3.11.3"; strip the leading "v" for comparison.
          version="${tag#v}"
          echo "tag=$tag" >> "$GITHUB_OUTPUT"
          echo "version=$version" >> "$GITHUB_OUTPUT"
          echo "Latest nlohmann/json release: $tag (version $version)"

      - name: Up to date
        if: steps.latest.outputs.version == steps.bundled.outputs.bundled
        run: echo "Bundled nlohmann/json (${{ steps.bundled.outputs.bundled }}) matches the latest release; nothing to do."

      - name: Download new json.hpp from upstream release
        if: steps.latest.outputs.version != steps.bundled.outputs.bundled
        env:
          TAG: ${{ steps.latest.outputs.tag }}
        run: |
          url="https://github.com/nlohmann/json/releases/download/${TAG}/json.hpp"
          echo "Downloading $url"
          # Download to a temporary file, then verify the version matches before
          # overwriting the bundled header.
          tmp=$(mktemp)
          curl -fsSL --retry 3 -o "$tmp" "$url"

          # Sanity check: ensure the downloaded file contains the expected version macros.
          new_major=$(grep -E '^#define NLOHMANN_JSON_VERSION_MAJOR' "$tmp" | awk '{print $3}')
          new_minor=$(grep -E '^#define NLOHMANN_JSON_VERSION_MINOR' "$tmp" | awk '{print $3}')
          new_patch=$(grep -E '^#define NLOHMANN_JSON_VERSION_PATCH' "$tmp" | awk '{print $3}')
          new_version="${new_major}.${new_minor}.${new_patch}"
          expected="${TAG#v}"
          if [ "$new_version" != "$expected" ]; then
            echo "::error::Downloaded json.hpp version ($new_version) does not match release tag ($expected)"
            exit 1
          fi

          mv "$tmp" src/nlohmann/json.hpp
          echo "Replaced src/nlohmann/json.hpp with upstream $TAG"

      - name: Create pull request
        if: steps.latest.outputs.version != steps.bundled.outputs.bundled
        uses: peter-evans/create-pull-request@v6
        with:
          token: ${{ github.token }}
          branch: chore/update-nlohmann-json-${{ steps.latest.outputs.version }}
          delete-branch: true
          commit-message: |
            Update bundled nlohmann/json to ${{ steps.latest.outputs.version }}

            Replaces src/nlohmann/json.hpp with the upstream single-header release
            from https://github.com/nlohmann/json/releases/tag/${{ steps.latest.outputs.tag }}.
          title: "Update bundled nlohmann/json to ${{ steps.latest.outputs.version }}"
          body: |
            Automated update of the bundled [nlohmann/json](https://github.com/nlohmann/json) single-header library.

            - Previous version: `${{ steps.bundled.outputs.bundled }}`
            - New version: `${{ steps.latest.outputs.version }}` (tag `${{ steps.latest.outputs.tag }}`)
            - Source: https://github.com/nlohmann/json/releases/download/${{ steps.latest.outputs.tag }}/json.hpp
            - Release notes: https://github.com/nlohmann/json/releases/tag/${{ steps.latest.outputs.tag }}

            The downloaded `json.hpp` was verified to advertise version `${{ steps.latest.outputs.version }}` via its `NLOHMANN_JSON_VERSION_*` macros before being committed.

            _Opened automatically by the `update-nlohmann-json` workflow._
          labels: dependencies
          author: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
          committer: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>