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From: Junio C Hamano <gitster@pobox.com>
To: "brian m. carlson" <sandals@crustytoothpaste.net>
Cc: "Martin Ågren" <martin.agren@gmail.com>,
	git@vger.kernel.org, "Derrick Stolee" <stolee@gmail.com>
Subject: Re: [PATCH 1/5] http-protocol.txt: document SHA-256 "want"/"have" format
Date: Fri, 14 Aug 2020 13:47:30 -0700	[thread overview]
Message-ID: <xmqqft8puf8d.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <xmqqo8ndufli.fsf@gitster.c.googlers.com> (Junio C. Hamano's message of "Fri, 14 Aug 2020 13:39:37 -0700")

Junio C Hamano <gitster@pobox.com> writes:

> "brian m. carlson" <sandals@crustytoothpaste.net> writes:
>
>> On 2020-08-14 at 17:28:27, Junio C Hamano wrote:
>>> Martin Ågren <martin.agren@gmail.com> writes:
>>> 
>>> > Document that in SHA-1 repositories, we use SHA-1 for "want"s and
>>> > "have"s, and in SHA-256 repositories, we use SHA-256.
>>> 
>>> Ehh, doesn't this directly contradict the transition plan of "on the
>>> wire everything will use SHA-1 version for now?"
>>
>> SHA-256 repositories interoperate currently using SHA-256 object IDs.
>> It was originally intended that we wouldn't update the protocol, but
>> that leads to much of the testsuite failing since it's impossible to
>> move objects from one place to another.
>>
>> If we wanted to be more pedantically correct and optimize for the
>> future, we could say that the values use the format negotiated by the
>> "object-format" protocol extension and SHA-1 otherwise.

Yes, that's wonderful.  I was confused when I said about the
evolution path.  We still would want to eventually do the on-the-fly
migration over the wire to make SHA-1 and SHA-256 repositories
interoperate, but at least we already can allow SHA-256 repositories
safely attempt to talk to SHA-1 repositories and gracefully fail.

Thanks.


  reply	other threads:[~2020-08-14 20:47 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-13 22:48 [PATCH 0/2] Documentation updates for SHA-256 brian m. carlson
2020-08-13 22:49 ` [PATCH 1/2] docs: document SHA-256 pack and indices brian m. carlson
2020-08-14  2:26   ` Derrick Stolee
2020-08-13 22:49 ` [PATCH 2/2] docs: fix step in transition plan brian m. carlson
2020-08-14 12:21   ` Martin Ågren
2020-08-14  2:33 ` [PATCH 0/2] Documentation updates for SHA-256 Derrick Stolee
2020-08-14  4:47   ` Junio C Hamano
2020-08-14 20:20     ` brian m. carlson
2020-08-14 20:25       ` Junio C Hamano
2020-08-14 12:21 ` [PATCH 0/5] more SHA-256 documentation Martin Ågren
2020-08-14 12:21   ` [PATCH 1/5] http-protocol.txt: document SHA-256 "want"/"have" format Martin Ågren
2020-08-14 17:28     ` Junio C Hamano
2020-08-14 20:23       ` brian m. carlson
2020-08-14 20:32         ` Martin Ågren
2020-08-14 20:39         ` Junio C Hamano
2020-08-14 20:47           ` Junio C Hamano [this message]
2020-08-14 12:21   ` [PATCH 2/5] index-format.txt: document SHA-256 index format Martin Ågren
2020-08-14 12:28     ` Derrick Stolee
2020-08-14 14:05       ` Martin Ågren
2020-08-14 12:21   ` [PATCH 3/5] protocol-capabilities.txt: clarify "allow-x-sha1-in-want" re SHA-256 Martin Ågren
2020-08-14 12:31     ` Derrick Stolee
2020-08-14 14:05       ` Martin Ågren
2020-08-14 17:33     ` Junio C Hamano
2020-08-14 20:35       ` Martin Ågren
2020-08-14 20:43         ` Junio C Hamano
2020-08-14 12:21   ` [PATCH 4/5] shallow.txt: document SHA-256 shallow format Martin Ågren
2020-08-14 12:21   ` [PATCH 5/5] commit-graph-format.txt: fix "Hash Version" description Martin Ågren
2020-08-14 12:37     ` Derrick Stolee
2020-08-14 14:10       ` Martin Ågren
2020-08-14 20:28   ` [PATCH 0/5] more SHA-256 documentation brian m. carlson
2020-08-15 16:05   ` [PATCH v2 0/4] " Martin Ågren
2020-08-15 16:05     ` [PATCH v2 1/4] http-protocol.txt: document SHA-256 "want"/"have" format Martin Ågren
2020-08-15 16:06     ` [PATCH v2 2/4] index-format.txt: document SHA-256 index format Martin Ågren
2020-08-15 16:06     ` [PATCH v2 3/4] protocol-capabilities.txt: clarify "allow-x-sha1-in-want" re SHA-256 Martin Ågren
2020-08-15 16:06     ` [PATCH v2 4/4] shallow.txt: document SHA-256 shallow format Martin Ågren

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