Re: Suggestion: error "tag ... already exists" should distinguish between tagging different or same commit:

From: Junio C Hamano <gitster@pobox.com>
Date: Jun 9, 2025, 18:42 UTC
Message-ID: <xmqqcybcrc2u.fsf@gitster.g>
In-Reply-To: <CAGJzqsnvTnp3k8Ab2exaBAw5pszQRz00UcucnK=ECtY5vhG+1A@mail.gmail.com>

M Hickford <mirth.hickford@gmail.com> writes:

Show 24 quoted lines

> 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.