From: Junio C Hamano <gitster@pobox.com>
To: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
Cc: Philip Oakley <philipoakley@iee.email>,
"Gamblin, Todd" <gamblin2@llnl.gov>,
"git@vger.kernel.org" <git@vger.kernel.org>
Subject: Re: Commit SHA1 == SHA1 checksum?
Date: Mon, 07 Feb 2022 12:57:55 -0800 [thread overview]
Message-ID: <xmqqczjyiecs.fsf@gitster.g> (raw)
In-Reply-To: <20220207133244.kpyczjsxriepjtdt@meerkat.local> (Konstantin Ryabitsev's message of "Mon, 7 Feb 2022 08:32:44 -0500")
Konstantin Ryabitsev <konstantin@linuxfoundation.org> writes:
> On Sun, Feb 06, 2022 at 12:02:34PM -0800, Junio C Hamano wrote:
>> Philip Oakley <philipoakley@iee.email> writes:
>>
>> > I think part of Todd's question was how the tag and uncompressed archive
>> > 'checksums' (e.g. hashes) relate to each other and where those
>> > guarantees come from.
>>
>> There is no such linkage, and there are no guarantees. The trust
>> you may or may not have on the PGP key that signs the tag and the
>> checksums of the tarball is the only source of such assurance.
>>
>> More importantly, I do not think there can be any such linkage
>> between the Git tree and release tarball:
>
> Hmm... I've actually considered writing a tool that would verify whether a
> tarball corresponds to a signed tag/commit. It should be entirely possible,
> no?
I was saying "I have this git commit (or tree) object name. Compute
the hash for a .tar archive that would contain the contents of that
tree." has no unique answer.
You are solving a different problem: "I have this tar archive; what
git tree object would I get if I extract this archive to an empty
directory and said 'git add . && git write-tree'?".
I agree that one is computable.
Of course, even that reverse problem will break once we consider the
release tarball generation procedure where we _add_ some generated
files that are not in the Git tree, for builder's convenience.
next prev parent reply other threads:[~2022-02-07 20:58 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-05 1:19 Commit SHA1 == SHA1 checksum? Gamblin, Todd
2022-02-06 0:22 ` Philip Oakley
2022-02-06 9:00 ` Gamblin, Todd
2022-02-06 10:23 ` Johannes Sixt
2022-02-06 10:15 ` Junio C Hamano
2022-02-06 19:25 ` Philip Oakley
2022-02-06 20:02 ` Junio C Hamano
2022-02-06 21:33 ` Philip Oakley
2022-02-07 8:15 ` Gamblin, Todd
2022-02-07 13:15 ` Konstantin Ryabitsev
2022-02-07 21:08 ` Gamblin, Todd
2022-02-07 13:32 ` Konstantin Ryabitsev
2022-02-07 20:57 ` Junio C Hamano [this message]
2022-02-07 21:34 ` Konstantin Ryabitsev
2022-02-07 22:29 ` Gamblin, Todd
2022-02-07 22:46 ` Konstantin Ryabitsev
2022-02-08 6:23 ` Gamblin, Todd
2022-02-07 22:49 ` Junio C Hamano
2022-02-07 23:02 ` Konstantin Ryabitsev
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