Re: [dev] [license] gpl issues

From: Страхиња Радић <contact_AT_strahinja.org>
Date: Sun, 18 Jun 2023 21:01:03 +0200

On 23/06/18 04:58PM, Miles Rout wrote:
> As far as I understand, if you create a work (A) that is a fork of another
> work (B), where B is MIT-licensed, nothing stops you from licensing A as GPL. I
> wouldn't call it "relicensing": you're licensing your own work, A, which
> happens to be derived from B. You aren't licensing B, which is someone else's
> work. You do need to credit B's copyright holders of course.
>
> Have I got something wrong here? I am no copyright lawyer, that is for sure,
> so I cannot claim any expertise. Or did you mean something different?

You can't license the whole of A as GPL, only your modifications. Expat license
requires that:

> The above copyright notice and this permission notice shall be included in all
> copies or substantial portions of the Software.

which explicitely forbids removing the copyright and permission notices on
Expat-licensed code, or replacing them with, say, GPL notices.

Like I said, Expat license is GPL-compatible[1]. That means[2]:
> It means that the other license and the GNU GPL are compatible; you can combine
> code released under the other license with code released under the GNU GPL in
> one larger program.
>
> All GNU GPL versions permit such combinations privately; they also permit
> distribution of such combinations provided the combination is released under
> the same GNU GPL version. The other license is compatible with the GPL if it
> permits this too.
>
> GPLv3 is compatible with more licenses than GPLv2: it allows you to make
> combinations with code that has specific kinds of additional requirements that
> are not in GPLv3 itself. Section 7 has more information about this, including
> the list of additional requirements that are permitted.

However, it *doesn't* mean that I can just take someone's program A licensed
under Expat and relicense the parts of my fork B (realistically, perhaps 95% of
program A) under GPL. More precisely, that is not legally possible, as I stated
before.


[1]: https://www.gnu.org/licenses/license-list.html#Expat
[2]: https://www.gnu.org/licenses/gpl-faq.html#WhatDoesCompatMean

Received on Sun Jun 18 2023 - 21:01:03 CEST

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