Add a check-only mode or action

In some workflows, there are jobs whose only purpose is to ensure that proper cache state exists for other jobs to pick up. If such a job hits an already stored state, downloading that state for this job only wastes time and network bandwidth because the job does not need to do anything. Here’s an example.

It would be nice to add a mode that only checks existence of the key and sets the cache-hit output.

[aparna-ravindra]

There is now an open issue in the roadmap to provide a cache management experience to view the available caches (here) that will address the scenarios described in this issue.

[MartijnHols]

All my previous PRs were ignored, and I think it’s cleaner to separate the actions than to add dozens of inputs. I waited a year for my PRs to get any kind of response (still none). Eventually I decided I wanted to clean up my workflows and during the refactor I figured making it PR-ready would be a serious waste of time.