On Sun, Feb 25, 2024 at 09:16:49AM -0800, Junio C Hamano wrote:
> Patrick Steinhardt <ps@pks.im> writes:
> 
> > That's ultimately the reason why I don't want HEAD to look like a proper
> > ref. But doing the "refs/heads/.invalid" workaround shouldn't be too bad,
> > I guess.
> 
> Isn't the reason why reftable backend initializes refs/heads to be a
> regular file exactly because we want to reject an attempt to create
> such a file on the filesystem, though?

Yeah, "refs/heads" being a file is also part of this mechanism. But that
wouldn't help a client that e.g. uses git-symbolic-ref(1) while assuming
the old "files" backend, because they would now get a plausible value of
whatever value we have in there if we were to initialize it e.g. with
"refs/heads/main".

That's why we have both mechanisms -- it's a bit like defense in depth.
One could go even further and make "HEAD" contain complete garbage,
only, so that anybody who was trying to read it would fail immediately.

Patrick