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

From: Junio C Hamano <[email-masked]>
Date: Mon, 09 Jun 2025 11:42:33 -0700

M Hickford <[email-masked]> 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.