Re: [PATCH 0/2] optimize string hashing in xdiff

From: Eli Schwartz <eschwartz@gentoo.org>
Date: Jul 28, 2025, 19:56 UTC
Message-ID: <2e70fce9-1779-4d35-ae65-42792e710054@gentoo.org>
In-Reply-To: <xmqqa54oun5w.fsf@gitster.g>

On 7/28/25 3:32 PM, Junio C Hamano wrote:

Show 6 quoted lines

>> The additive variant of the djb2 hash is used in ELF symbol lookup, and
>> Noah Goldstein contributed a well-optimized implementation to Glibc.
> 
> What is the licensing terms for that code you are proposing us to
> borrow?  If it is anything recent in GNU, I'd expect that it would
> be GPLv3, which would be incompatible with our code base?

That feels like a quite surprising assessment. Many GNU projects make specific calculations here. See:

https://www.gnu.org/licenses/gpl-faq.html#DoesAllGNUSoftwareUseTheGNUGPLAsItsLicense

https://www.gnu.org/licenses/why-not-lgpl.html

At any rate, quite untrue. Glibc's wikipedia page -- and also its source code, luckily -- documents "LGPL-2.1-or-later", which is more permissive than git (and equally as permissive as xdiff).

Reason is documented in the second link. :)

-- 
Eli Schwartz