json/.github/workflows/check_amalgamation.yml

name: "Check amalgamation"

on:
  pull_request:
  # also check develop itself: a PR can be merged before its own run of this
  # workflow completes (e.g. while it is still queued), leaving single_include
  # stale on develop without any failing check
  push:
    branches:
      - develop

concurrency:
  group: ${{ github.workflow }}-${{ github.ref || github.run_id }}
  cancel-in-progress: ${{ github.event_name == 'pull_request' }}

permissions:
  contents: read

jobs:
  save:
    if: github.event_name == 'pull_request'
    runs-on: ubuntu-latest
    steps:
      - name: Harden Runner
        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

      - name: Save PR number
        run: |
          mkdir -p ./pr
          echo ${{ github.event.number }} > ./pr/number
          echo ${{ github.event.pull_request.user.login }} > ./pr/author
      - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
        with:
          name: pr
          path: pr/

  check:
    runs-on: ubuntu-latest
    env:
      MAIN_DIR: ${{ github.workspace }}/main
      INCLUDE_DIR: ${{ github.workspace }}/main/single_include/nlohmann
      TOOL_DIR: ${{ github.workspace }}/tools/tools/amalgamate
      NATVIS_TOOL_DIR: ${{ github.workspace }}/tools/tools/generate_natvis

    steps:
      - name: Harden Runner
        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
        with:
          egress-policy: audit

      - name: Checkout pull request or pushed commit
        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
        with:
          path: main
          ref: ${{ github.event.pull_request.head.sha || github.sha }}
          persist-credentials: false

      - name: Checkout tools
        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
        with:
          path: tools
          ref: develop
          persist-credentials: false

      - name: Install astyle
        run: |
          python3 -mvenv venv
          venv/bin/pip3 install -r $MAIN_DIR/tools/astyle/requirements.txt

      - name: Install generate_natvis dependencies
        run: pip3 install -r $NATVIS_TOOL_DIR/requirements.txt

      - name: Regenerate the tools/macro_builder tables in macro_scope.hpp
        run: |
          cd $MAIN_DIR

          # Built from this PR's own tools/macro_builder/main.cpp, not a
          # develop checkout: unlike amalgamate.py and generate_natvis.py,
          # this tool has no other source of truth to check against (its
          # own README documents that it must reproduce macro_scope.hpp
          # byte for byte), so there is nothing to gain from checking out a
          # separate copy, and doing so would make this step fail on a PR
          # that adds support for a new dispatch table until that PR itself
          # merges to develop.
          TMPDIR=$(mktemp -d ./macro_builder_check.XXXXXX)
          c++ -std=c++11 tools/macro_builder/main.cpp -o "$TMPDIR/macro_builder"
          "$TMPDIR/macro_builder" > "$TMPDIR/paste.hpp"
          "$TMPDIR/macro_builder" type_body > "$TMPDIR/type_body.hpp"

          # Splice the (still unindented) generated blocks back into
          # macro_scope.hpp; the astyle pass below indents their
          # continuation lines the same way it does for the rest of
          # include/, so a correctly regenerated file comes out unchanged.
          awk -v newfile="$TMPDIR/paste.hpp" '
            BEGIN { while ((getline line < newfile) > 0) { new = new line "\n" } }
            /^#define NLOHMANN_JSON_EXPAND\( x \) x$/ { printf "%s", new; skip=1 }
            skip && /^#define NLOHMANN_JSON_DOUBLE_PASTE63\(/ { skip=0; next }
            skip { next }
            { print }
          ' include/nlohmann/detail/macro_scope.hpp > "$TMPDIR/macro_scope_1.hpp"
          awk -v newfile="$TMPDIR/type_body.hpp" '
            BEGIN { while ((getline line < newfile) > 0) { new = new line "\n" } }
            /^#define NLOHMANN_JSON_TYPE_BODY\(Prefix, \.\.\.\)/ { printf "%s", new; skip=1 }
            skip && /^[[:space:]]*NLOHMANN_JSON_TYPE_BODY_SENTINEL\)\)$/ { skip=0; next }
            skip { next }
            { print }
          ' "$TMPDIR/macro_scope_1.hpp" > "$TMPDIR/macro_scope_2.hpp"
          mv "$TMPDIR/macro_scope_2.hpp" include/nlohmann/detail/macro_scope.hpp
          rm -rf "$TMPDIR"

      - name: Regenerate amalgamation, formatting, and BUILD.bazel
        run: |
          cd $MAIN_DIR

          python3 $TOOL_DIR/amalgamate.py -c $TOOL_DIR/config_json.json -s .
          python3 $TOOL_DIR/amalgamate.py -c $TOOL_DIR/config_json_fwd.json -s .

          # the header list of the Bazel "json" target must match the files in include/
          cmake -P cmake/scripts/gen_bazel_build_file.cmake

          ${{ github.workspace }}/venv/bin/astyle --project=tools/astyle/.astylerc --suffix=none --quiet \
            $INCLUDE_DIR/json.hpp $INCLUDE_DIR/json_fwd.hpp

          # fail loudly if a directory is renamed or removed: find would only warn
          # about the missing path and silently drop its files from the check
          SOURCE_DIRS="docs/mkdocs/docs/examples include tests"
          for DIR in $SOURCE_DIRS; do
            if [ ! -d "$DIR" ]; then
              echo "::error::source directory '$DIR' does not exist"
              exit 1
            fi
          done

          ${{ github.workspace }}/venv/bin/astyle --project=tools/astyle/.astylerc --suffix=none --quiet \
            $(find $SOURCE_DIRS -type f \( -name '*.hpp' -o -name '*.cpp' -o -name '*.cu' \) -not -path 'tests/thirdparty/*' -not -path 'tests/abi/include/nlohmann/*' | sort)

          # json_literals.hpp is copied verbatim from the (now formatted) include/
          # directory, like `make amalgamate` does
          cp include/nlohmann/json_literals.hpp $INCLUDE_DIR/json_literals.hpp

      - name: Regenerate nlohmann_json.natvis
        run: |
          cd $MAIN_DIR
          # The template is what this check verifies the committed natvis
          # file against, so take it from this PR rather than from the
          # develop checkout: generate_natvis.py loads the template from its
          # own directory, and with develop's copy a PR that changes the
          # template could never pass. Like the macro_builder step above,
          # this only renders PR content in a job without credentials.
          cp tools/generate_natvis/nlohmann_json.natvis.j2 $NATVIS_TOOL_DIR/
          python3 $NATVIS_TOOL_DIR/generate_natvis.py $MAIN_DIR

      - name: Build patch and check for differences
        id: diff
        run: |
          cd $MAIN_DIR
          mkdir -p ${{ github.workspace }}/patch
          git diff --patch --no-color > ${{ github.workspace }}/patch/amalgamation.patch
          if [ -s ${{ github.workspace }}/patch/amalgamation.patch ]; then
            echo "The source code has not been amalgamated/formatted correctly, or BUILD.bazel, nlohmann_json.natvis, or the macro_builder tables in macro_scope.hpp are out of date ('make amalgamate BUILD.bazel natvis' fixes all but the tables, see tools/macro_builder/README.md). Diff:"
            cat ${{ github.workspace }}/patch/amalgamation.patch
            echo "has_diff=true" >> "$GITHUB_OUTPUT"
          else
            echo "has_diff=false" >> "$GITHUB_OUTPUT"
          fi

      # Uploaded so contributors can fix their PR with `git apply amalgamation.patch`
      # instead of installing the pinned astyle version locally.
      - name: Upload patch
        if: steps.diff.outputs.has_diff == 'true'
        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
        with:
          name: amalgamation-patch
          path: patch/amalgamation.patch

      - name: Fail if not amalgamated/formatted
        if: steps.diff.outputs.has_diff == 'true'
        run: exit 1