Make locally defined composite actions always accessible for local runs

[aramfe]

I really like the concept of composite actions, but there is a fundamental problem with composite actions and templates which are supposed to be used in the same repository. Let's look how it is currently done, to re-use composite actions, which are located in the very same repository.

    # References a local action
    - uses: ./.github/actions/my-action

So far so good, BUT:

In our CI / CD workflow, we check out the repository only once in the very first job. We do that, because the checkout takes some time, as our mono repository is quite large. From this initial checkout, we then pass relevant parts of our repository to the corresponding, following jobs as artifacts. And it works fine and makes our CI / CD architecture much faster. In fact, there are also tons of other use-cases for doing so.

But the issue with that, is that I basically can't use template actions from the repositories .github directory in all the following jobs anymore. The workaround would be, to also upload the .github directory as an artifact and to pass them to all following jobs as well, but I don't really like this approach, because it creates so much more boilerplate definitions/steps in the YAML file.

An additional for an "uses" option like it's the case with reusable workflows would really help to solve this problem:

    # References a local action (even if no checkout action was done)
    - uses: ./.github/actions/my_composite_action.yml

It would be basically a sparse checkout, without doing all this overhead definitions to make them re-usable in every job. Just like I guess it's the case with reusable workflows.

In fact, my expectation was though, that the .github directory is always accessible from all jobs, even if there is no checkout of the source at all, as it's more of a meta definition for the pipeline and not part of the actual source code. I could see future problems regarding this as well for upcoming features, as this could always be a problem, which needs to be handled. As far as I know reusable workflows also didn't support this in the very beginning. At least some kind of option in jobs or whatever, where you can basically define to always have access to reusable workflows, even without any checkouts done beforehand, would help immensely here. Basically something like this:

jobs: 
  call_do_x:
    runs-on: ubuntu-latest
    local-github-access: true
    steps:
      uses: ./.github/actions/do_composite_action_x.yml

Either this is already possible, and I am doing something wrong, or this is really something, which needs to be supported as well. Because having not ability of reusing workflows in reusable workflows makes it sadly not that mighty in comparison to composite actions, which are capable of doing so, as described in here.

I would love to find a better approach for handling templates by getting some kind of support for this!

[makslevental]

here's my solution using sparse-checkout:

    - name: Checkout actions
      uses: actions/checkout@v3
      with:
        sparse-checkout: |
          .github/actions
        path: actions

    - uses: ./actions/.github/actions/setup_base
      id: setup_base
      with:
        # optional
        DEBUG_ENABLED: ${{ inputs.DEBUG_ENABLED }}
        DEBUG_OS: ${{ inputs.DEBUG_OS }}
        DEBUG_ARCH: ${{ inputs.DEBUG_ARCH }}
        DEBUG_DETACHED: ${{ inputs.DEBUG_DETACHED }}
        # required
        MATRIX_OS: ${{ matrix.OS }}
        MATRIX_ARCH: ${{ matrix.ARCH }}

    - name: Checkout to workspace
      shell: bash
      run: |
        if [ -d ${{ steps.setup_base.outputs.WORKSPACE_ROOT }} ]; then
          rm -rf ${{ steps.setup_base.outputs.WORKSPACE_ROOT }}/*
          rm -rf ${{ steps.setup_base.outputs.WORKSPACE_ROOT }}/*.*
        fi 
        git clone -b ${{ github.head_ref || github.ref_name }} https://github.com/${{ github.repository }}.git ${{ steps.setup_base.outputs.WORKSPACE_ROOT }}
        ls ${{ steps.setup_base.outputs.WORKSPACE_ROOT }}

details here.