Feature: add support for path as environment variable

[jwillemsen]

We are using environment variables throughout our scripts to point to the location of the various git repositories we are using. Within our github action we are using for example

env:
  DOC_ROOT: ${{ github.workspace }}/ACE_TAO

When now using checkout we need to pass ACE_TAO as path but it would be more easier for maintenance that we can use $DOC_ROOT, so

    - name: checkout ACE_TAO
      uses: actions/checkout@v2
      with:
        repository: DOCGroup/ACE_TAO
        path: ACE_TAO
        ref: Latest_Micro

to something like below, refer to DOC_ROOT env

    - name: checkout ACE_TAO
      uses: actions/checkout@v2
      with:
        repository: DOCGroup/ACE_TAO
        path: $DOC_ROOT
        ref: Latest_Micro

[jwillemsen]

Ok, this seems to work, so the documentation should be enhanced

name: linux

on:
  push:
  pull_request:

jobs:
  build:
    strategy:
      matrix:
        include:
          - os: ubuntu-18.04
    runs-on: ${{ matrix.os }}
    name: ${{ matrix.os }}
    env:
      DOC_ROOT: ${{ github.workspace }}/FOO/ACE
    steps:
    - name: checkout ACE_TAO
      uses: actions/checkout@v2
      with:
        repository: DOCGroup/ACE_TAO
        path: ${{ env.DOC_ROOT }}
    - name: Check file existence
      id: check_files
      uses: andstor/file-existence-action@v1
      with:
        files: "FOO/ACE/README.md"

[mtazzari]

Thanks for posting the working solution! I was surprised that this was not working:

env:
  BUILD_REPO: owner/repo

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: clone build repository
        uses: actions/checkout@v3
        with:
          repository: $BUILD_REPO

and using "$BUILD_REPO" or ${BUILD_REPO} or any combination didn't work either. I was getting the following error in GH Actions:

Invalid repository '${BUILD_REPO}'. Expected format {owner}/{repo}.

However, using contexts works:

env:
  BUILD_REPO: owner/repo

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: clone build repository
        uses: actions/checkout@v3
        with:
          repository: ${{ env.BUILD_REPO }}

[raidski20]

@mtazzari

I run into the same situation now, and I can't understand why I must use contexts ${{ env.BUILD_REPO }} instead of typical environment variables $BUILD_REPO?