From: Phillip Wood <phillip.wood123@gmail•com>
To: Jeff King <peff@peff•net>,
Johannes Schindelin <Johannes.Schindelin@gmx•de>
Cc: Ezekiel Newren via GitGitGadget <gitgitgadget@gmail•com>,
git@vger•kernel.org, Elijah Newren <newren@gmail•com>,
Ezekiel Newren <ezekielnewren@gmail•com>,
"brian m. carlson" <sandals@crustytoothpaste•net>
Subject: Re: gitoxide-compatible licensing of Git's Rust code, was Re: [PATCH 6/7] xdiff: conditionally use Rust's implementation of xxhash
Date: Wed, 24 Sep 2025 14:48:26 +0100 [thread overview]
Message-ID: <bfaaf26f-5759-4812-9057-b3e0bf7c7949@gmail.com> (raw)
In-Reply-To: <20250923174825.GB1136654@coredump.intra.peff.net>
On 23/09/2025 18:48, Jeff King wrote:
> On Tue, Sep 23, 2025 at 11:57:18AM +0200, Johannes Schindelin wrote:
>
>> It would not even take more than something as simple as GPLv2+exception.
>> We do have prior art for that: The Git project itself suggests in its very
>> own `COPYING` file to use the following license in new files:
>>
>> This file is licensed under the GPL v2, or a later version
>> at the discretion of Linus.
>>
>> Note the exception? For new Rust code (and of course excluding code that
>> has been ported verbatim from GPLv2-licensed code), GPL v2 could be used
>> with an exception along these lines: This file is licensed under the GPL
>> v2, with the exception that it can be freely used in the Gitoxide project.
>
> I think this "and of course" parenthetical might be a sticking point.
> Obviously taking the code verbatim and re-licensing it is not allowed.
> But I think even reading the C code and then writing substantially
> similar Rust code may be legally questionable. The Rust code under the
> more permissive license has to either be clean-room, or have permission
> for re-licensing from the original authors (which is getting to be all
> but impossible over time as code ends up being touched by many people).
>
> I think this is the same issue that libgit2 ran into. If it were just a
> matter of porting over and re-writing new features, more of it would
> have been done. But for code to come under the new license it can't just
> be a port, but has to be an independent work.
Thanks for putting this so clearly, I agree with everything that you've
written here. Another thing I'm concerned/confused about is how the
exception for a single project works in practice. Does it mean that a
third party that wants to re-use some code from GitOxide has to check if
the code originally came from Git to determine which license it is
under? Or does it mean that anyone who wants to use Git's code without
the copyleft restrictions can do so if they launder it through GitOxide
first? Neither of those seems like a great outcome.
Thanks
Phillip
next prev parent reply other threads:[~2025-09-24 13:48 UTC|newest]
Thread overview: 204+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-17 20:32 [PATCH 0/7] RFC: Accelerate xdiff and begin its rustification Ezekiel Newren via GitGitGadget
2025-07-17 20:32 ` [PATCH 1/7] xdiff: introduce rust Ezekiel Newren via GitGitGadget
2025-07-17 21:30 ` brian m. carlson
2025-07-17 21:54 ` Junio C Hamano
2025-07-17 22:39 ` Taylor Blau
2025-07-18 23:15 ` Ezekiel Newren
2025-07-23 21:57 ` brian m. carlson
2025-07-23 22:26 ` Junio C Hamano
2025-07-28 19:11 ` Ezekiel Newren
2025-07-31 22:37 ` brian m. carlson
2025-07-22 22:02 ` Mike Hommey
2025-07-22 23:52 ` brian m. carlson
2025-07-17 22:38 ` Taylor Blau
2025-07-17 20:32 ` [PATCH 2/7] xdiff/xprepare: remove superfluous forward declarations Ezekiel Newren via GitGitGadget
2025-07-17 22:41 ` Taylor Blau
2025-07-17 20:32 ` [PATCH 3/7] xdiff: delete unnecessary fields from xrecord_t and xdfile_t Ezekiel Newren via GitGitGadget
2025-07-17 20:32 ` [PATCH 4/7] xdiff: make fields of xrecord_t Rust friendly Ezekiel Newren via GitGitGadget
2025-07-17 22:46 ` Taylor Blau
2025-07-17 23:13 ` brian m. carlson
2025-07-17 23:37 ` Elijah Newren
2025-07-18 0:23 ` Taylor Blau
2025-07-18 0:21 ` Taylor Blau
2025-07-18 13:35 ` Phillip Wood
2025-07-28 19:34 ` Ezekiel Newren
2025-07-28 19:52 ` Phillip Wood
2025-07-28 20:14 ` Ezekiel Newren
2025-07-31 14:20 ` Phillip Wood
2025-07-31 20:58 ` Ezekiel Newren
2025-08-01 9:14 ` Phillip Wood
2025-07-28 20:53 ` Junio C Hamano
2025-07-28 20:00 ` Collin Funk
2025-07-20 1:39 ` Johannes Schindelin
2025-07-17 20:32 ` [PATCH 5/7] xdiff: separate parsing lines from hashing them Ezekiel Newren via GitGitGadget
2025-07-17 22:59 ` Taylor Blau
2025-07-18 13:34 ` Phillip Wood
2025-07-17 20:32 ` [PATCH 6/7] xdiff: conditionally use Rust's implementation of xxhash Ezekiel Newren via GitGitGadget
2025-07-17 23:29 ` Taylor Blau
2025-07-18 19:00 ` Junio C Hamano
2025-07-31 21:13 ` Ezekiel Newren
2025-08-02 7:53 ` Matthias Aßhauer
2025-07-19 21:53 ` Johannes Schindelin
2025-07-20 10:14 ` Phillip Wood
2025-09-23 9:57 ` gitoxide-compatible licensing of Git's Rust code, was " Johannes Schindelin
2025-09-23 17:48 ` Jeff King
2025-09-24 13:48 ` Phillip Wood [this message]
2025-09-25 2:25 ` Jeff King
2025-09-25 5:42 ` Patrick Steinhardt
2025-09-26 10:06 ` Phillip Wood
2025-10-03 3:18 ` Jeff King
2025-10-03 9:51 ` Phillip Wood
2025-10-07 9:11 ` Patrick Steinhardt
2025-11-17 13:37 ` Johannes Schindelin
2025-10-05 5:32 ` Yee Cheng Chin
2025-07-17 20:32 ` [PATCH 7/7] github_workflows: install rust Ezekiel Newren via GitGitGadget
2025-07-17 21:23 ` brian m. carlson
2025-07-18 23:01 ` Ezekiel Newren
2025-07-25 23:56 ` Ben Knoble
2025-07-19 21:54 ` Johannes Schindelin
2025-07-17 21:51 ` [PATCH 0/7] RFC: Accelerate xdiff and begin its rustification brian m. carlson
2025-07-17 22:25 ` Taylor Blau
2025-07-18 0:29 ` brian m. carlson
2025-07-22 12:21 ` Patrick Steinhardt
2025-07-22 15:56 ` Junio C Hamano
2025-07-22 16:03 ` Sam James
2025-07-22 21:37 ` Elijah Newren
2025-07-22 21:55 ` Sam James
2025-07-22 22:08 ` Collin Funk
2025-07-18 9:23 ` Christian Brabandt
2025-07-18 16:26 ` Junio C Hamano
2025-07-19 0:32 ` Elijah Newren
2025-07-18 13:34 ` Phillip Wood
2025-07-18 21:25 ` Eli Schwartz
2025-07-19 0:48 ` Haelwenn (lanodan) Monnier
2025-07-22 12:21 ` Patrick Steinhardt
2025-07-22 14:24 ` Patrick Steinhardt
2025-07-22 15:14 ` Eli Schwartz
2025-07-22 15:56 ` Sam James
2025-07-23 4:32 ` Patrick Steinhardt
2025-07-24 9:01 ` Pierre-Emmanuel Patry
2025-07-24 10:00 ` Patrick Steinhardt
2025-07-28 9:06 ` Pierre-Emmanuel Patry
2025-07-18 14:38 ` Junio C Hamano
2025-07-18 21:56 ` Ezekiel Newren
2025-07-21 10:14 ` Phillip Wood
2025-07-21 18:33 ` Junio C Hamano
2025-07-19 21:53 ` Johannes Schindelin
2025-07-20 8:45 ` Matthias Aßhauer
2025-08-15 1:22 ` [PATCH v2 00/17] " Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 01/17] doc: add a policy for using Rust brian m. carlson via GitGitGadget
2025-08-15 17:03 ` Matthias Aßhauer
2025-08-15 21:31 ` Junio C Hamano
2025-08-16 8:06 ` Matthias Aßhauer
2025-08-19 2:06 ` Ezekiel Newren
2025-08-15 1:22 ` [PATCH v2 02/17] xdiff: introduce rust Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 03/17] xdiff/xprepare: remove superfluous forward declarations Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 04/17] xdiff: delete unnecessary fields from xrecord_t and xdfile_t Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 05/17] xdiff: make fields of xrecord_t Rust friendly Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 06/17] xdiff: separate parsing lines from hashing them Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 07/17] xdiff: conditionally use Rust's implementation of xxhash Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 08/17] github workflows: install rust Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 09/17] Do support Windows again after requiring Rust Johannes Schindelin via GitGitGadget
2025-08-15 17:12 ` Matthias Aßhauer
2025-08-15 21:48 ` Junio C Hamano
2025-08-15 22:11 ` Johannes Schindelin
2025-08-15 23:37 ` Junio C Hamano
2025-08-15 23:37 ` Junio C Hamano
2025-08-16 8:53 ` Matthias Aßhauer
2025-08-17 15:57 ` Junio C Hamano
2025-08-19 2:22 ` Ezekiel Newren
2025-08-15 1:22 ` [PATCH v2 10/17] win+Meson: allow for xdiff to be compiled with MSVC Johannes Schindelin via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 11/17] win+Meson: do allow linking with the Rust-built xdiff Johannes Schindelin via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 12/17] github workflows: define rust versions and targets in the same place Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 13/17] github workflows: upload Cargo.lock Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 14/17] xdiff: implement a white space iterator in Rust Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 15/17] xdiff: create line_hash() and line_equal() Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 16/17] xdiff: optimize case where --ignore-cr-at-eol is the only whitespace flag Ezekiel Newren via GitGitGadget
2025-08-15 1:22 ` [PATCH v2 17/17] xdiff: use rust's version of whitespace processing Ezekiel Newren via GitGitGadget
2025-08-15 15:07 ` [-SPAM-] [PATCH v2 00/17] RFC: Accelerate xdiff and begin its rustification Ramsay Jones
2025-08-19 2:00 ` Elijah Newren
2025-08-24 16:52 ` Patrick Steinhardt
2025-08-18 22:31 ` Junio C Hamano
2025-08-18 23:52 ` Ben Knoble
2025-08-19 1:52 ` Elijah Newren
2025-08-19 9:47 ` Junio C Hamano
2025-08-23 3:55 ` [PATCH v3 00/15] RFC: Cleanup " Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 01/15] doc: add a policy for using Rust brian m. carlson via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 02/15] xdiff: introduce rust Ezekiel Newren via GitGitGadget
2025-08-23 13:43 ` rsbecker
2025-08-23 14:26 ` Kristoffer Haugsbakk
2025-08-23 15:06 ` rsbecker
2025-08-23 18:30 ` Elijah Newren
2025-08-23 19:24 ` brian m. carlson
2025-08-23 20:04 ` rsbecker
2025-08-23 20:36 ` Sam James
2025-08-23 21:17 ` Haelwenn (lanodan) Monnier
2025-08-27 1:57 ` Taylor Blau
2025-08-27 14:39 ` rsbecker
2025-08-27 17:06 ` Junio C Hamano
2025-08-27 17:15 ` rsbecker
2025-08-27 20:12 ` Taylor Blau
2025-08-27 20:22 ` Junio C Hamano
2025-09-02 11:16 ` Patrick Steinhardt
2025-09-02 11:30 ` Sam James
2025-09-02 17:27 ` brian m. carlson
2025-09-02 18:47 ` Sam James
2025-09-03 18:22 ` Collin Funk
2025-09-03 5:40 ` Patrick Steinhardt
2025-09-03 16:22 ` Ramsay Jones
2025-09-03 22:10 ` Junio C Hamano
2025-09-03 22:48 ` Josh Steadmon
2025-09-04 11:10 ` Patrick Steinhardt
2025-09-04 15:45 ` Junio C Hamano
2025-09-05 8:23 ` Patrick Steinhardt
2025-09-04 0:57 ` brian m. carlson
2025-09-04 11:39 ` Patrick Steinhardt
2025-09-04 13:53 ` Sam James
2025-09-05 3:55 ` Elijah Newren
2025-09-04 23:17 ` Ezekiel Newren
2025-09-05 3:54 ` Elijah Newren
2025-09-05 6:50 ` Patrick Steinhardt
2025-09-07 4:10 ` Elijah Newren
2025-09-07 16:09 ` rsbecker
2025-09-08 10:12 ` Phillip Wood
2025-09-08 15:32 ` rsbecker
2025-09-08 15:10 ` Ezekiel Newren
2025-09-08 15:41 ` rsbecker
2025-09-08 15:31 ` Elijah Newren
2025-09-08 15:36 ` rsbecker
2025-09-08 16:13 ` Elijah Newren
2025-09-08 17:01 ` rsbecker
2025-09-08 6:40 ` Patrick Steinhardt
2025-09-05 10:31 ` Phillip Wood
2025-09-05 11:32 ` Sam James
2025-09-05 13:14 ` Phillip Wood
2025-09-05 13:23 ` Patrick Steinhardt
2025-09-05 15:37 ` Junio C Hamano
2025-09-08 6:40 ` Patrick Steinhardt
2025-08-23 14:29 ` Ezekiel Newren
2025-08-23 3:55 ` [PATCH v3 03/15] github workflows: install rust Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 04/15] win+Meson: do allow linking with the Rust-built xdiff Johannes Schindelin via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 05/15] github workflows: upload Cargo.lock Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 06/15] ivec: create a vector type that is interoperable between C and Rust Ezekiel Newren via GitGitGadget
2025-08-23 8:12 ` Kristoffer Haugsbakk
2025-08-23 9:29 ` Ezekiel Newren
2025-08-23 16:14 ` Junio C Hamano
2025-08-23 16:37 ` Ezekiel Newren
2025-08-23 18:05 ` Junio C Hamano
2025-08-23 20:29 ` Ezekiel Newren
2025-08-25 19:16 ` Elijah Newren
2025-08-26 5:40 ` Junio C Hamano
2025-08-24 13:31 ` Ben Knoble
2025-08-25 20:40 ` Ezekiel Newren
2025-08-26 13:30 ` D. Ben Knoble
2025-08-26 18:47 ` Ezekiel Newren
2025-08-26 22:01 ` brian m. carlson
2025-08-23 3:55 ` [PATCH v3 07/15] xdiff/xprepare: remove superfluous forward declarations Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 08/15] xdiff: delete unnecessary fields from xrecord_t and xdfile_t Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 09/15] xdiff: make fields of xrecord_t Rust friendly Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 10/15] xdiff: use one definition for freeing xdfile_t Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 11/15] xdiff: replace chastore with an ivec in xdfile_t Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 12/15] xdiff: delete nrec field from xdfile_t Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 13/15] xdiff: delete recs " Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 14/15] xdiff: make xdfile_t more rust friendly Ezekiel Newren via GitGitGadget
2025-08-23 3:55 ` [PATCH v3 15/15] xdiff: implement xdl_trim_ends() in Rust Ezekiel Newren via GitGitGadget
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