This is a feature request. Because it's an advanced feature, I understand that it might not be directly implemented but some smaller features would unlock it.

Use case

At Open Collective, we have 2 main repositories, one for our API and one for our Frontend. In our CI, we have e2e tests which are requiring a checkout of both API and Frontend to run.

• In the most simple scenario, we run a checkout of master in both projects
• In the most common scenario, we run the e2e tests on feature branches of the API, and they run fine with the master Frontend because they don't require any modifications of the Frontend
• In an advanced scenario, if a feature needs a modification on both API and Frontend, we're using by convention the same exact branch name on API and Frontend (ie: feat/new-events-page) and we want the e2e test to use checkouts of these branches.

Status Quo

We're using some magic script that is implementing the functionality using downloaded tarballs (didn't write that!) .
https://github.com/opencollective/opencollective-api/blob/master/scripts/ci_checkout_frontend.sh

GitHub Actions to the rescue

We would like to use a nicely written GitHub Action for that. My initial implementation would be:

      - name: Checkout (frontend - matching branch)
        uses: actions/checkout@v2-beta
        with:
          repository: opencollective/opencollective-frontend
          path: opencollective-frontend
          ref: ${{ github.ref }}

      - name: Checkout (frontend - master)
        if: failure()
        uses: actions/checkout@v2-beta
        with:
          repository: opencollective/opencollective-frontend
          path: opencollective-frontend
          ref: master

opencollective/opencollective-api#3031
https://github.com/opencollective/opencollective-api/pull/3031/checks?check_run_id=343540511

It's almost working but unfortunately the first command is sending a CI failure and we can't proceed normally after.

Feature Request

1. Ability to skip the failure signal if the checkout doesn't work

      - name: Checkout (frontend - matching branch)
        uses: actions/checkout@v2-beta
        with:
          repository: 'opencollective/opencollective-frontend'
          ref: ${{ github.ref }}
          silentFailure: true

2. Ability to know if the checkout with a given id failed

      - name: Checkout (frontend - matching branch)
        uses: actions/checkout@v2-beta
        id: checkout-matching-branch
        with:
          repository: 'opencollective/opencollective-frontend'
          ref: ${{ github.ref }}
          silentFailure: true

      - name: Checkout (frontend - master)
        if: steps.checkout-matching-branch.outputs.failure === 'true'
        uses: actions/checkout@v2-beta
        with:
          repository: 'opencollective/opencollective-frontend'
          ref: master