Delete Stale MR Branches and close MRs with external/missing branches (Step 2 part 2)

Overview

1. Run a script to do the following for all open MRs which still have the "stale" label:
   1. Delete the branches which are in the www-gitlab-com repo. This will cause their MRs to automatically be closed.
   2. Directly close any which have branches on forks (non www-gitlab-com repo). These are external contributions, and their branches cannot (and should not) be deleted.
   3. Directly close any for which the associated branch does not exist anymore (this is possible).

This is the last part of "Step 2" in #5525 (closed)

Dev Notes

Here's a GraphQL query to retrieve MRs with labels. Unfortunately, the GitLab GraphQL API does not provide a way to filter queries by values (e.g. label title: "stale - to be closed") - at least not the labels resource. It doesn't even allow you to filter on iid via mergeRequest(iid: "123") or mergeRequests(iids: ["123", "456"]) - this gives a backend error. We should open issues against the API for this.

{
  project(fullPath: "gitlab-com/www-gitlab-com") {
    mergeRequests {
    	nodes {
        id
        iid
        state
        updatedAt
        sourceBranch
        labels {
          nodes {
            title
          }
        }
      }
      pageInfo {
        endCursor
        hasNextPage
      }
    }
  }
}

Closed MRs with Fork Branches

Here is an except of the script run log output showing which MRs with fork branches (i.e. external contributors) were closed. This is just a subset of the entire log, which can't be included because it might contain data from confidential issues.

closed-mrs-with-fork-branches.txt

Related Issues

references #5525 (closed)