From mboxrd@z Thu Jan  1 00:00:00 1970
From: Junio C Hamano <gitster@pobox.com>
Subject: Re: [PUB]corrupt repos does not return error with `git fsck`
Date: Wed, 20 May 2015 14:06:59 -0700
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Cc: Jeff King <peff@peff.net>,
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To: Stefan Beller <sbeller@google.com>
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In-Reply-To: <CAGZ79kY7wg1JjshwZOtWhm_0qP=CBQqvhqayZpvhu35WuMhxWQ@mail.gmail.com>
	(Stefan Beller's message of "Wed, 20 May 2015 13:57:45 -0700")
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Stefan Beller <sbeller@google.com> writes:

> On Wed, May 20, 2015 at 1:39 PM, Junio C Hamano <gitster@pobox.com> wrote:
>>
>> So...
>
> maybe we need a command:
>
> Given this SHA1, tell me anything you know about it,
> Is it a {blob,tree,commit,tag}?
> Is it referenced from anywhere else in this repository and if so, which type?
> And if it is not referenced, nor an object, tell me so explicitely.

Let me add another to that list ;-)

  I have this prefix; please enumerate all known objects that share it.

I do not know the value of the first two in your list.  If it is a
known object, then you throw it at "git show", "git cat-file -t" and
dig from there.  If it is not known, there is nothing more to do.

I do not know if "need" is the right word, but I hope that you
realize the last two among the four you listed need the equivalent
of "git fsck".  It is an expensive operation.