GitHub support got back to me with a cause and work-around for an issue where we can't merge PRs created by the GitHub Action. This PR implements the work-around. More details about the bug from GH support:
The cause of the issue here is a bit obscure, and fundamentally a bug on our end. We're already working on a long-term fix in the product, but in the meantime, I've included an explanation and workaround below.
It turns out that the base ref specified in the pull request created by GitHub Actions is refs/heads/master. A typical, user-created pull request would have instead specified a base ref of just master.
The fully qualified base ref provided by GitHub Actions is equivalent to master in most contexts, but for one issue: it prevents our protected branch checks from locating required reviews, as we only search for reviews attached to a base ref without the refs/heads/ prefix. For this reason, our checks couldn't detect the various approvals you and your colleagues had provided, hence the perplexing error.
GitHub support got back to me with a cause and work-around for an issue where we can't merge PRs created by the GitHub Action. This PR implements the work-around. More details about the bug from GH support:
@jhump