Subject: Re: Should `@` be really a valid git tag name?

From: Junio C Hamano <[email-masked]>
Date: Fri, 17 Sep 2021 13:53:52 -0700

Carlo Arenas <[email-masked]> writes:

> On Fri, Sep 17, 2021 at 7:12 AM <[email-masked]> wrote:
>>
>> A SO commenter pointed out, that git-check-ref-format forbids @ and
>> maybe I should report this as a potential bug. Is it?
>
> a reference that is named "@" only is invalid, but refs/tags/@ is not.

;-)  

"git check-ref-format master ; echo $?" would show that any single
level name is "forbidden", so probably the SO commenter (whatever
that is) was confused---it is not about @ at all.

In any case, a tag whose name is @ may be another source of
confusion in the modern world, after we added @ as a synonym to
HEAD.  I do not know, for example, offhand which between the HEAD or
that tag "git show @" would choose.  It makes sense to avoid it.