Re: [PATCH v4 1/4] t1400: avoid touching refs on filesystem

> The testcase t1400 exercises the git-update-ref(1) utility. To do so,
> many tests directly read and write references via the filesystem,
> assuming that we always use loose and/or packed references. While this
> is true now, it'll change with the introduction of the reftable backend.
> 
> Convert those tests to use git-update-ref(1) and git-show-ref(1) where
> possible. Furthermore, two tests are converted to not delete HEAD
> anymore, as this results in a broken repository. They've instead been
> updated to create a non-mandatory symybolic reference and delete that
> one instead.