fromJson trick for GitHub Actions

ppd.yml

name: Parallel Poetry Discovery

on:
  push: {branches-ignore: ["**"]}

env:
  COMMENT_PFX: "# RPOOLEY "

jobs:

  matrix:
    name: Generate Matrix
    runs-on: "ubuntu-latest"
    steps:
      - {uses: actions/checkout@v2}
      - {run: 'grep -oP "^$COMMENT_PFX\K[\w-]+" pyproject.toml |tee matches.txt'}
      - {run: "jq -cMRn '[inputs|select(length>0)]' matches.txt |tee array.json"}
      - {run: "echo ::set-output name=out::$(cat array.json)", id: array}
    outputs: {array: "${{steps.array.outputs.out}}"}

  test:
    name: Test
    needs: "matrix"
    strategy:
      fail-fast: false
      matrix: {name: "${{fromJson(needs.matrix.outputs.array)}}"}
    runs-on: "ubuntu-latest"
    steps:
      - {name: Check out repository code, uses: actions/checkout@v2}
      - {name: Install Python, uses: actions/setup-python@v3, with: {python-version: "3.10"}}
      - {name: Install Poetry, uses: abatilo/actions-poetry@v2.1.4}

      - name: Uncomment
        env:
          PATTERN: "^${{env.COMMENT_PFX}}${{matrix.name}} "
          SCRIPT: "$0~PATTERN{$0 = substr($0, length(COMMENT_PFX)+1)} {print}"
        run: |
          awk -v COMMENT_PFX="$COMMENT_PFX" -v PATTERN="$PATTERN" "$SCRIPT" pyproject.toml > pyproject.toml.new
          mv pyproject.toml.new pyproject.toml && git diff --color=always "$_"

      - {name: Poetry Lock, run: rm -f poetry.lock && poetry lock}
      - {name: Store, uses: actions/upload-artifact@v2, with: {name: poetry_lock, path: "p*o*e*t*.?o??"}}