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From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: "brian m. carlson" <sandals@crustytoothpaste.net>
Cc: Konstantin Ryabitsev <konstantin@linuxfoundation.org>,
	Eli Schwartz <eschwartz93@gmail.com>,
	Git List <git@vger.kernel.org>
Subject: Re: Stability of git-archive, breaking (?) the Github universe, and a possible solution
Date: Wed, 01 Feb 2023 10:40:57 +0100	[thread overview]
Message-ID: <230201.86pmatr9mj.gmgdl@evledraar.gmail.com> (raw)
In-Reply-To: <Y9mXB1LaYSUJBlwF@tapette.crustytoothpaste.net>


On Tue, Jan 31 2023, brian m. carlson wrote:

> As far as whether other people want to implement consistent compression,
> they are welcome to also write a spec and implement it.  I personally
> feel that's too hard to get right and am not planning on working on it.

"A spec" here seems like overkill to me, so far on that front we've been
shelling out to gzip(1), and the breakage/event that triggered this
thread is rectified by starting to do that again by default.

It means that someone writing a clean-room implementation of git would
likely run into the same issue, if they used e.g. the Go language and a
native Go implementation of deflate.

But so what? We don't need to make promises for all potential git
implementations, just this one. So we could add a blurb like this to the
docs:

	As people have come to rely on the exact "deflate"
	implementation "git archive" promises to invoke the system's
	"gzip" binary by default, under the assumption that its output
	is stable. If that's no longer the case you'll need to complain
	to whoever maintains your local "gzip".

If we wanted to be even more helpful we could bunde and ship an old
version of GNU gzip with our sources, and either default to that, or
offer it as a "--stable" implementation of deflate.

That would be going above & beyond what's needed IMO, but still a lot
easier than the daunting task of writing a specification that exactly
described GNU gzip's current behavior, to the point where you could
clean-room implement it and be guaranteed byte-for-byte compatibility.

  reply	other threads:[~2023-02-01  9:57 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-31  0:06 Stability of git-archive, breaking (?) the Github universe, and a possible solution Eli Schwartz
2023-01-31  7:49 ` Ævar Arnfjörð Bjarmason
2023-01-31  9:11   ` Eli Schwartz
2023-02-02  9:32   ` [PATCH 0/9] git archive: use gzip again by default, document output stabilty Ævar Arnfjörð Bjarmason
2023-02-02  9:32     ` [PATCH 1/9] archive & tar config docs: de-duplicate configuration section Ævar Arnfjörð Bjarmason
2023-02-02  9:32     ` [PATCH 2/9] git config docs: document "tar.<format>.{command,remote}" Ævar Arnfjörð Bjarmason
2023-02-02  9:32     ` [PATCH 3/9] archiver API: make the "flags" in "struct archiver" an enum Ævar Arnfjörð Bjarmason
2023-02-02  9:32     ` [PATCH 4/9] archive: omit the shell for built-in "command" filters Ævar Arnfjörð Bjarmason
2023-02-02  9:32     ` [PATCH 5/9] archive-tar.c: move internal gzip implementation to a function Ævar Arnfjörð Bjarmason
2023-02-02  9:32     ` [PATCH 6/9] archive: use "gzip -cn" for stability, not "git archive gzip" Ævar Arnfjörð Bjarmason
2023-02-02  9:32     ` [PATCH 7/9] test-lib.sh: add a lazy GZIP prerequisite Ævar Arnfjörð Bjarmason
2023-02-02  9:32     ` [PATCH 8/9] archive tests: test for "gzip -cn" and "git archive gzip" stability Ævar Arnfjörð Bjarmason
2023-02-02  9:32     ` [PATCH 9/9] git archive docs: document output non-stability Ævar Arnfjörð Bjarmason
2023-02-02 10:25       ` brian m. carlson
2023-02-02 10:30         ` Ævar Arnfjörð Bjarmason
2023-02-02 16:34         ` Junio C Hamano
2023-02-04 17:46           ` brian m. carlson
2023-02-02 16:17     ` [PATCH 0/9] git archive: use gzip again by default, document output stabilty Phillip Wood
2023-02-02 16:40       ` Junio C Hamano
2023-02-03 13:49       ` Ævar Arnfjörð Bjarmason
2023-02-06 14:46         ` Phillip Wood
2023-02-03 15:47       ` Theodore Ts'o
2023-02-02 16:25     ` Junio C Hamano
2023-02-04 18:08       ` René Scharfe
2023-02-05 21:30         ` Ævar Arnfjörð Bjarmason
2023-02-12 17:41           ` René Scharfe
2023-02-02 19:23     ` Raymond E. Pasco
2023-02-03  8:06       ` [PATCH] archive: document output stability concerns Raymond E. Pasco
2023-01-31  9:54 ` Stability of git-archive, breaking (?) the Github universe, and a possible solution brian m. carlson
2023-01-31 11:31   ` Ævar Arnfjörð Bjarmason
2023-01-31 15:05   ` Konstantin Ryabitsev
2023-01-31 22:32     ` brian m. carlson
2023-02-01  9:40       ` Ævar Arnfjörð Bjarmason [this message]
2023-02-01 11:34         ` demerphq
2023-02-01 12:21           ` Michal Suchánek
2023-02-01 12:48             ` demerphq
2023-02-01 13:43               ` Ævar Arnfjörð Bjarmason
2023-02-01 15:21                 ` demerphq
2023-02-01 18:56                   ` Theodore Ts'o
2023-02-02 21:19                     ` Joey Hess
2023-02-03  4:02                       ` Theodore Ts'o
2023-02-03 13:32                         ` Ævar Arnfjörð Bjarmason
2023-02-01 23:16         ` brian m. carlson
2023-02-01 23:37           ` Junio C Hamano
2023-02-02 23:01             ` brian m. carlson
2023-02-02 23:47               ` rsbecker
2023-02-03 13:18                 ` Ævar Arnfjörð Bjarmason
2023-02-02  0:42           ` Ævar Arnfjörð Bjarmason
2023-02-01 12:17       ` Raymond E. Pasco
2023-01-31 15:56   ` Eli Schwartz
2023-01-31 16:20     ` Konstantin Ryabitsev
2023-01-31 16:34       ` Eli Schwartz
2023-01-31 20:34         ` Konstantin Ryabitsev
2023-01-31 20:45         ` Michal Suchánek
2023-02-01  1:33     ` brian m. carlson
2023-02-01 12:42   ` Ævar Arnfjörð Bjarmason
2023-02-01 23:18     ` brian m. carlson

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