From: M Hickford <mirth.hickford@gmail.com>
Date: Tue, 10 Jun 2025 07:00:00 GMT
Subject: Re: Suggestion: error "tag ... already exists" should distinguish between tagging different or same commit:
Message-ID: <CAGJzqskj803dUcEuV+P-yuWdT0tiaidb7h3YxQSCgYHWgBfaWA@mail.gmail.com>
In-Reply-To: <xmqqcybcrc2u.fsf@gitster.g>

On Mon, 9 Jun 2025 at 19:42, Junio C Hamano <gitster@pobox.com> wrote:
>
> M Hickford <mirth.hickford@gmail.com> writes:
>
> > Hi. Presently, the error "tag ... already exists" doesn't distinguish
> > between tagging the same commit or a different commit:
> >
> >      >git tag hello v1.9.5
> >
> >      >git tag hello v1.9.5
> >      fatal: tag 'hello' already exists
> >
> >      >git tag hello v2.0.0
> >      fatal: tag 'hello' already exists
> >
> > To inform the user, it would be nice to distinguish these cases, perhaps:
> >
> >      >git tag hello v1.9.5
> >      fatal: tag 'hello' already exists pointing at
> > d4e6038a068d0aecd5ec28c83afbfc6d4903092f
> >
> >      >git tag hello v2.0.0
> >      fatal: tag 'hello' already exists but points at
> > 18a07354e33f86c8349ffdc300d9087876658264
> >
> > The second error is typically more concerning than the first.
> >
> > What do you think?
>
> Not interested.  When the user gets that "fatal" message, the
> existing tag did not get modified, so they can just do whatever
> check they want (like "git range-diff v1.9.5...hello") themselves.
>
> Besides, in the above examples, is d4e6038a something the user
> immediately recognises as the same as v1.9.5 or the object existing
> v1.9.5 tag points at?  I somehow doubt it.  So after getting the
> error, there needs some digging to figure out how v1.9.5 and
> existing hello are related to each other _anyway_, I would think.

Good point. How about just changing the second error message?

>git tag hello v1.9.5

>git tag hello v1.9.5
fatal: tag 'hello' already exists

>git tag hello v2.0.0
fatal: tag 'hello' already exists but points at a different commit