Subject: Should "git symbolic-ref -d HEAD" be forbidden?

From: Junio C Hamano <[email-masked]>
Date: Thu, 01 Sep 2016 14:08:08 -0700

I think we should.

t1401 expects to be able to, but if you really do it:

	$ cd /tmp
	$ git init throwaway
        $ cd throwaway
        $ git symbolic-ref -d HEAD

the setup machinery considers that you are no longer in a working
tree that is controlled by a repository at .git/ because .git/ is
no longer a valid repository, so you cannot even do

	$ git symbolic-ref HEAD refs/heads/master

to recover.